BTV Pro
Version
5.4.3b2
User Manual
Written by Ben Bird
Contents
Introduction
Welcome to BTV Pro!
BTV Pro is an application for the Macintosh that allows you to view, capture and edit video, create stop-motion animations, and also has advanced capture features such as time lapse, motion detection and DV input/output.
Viewing Video
Viewing modes
Live video can be displayed either in a window that can be resized and dragged around the screen, or full screen on an entire monitor. You can adjust the size and mode of the video display using the 'Video size' menu:
There are five preset video sizes. Initially the capabilities of your video hardware will determine which sizes are set up. The menu above shows default sizes for PAL format video. These video sizes apply to both window mode and full screen mode. You can enter your own values for these preset sizes by choosing 'Video sizes...' from the menu.
When you switch to full screen mode, the 'Go to full screen mode' item changes to 'Go to window mode', allowing you to switch back to window mode. When in full screen mode you can select the 'Fill the screen with video' option - BTV Pro will attempt to fill the screen with as much video as possible (depending on your screen resolution and capabilities of your video hardware).
Full screen resolution
There are two resolutions to consider for full screen video: monitor resolution and video resolution. The video resolution you are using is fixed and depends on your video hardware and the video format. Your monitor has several different resolutions for you to choose from. When you go to full screen mode BTV Pro automatically switches your monitor to the desired resolution, and switches it back again when going to window mode.
If you are using a video source with a maximum size of 640x480, such as from a FireWire webcam or NTSC format video, a monitor resolution of 640x480 should be used so that the video completely fills the screen.
If you are using PAL format video then a monitor resolution of 800x600 should be used and the video displayed at the maximum size of 768x576 centred on the monitor. Although this results in a small black border around the edge of the video, it will give you the best viewing quality.
Initially, BTV Pro automatically attempts to choose the best monitor resolution, but you can change the monitor settings at any time from under the Monitors section of the preferences.
Viewing 16:9 widescreen video
Video normally has an aspect ratio of 4:3, however widescreen video has a wider aspect ratio of 16:9. Since most video inputs are designed to work with 4:3 video, when viewing widescreen video there will be black borders at the top and bottom of the video image. BTV Pro can crop the top and bottom of the video to remove these borders. You can turn this option on and off by going to 'Video Sizes' under the Video Size menu (see the picture below).
If you are viewing widescreen video from a DV source on a widescreen monitor (such as the Apple Cinema Display) you can display the video fullscreen by doing the following: select any widescreen monitor resolution in the preferences, turn on cropping for widescreen video in the Video Sizes window (below), and then switch to full screen mode and select 'Fill the screen with video' from the Video Size menu. This setup only needs to be done once.
Multiple monitor support
If you have more than one monitor attached to your computer you can view full screen video on any monitor. You can choose which monitor displays full screen video from the Monitors section of the preferences.
QuickTime Movies
The QuickTime Movie file format
Invented by Apple Computer, the QuickTime Movie file format is industry standard for storage, transfer and playback of time-based media on Macintosh Computers, and it is also widely used on Microsoft Windows PCs. It is a very flexible file format that has ability to store many different types of time based media such as video, sound, text, video effects, MIDI data, time code, and animations. BTV Pro creates QuickTime movie files containing video and sound.
Virtually all video-related Macintosh software works with QuickTime files, so you can capture video with BTV Pro and then open it with another video application. Also, BTV Pro can open any QuickTime movie made by any other application.
A movies does not necessarily contain all of its data in a single file; it may contain references to several other movie files, or references to data elsewhere in the movie. This is useful because it allows data to be included in movies without increasing the movie's file size, since the data isn't actually in the movie itself but rather pointed to by a reference. BTV Pro creates references when you use copy-and-paste operations to edit movies. It also uses references when it splits movie captures into several files.
If you have a movie that contains references to other files then all the files must be present for the movie to be played back properly. When you open such a movie BTV Pro attempts to find all the files; if any of the files cannot be found you will be asked to find them manually. To make a movie self contained with no references to other files, select 'Save as...' from the File menu and turn on the 'Flatten' option.
Transferring files to a Microsoft Windows PC
If the PC has QuickTime installed it will be able to read any image file created by BTV Pro, and any ordinary captured movie. It will also be able to read DV stream files. However, movie files created by time lapse or motion detection capture, and new movies created by the 'New movie' command in the File menu, are Macintosh-only and can't be read on a PC. To allow these movie files to be read on a PC you need to either flatten them or export them.
When transferring files to a PC always make sure that you have added the file extension (.jpg .mov .dv etc.) to the end of the file name so that the PC can recognise the file type. File extensions can be added for you automatically if this option is set in the preferences).
Fast Start movies
This is a method of saving a QuickTime movie in such a way that it can be played back from the hard disk at the same time as it is being downloaded from a network (such as the Internet). You can create Fast Start movies by using the 'Export Movie...' command from the File menu.
Streaming
Streaming is the process of playing a movie while it is being received over a network from a remote location (for example, over the Internet). This is different from Fast Start movies; the streamed video is transferred over the network in real time and is not saved to the computer's hard disk. Streamed video is broadcast by a Streaming Server.
To create movies in BTV Pro that can be streamed by a Streaming Server, first choose suitable video and sound compression codecs (for more info see here). Then export the movie as a Hinted Movie. This adds an extra Hint Track to the movie that enables the Streaming Server to stream the movie over the network. To export the movie choose "Export movie..." from the File menu.
Compression Settings
There are a variety of compression settings that can be used for the capture of video, sound and still images. These can be configured by selecting 'Compression Settings' from the Settings menu:
Video: Codec
This menu allows you to choose from the standard QuickTime spatial compression codecs to use for video compression. The codec chosen here is used whenever frames are being added to movies: normal video capture, adding individual frames to movies, motion detection capture and time lapse capture. See below for detailed information about each compression codec available. If you choose 'No recompression' from this menu, then the frames of video are used directly from the video input device with no additional recompression in software. This generally results in the highest quality capture with the best performance (but the captured files can be very large, depending on what video input device you are using).
Spatial compression is a method of reducing the storage space needed for an image (or a frame of video in this case) while maintaining quality as much as possible. There is always a tradeoff between storage space and image quality. Compression methods are referred to as "codecs" because they specify both a compression and a decompression scheme.
Spatial compression can significantly reduce the size of captured files, and can improve capture and playback speed since the rate of transfer of data to and from the hard drive is reduced. A measure of the amount of compression provided by the codec is the compression ratio. For example, if a compressed image uses half its original storage space then the compression ratio is 2:1.
Spatial compression codecs are either lossless or lossy. A lossless compression codec is one that does not lose any data when it compresses an image – the original image can be perfectly reconstructed from the compressed data. Conversely, a lossy compression codec is one that loses data when it compresses an image – the original image can never be reconstructed perfectly from the compressed data.
Lossless compression codecs are suited for computer-generated images where there are large areas of constant colour. Lossy compression codecs need to be used to obtain good compression ratios for a photograph-type image, such as one in a stream of live video. Most spatial compression codecs are lossy.
