[FFmpeg-devel] [PATCH v8] Fix integer parameters size check in SDP fmtp line

[Michael Niedermayer]

On Wed, Jul 24, 2019 at 10:20:14AM +0200, Olivier Maignial wrote:
> === PROBLEM ===
> 
> I was trying to record h264 + aac streams from an RTSP server to mp4 file. using this command line:
>     ffmpeg -v verbose -y -i "rtsp://<ip>/my_resources" -codec copy -bsf:a aac_adtstoasc test.mp4
> 
> FFmpeg then fail to record audio and output this logs:
>     [rtsp @ 0xcda1f0] The profile-level-id field size is invalid (40)
>     [rtsp @ 0xcda1f0] Error parsing AU headers
>     ...
>     [rtsp @ 0xcda1f0] Could not find codec parameters for stream 1 (Audio: aac, 48000 Hz, 1 channels): unspecified sample format
> 
> In SDP provided by my RTSP server I had this fmtp line:
>     a=fmtp:98 streamType=5; profile-level-id=40; mode=AAC-hbr; config=1188; sizeLength=13; indexLength=3; indexDeltaLength=3;
> 
> In FFmpeg code, I found a check introduced by commit 24130234cd9dd733116d17b724ea4c8e12ce097a. It disallows values greater than 32 for fmtp line parameters.
> RFC-4566 (SDP: Session Description Protocol) do not give any limit of size on interger parameters given in an fmtp line.
> 
> However, In RFC-6416 (RTP Payload Format for MPEG-4 Audio/Visual Streams) give examples of "profile-level-id" values for AAC, up to 55.
> 
> === FIX ===
> 
> As each parameter may have its own min and max values
> I propose to introduce a range for each parameter.
> For this patch I used RFC-3640 and ISO/IEC 14496-1 as reference for validity ranges.
> 
> This patch fix my problem and I now can record my RTSP AAC stream to mp4.
> It has passed the full fate tests suite sucessfully.
> 
> Signed-off-by: Olivier Maignial <olivier.maignial at smile.fr>
> ---
> Changes v7 --> v8:
>     Indroduced a per parameter validity range 

thanks, yes this should resolve the issue


[...]
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Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Complexity theory is the science of finding the exact solution to an
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