[FFmpeg-devel] Patch to WAV to accurately report duration

[Frank Barchard]

On Wed, Jan 12, 2011 at 8:04 AM, Michael Niedermayer <michaelni at gmx.at>wrote:

> On Mon, Jan 10, 2011 at 06:51:18PM -0800, Frank Barchard wrote:
> > Patch to accurately report duration of a WAV.
>
> -    } else
> > +    } else {
> >          wav->data_end= url_ftell(pb) + size;
> > +        st->nb_frames = size /
> > +            (st->codec->channels * (st->codec->bits_per_coded_sample >>
> 3));
> > +        st->duration = st->codec->frame_size ?
> > +            st->nb_frames * st->codec->frame_size : st->nb_frames;
> > +    }
>
> this is wrong, iam not even sure its guranteed to work with PCM
>

The patch has certainly worked for 8-bit, 16-bit, and 24-bit wav files that
we've tested.  With the patch, the number of frames is reported as exactly
right (as compared with the results returned by Apple's 'afinfo' tool).
 Without the patch it is not accurate.