core: redo how codecs are mapped, remove codecs.conf

Use codec names instead of FourCCs to identify codecs. Rewrite how
codecs are selected and initialized. Now each decoder exports a list
of decoders (and the codec it supports) via add_decoders(). The order
matters, and the first decoder for a given decoder is preferred over
the other decoders. E.g. all ad_mpg123 decoders are preferred over
ad_lavc, because it comes first in the mpcodecs_ad_drivers array.
Likewise, decoders within ad_lavc that are enumerated first by
libavcodec (using av_codec_next()) are preferred. (This is actually
critical to select h264 software decoding by default instead of vdpau.
libavcodec and ffmpeg/avconv use the same method to select decoders by
default, so we hope this is sane.)

The codec names follow libavcodec's codec names as defined by
AVCodecDescriptor.name (see libavcodec/codec_desc.c). Some decoders
have names different from the canonical codec name. The AVCodecDescriptor
API is relatively new, so we need a compatibility layer for older
libavcodec versions for codec names that are referenced internally,
and which are different from the decoder name. (Add a configure check
for that, because checking versions is getting way too messy.)

demux/codec_tags.c is generated from the former codecs.conf (minus
"special" decoders like vdpau, and excluding the mappings that are the
same as the mappings libavformat's exported RIFF tables). It contains
all the mappings from FourCCs to codec name. This is needed for
demux_mkv, demux_mpg, demux_avi and demux_asf. demux_lavf will set the
codec as determined by libavformat, while the other demuxers have to do
this on their own, using the mp_set_audio/video_codec_from_tag()
functions. Note that the sh_audio/video->format members don't uniquely
identify the codec anymore, and sh->codec takes over this role.

Replace the --ac/--vc/--afm/--vfm with new --vd/--ad options, which
provide cover the functionality of the removed switched.

Note: there's no CODECS_FLAG_FLIP flag anymore. This means some obscure
container/video combinations (e.g. the sample Film_200_zygo_pro.mov)
are played flipped. ffplay/avplay doesn't handle this properly either,
so we don't care and blame ffmeg/libav instead.

1 files changed, 379 insertions, 0 deletions

diff --git a/demux/codec_tags.c b/demux/codec_tags.c
new file mode 100644
index 0000000000..1719a4373f
--- /dev/null
+++ b/demux/codec_tags.c
@@ -0,0 +1,379 @@
+/*
+ * This file is part of mpv.
+ *
+ * mpv is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * mpv is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with mpv.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <libavformat/avformat.h>
+#include <libavcodec/avcodec.h>
+#include <libavutil/common.h>
+#include "codec_tags.h"
+#include "stheader.h"
+#include "core/av_common.h"
+
+/* The following tables map FourCCs to codec names (as defined by libavcodec).
+ * However, this includes only names that are not defined by libavformat's
+ * RIFF tag tables, or which are mapped differently (for unknown reasons).
+ * These mappings were extracted from the codecs.conf file when it was removed,
+ * and these mappings have been maintained for years, meaning they are well
+ * tested and possibly make some files work. Or they could just be bugs.
+ *
+ * Note that demux_lavf does not use these tables, and always uses the native
+ * libavformat mappings.
+ *
+ * Note about internal mplayer FourCCs:
+ *
+ * These are made-up FourCCs which don't actually show up in files, but which
+ * were used by the original MPlayer to identify codecs. Since we don't quite
+ * know/care if there are still some uses of them left, they're still here.