Note that each time an image is compressed by a lossy compression codec it loses some quality, so it is desirable to keep the number of times it is compressed as low as possible. If you are capturing video (or images) that are likely to be recompressed by a lossy compression codec in the future is it a good idea to choose a lossless (or at least high quality lossy) compression codec for the initial compression. This produces high file sizes initially but ensures that the quality of the final output is as high as possible.
For a list of available video codecs click here.
Video: Codec quality
Most codecs have a quality setting. The higher this setting the better quality the resulting image, but the more storage space is used. For compressing video to be sent over the Internet it is generally necessary to turn down the quality setting so that the resulting movie is small.
Video: Color depth
Some compression codecs support several different colour depths. Generally, the lower the colour depth the smaller the resulting file size but the lower the quality. Colour depths are named by the number of colours that are used in the image, for example 16 grays, 256 colors, thousands, millions etc.
If you choose 'Auto', BTV Pro will pick the best color depth available that is supported by both the video input device and the compression codec.
Video: Frame rate
You can enter a desired frame rate here for captured video. This frame rate applies to normal video capture as well as motion detection capture.
If you leave this box empty, video is captured at the maximum possible rate. The maximum rate you will be able to obtain depends on your video input hardware, the speed of your computer and hard disk, and the type of compression codec in use. Reducing the frame rate proportionally affects the file size of the captured video, so for transmission of video over the internet it is advisable to limit the frame rate so that the file size of the resulting movie is small.
Video: Key frame rate
Entering a key frame rate allows you to use temporal compression. Depending on the content, video can have a high level of temporal redundancy, that is, very often one frame is quite similar to the next frame. Temporal compression exploits this redundancy to reduce the file size of the resulting movie. The success of temporal compression depends very much on the content of the video; if adjacent frames are very similar then file sizes can be significantly reduced but if adjacent frames in the video are generally quite different then the video is not suitable for temporal compression.
Temporal compression works by using "key frames" at regular intervals, followed by several "delta frames". The key frames contain the complete video image, the delta frames only contain the portions of the image that have changed since the last key frame.
For compression codecs that support temporal compression you can enter a key frame rate here. Note that the key frame rate that you enter here is the minimum key frame rate that is used; if the compressor codec decides that more key frames should be used it will do so (for example, if there is a segment of the video with a low temporal redundancy many key frames will be used but a different segment of the video with high temporal redundancy only the specified rate of key frames will be used).
Video: limit data rate
Some compression codecs allow you to enter a value here to limit the data rate (also referred to as the "bit rate"). This is useful when creating a movie that will be transferred of streamed over the Internet, so that you can make sure that the file size of the resulting movie is small. When you enter a value in this field the codec will automatically adjust its quality setting during compression to try to obtain the desired data rate.
Video: Options button
Some video codecs have extra configuration options. Click this button to display and configure the codec's extra options.
Video: Advanced
Click this button to display advanced video compression options. Currently there is one advanced option: Quality setting for decompressing incoming video. If the video input device is supplying compressed data, a software decompressor component is used to decompress this data so that it can be processed and/or displayed to the screen. This software decompressor may have several quality settings to adjust the quality/speed tradeoff when decompressing the video. For example, the Apple DV decompressor (which is used by BTV Pro for decompressing video from DV devices) has a low quality mode (quality less than 50) that only uses a quarter of the DV data and is therefore faster.
Sound: Codec
This is similar to image compression in that sound compression reduces the data rate of digital audio at the expense of quality, but since sound is continuous (not discrete, like frames of video) it cannot be temporally compressed and all sound compression schemes are lossy.
The best sound compression schemes work on a principal known as "Perceptual Encoding". The idea is that the codec removes the data in the sound that humans cannot hear, therefore significantly reducing the amount of data while maintaining sound quality. Perceptual Encoding schemes can achieve very high compression ratios (10:1 or higher) without much loss of quality. The audio codecs available in BTV Pro that use perceptual encoding are called "QDesign Music" and "Qualcomm PureVoice".
If you choose 'No recompression' from this menu, then the sound is captured directly from the sound input device with no additional software recompression. This generally results in the highest quality capture with the best performance.
For a list of available sound codecs click here.
Sound: Sample rate
Sound is continuous variations in air pressure that is converted to an analogue electrical signal by a microphone, and finally sampled and stored by the computer. When a sound wave is recorded on a computer it undergoes sampling. That is, at regular intervals the value of the sound wave is measured and stored, so that the computer builds up a digital representation of the sound wave.
The higher the sample frequency the more of the audio spectrum is accurately recorded. Using low sample rates cause noise to be introduced into the signal and reduces the range of audio frequencies that can be represented by the samples, so it is desirable to use a high sampling rate for best quality. 44kHz is the sample rate used in audio CDs and it can accurately reproduce the entire audio frequency range of human hearing.
The sampling rates that are supported in the hardware of the sound input device appear in the menu in bold text - other sample rates will have to be converted to in software.
Sound: Format
The other factor that determines the quality of sampling is the sample size. Each sample is stored on the computer as a number of bits. The higher the number of bits used to store a sample the more accurate the sampling is. Using a low number of bits introduces what is called "quantisation noise" into the sound. Audio CDs use 16 bit sample sizes.
Recording in stereo uses two sound channels and therefore uses more storage space, so if you are using a mono sound source it is best to switch this setting to mono.
As for the sample rate, the formats that are supported directly by the sound input device are listed in the format menus in bold text.
Sound: Options button
Some sound codecs have extra configuration options. Click this button to display and configure the codec's extra options.
Still image: Format
This menu allows you to choose the format that BTV Pro uses when capturing still images. For a list of available still image formats click here.
Still image: Options button
Click this button to configure settings for the still image format. The settings window is specific to the format that you have selected, but generally it will contatain color depth settings.
Settings for sending files over the internet
Although the speed of internet connections are getting faster all the time, the majority of people around the world use modems for connecting to the internet. Sending large files (such as movies and images) over a slow modem connection can take a long time, so it is necessary to make the file sizes of your movies and images small before you send them over the internet. The following settings are suggested:
Use the JPEG format for still images. This produces small files and since JPEG is such a popular file format (on both Mac and PC) there should be no problem with viewing the file at the other end.
Video settings: if you have QuickTime 6 Pro use MPEG-4, otherwise use Sorenson. At medium to low quality these codecs produce small file sizes while still retaining good quality. Limit the frame rate of the video capture by typing in a value for the frame rate in the Compression Settings window. This can make a big difference to the file sizes so use the lowest frame rate that is acceptable. Also, use the smallest video size that is acceptable. Halving the video dimensions results in four times fewer pixels in the image, so this makes a big difference to the file size of the movie.
Sound settings: if the sound is speech then use Qualcomm PureVoice; if the sound is music then use QDesign Music. Both allow you to adjust the bit rate (quality setting), so choose a medium to low bit rate. Try using 16 bit, 22KHz sampling - this gives reasonably high quality and small file sizes with the above sound compression codecs.
