[Libav-user] muxer ignoring my PTS audio values

Carl Eugen Hoyos cehoyos at ag.or.at
Thu Jan 3 17:16:19 CET 2013

Michael R. Hines <michael at ...> writes:

> the problem was that I was not using a *actual* 
> container to encapsulate my audio/video streams.
> For example, if you make a call like this, for example:
> avformat_alloc_output_context2(&ctx->outAudioFormatCtx, NULL, "ac3", NULL)
> or  avformat_alloc_output_context2(&ctx->outAudioFormatCtx, NULL, "h264", NULL)

Please understand that both "ac3" and "h264" are "actual" 
containers in the sense that they are defined by public 
You can test those containers with ffmpeg (the application):
$ ffmpeg -i input -f ac3 out1
$ ffmpeg -i input -f h264 out2
(The second example needs a ffmpeg executable with x264 support.)

Both output files should decode fine with FFmpeg (and out2 for 
example with the H264 reference decoder).

Both "ac3" and "h264" are of course raw containers, but that 
does not make them less "actual" imo (especially given that 
both are defined in "actual" codec standards).

Please note that I suspect the h264 format does support 
timestamps, FFmpeg support for these timestamps is 
unfortunately limited, several tickets are open.

I am not sure how timestamps for encoded audio would help, 
afaik when decoding ac3 streams the decoding speed is 

Carl Eugen

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