mpv/demux/codec_tags.c

/*
 * This file is part of mpv.
 *
 * mpv is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser 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 "common/av_common.h"

#define HAVE_QT_TAGS (LIBAVFORMAT_VERSION_MICRO >= 100)

static const char *lookup_tag(int type, uint32_t tag)
{
    const struct AVCodecTag *av_tags[3] = {0};
    switch (type) {
    case STREAM_VIDEO: {
        av_tags[0] = avformat_get_riff_video_tags();
#if HAVE_QT_TAGS
        av_tags[1] = avformat_get_mov_video_tags();
#endif
        break;
    }
    case STREAM_AUDIO: {
        av_tags[0] = avformat_get_riff_audio_tags();
#if HAVE_QT_TAGS
        av_tags[1] = avformat_get_mov_audio_tags();
#endif
        break;
    }
    }

    int id = av_codec_get_id(av_tags, tag);
    return id == AV_CODEC_ID_NONE ? NULL : mp_codec_from_av_codec_id(id);
}

static const char *const pcm_le[] = {"pcm_u8", "pcm_s16le", "pcm_s24le", "pcm_s32le"};
static const char *const pcm_be[] = {"pcm_s8", "pcm_s16be", "pcm_s24be", "pcm_s32be"};

static const char *map_audio_pcm_tag(uint32_t tag, int bits)
{
    int bytes = (bits + 7) / 8;
    switch (tag) {
    case 0x0:       // Microsoft PCM
    case 0x1:
    case 0xfffe:    // MS PCM, Extended
        return bytes >= 1 && bytes <= 4 ? pcm_le[bytes - 1] : NULL;
    case 0x3:       // IEEE float
        return bits == 64 ? "pcm_f64le" : "pcm_f32le";
    case 0x20776172:// 'raw '
        return bits == 8 ? "pcm_u8" : "pcm_s16be";
    case MKTAG('t', 'w', 'o', 's'): // demux_mkv.c internal
        return bytes >= 1 && bytes <= 4 ? pcm_be[bytes - 1] : NULL;
    default:
        return NULL;
    }
}

void mp_set_codec_from_tag(struct mp_codec_params *c)
{
    c->codec = lookup_tag(c->type, c->codec_tag);

    if (c->type == STREAM_AUDIO && c->bits_per_coded_sample) {
        const char *codec =
            map_audio_pcm_tag(c->codec_tag, c->bits_per_coded_sample);
        if (codec)
            c->codec = codec;
    }
}

void mp_set_pcm_codec(struct mp_codec_params *c, bool sign, bool is_float,
                      int bits, bool is_be)
{
    // This uses libavcodec pcm codec names, e.g. "pcm_u16le".
    char codec[64] = "pcm_";
    if (is_float) {
        mp_snprintf_cat(codec, sizeof(codec), "f");
    } else {
        mp_snprintf_cat(codec, sizeof(codec), sign ? "s" : "u");
    }
    mp_snprintf_cat(codec, sizeof(codec), "%d", bits);
    if (bits != 8)
        mp_snprintf_cat(codec, sizeof(codec), is_be ? "be" : "le");
    c->codec = talloc_strdup(c, codec);
}

static const char *const mimetype_to_codec[][2] = {
    {"image/jpeg",      "mjpeg"},
    {"image/png",       "png"},
    {0}
};

const char *mp_map_mimetype_to_video_codec(const char *mimetype)
{
    if (mimetype) {
        for (int n = 0; mimetype_to_codec[n][0]; n++) {
            if (strcasecmp(mimetype_to_codec[n][0], mimetype) == 0)
                return mimetype_to_codec[n][1];
        }
    }
    return NULL;
}