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demux_lavf: add a hack to work around other hacks

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mplayer (and all forks) use a single FourCC field to map codecs. This is
what sh_video->format and sh_audio->format is used for. Basically it's a
key into the codecs.conf table to find out what decoder to use. (There's
only one video codec and one major audio codec left - both libavcodec.
But we still have to deal with mapping coming from non-libavformat
demuxers.)

It seems this causes some video codecs to fail, such as WV1F in AVI [1].
demux_lavf generally throws away the codec_tag from libavformat if the
codec is MPEG-in-AVI. There are probably other cases like this. Add a
hack to enforce passing the correct codec tag when only ffmpeg demuxers
and decoders involved.

Note: the sample [1] needs to be flipped. With --demuxer=avi, this is
done correctly, because unlike demux_lavf, the demuxer uses the FourCC
directly for the sh_video->format tag, and finds the correct codecs.conf
entry (which contains the flip flag). We could just add a "whitelist" of
codec tags which can be passed through to sh_video->format, but I don't
want to do that just for such an obscure format as the sample at hand.

Note 2: when demux_lavf is used, the AVCodecContext could be passed
directly to vd_ffmpeg/ad_ffmpeg. The code to convert to/from the
internal mplayer stream headers is probably still needed, as there are
non-ffmpeg demuxers and audio decoders.

[1] http://samples.mplayerhq.hu/V-codecs/WV1F/AVI/title2.avi
This commit is contained in:
wm4 2012-10-29 00:06:51 +01:00
parent 0c95e139a9
commit 219e1ab1e7
4 changed files with 12 additions and 0 deletions
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2
libmpcodecs/ad_ffmpeg.c
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@ -159,6 +159,8 @@ static int init(sh_audio_t *sh_audio)
}
lavc_context->request_channels = opts->audio_output_channels;
lavc_context->codec_tag = sh_audio->format; //FOURCC
if (sh_audio->gsh->lavf_codec_tag)
lavc_context->codec_tag = sh_audio->gsh->lavf_codec_tag;
lavc_context->codec_type = AVMEDIA_TYPE_AUDIO;
lavc_context->codec_id = lavc_codec->id; // not sure if required, imho not --A'rpi

2
libmpcodecs/vd_ffmpeg.c
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@ -239,6 +239,8 @@ static int init(sh_video_t *sh)
} else {
avctx->pix_fmt = rawfmt;
}
if (sh->gsh->lavf_codec_tag)
avctx->codec_tag = sh->gsh->lavf_codec_tag;
avctx->stream_codec_tag = sh->video.fccHandler;
avctx->idct_algo = lavc_param->idct_algo;
avctx->error_concealment = lavc_param->error_concealment;

5
libmpdemux/demux_lavf.c
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@ -292,6 +292,8 @@ static void handle_stream(demuxer_t *demuxer, AVFormatContext *avfc, int i)
int stream_id;
AVDictionaryEntry *lang = av_dict_get(st->metadata, "language", NULL, 0);
AVDictionaryEntry *title = av_dict_get(st->metadata, "title", NULL, 0);
// Work around collisions resulting from the hacks changing codec_tag.
int lavf_codec_tag = codec->codec_tag;
// Don't use native MPEG codec tag values with our generic tag tables.
// May contain for example value 3 for MP3, which we'd map to PCM audio.
if (matches_avinputformat_name(priv, "mpeg") ||
@ -320,6 +322,7 @@ static void handle_stream(demuxer_t *demuxer, AVFormatContext *avfc, int i)
stream_type = "audio";
priv->astreams[priv->audio_streams] = i;
sh_audio->libav_codec_id = codec->codec_id;
sh_audio->gsh->lavf_codec_tag = lavf_codec_tag;
wf = calloc(sizeof(*wf) + codec->extradata_size, 1);
// mp4a tag is used for all mp4 files no matter what they actually contain
if (codec->codec_tag == MKTAG('m', 'p', '4', 'a'))
@ -403,6 +406,7 @@ static void handle_stream(demuxer_t *demuxer, AVFormatContext *avfc, int i)
stream_type = "video";
priv->vstreams[priv->video_streams] = i;
sh_video->libav_codec_id = codec->codec_id;
sh_video->gsh->lavf_codec_tag = lavf_codec_tag;
bih = calloc(sizeof(*bih) + codec->extradata_size, 1);
if (codec->codec_id == CODEC_ID_RAWVIDEO) {
@ -517,6 +521,7 @@ static void handle_stream(demuxer_t *demuxer, AVFormatContext *avfc, int i)
stream_type = "subtitle";
priv->sstreams[priv->sub_streams] = i;
sh_sub->libav_codec_id = codec->codec_id;
sh_sub->gsh->lavf_codec_tag = lavf_codec_tag;
sh_sub->type = type;
if (codec->extradata_size) {
sh_sub->extradata = malloc(codec->extradata_size);

3
libmpdemux/stheader.h
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@ -54,6 +54,9 @@ struct sh_stream {
struct sh_video *video;
struct sh_sub *sub;
// Work around other hacks.
int lavf_codec_tag;
char *title;
bool default_track;