[FFmpeg-devel] [PATCH]Warn if vorbis files with wrong channel layout are encoded

[Stefano Sabatini]

On date Thursday 2011-04-14 21:18:44 +0200, Carl Eugen Hoyos encoded:
> Hi!
> 
> I'm going to commit if nobody objects, but I'd be happy if somebody from the 
> language police comments. (I prefer AV_LOG_ERROR because the resulting streams 
> are mostly unusable.)
> 
> Carl Eugen

> diff --git a/libavcodec/libvorbis.c b/libavcodec/libvorbis.c
> index 9324b28..acbaa8c 100644
> --- a/libavcodec/libvorbis.c
> +++ b/libavcodec/libvorbis.c
> @@ -96,6 +96,32 @@ static av_cold int oggvorbis_init_encoder(vorbis_info *vi, AVCodecContext *avcco
>          vorbis_encode_ctl(vi, OV_ECTL_IBLOCK_SET, &context->iblock);
>      }
>  
> +    if (avccontext->channels == 3 &&
> +            avccontext->channel_layout != (AV_CH_LAYOUT_STEREO|AV_CH_FRONT_CENTER) ||
> +        avccontext->channels == 4 &&
> +            avccontext->channel_layout != AV_CH_LAYOUT_2_2 &&
> +            avccontext->channel_layout != AV_CH_LAYOUT_QUAD ||
> +        avccontext->channels == 5 &&
> +            avccontext->channel_layout != AV_CH_LAYOUT_5POINT0 &&
> +            avccontext->channel_layout != AV_CH_LAYOUT_5POINT0_BACK ||
> +        avccontext->channels == 6 &&
> +            avccontext->channel_layout != AV_CH_LAYOUT_5POINT1 &&
> +            avccontext->channel_layout != AV_CH_LAYOUT_5POINT1_BACK ||
> +        avccontext->channels == 7 &&
> +            avccontext->channel_layout != (AV_CH_LAYOUT_5POINT1|AV_CH_BACK_CENTER) ||
> +        avccontext->channels == 8 &&
> +            avccontext->channel_layout != AV_CH_LAYOUT_7POINT1) {
> +        if (avccontext->channel_layout) {
> +            av_log(avccontext, AV_LOG_ERROR, "Channel layout not supported by Vorbis, "
> +                                             "output stream will have incorrect "
> +                                             "channel layout.\n");

And while at it also tell which is the problematic channel layout (see
libavutil/audioconvert.h:av_get_channel_layout_string()):

Channel layout '%s' not supported by Vorbis...

Also maybe more precise:
Channel layout '%s' and number of channels '%d' combination not supported by Vorbis...

Also it is quite weird to log with AV_LOG_ERROR if the error is not
issued immediately, maybe it would be better to move the check
directly in the setup function.

> +        } else {
> +            av_log(avccontext, AV_LOG_WARNING, "No channel layout specified. The encoder "
> +                                               "will use Vorbis channel layout for "
> +                                               "%d channels.\n", avccontext->channels);
> +        }
> +    }
> +
>      return vorbis_encode_setup_init(vi);
>  }
-- 
FFmpeg = Freak and Fantastic Most Problematic Eager God