On Tue, Mar 18, 2014 at 06:26:47PM +0100, Anton Khirnov wrote:
> @@ -229,8 +238,38 @@ static int filter_frame(AVFilterLink *inlink, AVFrame
> *buf)
> AVFilterLink *outlink = inlink->dst->outputs[0];
> int nb_samples = buf->nb_samples;
> AVFrame *out_buf;
> + AVFrameSideData *sd = av_frame_get_side_data(buf,
> AV_FRAME_DATA_REPLAYGAIN);
Now that the patches have been merged, I've been trying to use this filter with
mpv to play a few mp3s and see if it can be used to replace mpv's af_volume
(which already supports replaygain).
The problem is, libav's af_volume replaygain support doesn't seem to work at all
(with my mp3 files anyway), i.e. av_frame_get_side_data() always returns NULL
even if the files do have replaygain tags (and ff_export_replaygain() is called
without errors in mp3dec.c).
So, it is my understanding that the AVFrame's replaygain side data used by the
filter is initialized from the AVPacket side data by ff_decode_frame_props(),
so I added a call to that function in decode_frame() in mpegaudiodec_template.c
but it still doesn't work, because apparently the packet's replaygain side data
isn't initialized either... then I noticed this comment in the AVStream
definition:
> * There may be no overlap between the side data in this array and side data
> * in the packets. I.e. a given side data is either exported by the muxer
> * (demuxing) / set by the caller (muxing) in this array, then it never
> * appears in the packets, or the side data is exported / sent through
> * the packets (always in the first packet where the value becomes known or
> * changes), then it does not appear in this array.
> ...
> AVPacketSideData *side_data;
Which, if I understand it correctly, means that the replaygain data is either
in the stream (put there by ff_replaygain_export() in mp3dec.c) or in the
packets, which in turn means that the av_frame_get_side_data() call in af_volume
will always return NULL, at least for mp3s, since that information is always
in the AVStream.
So, is this on purpose (meaning that the replaygain support in af_volume
can't be used with mp3/flac/ogg/...)? Is there any way this could be fixed?
Cheers
--
perl -E '$_=q;$/= @{[@_]};and s;\S+;<inidehG ordnasselA>;eg;say~~reverse'
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