Record clip from Live View?
Soz for the pre-school question but I can't see how to record a short video clip from a PTZ camera's Live View window. I usually just capture motion events but sometimes need to capture footage (including patrol tours) where there is no motion. I guess I could turn on Continuous Recording pro tem but that seems to stay on for 1 hour and I only want 10-20 seconds of footage.
The Trigger Motion Detection command in the contextual menu seems to do the trick up to a point but it doesn't keep recording if I P, T or Z…
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The main way to do this is to set the Continuous Capture schedule to Armed 24/7 when you want to start recording, and then set it back to Unarmed 24/7 when you want to stop recording. There is no 1-hour minimum here (like there would be for a schedule override); recording happens only while the Armed schedule is set.
The other possibility is to use the Instant Replay feature - turn this on in the General Preferences, and then you can save the instant replay buffer at any time (right-click on a camera's image for this option). However this will save just the last X seconds, and won't continue to record.
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Thanks Ben. I was obviously confused by something I read somewhere about Continuous Capture being available in 1 hour chunks.
I feel there should be an easier/instant route to achieve this though: the contextual menu offers me an instant still image and should logically also offer me an instant video recording (according to the logical side of my brain)…
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I discovered that Instant Replay function doesn't work well on my rig (27in 2017 5k Retina iMac with 3.4 GHz Intel Core i5/Radeon Pro 570 4096 MB and 4TB SSD HD). It dropped a lot of frames when writing the cache to disk - and when viewing the live stream after enabling Instant Replay for 20secs @ 2304x1296 and 25fps.
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I'm surprised to hear that - the Instant Replay feature should not drop frames. Under Preferences > General, for the Instant Replay feature, what is the frame rate that you have specified there?
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25fps
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Two more things to check:
- What is the FPS as displayed above the camera's live view in video windows (if you see two numbers here, it's the first one)?
- Open the movie file in QuickTime Player, and Get Info (Command-i) - what is the frame rate displayed there?
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Testing a PTZ patrol on a Reolink RLC-823A POE camera running at 2304 x 1296 and 25fps at a bitrate of 6144…
WITHOUT activating the Instant Replay function, the camera data shows:
RECEIVED frame rate: constant 25fps
DISPLAYED frame rate: variable 17-28fps
WITH Instant Replay activated for 30secs at 25fps:
RECEIVED frame rate: constant 25fps
DISPLAYED frame rate: variable 2-23fps
The Quicktime movie was recorded at 13.7fps
In case it helps, with continuous recording armed, the displayed frame rate data was the same as the first set above (no Instant Replay) and the resulting Quicktime movie has a frame rate of 25.01fps.
Maybe a PTZ patrol with short dwells and long zooms is a tough ask for Instant Replay - or my rig?
PS. Now that you have taught me how to use Continuous Recording selectively via the contextual menu, I'm very happy with it as an instant route to a short live recording -- although I bet I'm not the only one who didn't realise Continuous Capture could be called upon like this with a single click.
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The numbers you are reporting here are consistent with decoder overload, which results in incoming video frames failing to be decoded because the Mac's decoding hardware can't keep up. This would explain the lower display vs. incoming frame rates, and is the only reason I can think of why the frame rate of the movie captured from the pre-capture buffer could be lower than the incoming frame rate being delivered by the camera. To confirm whether or not this is actually the case, check the log file (File menu > Open Log) for "decoder overload" messages, and if these are present, pease refer to this FAQ about how to resolve this problem: I'm getting a "decoder overload" warning, what does this mean? (TL;DR: lower the camera frame rates).
In any case, I'm glad that the option to turn on/off Continuous Capture recording manually does the job for you!
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Yes I did get a decoder overload alert during the instant replay process:
09/03/2022 15:46:41: A significant number of video frames could not be decoded due to decoder overload - this can result in jerky/uneven video in live displays and/or captured footage - try reducing camera frame rates.
However, my iMac seems to have no difficulty recording a live stream directly. I'm not sure what the processing differences are.
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This message means that you are near or above the limit for the Mac's ability to decode video generally, and is not related to the Instant Replay feature. My recommendation is still to reduce camera frame rates until this message no longer appears. Recording video (as long as you have the "Recompress video data" option under Preferences > Cameras > Device turned OFF, as it is by default), as well as the Instant Replay feature, barely use any processing resources, and would not be the cause of this message.