+ */
+
+struct mp_codec_tag {
+    uint32_t tag;
+    const char *codec;
+};
+
+static const struct mp_codec_tag mp_audio_codec_tags[] = {
+    {MKTAG('Q', 'D', 'M', '2'), "qdm2"},
+    {MKTAG('Q', 'c', 'l', 'p'), "qcelp"},
+    {MKTAG('s', 'q', 'c', 'p'), "qcelp"},
+    {MKTAG('Q', 'c', 'l', 'q'), "qcelp"},
+    {MKTAG('1', '4', '_', '4'), "ra_144"},
+    {MKTAG('l', 'p', 'c', 'J'), "ra_144"},
+    {MKTAG('2', '8', '_', '8'), "ra_288"},
+    {MKTAG('c', 'o', 'o', 'k'), "cook"},
+    {MKTAG('a', 't', 'r', 'c'), "atrac3"},
+    {MKTAG('s', 'i', 'p', 'r'), "sipr"},
+    {MKTAG('S', 'M', 'K', 'A'), "smackaudio"},
+    {MKTAG('A', 'x', 'a', 'n'), "xan_dpcm"},
+    {0x594a                   , "xan_dpcm"},
+    {MKTAG('T', 'H', 'P', 'A'), "adpcm_thp"},
+    {MKTAG('R', 'A', 'D', 'V'), "dvaudio"},
+    {MKTAG('v', 'd', 'v', 'a'), "dvaudio"},
+    {MKTAG('d', 'v', 'c', 'a'), "dvaudio"},
+    {MKTAG('d', 'v', 'a', 'u'), "dvaudio"},
+    {MKTAG('m', 'p', '4', 'a'), "aac"},
+    {MKTAG('M', 'P', '4', 'A'), "aac"},
+    {MKTAG('r', 'a', 'a', 'c'), "aac"},
+    {MKTAG('r', 'a', 'c', 'p'), "aac"},
+    {0xa106                   , "aac"}, // libav 0.8: -, ffmpeg 1.1: aac
+    {0xaac0                   , "aac"},
+    {MKTAG('f', 'L', 'a', 'C'), "flac"},
+    {MKTAG('m', 's', 241, 172), "flac"},
+    {MKTAG('a', 'l', 'a', 'c'), "alac"},
+    {MKTAG('A', 'P', 'E', ' '), "ape"},
+    {MKTAG('d', 'a', 'u', 'd'), "pcm_s24daud"},
+    {MKTAG('W', 'M', 'A', '3'), "wmapro"},
+    {MKTAG('M', 'A', 'C', '3'), "mace3"},
+    {MKTAG('M', 'A', 'C', '6'), "mace6"},
+    {MKTAG('S', 'O', 'N', 'C'), "sonic"},
+    {0x2048                   , "sonic"}, // libav 0.8: -, ffmpeg 1.1: sonic
+    {MKTAG('T', 'S', 0  , 'U'), "mp3"},
+    {MKTAG('G', 'S', 'M', ' '), "gsm"},
+    {0x1500                   , "gsm"}, // lavf: gsm_ms
+    {MKTAG('a', 'g', 's', 'm'), "gsm"},
+    {0x32                     , "gsm_ms"},
+    {MKTAG(1  , 0  , 1  , 0  ), "pcm_dvd"},
+    {MKTAG('B', 'S', 'S', 'D'), "s302m"},
+    {MKTAG('A', 'C', '-', '3'), "ac3"},
+    {MKTAG('d', 'n', 'e', 't'), "ac3"},
+    {MKTAG('s', 'a', 'c', '3'), "ac3"},
+    {MKTAG('E', 'A', 'C', '3'), "eac3"},
+    {0x86                     , "dts"},
+    {MKTAG('M', 'P', 'C', ' '), "musepack7"},
+    {MKTAG('M', 'P', 'C', '8'), "musepack8"},
+    {MKTAG('M', 'P', 'C', 'K'), "musepack8"},
+    {MKTAG('s', 'a', 'm', 'r'), "amr_nb"},
+    {MKTAG('s', 'a', 'w', 'b'), "amr_wb"},
+    {MKTAG('v', 'r', 'b', 's'), "vorbis"},
