codec/mjpeg: create RTP MJPEG 'extractor' to parse out MJPEG from RTP packets

[Saxon Milton]

The GeoVision will send MJPEG over RTP when in MJPEG mode. As such, we will need an extractor to retrieve the MJPEG from the RTP packets; probably something similar to the RTP H264 extractor. Specifications for MJPEG over RTP are here.

[Alan Noble]

Are you sure it is not possible to configure the GeoVision to send MJPEG over HTTP?

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[Saxon Milton]

RTSP can only request an RTP stream, and I can’t find anything on the web interface to set up video over HTTP. Did something give you the impression that this is possible ?

[Alan Noble]

I only ask the question because when MJPEG is played by a web browser using the HTML <img> element, it is over HTTP, using the latter’s “chunked” transfer encoding. Browsers generally don’t have built in support for RTP…

[Saxon Milton]

yeah okay, I see what you mean.

Interestingly you can watch the live streams in the browser on the web interface, and looking at what’s happening over wireshark, it probably is MJPEG over HTTP, however, these streams seem not to be affected by changes in settings - so maybe they are encoded separately. Also, these streams viewable in the browser are only 1 fps.

[Alan Noble]

If RTP is needed for the GV cameras, so be it. I just wanted to ensure we’re not missing a simpler solution.

In summary, GV cameras would be configured to send MJPEG/RTP and revid would then transmux that to MJPEG/MTS/HTTP.

And MJPEG/RTMP is not an option.

[Saxon Milton]

Assigned @Saxon Milton

[Saxon Milton]

Resolved in PR #289