I'm working with guys at Elphel to enable RTP streaming of their raw
format (called JP4). The JP4 format is stored as MJPEG file with
single component JPEG frames. Elphel uses a custom RTP server, but the
client (mplayer) uses live55 library and without single component
support, all decoded JPEG frames get wrong headers.
Per RFC 2435, only three component JPEG files have a defined 'type' on
the RTP/MJPEG packet header.
I was wondering if a patch to support single component JPEGs on
live555 would be accepted, using a non standard 'type' field (type >
127),
Another possibility is to use a x-* field on the SDP file, as used to
support frame dimensions larger than 2048.
Paulo,
Note that we have already (in December 2007) added the patch that
Andrey Filippov described here:
http://lists.live555.com/pipermail/live-devel/2007-November/007760.html
This patch allows the server to specify the JPEG width and height in
the SDP description, using the "a=x-dimensions:<width>,<height>".
(These will then be used if the 'width' and 'height' fields in the
JPEG header are 0.)
If that's not sufficient for your needs, and you instead (or also)
want to use a non-standard JPEG type field, then this would
constitute an extension (albeit a backwards-compatible one) to the
RFC 2435 RTP payload format. In that case, you should contact the
IETF's AVT working group (a...@ietf.org), outlining your problem, and
your proposed solution. If the AVT working group adopts your
proposed solution (this might require that you write an Internet
Draft that describes it), then I would be happy to add a patch to our
code to support it.
--
Ross Finlayson
Live Networks, Inc.
http://www.live555.com/
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