+    // Special cased in ad_lavc:
+    {0                        , "pcm"},
+    {0x1                      , "pcm"}, // lavf: pcm_s16le
+    {0x3                      , "pcm"}, // lavf: pcm_f32le
+    {0xfffe                   , "pcm"},
+    // ------- internal mplayer FourCCs ------
+    {MKTAG('S', 'a', 'd', 'x'), "adpcm_adx"},
+    {MKTAG('A', 'M', 'V', 'A'), "adpcm_ima_amv"},
+    {MKTAG('R', 'o', 'Q', 'A'), "roq_dpcm"},
+    {MKTAG('B', 'A', 'U', '1'), "binkaudio_dct"},
+    {MKTAG('B', 'A', 'U', '2'), "binkaudio_rdft"},
+    {MKTAG('D', 'C', 'I', 'A'), "dsicinaudio"},
+    {MKTAG('4', 'X', 'M', 'A'), "adpcm_4xm"},
+    {MKTAG('A', 'I', 'W', 'S'), "adpcm_ima_ws"},
+    {MKTAG('S', 'N', 'D', '1'), "westwood_snd1"},
+    {MKTAG('I', 'N', 'P', 'A'), "interplay_dpcm"},
+    {MKTAG('A', 'D', 'E', 'A'), "adpcm_ea"},
+    {MKTAG('A', 'D', 'X', 'A'), "adpcm_ea_maxis_xa"},
+    {MKTAG('P', 'S', 'X', 'A'), "adpcm_xa"},
+    {MKTAG('M', 'P', '4', 'L'), "aac_latm"},
+    {MKTAG('T', 'T', 'A', '1'), "tta"},
+    {MKTAG('W', 'V', 'P', 'K'), "wavpack"},
+    {MKTAG('s', 'h', 'r', 'n'), "shorten"},
+    {MKTAG('A', 'L', 'S', ' '), "mp4als"},
+    {MKTAG('M', 'L', 'P', ' '), "mlp"},
+    {MKTAG('T', 'R', 'H', 'D'), "truehd"},
+    {MKTAG('N', 'E', 'L', 'L'), "nellymoser"},
+    {MKTAG('m', '4', 'a', 29 ), "mp3on4"},
+    {MKTAG('a', 'd', 'u', 'U'), "mp3adu"},
+    {MKTAG('B', 'P', 'C', 'M'), "pcm_bluray"},
+    {MKTAG('P', 'L', 'X', 'F'), "pcm_lxf"},
+    {MKTAG('T', 'W', 'I', '2'), "twinvq"},
+    {0x20776172,                "pcm"}, // demux_mpg.c dvdpcm
+    {0},
+};
+
+static const struct mp_codec_tag mp_video_codec_tags[] = {
+    {MKTAG('V', 'B', 'V', '1'), "vb"},
+    {MKTAG('M', 'L', '2', '0'), "mimic"},
+    {MKTAG('R', '1', '0', 'g'), "r10k"},
+    {MKTAG('m', '1', 'v', '1'), "mpeg1video"},
+    {MKTAG('m', 'p', 'g', '2'), "mpeg2video"}, // lavf: mpeg1video
+    {MKTAG('M', 'P', 'G', '2'), "mpeg2video"}, // lavf: mpeg1video
+    {MKTAG('m', 'x', '5', 'p'), "mpeg2video"},
+    {MKTAG('h', 'd', 'v', '1'), "mpeg2video"},
+    {MKTAG('h', 'd', 'v', '2'), "mpeg2video"},
+    {MKTAG('h', 'd', 'v', '3'), "mpeg2video"},
+    {MKTAG('h', 'd', 'v', '4'), "mpeg2video"},
+    {MKTAG('h', 'd', 'v', '5'), "mpeg2video"},
+    {MKTAG('h', 'd', 'v', '6'), "mpeg2video"},
+    {MKTAG('h', 'd', 'v', '7'), "mpeg2video"},
+    {MKTAG('h', 'd', 'v', '8'), "mpeg2video"},
+    {MKTAG('h', 'd', 'v', '9'), "mpeg2video"},
