[FFmpeg-devel] [PATCH] share xiph rtp code

Josh Allmann joshua.allmann
Sun Mar 28 22:41:48 CEST 2010


On 28 March 2010 07:26, Luca Barbato <lu_zero at gentoo.org> wrote:
> On 03/28/2010 10:24 AM, Josh Allmann wrote:
>>
>> Tested this with feng and gst-rtsp, and things seem to work but if
>> someone could double-check the audio for me that'd be great.
>
> the main difference between vorbis and theora in the producer side is
> due the fact you need to pick some information from the extradata to get
> the right timings from the granulepos. iirc the receiver side should be
> identical so it looks fine.
>
> The output is completely broken? trying to do a streamcopy results in a
> broken vorbis?
>

By streamcopy I assume you mean "-acodec copy" ? It seems that
ffmpeg's default behavior for vorbis, lacking the copy, is to
re-encode through flac.

As far as I can tell, Vorbis streamcopy output is bitexact
before-and-after this patch, so if it's broken now, then it always has
been.
(this is true using feng; gst-rtsp differs since it makes use of
multiple frames per packet, a new feature introduced by this patch)

Ffmpeg seems picky about the samples used though; most I've tried will
throw one error or another (usually timestamp-related). I have been
using this to streamcopy vorbis:
http://samples.mplayerhq.hu/V-codecs/Theora/Sahara.ogg

Josh



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