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in https://www.cisco.com/c/en/us/td/docs/solutions/Enterprise/Video/pktvideoaag.html

it says:

Another type of video compression is MJPEG … the resulting video stream is larger but the packet sizes are more consistent at 1316 bytes (payload)

is that true?

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  • Probably. Mjpeg has no inter frame compression. Makes data rates more predictable. – user24601 Oct 2 '18 at 20:26
  • @DigiVisionMedia Ok, does that have anything to do with the packet size? – Andyz Smith Oct 3 '18 at 14:15
  • I don't know. I'm just speculating. With a compression scheme like mjpeg, each frame is typically very close in size to the ones just before and after it. A smart stream protocol could use this to its advantage. – user24601 Oct 3 '18 at 16:57
  • See MJPEG wikipedia article. "HTTP [MJPEG] streaming creates packets of a sequence of JPEG images that can be received by clients." Supports my speculation. As for verifying that exact packet size number, I can't find anything. Part of the issue is there's no official standard on MJPEG. It's like the great great grandfather of modern web video, born when the web was still wild. – user24601 Oct 3 '18 at 17:08
  • @DigiVisionMedia I guess. I think each frame is never going to fit in a Ethernet and IP or RTTY or ATM or X.25 or Ku Band QAM satellite packet anyway. So whether the frames are similar size doesn't have anything to do with the packets. You're going to fill a bunch of packets, like thousands upon thousands before you get even a full frame. Whether you fill that last packet to 1299 or 1305 isn't going to make any difference. – Andyz Smith Oct 3 '18 at 21:14
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Although MJPEG may have a more stable and higher temporally local average bitrate, it's bitrate can vary widely given the input content. See MJPEG Compression ; the assertion that the resulting network frames/packets will be more consistent is totally unsubstantiated. It may be, at a macro level, given, say a 10Mb/s Ku Band spotbeam satellite transponder, MJPEG may actually simulate a HARD MUXRATE function that the MPEG Transport Stream muxer typically would perform, but even this is questionable, given MJPEG's highly variable bitrate given very simple content.

Hard Muxrate: https://stackoverflow.com/questions/44392689/ffmpeg-vbr-cbr-conversion-and-streaming-of-mpeg-2-ts-video-files

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