+    {MKTAG('x', 'd', 'v', '1'), "mpeg2video"},
+    {MKTAG('x', 'd', 'v', '2'), "mpeg2video"},
+    {MKTAG('x', 'd', 'v', '3'), "mpeg2video"},
+    {MKTAG('x', 'd', 'v', '4'), "mpeg2video"},
+    {MKTAG('x', 'd', 'v', '5'), "mpeg2video"},
+    {MKTAG('x', 'd', 'v', '6'), "mpeg2video"},
+    {MKTAG('x', 'd', 'v', '7'), "mpeg2video"},
+    {MKTAG('x', 'd', 'v', '8'), "mpeg2video"},
+    {MKTAG('x', 'd', 'v', '9'), "mpeg2video"},
+    {MKTAG('x', 'd', 'v', 'a'), "mpeg2video"},
+    {MKTAG('x', 'd', 'v', 'b'), "mpeg2video"},
+    {MKTAG('x', 'd', 'v', 'c'), "mpeg2video"},
+    {MKTAG('x', 'd', 'v', 'd'), "mpeg2video"},
+    {MKTAG('x', 'd', 'v', 'e'), "mpeg2video"},
+    {MKTAG('x', 'd', 'v', 'f'), "mpeg2video"},
+    {MKTAG('x', 'd', '5', 'a'), "mpeg2video"},
+    {MKTAG('x', 'd', '5', 'b'), "mpeg2video"},
+    {MKTAG('x', 'd', '5', 'c'), "mpeg2video"},
+    {MKTAG('x', 'd', '5', 'd'), "mpeg2video"},
+    {MKTAG('x', 'd', '5', 'e'), "mpeg2video"},
+    {MKTAG('x', 'd', '5', 'f'), "mpeg2video"},
+    {MKTAG('x', 'd', '5', '9'), "mpeg2video"},
+    {MKTAG('x', 'd', '5', '4'), "mpeg2video"},
+    {MKTAG('x', 'd', '5', '5'), "mpeg2video"},
+    {MKTAG('m', 'x', '5', 'n'), "mpeg2video"},
+    {MKTAG('m', 'x', '4', 'n'), "mpeg2video"},
+    {MKTAG('m', 'x', '4', 'p'), "mpeg2video"},
+    {MKTAG('m', 'x', '3', 'n'), "mpeg2video"},
+    {MKTAG('m', 'x', '3', 'p'), "mpeg2video"},
+    {MKTAG('A', 'V', 'm', 'p'), "mpeg2video"},
+    {MKTAG('V', 'C', 'R', '2'), "mpeg2video"}, // lavf: mpeg1video
+    {MKTAG('m', 'p', '2', 'v'), "mpeg2video"},
+    {MKTAG('m', '2', 'v', '1'), "mpeg2video"},
+    {MKTAG('R', 'J', 'P', 'G'), "nuv"},
+    {MKTAG('b', 'm', 'p', ' '), "bmp"},
+    {MKTAG('b', 'm', 'p', 0  ), "bmp"},
+    {MKTAG('g', 'i', 'f', ' '), "gif"},
+    {MKTAG('t', 'i', 'f', 'f'), "tiff"},
+    {MKTAG('p', 'c', 'x', ' '), "pcx"},
+    {MKTAG('m', 't', 'g', 'a'), "targa"},
+    {MKTAG('M', 'T', 'G', 'A'), "targa"},
+    {MKTAG('r', 'l', 'e', ' '), "qtrle"},
+    {MKTAG('s', 'm', 'c', ' '), "smc"},
+    {MKTAG('8', 'B', 'P', 'S'), "8bps"},
+    {MKTAG('W', 'R', 'L', 'E'), "msrle"},
+    {MKTAG('F', 'F', 'V', 'H'), "huffyuv"}, // lavf: ffvhuff
+    {MKTAG('P', 'I', 'X', 'L'), "vixl"},
+    {MKTAG('X', 'I', 'X', 'L'), "vixl"},
+    {MKTAG('q', 'd', 'r', 'w'), "qdraw"},
+    {MKTAG('D', 'I', 'V', 'F'), "msmpeg4v3"},
+    {MKTAG('d', 'i', 'v', 'f'), "msmpeg4v3"},
+    {MKTAG('3', 'I', 'V', 'D'), "msmpeg4v3"},
+    {MKTAG('3', 'i', 'v', 'd'), "msmpeg4v3"},