The above compression settings generally require a lot of processing time, so if you are applying the compression on-the-fly as the movie is captured then you may get low frame rates unless you are using a very fast computer. In this case you can capture video in an intermediate format that is quick to compress, and then use the Export command (under the File menu) to compress the movie to your final compression settings. As an intermediate video format you should generally choose 'No recompression' for both sound and video from the Compression Settings window.
Remember when sending files to a Windows PC to include the three letter file extension that tells the PC what type of file it is. For JPEG files the extension is .jpg and for movie files the extension is .mov. BTV Pro can add these file extensions for you if this option is turned on in the preferences).
Capturing movies and images
All options for capture are available from the Capture menu:
There is also a floating window that contains frame capture and movie capture controls. This is available from the Window menu:
When you choose 'Capture frame' from the Capture menu or from the floating window, an image is captured from the video input and saved straight to the hard drive with an automatic name and destination. The destination can be set in the capture destination settings and the naming settings can be set in the preferences.
Alternatively, when the video input window is at the front, choosing 'Save' or 'Save as...' from the File menu will display a window allowing you to choose a destination for the file, as well as the file format and other options.
When you start capturing a movie it is saved to the destination(s) that you have supplied and an automatic name is created for it. During video capture the Capture Controls window shows the elapsed time:
If you have many hard disks connected to your computer you can define up to three destinations for video capture; when the first is full the second is used and when that is full the third is used. When the capture has been split into several files an index is added to the files so that you know the order in which they were captured. For example, if the main file name is "My Movie" then the other files are named "My Movie-01", "My Movie-02" etc. You can only open the first file but it contains the data of all the files.
The frame averaging feature takes a number of frames from the video input and blends them together to produce a single image. This can eliminate noise on a still image capture and is useful in a number of situations such as capturing noise-free still images from a digital camera, capturing clean images from a noisy VHS video, or even to remove a moving element in a video sequence (for example, if a sequence of video shows a street with a person walking down it then averaging all the frames removes the person and reduce any video noise in the image of the street).Frame averaging works because the image is constant but the noise is quickly varying so over many frames it averages to zero. See the following example:
 |
 |
|
A
noisy video signal
|
Averaged
over 40 frames
|
It is also worth noting that due to the removal of noise the file size of the averaged image is often significantly smaller than the size of the normal still capture.
The number of frames used for averaging is adjustable in the preferences. The frames are taken from the video input and processed as fast as possible but because some processing has to be done on each frame, the frame rate you obtain when averaging depends on the speed of your computer. BTV Pro also has a feature to average a number of frames in a movie rather than the live video input. This gives more control over exactly which frames are used in the averaging process. To do this, select a portion of an open movie (by holding the shift key and dragging the movie cursor with the mouse) and select 'Average selected frames' from the Movie menu.
The time lapse feature schedules the capture of a number of frames over a period of time at precise intervals. To start a time lapse select 'Time lapse...' from the Capture menu; you will get this setup window:
Interval
between captures
This is the time interval between frame captures. From the popup menu you
can choose either 'Time' to enter the time between captures in the format
hours:minutes:seconds, or 'Seconds' to enter the number of seconds between
captures.
Time
lapse duration
You can choose to limit the duration of the time lapse. From the popup menu
you can choose either 'Time' to enter the duration in the format
hours:minutes:seconds, or 'Captures' to enter the number of captures.
If you do not limit the duration then the time lapse will continue until it
is stopped manually.
Multiple
capture/averaging
You can choose to capture or average a certain number of frames each time
interval. If the capturing goes on too long (longer than the time interval)
it will be stopped so that the time lapse does not get behind schedule.
Preview
This option controls whether the video is played to the window during the
time lapse capture. Turning preview off shortens the time it takes to average
frames and slightly increases the accuracy of the time lapse.
Warning
sound before capture
If this option is on an audio warning is played before each frame capture.
From the popup menu you can choose a number of beeps to play before each capture.
Draw
clock on captured frames
If this option is on then an image of a clock is drawn on every frame. Clicking
the 'Clock options...' buttons shows this window:
You can choose to display an analogue and/or digital clock, and you can adjust the size of the clock and the position in the image.
If the timelapse is capturing a movie, the clock is drawn onto a second video track. Therefore it does not wipe out the image behind it, and can be removed later or disabled/enabled at playback. If the timelapse is creating separate image files, the clock is drawn into the actual image.
Create
movie / separate image files
You can choose to create either a movie with the captured frames, (in which
case the normal movie capture settings are used) or you can choose to create
separate image files (in which case the normal frame capture settings are
used).
FPS
of movie
If you are creating a movie, this defines the FPS (frames per second) of the
frames in the created movie.
Settings
This popup menu allows you to create sets of different time lapse settings.
During the time lapse there is a progress window like the one below that shows you the number of frames captured, elapsed time, remaining time, countdown to next frame, and averaging progress (if you are averaging frames every capture). There is also an option to turn on and off preview at any time during the time lapse:
This feature only captures video when there is motion in the video image. To start a motion detection capture select 'Motion detection...' from the Capture menu; you will get this setup window:
Motion
bar
This bar indicates the amount of motion in the video.
Trigger
level
When the amount of motion in the video goes above this trigger level video
is captured.
Sensitivity
Increasing the sensitivity produces a larger effect for the same amount of
motion. At the highest setting it is extremely sensitive, so very small amounts
of motion can be detected.
Delay
to stop capturing
Once motion is detected and video is being captured, this delay controls how
long to wait before stopping the capture after the motion has stopped.
Preview
This option controls whether the video is played to the window while it is
captured. Turning this option off gives you better responsiveness and capture
performance.
Draw
clock
You can choose to draw a clock on all frames - see the section above about
timelapse setup for details about clock settings.
When motion is detected video is captured with the frame rate and compression settings specified in the Compression Settings window (click the 'Compression settings...' button in the motion detection window above for these settings). During the motion detection, a progress window displays the duration of video captured and the number of separate segments. There is also an option to turn on and off preview at any time during the motion detection.
Processing digital video involves moving, calculating and storing extremely large amounts of data compared to other kinds of computer files. To get the most out of your computer you should:
• If running on Mac OS 8-9, turn off Virtual Memory (using the Memory control panel in the Control Panels folder under the Apple Menu).
• Turn off AppleTalk (using the Chooser under the Apple Menu in Mac OS 8-9 or the Network System Preference on Mac OS X).
• Eject all removable disks.
• Make sure that you are using the latest version of the driver software from the manufacturer of your video input device.
• Use the 'No recompression' option for video in the Compression Settings window. This will capture the video directly from the device with no additional compression, resulting in a fast capture (but usually a very large movie file). Alternatively you can use a fast compression codec at a high quality setting, such as Motion JPEG A or Video.
• If you are using compression codecs that require a lot of processing time (such as Sorenson video) then you will get a low frame rate when using them for on-the-fly compression. In this case you can capture video in an intermediate format that is quick to compress, and then use the Export command (under the File menu) to compress the movie to your final compression settings.
