mpv/libmpdemux/demux_lavf.c

/*
 * Copyright (C) 2004 Michael Niedermayer <michaelni@gmx.at>
 *
 * This file is part of MPlayer.
 *
 * MPlayer 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.
 *
 * MPlayer 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 MPlayer; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

// #include <stdio.h>
#include <stdlib.h>
// #include <unistd.h>
#include <limits.h>
#include <stdbool.h>
#include <string.h>

#include <libavformat/avformat.h>
#include <libavformat/avio.h>
#include <libavutil/avutil.h>
#include <libavutil/avstring.h>
#include <libavutil/mathematics.h>
#include <libavutil/opt.h>

#include "config.h"
#include "options.h"
#include "mp_msg.h"
#include "av_opts.h"
#include "bstr.h"

#include "stream/stream.h"
#include "aviprint.h"
#include "demuxer.h"
#include "stheader.h"
#include "m_option.h"
#include "sub/sub.h"

#include "mp_taglists.h"

#define INITIAL_PROBE_SIZE STREAM_BUFFER_SIZE
#define SMALL_MAX_PROBE_SIZE (32 * 1024)
#define PROBE_BUF_SIZE (2 * 1024 * 1024)

const m_option_t lavfdopts_conf[] = {
    OPT_INTRANGE("probesize", lavfdopts.probesize, 0, 32, INT_MAX),
    OPT_STRING("format", lavfdopts.format, 0),
    OPT_INTRANGE("analyzeduration", lavfdopts.analyzeduration, 0, 0, INT_MAX),
    OPT_STRING("cryptokey", lavfdopts.cryptokey, 0),
    OPT_STRING("o", lavfdopts.avopt, 0),
    {NULL, NULL, 0, 0, 0, 0, NULL}
};

#define BIO_BUFFER_SIZE 32768

typedef struct lavf_priv {
    AVInputFormat *avif;
    AVFormatContext *avfc;
    AVIOContext *pb;
    uint8_t buffer[BIO_BUFFER_SIZE];
    int audio_streams;
    int video_streams;
    int sub_streams;
    int64_t last_pts;
    int astreams[MAX_A_STREAMS];
    int vstreams[MAX_V_STREAMS];
    int sstreams[MAX_S_STREAMS];
    int cur_program;
    int nb_streams_last;
    bool internet_radio_hack;
    bool use_dts;
    bool seek_by_bytes;
    int bitrate;
} lavf_priv_t;

static int mp_read(void *opaque, uint8_t *buf, int size)
{
    struct demuxer *demuxer = opaque;
    struct stream *stream = demuxer->stream;
    int ret;

    ret = stream_read(stream, buf, size);

    mp_msg(MSGT_HEADER, MSGL_DBG2,
           "%d=mp_read(%p, %p, %d), pos: %"PRId64", eof:%d\n",
           ret, stream, buf, size, stream_tell(stream), stream->eof);
    return ret;
}

static int64_t mp_seek(void *opaque, int64_t pos, int whence)
{
    struct demuxer *demuxer = opaque;
    struct stream *stream = demuxer->stream;
    int64_t current_pos;
    mp_msg(MSGT_HEADER, MSGL_DBG2, "mp_seek(%p, %"PRId64", %d)\n",
           stream, pos, whence);
    if (whence == SEEK_CUR)
        pos += stream_tell(stream);
    else if (whence == SEEK_END && stream->end_pos > 0)
        pos += stream->end_pos;
    else if (whence == SEEK_SET)
        pos += stream->start_pos;
    else if (whence == AVSEEK_SIZE && stream->end_pos > 0) {
        off_t size;
        if (stream_control(stream, STREAM_CTRL_GET_SIZE, &size) == STREAM_OK)
            return size;
        return stream->end_pos - stream->start_pos;
    } else
        return -1;

    if (pos < 0)
        return -1;
    current_pos = stream_tell(stream);
    if (stream_seek(stream, pos) == 0) {
        stream_reset(stream);
        stream_seek(stream, current_pos);
        return -1;
    }

    return pos - stream->start_pos;
}

static int64_t mp_read_seek(void *opaque, int stream_idx, int64_t ts, int flags)
{
    struct demuxer *demuxer = opaque;
    struct stream *stream = demuxer->stream;
    struct lavf_priv *priv = demuxer->priv;

