[Ffmpeg-devel] ogg vorbis encode?

[Rich Felker]

On Mon, Aug 15, 2005 at 06:08:23PM -0400, Justin Ruggles wrote:
> hello,
> 
> small fix for vorbis pts.  after playing around with trying to set the
> time_base to the sample_rate, i found that doing this was much easier
> and more in line with how ogg2.c and the vorbis decoder do things.
> vorbis still has to have the analysis buffer fill up before sending any
> data through, but now it gives the correct time/bitrate once the ogg
> writing starts.  one oddity, it always gives a "non monotone timestamp"
> error on the 3rd to last ogg packet, but I can't figure out why...
> 
> -justin

> Index: libavcodec/oggvorbis.c
> ===================================================================
> RCS file: /cvsroot/ffmpeg/ffmpeg/libavcodec/oggvorbis.c,v
> retrieving revision 1.19
> diff -u -r1.19 oggvorbis.c
> --- libavcodec/oggvorbis.c	19 May 2005 11:45:10 -0000	1.19
> +++ libavcodec/oggvorbis.c	15 Aug 2005 22:00:20 -0000
> @@ -90,6 +90,7 @@
>   
>      avccontext->coded_frame= avcodec_alloc_frame();
>      avccontext->coded_frame->key_frame= 1;
> +    avccontext->time_base= (AVRational){1, AV_TIME_BASE};
>      
>      return 0 ;
>  }
> @@ -140,7 +141,7 @@
>          op2->packet = context->buffer + sizeof(ogg_packet);
>  
>          l=  op2->bytes;
> -        avccontext->coded_frame->pts= op2->granulepos;
> +        avccontext->coded_frame->pts= op2->granulepos * 1000000LL / avccontext->sample_rate;
>  
>          memcpy(packets, op2->packet, l);
>          context->buffer_index -= l + sizeof(ogg_packet);

This is totally wrong. Vorbis has a time base, you just need to
extract it based on the samplerate.

Rich