• When you capture video make sure that BTV Pro is the only application loaded.
• For best performance make sure you defragment your hard drive regularly. Defragmenting your hard drive makes all the free space continuous, so that the hard drive mechanism doesn't have to waste time moving to free areas of the drive during video capture. Defragmenting can be done with most good disk utility software.
DV Video
DV device control
If your video input is a DV device you will have an extra option in the Window menu called 'DV Device Control', selecting it will display this floating window:
This gives you standard transport buttons for controlling the tape in the DV device and easy access to DV input and DV output features. Clicking on the button on the right will display a popup menu containing controls such as fast rewind, eject, and all available play modes supported by your DV device. This popup menu also contains the option 'Wind tape to timecode', selecting it will display this dialog box:
This allows you to enter a timecode in the form hours:minutes:seconds and BTV Pro will then wind the tape to that timecode.
All the above controls, including DV stream capture and output, can be accessed by AppleScript. For more information please see the AppleScript section of this manual.
This feature captures a DV stream from a DV device; it effectively downloads the raw DV data directly from the device to your hard drive, resulting in a very reliable capture. The captured DV stream can be played back by BTV Pro or directly imported into other video software such as Apple's iMovie. This feature is available from the button in the DV Device Control floating window or by selecting 'Capture DV stream' in the Capture menu. You will get this setup window:
Source
You can choose 'Live video' to capture live DV video, or 'Tape' to capture
from the tape in the DV device. If you select 'Tape' then BTV Pro will automatically
start the tape playing.
Tape
start time
If you are capturing from tape and you enter a timecode here, BTV Pro will
wind the tape to this timecode before capturing.
Duration/End
time
You can enter a capture duration or, if you are capturing from tape, you can
enter a tape end timecode.
Abort
at break in timecode
If you are capturing from tape and check this option then the capture will
be aborted if a break in timecode on the tape is detected.
Convert
to QuickTime movie after capture
If you turn on this option the DV stream will be converted into a QuickTime
movie after capture. This is useful if you want to open the captured file
in other software that supports QuickTime movies but not DV streams (such
as Apple's iDVD software).
File
Name
This is the file name of the DV stream that will be saved to your hard disk.
Capture
destinations
Clicking this button will give you the standard Capture
Destinations window that allows you to choose multiple destinations for
the capture.
This feature outputs a DV stream (or a QuickTime movie containing a DV stream) to a DV device. This feature is available from the button in the DV Device Control floating window or by selecting 'Output DV stream' in the Capture menu. You will be asked to select a DV stream or movie to output and then you will get this setup window:
Destination
You can choose 'Live video' to output live video, or 'Tape' to output to the
tape in the DV device. If you select 'Tape' then BTV Pro will automatically
start the tape recording.
DV
stream start time
You can start the DV stream playing at any point by entering a timecode here.
Tape
start time
If you are outputting to tape and you enter a timecode here, BTV Pro will
wind the tape to this timecode before outputting. Note that tape will only
have a timecode if it has been previously recorded.
Duration
You can enter a duration for the DV output.
Wait
for device before starting
The device will take some time to switch into the right mode and/or start
the tape recording before it is ready to receive video. The amount of time
needed varies so you can enter a delay here that works best for your device.
Another way to output a DV stream (or a QuickTime movie containing a DV stream) is to open the DV stream or movie in BTV Pro and turn on the option 'Output to DV device' in the Movie menu. Then you can play the movie to the DV device and still have access to the movie controller so you can jump to any point in the movie, fast forward, rewind, etc. When this option is enabled is enabled for a movie there are two additional options in the Movie menu:
•
Also play to window: plays the movie to the movie window as well as to the
DV device. Turning this option off improves performance.
• Sound on: outputs sound to the DV device as well as video.
Other features
You can open a movie file by using the open command in the file menu, by dragging a movie file onto the BTV Pro icon in the Finder, or by capturing a movie from the video input. When you open a movie it is displayed in its own window with a QuickTime controller. The appearance of the controller depends on what version of QuickTime is installed on your computer, but the functionality is the same. It will look something like this:
You can use the arrow keys on the keyboard to step through the frames of the movie, and the space bar to start and stop the movie. There are also shortcut keys to fast forward and rewind the movie - choose 'Keyboard shortcuts...' from the Settings menu for a list of all keyboard shortcuts.
Saving and exporting QuickTime movies
By default, movies are saved normally, possibly containing references to other movies. When you choose 'Save as...' from the file menu to save a movie there is an option called 'Flatten'. If this option is checked then the references in the movie are resolved and the resulting movie is entirely self-contained, with no references. Saving the movie in this way has the added advantage that all tracks are re-interleaved for optimum playback performance and any unused data in the movie is removed.
To
export the movie choose "Export movie..." from the File menu. You
will be able to choose new sound and video settings, adjust the movie size,
and apply filters. You can also use the Export feature to save a movie as
a sequence of images, a DV stream, or a hinted movie ready for streaming over
the Internet.
For information on how to save individual frames from a movie, see 'Saving
and exporting image files' below.
Converting DV streams into QuickTime movies
You can select this option from the File menu to convert any DV stream into a QuickTime movie. This is useful if you want to open the DV stream in software that supports QuickTime movies but not DV streams (such as Apple's iDVD software). A movie resource is added to the file without the DV data itself being processed, avoiding the lengthy export operation normally needed for this conversion.
You can edit movies using simple copy-and-paste or drag-and-drop operations. To select a portion of a movie hold down the shift key as you drag the position cursor or as you step through frames:
Now a portion of the movie is selected and you can use the copy command (in the Edit menu) to copy it to the clipboard, and the paste command to paste it into another movie (or to a different place in the same movie). Alternatively you can drag and drop from one movie to another.
When you edit in this way, you are placing references to the source movie into the destination movie, rather than the actual movie data itself. If you need to reuse portions of the same movie several times, using references saves disk space. The disadvantage with using references is that movies may not play properly if they refer to other movies that are missing.
There are two ways to make a stop-motion animation in BTV Pro: you can create a new movie and add frames to it, or you can capture image files first and then compose them into a movie later.
The advantage of making a movie as you go along is that you can instantly play back what you have animated, and you have access to the onion skin feature (described below). To add frames you can use the 'Add one frame' command in the Movie menu, or you can define your own shortcut key to add a frame (go to 'Keyboard shortcuts' under the Settings menu to see and adjust the keyboard shortcuts).
When you add a frame to a movie it is compressed using the compression settings that you have set in the Compression Settings window (under the Settings menu). Note that if you choose 'No recompression' for the video codec in the Compression Settings window then no recompression is performed; the raw data directly from the video input hardware is added to the movie. This ensures that there is no image degradation.
Frames are added to movies with the fps (frames per second) set in the preferences.
The onion skin feature displays the last captured frame superimposed over the current video input. This is very useful for checking and precisely adjusting changes between consecutive frames. To activate the onion skin feature you must have a movie open with at least one frame already captured, then select 'Onion skin' from the Movie menu.