    AVStream *st = priv->avfc->streams[stream_idx];
    double pts = (double)ts * st->time_base.num / st->time_base.den;
    int ret = stream_control(stream, STREAM_CTRL_SEEK_TO_TIME, &pts);
    if (ret < 0)
        ret = AVERROR(ENOSYS);
    return ret;
}

static void list_formats(void)
{
    mp_msg(MSGT_DEMUX, MSGL_INFO, "Available lavf input formats:\n");
    AVInputFormat *fmt = NULL;
    while ((fmt = av_iformat_next(fmt)))
        mp_msg(MSGT_DEMUX, MSGL_INFO, "%15s : %s\n", fmt->name, fmt->long_name);
}

static int lavf_check_file(demuxer_t *demuxer)
{
    struct MPOpts *opts = demuxer->opts;
    struct lavfdopts *lavfdopts = &opts->lavfdopts;
    AVProbeData avpd;
    lavf_priv_t *priv;
    int probe_data_size = 0;
    int read_size = INITIAL_PROBE_SIZE;
    int score;

    if (!demuxer->priv)
        demuxer->priv = calloc(sizeof(lavf_priv_t), 1);
    priv = demuxer->priv;

    char *format = lavfdopts->format;
    if (!format)
        format = demuxer->stream->lavf_type;
    if (format) {
        if (strcmp(format, "help") == 0) {
            list_formats();
            return 0;
        }
        priv->avif = av_find_input_format(format);
        if (!priv->avif) {
            mp_msg(MSGT_DEMUX, MSGL_FATAL, "Unknown lavf format %s\n", format);
            return 0;
        }
        mp_msg(MSGT_DEMUX, MSGL_INFO, "Forced lavf %s demuxer\n",
               priv->avif->long_name);
        return DEMUXER_TYPE_LAVF;
    }

    avpd.buf = av_mallocz(FFMAX(BIO_BUFFER_SIZE, PROBE_BUF_SIZE) +
                          FF_INPUT_BUFFER_PADDING_SIZE);
    do {
        read_size = stream_read(demuxer->stream, avpd.buf + probe_data_size,
                                read_size);
        if (read_size < 0) {
            av_free(avpd.buf);
            return 0;
        }
        probe_data_size += read_size;
        avpd.filename = demuxer->stream->url;
        if (!avpd.filename) {
            mp_msg(MSGT_DEMUX, MSGL_WARN, "Stream url is not set!\n");
            avpd.filename = "";
        }
        if (!strncmp(avpd.filename, "ffmpeg://", 9))
            avpd.filename += 9;
        avpd.buf_size = probe_data_size;

        score = 0;
        priv->avif = av_probe_input_format2(&avpd, probe_data_size > 0, &score);
        read_size = FFMIN(2 * read_size, PROBE_BUF_SIZE - probe_data_size);
    } while ((demuxer->desc->type != DEMUXER_TYPE_LAVF_PREFERRED ||
              probe_data_size < SMALL_MAX_PROBE_SIZE) &&
             score <= AVPROBE_SCORE_MAX / 4 &&
             read_size > 0 && probe_data_size < PROBE_BUF_SIZE);
    av_free(avpd.buf);

    if (!priv->avif || score <= AVPROBE_SCORE_MAX / 4) {
        mp_msg(MSGT_HEADER, MSGL_V,
               "LAVF_check: no clue about this gibberish!\n");
        return 0;
    } else
        mp_msg(MSGT_HEADER, MSGL_V, "LAVF_check: %s\n", priv->avif->long_name);

    demuxer->filetype = priv->avif->long_name;
    if (!demuxer->filetype)
        demuxer->filetype = priv->avif->name;

    return DEMUXER_TYPE_LAVF;
}

static bool matches_avinputformat_name(struct lavf_priv *priv,
                                       const char *name)
{
    const char *avifname = priv->avif->name;
    while (1) {
        const char *next = strchr(avifname, ',');
        if (!next)
            return !strcmp(avifname, name);
        int len = next - avifname;
        if (len == strlen(name) && !memcmp(avifname, name, len))
            return true;
        avifname = next + 1;
    }
}

