[FFmpeg-devel] [PATCH] fix swf playback with bad audio track

[Baptiste Coudurier]

Hi

Aurelien Jacobs wrote:
> Hi,
> 
> Right now, when the swf demuxer find an audio track with unrecognized
> samplerate, it simply return AVERROR(EIO). This prevent playing the
> video track.

It seems weird, samplerate should not be "unrecognized", Im curious, is
such a file available somewhere ?

> With the attached patch, the swf demuxer simply ignore the unrecognized
> audio track, but still allows to play the video track of such a file.
> 
> Aurel
> 
> 
> ------------------------------------------------------------------------
> 
> Index: libavformat/swf.c
> ===================================================================
> --- libavformat/swf.c	(revision 10438)
> +++ libavformat/swf.c	(working copy)
> @@ -682,17 +682,17 @@
>              get_byte(pb);
>              v = get_byte(pb);
>              swf->samples_per_frame = get_le16(pb);
> +            sample_rate_code= (v>>2) & 3;
> +            if (sample_rate_code) {
>              ast = av_new_stream(s, -1); /* -1 to avoid clash with video stream ch_id */
>              swf->audio_stream_index = ast->index;
>              ast->codec->channels = 1 + (v&1);
>              ast->codec->codec_type = CODEC_TYPE_AUDIO;
>              ast->codec->codec_id = codec_get_id(swf_audio_codec_tags, (v>>4) & 15);
>              ast->need_parsing = AVSTREAM_PARSE_FULL;
> -            sample_rate_code= (v>>2) & 3;
> -            if (!sample_rate_code)
> -                return AVERROR(EIO);
>              ast->codec->sample_rate = 11025 << (sample_rate_code-1);
>              av_set_pts_info(ast, 64, 1, ast->codec->sample_rate);
> +            }
>              len -= 4;
>          } else if (tag == TAG_VIDEOFRAME) {
>              int ch_id = get_le16(pb);
> 

Im not against it, though maybe we should still export the track, to
permit stream copy/extraction somehow. I'd like to know which codec it
is supposed to be.

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