You can also create a stop motion animation by capturing a series of separate image files and then creating a movie out of them. While doing this it is useful to keep a count of the number of frames that you have captured; for this purpose there is a "Frame Capture Count" floating window, available under the Window menu:
Once you have captured a series of image files you can make them into a movie with the "Make movie from folder of images..." option in the File menu. You will get this window:
This will take all the image files in the specified folder in alphabetical order and make them into a movie. The images are compressed with the specified compression settings and made into a movie with the specified FPS. The dimensions of the movie is based on the first image; if the subsequent images are different dimensions they will be scaled. The images can be in any image file format.
You can have the best of both worlds and capture straight to a movie while generate separate image files at the same time. The advantage of doing this is that you get the flexibility of having separate image files as well as instant playback of your animation as you go along and access to the onion skin feature. There is a shortcut key that you can define to do this (go to 'Keyboard shortcuts' under the Settings menu to see and adjust the keyboard shortcuts).
The Frame Position floating window
If you select 'Frame Position' from the Window menu this floating window appears displaying time code and frame count:
The timecode is in the format hours:minutes:seconds.frames, and is updated as the movie is played or as the movie position cursor is dragged. The frames value displayed in the timecode is calculated from the fps you have specified in the preferences. You can enter a time value or frame count into this window to jump to a specific time in the movie.
Note that when this window is open movie playback will be slower since calculating the frame count takes time.
An undo/redo feature is available (from the Edit menu) for any edit function that is performed.
It should be noted however that if you add a frame to a movie and then use the undo function the frame is removed from the video track but the actual image data remains (unused) in the movie file. To remove all unused data from the movie file go to 'Save as...' in the File menu, turn on the 'Flatten' option, and save the movie.
BTV Pro can open image files of many different formats including PICT, JPEG, GIF, Photoshop, TIFF, PNG and BMP. You can then copy and paste them into movies and they are automatically resized and recompressed before being added to the movie.
Saving and exporting image files
BTV Pro can save image files in many different formats including PICT, JPEG, Photoshop, TIFF, PNG and BMP (the number of formats available depends on the version of QuickTime that you have installed on your computer).
To save an open image choose 'Save' from the File menu, and to export an image file (either from an open movie at its current position or from an open image) choose 'Export image...' from the file menu.
You will be able to set the file format and other settings relating to the file format (such as quality setting for JPEG images, for example). The only difference with saving and exporting is that the image is open after it is saved, but it is not opened after it is exported.
Exporting movie files for Apple's iMovie
To open a movie created by BTV Pro in Apple's iMovie software you need to first export the movie as a DV stream. To do this go to 'Export movie' under the File menu and select 'Movie to DV stream' from the options at the bottom of the window. Make sure you select the correct format setting (DV-PAL or DV-NTSC) depending on which format you are using in iMovie. Then, in iMovie, select 'Import' from the File menu and choose the DV stream that you have just created.
Alternatively, if you use the DV stream capture feature to capture video from a DV device then the resulting file can be imported directly into iMovie.
When you import a file into iMovie a duplicate copy is made in the Media folder within your iMovie project folder. To avoid this copy (which will take time and fill up your hard disk) you can manually move the DV stream file created by BTV Pro to the Media folder; when you then open the project in iMovie the DV stream will be added to the project without the creation of a duplicate file.
The folder viewer feature displays resizable thumbnails of all the image files in a folder and any subfolders within it. To access the folder viewer select 'View folder of images' from the File menu - you will then be asked to select a folder containing image files.
You can delete or rename an image file straight from the viewer, or double click on an image to display it full size. You can also drag images from the viewer onto other applications or onto movies in BTV Pro.
To save all the thumbnails as a single image file choose 'Save' from the File menu - you will be asked to choose a format and location for the image file. You can also print the thumbnails by choosing 'Print' form the File menu. If you select a thumbnail and choose 'Clear' from the Edit menu it is removed from the view but the original image file is not deleted.
AppleScript
AppleScript is a way of controlling an application either from a written script or from another application. Once you get the hang of it it is easy and quick to write your own scripts that can control BTV Pro. To write scripts you can use Apple's 'Script Editor' application (it is installed as a part of the Macintosh operating system and should be in the folder 'Apple Extras' on your hard drive).
Once you open the Script Editor you should see a window like the one below. The 'tell' and 'end tell' commands are needed to define which application you are controlling, in this case BTV Pro. Everything you want to tell BTV Pro goes between these commands.
To see all available commands choose 'Open Dictionary...' from the File menu in Script Editor and select BTV Pro. Script Editor will show you all commands with a brief description of each one.
An
object is any distinct item that can be modified or interrogated using AppleScript.
Movies, images and windows are objects.
Each object has a number of properties. Each property defines a different
characteristic of the object. For example the window object has properties
including name and position.
Objects can be referred to by name or by number. Whenever you open a movie or an image it is assigned a unique number so that it can be identified. Also, each window has a unique number.
To make things easier, "movie 0" refers to the most recently opened movie, "image 0" refers to the most recently opened image, and "window 0" refers to the video input window. So if you are working with only one movie (or image) at a time then you don't have to worry about the numbers.
If you are working with more than one movie (or image) at a time then you can either refer to the movies by name or by their unique number. An easy way to get the movie number is to remember the return value from the open command:
set movieNum to (open file "Hard disk:Movie name.mov")
The two commands that you can use to launch BTV Pro are activate and launch.
If
you tell BTV Pro to activate it loads up and come to the front. In fact, any
time you tell BTV Pro to activate it comes to the front.
If you tell BTV Pro to launch it loads up in the background with no open windows
and awaits further instructions. The launch command is useful if you want
to define the viewing mode (full screen or window mode) before BTV Pro switches
to the mode that was last used.
quit
Tells BTV Pro to quit. If there are open movies that need to be saved BTV
Pro displays a window for each movie asking if you want to save it before
quitting. To prevent the display of these windows you can specify a saving
method when issuing the quit command. The three possibilities are:
quit
saving yes
quit saving no
quit saving ask
open
Tells BTV Pro to open a file (it could be a movie file or an image file).
For example:
open
file "Hard disk:Documents:Movie1.mov"
open file "Hard disk:Documents:Image1.jpg"
The open command returns the movie number if you opened a movie, or the image number if you opened an image.
save
Tells BTV Pro to save a movie, for example:
save
movie 1
save movie "Movie name"
close
Tells BTV Pro to close an object. The object can be a movie, an image, or
a window. For example:
close
movie 1
close window 0
When closing a movie you can specify a saving method:
close movie 1 saving no
print
Tells BTV Pro to print an object. The object can be a movie, an image or a
window.
full
screen mode / window mode
Sets the video display to full screen mode or window mode
pause
/ resume
Pauses or resumes the video display
hide
mouse / show mouse
Hides or shows the mouse cursor. Only available in full screen mode.
mute
on / mute off
Turns the sound mute on or off
set
volume
Sets the computer speaker volume to a value between 0 and 7, for example:
set volume to 5
blank
other monitors / show other monitors
Turns on or off monitor blanking
set
width / set height
Sets the current video dimensions. For example:
set
width to 640
set height to 480
In window mode this resizes the window to the specified size; in full screen mode this adjusts the video display and centres it on the screen.
capture
frame
Captures a frame of video to the hard drive. Uses the current setting for
frame capture that are set in the preferences.