/* formats for which an internal demuxer is preferred */
static const char * const preferred_internal[] = {
    /* lavf Matroska demuxer doesn't support ordered chapters and fails
     * for more files */
    "matroska",
    NULL
};

static int lavf_check_preferred_file(demuxer_t *demuxer)
{
    if (lavf_check_file(demuxer)) {
        const char * const *p;
        lavf_priv_t *priv = demuxer->priv;
        for (p = preferred_internal; *p; p++)
            if (matches_avinputformat_name(priv, *p))
                return 0;
        return DEMUXER_TYPE_LAVF_PREFERRED;
    }
    return 0;
}

static uint8_t char2int(char c)
{
    if (c >= '0' && c <= '9') return c - '0';
    if (c >= 'a' && c <= 'f') return c - 'a' + 10;
    if (c >= 'A' && c <= 'F') return c - 'A' + 10;
    return 0;
}

static void parse_cryptokey(AVFormatContext *avfc, const char *str)
{
    int len = strlen(str) / 2;
    uint8_t *key = av_mallocz(len);
    int i;
    avfc->keylen = len;
    avfc->key = key;
    for (i = 0; i < len; i++, str += 2)
        *key++ = (char2int(str[0]) << 4) | char2int(str[1]);
}

static void handle_stream(demuxer_t *demuxer, AVFormatContext *avfc, int i)
{
    lavf_priv_t *priv = demuxer->priv;
    AVStream *st = avfc->streams[i];
    AVCodecContext *codec = st->codec;
    char *stream_type = NULL;
    int stream_id;
    AVDictionaryEntry *lang = av_dict_get(st->metadata, "language", NULL, 0);
    AVDictionaryEntry *title = av_dict_get(st->metadata, "title", NULL, 0);
    // 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") ||
            matches_avinputformat_name(priv, "mpegts"))
        codec->codec_tag = 0;
    int override_tag = mp_taglist_override(codec->codec_id);
    // For some formats (like PCM) always trust CODEC_ID_* more than codec_tag
    if (override_tag)
        codec->codec_tag = override_tag;

    AVCodec *avc = avcodec_find_decoder(codec->codec_id);
    const char *codec_name = avc ? avc->name : "unknown";

    switch (codec->codec_type) {
    case AVMEDIA_TYPE_AUDIO: {
        WAVEFORMATEX *wf;
        sh_audio_t *sh_audio;
        sh_audio = new_sh_audio_aid(demuxer, i, priv->audio_streams);
        if (!sh_audio)
            break;
        sh_audio->demuxer_id = i;
        sh_audio->demuxer_codecname = codec_name;
        stream_type = "audio";
        priv->astreams[priv->audio_streams] = i;
        sh_audio->libav_codec_id = codec->codec_id;
        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'))
            codec->codec_tag = 0;
        if (!codec->codec_tag)
            codec->codec_tag = mp_taglist_audio(codec->codec_id);
        wf->wFormatTag = codec->codec_tag;
        wf->nChannels = codec->channels;
        wf->nSamplesPerSec = codec->sample_rate;
        wf->nAvgBytesPerSec = codec->bit_rate / 8;
        wf->nBlockAlign = codec->block_align ? codec->block_align : 1;
        wf->wBitsPerSample = codec->bits_per_coded_sample;
        wf->cbSize = codec->extradata_size;
        if (codec->extradata_size)
            memcpy(wf + 1, codec->extradata, codec->extradata_size);
        sh_audio->wf = wf;
        sh_audio->audio.dwSampleSize = codec->block_align;
        if (codec->frame_size && codec->sample_rate) {
            sh_audio->audio.dwScale = codec->frame_size;
            sh_audio->audio.dwRate = codec->sample_rate;
        } else {
            sh_audio->audio.dwScale = codec->block_align ? codec->block_align * 8 : 8;
            sh_audio->audio.dwRate = codec->bit_rate;
        }
        int g = av_gcd(sh_audio->audio.dwScale, sh_audio->audio.dwRate);
        sh_audio->audio.dwScale /= g;
        sh_audio->audio.dwRate  /= g;
//          printf("sca:%d rat:%d fs:%d sr:%d ba:%d\n", sh_audio->audio.dwScale, sh_audio->audio.dwRate, codec->frame_size, codec->sample_rate, codec->block_align);
        sh_audio->ds = demuxer->audio;
        sh_audio->format = codec->codec_tag;
        sh_audio->channels = codec->channels;
        sh_audio->samplerate = codec->sample_rate;
        sh_audio->i_bps = codec->bit_rate / 8;
        switch (codec->codec_id) {
        case CODEC_ID_PCM_S8:
        case CODEC_ID_PCM_U8:
            sh_audio->samplesize = 1;
            break;
        case CODEC_ID_PCM_S16LE:
        case CODEC_ID_PCM_S16BE:
        case CODEC_ID_PCM_U16LE:
        case CODEC_ID_PCM_U16BE:
            sh_audio->samplesize = 2;
            break;
        case CODEC_ID_PCM_ALAW:
            sh_audio->format = 0x6;
            break;
        case CODEC_ID_PCM_MULAW:
            sh_audio->format = 0x7;
            break;
        }
        if (title && title->value) {
            sh_audio->title = talloc_strdup(sh_audio, title->value);
            mp_msg(MSGT_IDENTIFY, MSGL_INFO, "ID_AID_%d_NAME=%s\n",
                   priv->audio_streams, title->value);
        }
        if (lang && lang->value) {
            sh_audio->lang = talloc_strdup(sh_audio, lang->value);
            mp_msg(MSGT_IDENTIFY, MSGL_INFO, "ID_AID_%d_LANG=%s\n",
                   priv->audio_streams, sh_audio->lang);
        }
        if (st->disposition & AV_DISPOSITION_DEFAULT)
            sh_audio->default_track = 1;
        if (mp_msg_test(MSGT_HEADER, MSGL_V))
            print_wave_header(sh_audio->wf, MSGL_V);
        st->discard = AVDISCARD_ALL;
        stream_id = priv->audio_streams++;
        break;
    }
    case AVMEDIA_TYPE_VIDEO: {
        sh_video_t *sh_video;
        BITMAPINFOHEADER *bih;
        sh_video = new_sh_video_vid(demuxer, i, priv->video_streams);
        if (!sh_video)
            break;
        sh_video->demuxer_id = i;
        sh_video->demuxer_codecname = codec_name;
        stream_type = "video";
        priv->vstreams[priv->video_streams] = i;
        sh_video->libav_codec_id = codec->codec_id;
        bih = calloc(sizeof(*bih) + codec->extradata_size, 1);

