[FFmpeg-devel] [PATCH 0/3] Workaround for large JPEG over RTP

[Andrey Utkin]

On Wed, Dec 9, 2015 at 4:26 PM, Carl Eugen Hoyos <cehoyos at ag.or.at> wrote:
> On Tuesday 08 December 2015 01:10:30 pm Andrey Utkin wrote:
>> RFCs for JPEG over RTP don't support dimensions larger than pixels,
>> but it is possible to work around if we stick with information from SDP.
>
> Sorry if I misunderstand:
> If the rfc does not allow framesizes over 2040x2040 why should FFmpeg
> allow to send them?

The question sounds like you would prefer FFmpeg to fail voluntary in
this case rather than to work it around.

It currently allows this (rtp-encoding JPEG with larger dimensions),
with a downside that receiving side perceives 2048 pixels dimension
like 0 pixels, etc.

> And am I correct that you found the framesize attribute in rfc 6064?

I've found this during extensive online searches. Indeed, RFC 6064
seems the only source specifying this attribute, and it targets H.263
only.
There are some phrases that "ONVIF specifications have solution for
this shortcoming" (found on live555 maillist and somewhere else), but
I don't see what exactly that solution is.

> Is there another tool that is able to send or receive larger frames?

>From another FFmpeg ticket I see that Axis IP cameras do send:
http://trac.ffmpeg.org/ticket/3535

----- QUOTE -----
Opening an input file: rtsp://192.168.0.90/axis-media/media.amp?videocodec=jpeg.
[rtsp @ 0x1ce0940] SDP:
v=0
o=- 1396746078623612 1396746078623612 IN IP4 192.168.0.90
s=Media Presentation
e=NONE
t=0 0
a=control:rtsp://192.168.0.90:554/axis-media/media.amp?videocodec=jpeg
a=range:npt=0.000000-
m=video 0 RTP/AVP 26
c=IN IP4 0.0.0.0
a=framesize:26 2048-1536
a=control:rtsp://192.168.0.90:554/axis-media/media.amp/trackID=1?videocodec=jpeg
----- END QUOTE -----

And I'd assume Axis developers test it against something.

-- 
Bluecherry developer.