[FFmpeg-devel] [PATCH] Handle G.722 in RTP (both muxer and demuxer)
Sat Sep 11 21:39:15 CEST 2010
On Sat, 11 Sep 2010, Martin Storsj? wrote:
> The attached patch adds support for G.722 in RTP, both in the muxer and in
> the RTSP/SDP demuxers.
> In principle, all of this should be straightforward, but there's one
> weirdness, according to RFC 3551:
> Even though the actual sampling rate for G.722 audio is 16,000 Hz,
> the RTP clock rate for the G722 payload format is 8,000 Hz because
> that value was erroneously assigned in RFC 1890 and must remain
> unchanged for backward compatibility. The octet rate or sample-pair
> rate is 8,000 Hz.
> So all cases that do the normal mapping between AVStream->time_base and
> AVCodecContext->sample_rate to the stream clock rate as written in the SDP
> need exceptions for this. All of this is taken care of in the attached
> patch - the rate written into the SDP and set into AVStream->time_base is
> 8000, while AVCodecContext->sample_rate is set to 16000. Does it seem ok
> to you?
Agh, this time with the patch actually attached, too...
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