        if (codec->codec_id == CODEC_ID_RAWVIDEO) {
            switch (codec->pix_fmt) {
            case PIX_FMT_RGB24:
                codec->codec_tag = MKTAG(24, 'B', 'G', 'R');
            case PIX_FMT_BGR24:
                codec->codec_tag = MKTAG(24, 'R', 'G', 'B');
            }
            if (!codec->codec_tag)
                codec->codec_tag = avcodec_pix_fmt_to_codec_tag(codec->pix_fmt);
        } else if (!codec->codec_tag) {
            codec->codec_tag = mp_taglist_video(codec->codec_id);
            /* 0 might mean either unset or rawvideo; if codec_id
             * was not RAWVIDEO assume it's unset
             */
            if (!codec->codec_tag)
                codec->codec_tag = -1;
        }
        bih->biSize = sizeof(*bih) + codec->extradata_size;
        bih->biWidth = codec->width;
        bih->biHeight = codec->height;
        bih->biBitCount = codec->bits_per_coded_sample;
        bih->biSizeImage = bih->biWidth * bih->biHeight * bih->biBitCount / 8;
        bih->biCompression = codec->codec_tag;
        sh_video->bih = bih;
        sh_video->disp_w = codec->width;
        sh_video->disp_h = codec->height;
        if (st->time_base.den) {     /* if container has time_base, use that */
            sh_video->video.dwRate = st->time_base.den;
            sh_video->video.dwScale = st->time_base.num;
        } else {
            sh_video->video.dwRate = codec->time_base.den;
            sh_video->video.dwScale = codec->time_base.num;
        }
        /* Try to make up some frame rate value, even if it's not reliable.
         * FPS information is needed to support subtitle formats which base
         * timing on frame numbers.
         * Libavformat seems to report no "reliable" FPS value for AVI files,
         * while they are typically constant enough FPS that the value this
         * heuristic makes up works with subtitles in practice.
         */
        double fps;
        if (st->r_frame_rate.num)
            fps = av_q2d(st->r_frame_rate);
        else
            fps = 1.0 / FFMAX(av_q2d(st->time_base),
                              av_q2d(st->codec->time_base) *
                              st->codec->ticks_per_frame);
        sh_video->fps = fps;
        sh_video->frametime = 1 / fps;
        sh_video->format = bih->biCompression;
        if (st->sample_aspect_ratio.num)
            sh_video->aspect = codec->width  * st->sample_aspect_ratio.num
                    / (float)(codec->height * st->sample_aspect_ratio.den);
        else
            sh_video->aspect = codec->width  * codec->sample_aspect_ratio.num
                    / (float)(codec->height * codec->sample_aspect_ratio.den);
        sh_video->i_bps = codec->bit_rate / 8;
        if (title && title->value) {
            sh_video->title = talloc_strdup(sh_video, title->value);
            mp_msg(MSGT_IDENTIFY, MSGL_INFO, "ID_VID_%d_NAME=%s\n",
                   priv->video_streams, title->value);
        }
        mp_msg(MSGT_DEMUX, MSGL_DBG2, "aspect= %d*%d/(%d*%d)\n",
               codec->width, codec->sample_aspect_ratio.num,
               codec->height, codec->sample_aspect_ratio.den);