You can optionally specify a path and/or file name for the destination file,
and specify whether you want any previous file to be overwritten with the
new image file:
capture
frame
capture frame as "Hard disk:image1"
capture frame with overwrite
copy
Copies a frame from the video input to the clipboard. This only works if BTV
Pro is the front application so you need to use the activate command before
using the copy command.
start
recording
Starts recording a movie. As with frame capture you can optionally specify
the file name and/or path:
start
recording
start recording as "My Movie"
stop
recording
Stops a movie record operation.
add
frame
Adds a frame or frames to a movie from the video input. You can optionally
specify the number of frames to add:
add
frame to movie 0
add frame to movie 0 times 10
play
Plays a movie, for example this plays the most recently opened movie:
play movie 0
stop
playing
Stops playing the movie that is currently playing. You do not need to specify
the movie.
set
video input device
Sets the current video input device to the name specified. To see the names
of all video input devices available on your system go to 'Video Settings...'
under the Settings menu and look at the source options. The name is not case
sensitive. For example:
set video input device "DV Video"
DV stream capture / DV device control
play
dv device
Sends a play command to the DV device.
stop
dv device
Sends a stop command to the DV device.
wind
dv device to
Winds the tape to a particular timecode. The timecode is specified as a list
of format {hours,minutes,seconds}, for example:
wind dv device to {0,10,5}
get
dv tape time
Returns the current tape time as a list of format {hours,minutes,seconds}
capture
dv stream
Captures a DV stream to the hard drive. If you specify a start time then BTV
Pro will automatically wind the tape to the start time before capturing. You
can also specify the file name and capture duration, for example:
capture dv stream as "Filename.dv" start time {0,2,0} duration {0,10,30}
output
dv stream
Outputs a DV stream to a DV device. You have to specify the file name of the
DV stream (you can use a full path or a partial path relative to the first
movie capture destination). You can also specify whether the destination of
the video is live or tape - if you specify tape then BTV Pro will start the
DV device recording automatically. For example:
output dv stream "Filename.dv" destination tape
The times for some of the properties of movies are expressed as a list of format {hours,minutes,seconds,frames}. If you want to deal with seconds or frame numbers instead of this time format, you can use the convert command to convert this time format to and from a number of seconds, and to and from a number of frames. For example:
convert time {0,3,0,10} in movie 0 to seconds
This returns the number of seconds that corresponds to the time 3 minutes and 10 frames in the movie.
convert time {0,10,0,0} in movie 0 to frames
This returns the frame number that corresponds to the time 10 minutes in the movie. You can also use the convert command to convert between seconds and frames, for example:
convert frame number 100 in movie 0 to seconds
This returns the number of seconds corresponding to the frame number 100 in the movie. The convert function is useful for setting the current time of the movie when you want to easily set a particular frame number or a particular number of seconds. For example:
set current time of movie 0 to (convert frame number 200 in movie 0 to time)
These commands are used to get and set the properties of an object. To view all properties for the objects go to Script Editor, choose 'Open Dictionary...' from the File menu and select BTV Pro. Below are some examples of commands that involve common properties that are likely to be most useful:
Moving
Windows
Each window have a position and bounds property; the position property is
a point that defines the top left corner of the window, the bounds is a rectangle
that defines the complete bounds of the window. For example:
set position of window 0 to {400,100}
This sets the position of the video input window to the coordinates {400,100}. Note that the top left of the main monitor is {0,0}
Playing
Movies
This can be done with the play movie command (described above), but also each
movie has a play status property that is true if the movie is playing or false
if it is not. This can be used to check if a particular movie is playing,
or to start and stop a movie. The following example stops movie 0 if it is
currently playing, and starts it if it is not currently playing:
if
(get play status of movie 0) is false then set play status of movie 0 to true
else if (get play status of movie 0) is true then set play status of movie
0 to false
end if
Setting
the current time of movies
Each movie has a current time and a current seconds property. The current
time property is expressed as a list of format {hours,minutes,seconds,frames},
the current seconds property is expressed as a number of seconds. You can
convert between the different formats using the convert command. For example:
set
current time of movie 0 to {0,10,2,0}
set current seconds of movie 0 to 0
set current time of movie 0 to {0,0,0,0}
set current time of movie 0 to (get duration of movie 0)
set current time of movie 0 to (convert frame 100 in movie 0 to time)
Setting
FireWire output status
Each movie has a firewire output status property that can be set to true or
false to turn on and off output to FireWire for the movie. To use this property
the movie must contain a DV stream and your DV device must support DV input.
set
firewire output status of movie 0 to true
set firewire output status of movie 0 to false
There are two further options for FireWire output, defined by the firewire output preview status and firewire output sound status properties. The firewire output preview status property defines whether the video is played on the computer as well as output to FireWire, and the firewire output sound status property defines whether the sound is also output with the video:
set
firewire output preview status of movie 0 to false
set firewire output sound status of movie 0 to true
Setting
the loop status of movies
Each movie has a loop status setting that defines if the movie is set to loop
or not. If true, the movie will start again from the beginning when it gets
to the end.
set
loop status of movie 0 to true
set loop status of movie 0 to false
Preferences
The preferences window is available by selecting 'Preferences...' from the Settings menu. There are five sections: General, Frame capture, Movie capture, Animation, and Monitors.
Use
sound
This option controls whether sound input is used. If this option is off sound
will not be played while viewing video and will not be recorded while capturing
movies.
Remember
sound volume
If this option is on, the sound volume you set while watching video will be
remembered the next time you launch BTV Pro.
Hide
cursor when switching to full screen mode
If this option is on then the mouse cursor is hidden when switching to full
screen mode.
Add
file extensions
When this option is on BTV Pro automatically adds three-character file extensions
to the names of all files that are created. These file extensions are needed
by Windows PCs to determine the file type, so if you are sending files to
a PC then this option should be on.
Live
window dragging
Turning the option on enables all windows to be drawn and updated as they
are dragged.
Use
more processor time
When this option is on BTV Pro uses as much processor time as possible to
ensure smooth playback of video. This is only for playback; this automatically
happens during capture.
Make
video window float above other applications (Mac OS X only)
When this option is on the video window will float above the windows of all
other applications, allowing you to view the video even when BTV Pro is not
the front application.
Image
capture method
There are three different ways to capture an image. These are labelled in
this menu as:
• QuickTime: Uses the standard QuickTime frame grabbing routine to capture an image. This should work reliably but is inefficient and therefore likely to be slow (it is especially slow when using USB video input devices).