+    {MKTAG('w', 'm', 'v', 'p'), "wmv3"}, // lavf: wmv3image
+    {MKTAG('W', 'M', 'V', 'P'), "wmv3"}, // lavf: wmv3image
+    {MKTAG('v', 'c', '-', '1'), "vc1"},
+    {MKTAG('V', 'C', '-', '1'), "vc1"},
+    {MKTAG('v', 'v', 'v', 'c'), "h264"},
+    {MKTAG('a', 'i', '5', '5'), "h264"},
+    {MKTAG('a', 'i', '1', '5'), "h264"},
+    {MKTAG('a', 'i', '1', 'q'), "h264"},
+    {MKTAG('a', 'i', '5', 'q'), "h264"},
+    {MKTAG('a', 'i', '1', '2'), "h264"},
+    {MKTAG(5  , 0  , 0  , 16 ), "h264"},
+    {MKTAG('S', 'V', 'Q', '3'), "svq3"}, // libav 0.8: -, ffmpeg 1.1: svq3
+    {MKTAG('d', 'r', 'a', 'c'), "dirac"}, // libav 0.8: -, ffmpeg 1.1: dirac
+    {MKTAG('A', 'V', 'R', 'n'), "mjpeg"}, // libav 0.8: mjpeg, ffmpeg 1.1: avrn
+    {MKTAG('A', 'V', 'D', 'J'), "mjpeg"},
+    {MKTAG('A', 'D', 'J', 'V'), "mjpeg"},
+    {MKTAG('J', 'F', 'I', 'F'), "mjpeg"},
+    {MKTAG('M', 'J', 'L', 'S'), "mjpeg"}, // lavf: jpegls
+    {MKTAG('m', 'j', 'p', 'b'), "mjpegb"},
+    {MKTAG('U', '2', '6', '3'), "h263"}, // libav 0.8: -, ffmpeg 1.1: h263
+    {MKTAG('v', 'i', 'v', '1'), "h263"},
+    {MKTAG('s', '2', '6', '3'), "h263"}, // libav 0.8: -, ffmpeg 1.1: flv1
+    {MKTAG('S', '2', '6', '3'), "h263"}, // same
+    {MKTAG('D', '2', '6', '3'), "h263"},
+    {MKTAG('I', 'L', 'V', 'R'), "h263"},
+    {MKTAG('d', 'v', 'p', ' '), "dvvideo"},
+    {MKTAG('d', 'v', 'p', 'p'), "dvvideo"},
+    {MKTAG('A', 'V', 'd', 'v'), "dvvideo"},
+    {MKTAG('A', 'V', 'd', '1'), "dvvideo"},
+    {MKTAG('d', 'v', 'h', 'q'), "dvvideo"},
+    {MKTAG('d', 'v', 'h', 'p'), "dvvideo"},
+    {MKTAG('d', 'v', 'h', '5'), "dvvideo"},
+    {MKTAG('d', 'v', 'h', '6'), "dvvideo"},
+    {MKTAG('d', 'v', 'h', '3'), "dvvideo"},
+    {MKTAG('d', 'v', 's', '1'), "dvvideo"},
+    {MKTAG('R', 'V', '2', '0'), "rv20"},
+    {MKTAG('r', 'v', '2', '0'), "rv20"},
+    {MKTAG('R', 'V', 'T', 'R'), "rv20"},
+    {MKTAG('R', 'V', '3', '0'), "rv30"},
+    {MKTAG('r', 'v', '3', '0'), "rv30"},
+    {MKTAG('R', 'V', '4', '0'), "rv40"},
+    {MKTAG('r', 'v', '4', '0'), "rv40"},
+    {MKTAG('R', 'V', '1', '0'), "rv10"},
+    {MKTAG('r', 'v', '1', '0'), "rv10"},
+    {MKTAG('R', 'V', '1', '3'), "rv10"},
+    {MKTAG('r', 'v', '1', '3'), "rv10"},
+    {MKTAG('T', 'h', 'r', 'a'), "theora"},
+    {0xfffc                   , "theora"},
+    {MKTAG('V', 'P', '6', 'A'), "vp6a"},
+    {MKTAG('S', 'P', '5', '3'), "sp5x"},
+    {MKTAG('S', 'P', '5', '5'), "sp5x"},
+    {MKTAG('S', 'P', '5', '6'), "sp5x"},
