Colored "blocks" on H264 video
  • Hi,

    I use the AVTECH 552 with Security spy in the 1080p H264 mode. When it gets dark the camera switches automatically to IR, but at the same time the H264 video stream starts to show colored blocks. Unfortunately, I only found a manual way to fix this by unticking the camera enabled box in camera settings pressing "OK" and the ticking camera enabled again in camera settings (i.e. disconnecting from the camera and re-connecting). The recording of the stream shows the same colored blocks and in addition, the recording seems to be static, i.e. it is a video where all frames are the same still image from the time the colored blocks started to appear.

    Any idea how to avoid this?
  • Do you know if the actual resolution of the video changes when it switches to night mode? We have seen this in other cameras, and it affects the video decompression. To check this, right-click on the camera window in SecuritySpy and select "Save image as JPEG...". Do this both in day mode and night mode (after you have disconnected/reconnected) and compare the size of the resulting images.
  • Hi,

    I can check the JPEG specs tonight.

    What I did already yesterday was storing the movie "without re-compression". When I check these movies with a tool to show the specs of the video stream, I get the following:

    Daylight Video: H.264, 1920 × 1080, 25 fps, 4.81 Mbps
    Night Video: H.264, 1920 × 1080, 25 fps, 10.29 Mbps

    So it seems that the main difference between day and night is the data rate (I think due to the much higher noise level in the night movie). Perhaps this is the cause of the issue? But I do not know how to fix that.
  • Hi,

    I checked the JPEGS as you suggested. All are 1080p.
  • Thanks for checking that. So it must be something else about the stream that is changing that is affecting the decoding. Can you please send me an example of the "coloured blocks" effect? Take a screenshot and send it to (to capture a screenshot, press command-shift-4 and select the area you want to capture. A file called "Screen shot" will appear on your desktop.)
  • I also have this problem on the Foscam 9802W. I'll try and get a screenshot tonight. I have a couple other problems I'll detail in another post...
  • Certain cameras seem to change their stream in significant ways when switching between day and night modes. I'm in the process of adding code to SecuritySpy that will detect the change and will reset the decompression so that SecuritySpy can continue to correctly process the video stream.

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