• BTV: Uses BTV Pro's own routines to capture the frame which is often significantly faster than the QuickTime method.
• Directly from screen: This is very fast but if there are other windows in front of the video or the video is partially off screen then this will appear in the captured image. There is no loss of quality when capturing from the screen but the maximum colour depth of the captured image is determined by the color depth of the screen. You can use this method to capture frames even during a movie capture; since the image comes from the screen it doesn't affect the video input at all.
Name
This option selects the type of automatic name used for saving image files.
If 'Data stamped' is chosen then the filename contains the date
in the format "day|month hour|minute|second", if 'Numeric'
is chosen then the files are incrementally numbered "001", "002"
up to "9999".
Creator
The creator is a four-character code that defines the application that owns
the file, so that if you double-click on the file it automatically opens in
that application. You can define the creator for image files by selecting
one listed in the pop-up menu, typing in the code, or clicking the 'Make
like...' button and selecting a similar file or the desired application.
Always
capture frames at..
You can make all captured frames a set size by entering the size here. This
applies to normal frame captures as well as frames captured during time lapse.
If you don't specify a size here then captures will be at the current size
of the video input window.
Deinterlace
captured and exported frames
Analogue video (PAL, NTSC and SECAM) is interlaced, that is, each frame of
video is made up of two fields on alternate horizontal lines. DV video can
also be interlaced. Since there is a time delay between the two fields, if
there is motion in the frame this will show up as jagged lines in the area
of the motion. If this option is turned on BTV Pro will automatically deinterlace
any frames captured from the video input, exported from a movie, or copied
to the clipboard. This is done by eliminating the odd field and creating a
new odd field by interpolating pixels in the even field.
Open
image file after creation
If this option is on then the image file is be opened after it is created.
Play
click sound after capture
If this option is on a click sound is played when a frame is captured.
Number
of frames to average
Determines the number of frames used for the frame averaging feature. Enter
0 to average frames indefinitely.
Limit
capture time
You can enter a time here to limit the total capture time for normal movie
captures (not timelapse, motion detection or DV stream capture since these
have separate capture time settings). When the time has elapsed the capture
is automatically stopped.
Split
into 2GB files
When this option is on then the capture is automatically split into separate
2GB files. This option applies to all movies captured by BTV Pro, as well
as the DV stream capture feature. When the capture has been split into several
files an index is added to each file so that you know the order in which they
were captured. For example, if the main file name is "My Movie"
then the other files are named "My Movie-01", "My Movie-02"
etc. For normal movie captures you can only open the first file but it contains
the data of all the files; for other captures (time lapse, motion detection,
DV stream capture) each file is an independent movie file that can be opened
individually.
Name
This option selects the type of automatic name used for saving image files.
If 'Data stamped' is chosen then the filename contains the date
in the format "day|month hour|minute|second", if 'Numeric'
is chosen then the files are incrementally numbered "001", "002"
up to "9999".
Creator
The creator is a four-character code that defines the application that owns
the file, so that if you double-click on the file it automatically opens in
that application. You can define the creator for image files by selecting
one listed in the pop-up menu, typing in the code, or clicking the 'Make
like...' button and selecting a similar file or the desired application.
Always
capture movies at..
You can make all captured movies a set size by entering the size here. If
you don't specify a size here then captures will be at the current size of
the video input window.
Capture
video / Capture sound
These options control whether sound and/or video are captured. One of them
must be turned on.
Play
video during capture / Play sound during capture
These options allow you to control whether sound and video are played during
capture. Generally, turning these options off increases capture performance
resulting in higher frame rates (smoother, less 'jerky' video).
Preview
quality during capture
The lower the preview quality the faster the video preview, and therefore
the better the capture performance. If you select low or medium quality, not
all frames will be displayed to the screen, and the image quality may be reduced.
If you select high quality, all frames are displayed to the screen at the
highest image quality.
Display
settings before
When this options is on all capture settings are displayed and can be adjusted
before every movie capture.
Open
movie after
If this option is on then the movie file is be opened after it is captured.
FPS
used for displaying timecode
Time code is displayed in the Frame Position window in the form hours:minutes:seconds.frames.
This fps setting is used to calculate the frames value in the timecode. Set
this depending on what video format you are using (PAL and SECAM use 25 fps,
NTSC uses 29.97 fps).
FPS
for new frames
This FPS setting is used whenever a frame is added to a movie; it defines
the duration of the frame in the movie.
Always
add frames to end of movie
If this option is on then any new frames added to the movie from the video
input will be added at the end of the movie. If this option is off then frames
are added at the current movie position.
Average
You can turn this option on and enter a value to average frames for each stop-motion
capture. This is useful for creating animations with clean, noise-free frames.
Play
click sound after capture
If this option is on then a click sound is played whenever you add a new frame
to a movie.
Use
monitor
This pop-up menu allows you to choose which monitor is used for full screen
video.
Identify
monitors
Pressing this button displays numbers on each monitor to identify them.
Full
screen depth setting
The monitor is switched to this colour depth when viewing full screen video.
Depending on the particular video hardware in use, most users should choose
Thousands or Millions; the 256 option is included for completeness and to
retain compatibility with certain older video input devices.
Resolution
menus
There is a pop-up menu for each of your monitors allowing you to choose the
monitor resolution for full screen video. If the resolution is shown in italics
it needs to be confirmed the first time it is used to make sure that it is
supported by your monitor.
Capture destinations
The capture destinations window is available by selecting 'Capture destinations...' from the Settings menu.
This window allows you to choose destinations for capture movie and image files. If you have many hard disks connected to your computer you can use the movie capture destinations to capture to up to three of your hard disks in a row; when the first is full the second is used and when that is full the third is used. When the capture has been split into several files an index is added to the files so that you know the order in which they were captured. For example, if the main file name is "My Movie" then the other files are named "My Movie-01", "My Movie-02" etc. You can only open the first file but it contains the data of all the files.
Compression codecs
Following is a list of the video codecs available from the 'Compression Settings' window (under the Settings menu). The number of codecs you have available in BTV Pro depends on the version of QuickTime that is installed on your computer. Below is a list of codecs that are available if you have QuickTime 6 or later installed on your computer:
None
No compression at all, so results in very large inefficient files. It is preferable
to use a lossless compression codec instead, such as the Animation codec at
maximum quality. Supports all colour depths. Does not support spatial compression.
Animation
Best suited for computer-generated animations with broad areas of constant
colour. It is lossy at quality settings below maximum, but at the maximum
quality setting it is lossless and therefore generally used as an intermediate
work format. Supports all colour depths. Supports temporal compression.
Component
video
Not exactly a codec, but an image format that uses 4:2:2 YUV color space rather
than RGB. Good as an intermediate storage format for YUV video (such as from
a USB or FireWire webcam). Does not support temporal compression.
Video
Very fast compressing and decompressing with reasonable compression ratios.
Suitable for capturing video to the hard disk with high frame rates but unsuitable
for compressing video for transmission over the Internet. Supports 16 bit
colour. Supports temporal compression.