+    {MKTAG('S', 'P', '5', '7'), "sp5x"},
+    {MKTAG('S', 'P', '5', '8'), "sp5x"},
+    {MKTAG('S', 'M', 'K', '2'), "smackvideo"},
+    {MKTAG('S', 'M', 'K', '4'), "smackvideo"},
+    {MKTAG('a', 'v', 's', '2'), "cavs"},
+    {MKTAG('A', 'V', 'd', 'n'), "dnxhd"},
+    {MKTAG('a', 'p', 'c', 'h'), "prores"},
+    {MKTAG('a', 'p', 'c', 'n'), "prores"},
+    {MKTAG('a', 'p', 'c', 's'), "prores"},
+    {MKTAG('a', 'p', 'c', 'o'), "prores"},
+    {MKTAG('a', 'p', '4', 'h'), "prores"},
+    {MKTAG('f', 'V', 'G', 'T'), "tgv"},
+    // These are probably not correctly handled. The original codecs.conf
+    // entries mapped these to separate pixel formats via vd_raw and the
+    // "out" directive (look at MPlayer's codecs.conf).
+    // Should they be aliased to supported FourCCs of the same formats?
+    {MKTAG('A', 'V', '1', 'x'), "rawvideo"},
+    {MKTAG('A', 'V', 'u', 'p'), "rawvideo"},
+    {MKTAG('4', '4', '4', 'p'), "rawvideo"},
+    {MKTAG('4', '4', '4', 'P'), "rawvideo"},
+    {MKTAG('4', '2', '2', 'p'), "rawvideo"},
+    {MKTAG('4', '2', '2', 'P'), "rawvideo"},
+    // Unknown:
+    {MKTAG('r', 'a', 'w', ' '), "rawvideo"},
+    {MKTAG('D', 'V', 'O', 'O'), "rawvideo"},
+    // ------- internal mplayer FourCCs ------
+    {MKTAG('A', 'N', 'M', ' '), "anm"},
+    {MKTAG('B', 'I', 'K', 'f'), "binkvideo"},
+    {MKTAG('B', 'I', 'K', 'g'), "binkvideo"},
+    {MKTAG('B', 'I', 'K', 'h'), "binkvideo"},
+    {MKTAG('B', 'I', 'K', 'i'), "binkvideo"},
+    {MKTAG('C', 'D', 'G', 'R'), "cdgraphics"},
+    {MKTAG('M', 'V', 'I', '1'), "motionpixels"},
+    {MKTAG('M', 'D', 'E', 'C'), "mdec"},
+    {MKTAG('N', 'U', 'V', '1'), "nuv"},
+    {MKTAG('p', 't', 'x', ' '), "ptx"},
+    {MKTAG('S', 'G', 'I', '1'), "sgi"},
+    {MKTAG('s', 'u', 'n', ' '), "sunrast"},
+    {MKTAG('F', 'L', 'I', 'C'), "flic"},
+    {MKTAG('R', 'o', 'Q', 'V'), "roq"},
+    {MKTAG('A', 'M', 'V', 'V'), "amv"},
+    {MKTAG('F', 'F', 'J', 'V'), "jv"},
+    {MKTAG('T', 'S', 'E', 'Q'), "tiertexseqvideo"},
+    {MKTAG('V', 'M', 'D', 'V'), "vmdvideo"},
+    {MKTAG('D', 'X', 'A', '1'), "dxa"},
+    {MKTAG('D', 'C', 'I', 'V'), "dsicinvideo"},
+    {MKTAG('T', 'H', 'P', 'V'), "thp"},
+    {MKTAG('B', 'F', 'I', 'V'), "bfi"},
+    {MKTAG('B', 'E', 'T', 'H'), "bethsoftvid"},
+    {MKTAG('R', 'L', '2', 'V'), "rl2"},
+    {MKTAG('T', 'X', 'D', 'V'), "txd"},
+    {MKTAG('W', 'C', '3', 'V'), "xan_wc3"},
+    {MKTAG('I', 'D', 'C', 'I'), "idcin"},
+    {MKTAG('I', 'N', 'P', 'V'), "interplayvideo"},