MPEG-4
(Requires QuickTime 6 Pro)
Produces the best quality video at the lowest data rates compared to any other
standard QuickTime codec. Can be used for high quality captures or low data
rate streaming, depending on the quality settings used. It is reasonably fast
to compress and decompress. Supports temporal compression and data rate limiting.
DV-NTSC
and DV-PAL
Used with digital camcorders. DV-NTSC is used by devices manufactured in the
US and Japan, and DV-PAL is used by devices manufactured in Europe. Some DV
camcorders offer a "Progressive Scan" feature that records each
frame as a single non-interlaced image instead of two separate interlaced
fields. This is vastly superior for viewing video on a computer monitor so
it should always be used when filming DV footage that will be viewed on a
computer. DV compression is similar to JPEG compression but is more efficient.
Supports 24 bit colour only. Moderate decompression speed and compression
ratios. Does not support temporal compression.
Sorenson
Produces highly compressed video ideal for transfer or streaming over the
Internet. Achieves higher image quality at lower data rates than other similar
compression codecs. Very efficient at data rates ranging from 2 to 200 KBps.
Very slow to compress and required quite a fast computer for smooth playback,
especially if the video size is large or the data rate is high. When using
Sorenson you should make sure that the horizontal and vertical video dimensions
are a multiple of 4. Supports 24 bit colour only. Supports temporal compression
and data rate limiting.
Motion
JPEG A and Motion JPEG B
Commonly used by hardware Motion JPEG compression cards. (There is very little
difference between the A and B variants). Compresses the two fields of interlaced
images separately, as opposed to Photo JPEG which is for non-interlaced images.
Often used as storage formats for large files that need to be archived with
good quality; it is lossy but at maximum quality the image degradation is
minimal. Quick to compress and decompress, with reasonable compression ratios.
Supports 24 bit colour, and greyscale. Does not support temporal compression.
Photo
JPEG
Generally used for high quality still non-interlaced images but it is too
slow to decompress to be used for video playback. Useful for intermediate
high quality storage of video with good compression ratios. Works well for
slide-show type movies that require a low frame rate and high quality compression.
Supports 24 bit colour, and greyscale. Does not support temporal compression.
Cinepak
Designed in 1990 for the Macintosh computers of the day, this codec is therefore
very quick to decompress on modern computers (it is quite slow to compress
however). It is a good choice if the video has to be played back on older
computers, but otherwise other codecs (such as Sorenson) offer higher quality
at lower bit rates. Suitable for Internet transfer or streaming. Uses a compression
ratio of at least 10:1, supports 8 and 24 bit colour, and greyscale. Supports
temporal compression and data rate limiting.
H.261
Designed originally for video conferencing, so it is optimised for low data
rates and for video that contains a small amount of motion (high temporal
redundancy). Quick to compress and decompress, with very high compression
ratios. Suitable for Internet transfer or streaming. Supports 24 bit colour
only. Supports temporal compression and data rate limiting.
H.263
Similar to H.261 but optimised for video sizes of 352x288, 176x144, or 128x96.
It is better than H.261 at higher bitrates.
Indeo
Video 4/5
Primarily designed for Windows, so can be used to transfer video between Mac
and PC without requiring QuickTime to be installed on the PC. High image quality
and high compression ratios, but quite slow to compress and decompress and
image quality of Sorenson is generally better. Supports 32 bit colour only.
Supports temporal compression and data rate limiting.
Graphics
Similar to the Animation codec, but only for 8 bit images. It is usually better
than the Animation codec for 8 bit images but it is slower to decompress.
Supports temporal compression.
BMP
Used for still images; inappropriate for video playback. Does minimal compression,
supports most colour depths. Does not support temporal compression.
Planar
RGB
This is a lossless RGB format. Supports 8, 24, and 32 bit colour depths. Does
not support temporal compression.
Following is a list of the sound codecs available from the 'Compression Settings' window (under the Settings menu). The number of codecs you have available in BTV Pro depends on the version of QuickTime that is installed on your computer. Below is a list of codecs that are available if you have QuickTime 6 or later installed on your computer:
None
No sound compression. The sound is recorded with the sample rate and bit depth
specified without loss of quality, producing high data rates.
QDesign
Music
Excellent for music. Very high compression ratio and high quality. Good choice
for internet transfer and streaming.
Qualcomm
PureVoice
Excellent for voice. Very high compression ratio and high quality. Good choice
for internet transfer and streaming.
ALaw
2:1
An Internet standard for compressed audio everywhere except in the US and
Japan. Low compression ratio and low quality. Generally not recommended.
uLaw
2:1
An Internet standard for compressed audio in the US and Japan. Low compression
ratio and low quality. Generally not recommended.
MACE
3:1 and MACE 6:1
Older Macintosh compressors. Low quality. Generally not recommended.
IMA
4:1
Good quality reproduction of music and other audio content. Supports 16 bit
samples only. Relatively low compression ratio.
32
bit Floating Point and 64 bit Floating Point
Increases the sample size to 32 or 64 bits. This allows for more accuracy
when converting to other sample sizes and applying effects, therefore producing
less quantisation noise.
24
bit Integer and 32 bit Integer
Increases the sample size to 24 or 32 bits. Only specialist professional audio
hardware uses 24 or 32 bit audio.
Following is a list of the still image formats available from the 'Compression Settings' window (under the Settings menu).
PICT
The standard Macintosh image file format. Lossless compression, so produces
quite large files. Supports all colour depths.
JPEG
Very widely used lossy image compression format that produces high quality
images at low file sizes (there is a quality setting to adjust the amount
of compression). You should always use this format for photographic type images
that will be transferred over the Internet or put on web sites. Supports 24
bit colour, and greyscale.
TIFF
Traditionally used for images produced by scanners, this is a widely used
file format. Can choose either lossless compression, or no compression at
all. Produces quite large files, supports most colour depths.
BMP
Microsoft Windows Bitmap file format. Use this when you want to transfer lossless
images to a PC. It is lossless and supports most colour depths.
PNG
Designed as a replacement for the popular GIF file format (which is a very
useful format but is protected by a patent so that any manufacturer of software
that produces GIF files has to pay a licence fee to the inventors of the format).
PNG works well for computer generated images with a limited number of colours,
but also can be used for photographic type images. It is lossless and supports
all colour depths.
PSD
(Photoshop)
This is the native file format for the very popular industry standard image
editing application, Adobe Photoshop. Convenient to use if the images are
to be imported straight into Photoshop after capture. Lossless compression,
supports 8, 24 and 32 bit colour.
The JPEG, TIFF, PNG, BMP and PSD file formats are all commonly used on Windows PCs and so should be readable on any PC with graphics software, even if it does not have QuickTime installed on it. BMP and JPEG files should definitely be readable as these are standard formats on the PC. Make sure when transferring the images to a PC that you have added the three character file extension (.jpg .tif .png .bmp or .psd) to the file name so that it can recognise the file type.