+    {MKTAG('V', 'Q', 'A', 'V'), "ws_vqa"},
+    {MKTAG('C', '9', '3', 'V'), "c93"},
+    {0},
+};
+
+static const int mp_fourcc_video_aliases[][2] = {
+    // msmpeg4
+    {MKTAG('M', 'P', 'G', '3'), MKTAG('d', 'i', 'v', '3')},
+    {MKTAG('m', 'p', 'g', '3'), MKTAG('d', 'i', 'v', '3')},
+    {MKTAG('M', 'P', '4', '3'), MKTAG('d', 'i', 'v', '3')},
+    {MKTAG('m', 'p', '4', '3'), MKTAG('d', 'i', 'v', '3')},
+    {MKTAG('D', 'I', 'V', '5'), MKTAG('d', 'i', 'v', '3')},
+    {MKTAG('d', 'i', 'v', '5'), MKTAG('d', 'i', 'v', '3')},
+    {MKTAG('D', 'I', 'V', '6'), MKTAG('d', 'i', 'v', '4')},
+    {MKTAG('d', 'i', 'v', '6'), MKTAG('d', 'i', 'v', '4')},
+    {MKTAG('A', 'P', '4', '1'), MKTAG('d', 'i', 'v', '3')},
+
+    // msmpeg4v2
+    {MKTAG('D', 'I', 'V', '2'), MKTAG('m', 'p', '4', '2')},
+    {MKTAG('d', 'i', 'v', '2'), MKTAG('m', 'p', '4', '2')},
+    {MKTAG('D', 'I', 'V', '1'), MKTAG('d', 'i', 'v', 'x')},
+    {MKTAG('d', 'i', 'v', '1'), MKTAG('d', 'i', 'v', 'x')},
+
+    // mpeg4
+    {MKTAG('d', 'x', '5', '0'), MKTAG('D', 'X', '5', '0')},
+    {MKTAG('B', 'L', 'Z', '0'), MKTAG('D', 'X', '5', '0')},
+
+    {MKTAG('v', 'i', 'v', '1'), MKTAG('h', '2', '6', '3')},
+    {MKTAG('T', 'h', 'r', 'a'), MKTAG('t', 'h', 'e', 'o')},
+
+    {0},
+};
+
+static const char *lookup_tag(const struct mp_codec_tag *mp_table,
+                              const struct AVCodecTag *av_table,
+                              uint32_t tag)
+{
+    for (int n = 0; mp_table[n].codec; n++) {
+        if (mp_table[n].tag == tag)
+            return mp_table[n].codec;
+    }
+    const struct AVCodecTag *av_tags[] = {av_table, NULL};
+    int id = av_codec_get_id(av_tags, tag);
+    return id == CODEC_ID_NONE ? NULL : mp_codec_from_av_codec_id(id);
+}
+
+void mp_set_video_codec_from_tag(struct sh_video *sh)
+{
+    sh->gsh->codec = lookup_tag(mp_video_codec_tags,
+                                avformat_get_riff_video_tags(),
+                                sh->format);
+}
+
+void mp_set_audio_codec_from_tag(struct sh_audio *sh)
+{
+    sh->gsh->codec = lookup_tag(mp_audio_codec_tags,
+                                avformat_get_riff_audio_tags(),
+                                sh->format);
+}
+
+uint32_t mp_video_fourcc_alias(uint32_t fourcc)
+{
+    for (int n = 0; mp_fourcc_video_aliases[n][0]; n++) {
+        if (mp_fourcc_video_aliases[n][0] == fourcc)
+            return mp_fourcc_video_aliases[n][1];
+    }
+    return fourcc;
+}