        sh_video->ds = demuxer->video;
        if (codec->extradata_size)
            memcpy(sh_video->bih + 1, codec->extradata, codec->extradata_size);
        if ( mp_msg_test(MSGT_HEADER, MSGL_V))
            print_video_header(sh_video->bih, MSGL_V);
        if (demuxer->video->id != priv->video_streams
            && demuxer->video->id != -1)
            st->discard = AVDISCARD_ALL;
        else {
            demuxer->video->id = i;
            demuxer->video->sh = demuxer->v_streams[i];
        }
        stream_id = priv->video_streams++;
        break;
    }
    case AVMEDIA_TYPE_SUBTITLE: {
        sh_sub_t *sh_sub;
        char type;
        /* only support text subtitles for now */
        if (codec->codec_id == CODEC_ID_TEXT)
            type = 't';
        else if (codec->codec_id == CODEC_ID_MOV_TEXT)
            type = 'm';
        else if (codec->codec_id == CODEC_ID_SSA)
            type = 'a';
        else if (codec->codec_id == CODEC_ID_DVD_SUBTITLE)
            type = 'v';
        else if (codec->codec_id == CODEC_ID_XSUB)
            type = 'x';
        else if (codec->codec_id == CODEC_ID_DVB_SUBTITLE)
            type = 'b';
        else if (codec->codec_id == CODEC_ID_DVB_TELETEXT)
            type = 'd';
        else if (codec->codec_id == CODEC_ID_HDMV_PGS_SUBTITLE)
            type = 'p';
        else
            break;
        sh_sub = new_sh_sub_sid(demuxer, i, priv->sub_streams);
        if (!sh_sub)
            break;
        sh_sub->demuxer_id = i;
        sh_sub->demuxer_codecname = codec_name;
        stream_type = "subtitle";
        priv->sstreams[priv->sub_streams] = i;
        sh_sub->libav_codec_id = codec->codec_id;
        sh_sub->type = type;
        if (codec->extradata_size) {
            sh_sub->extradata = malloc(codec->extradata_size);
            memcpy(sh_sub->extradata, codec->extradata, codec->extradata_size);
            sh_sub->extradata_len = codec->extradata_size;
        }
        if (title && title->value) {
            sh_sub->title = talloc_strdup(sh_sub, title->value);
            mp_msg(MSGT_IDENTIFY, MSGL_INFO, "ID_SID_%d_NAME=%s\n",
                   priv->sub_streams, title->value);
        }
        if (lang && lang->value) {
            sh_sub->lang = talloc_strdup(sh_sub, lang->value);
            mp_msg(MSGT_IDENTIFY, MSGL_INFO, "ID_SID_%d_LANG=%s\n",
                   priv->sub_streams, sh_sub->lang);
        }
        if (st->disposition & AV_DISPOSITION_DEFAULT)
            sh_sub->default_track = 1;
        stream_id = priv->sub_streams++;
        break;
    }
    case AVMEDIA_TYPE_ATTACHMENT: {
        AVDictionaryEntry *ftag = av_dict_get(st->metadata, "filename",
                                              NULL, 0);
        char *filename = ftag ? ftag->value : NULL;
        if (st->codec->codec_id == CODEC_ID_TTF)
            demuxer_add_attachment(demuxer, bstr0(filename),
                                   bstr0("application/x-truetype-font"),
                                   (struct bstr){codec->extradata,
                                                 codec->extradata_size});
        break;
    }
    default:
        st->discard = AVDISCARD_ALL;
    }
    if (stream_type) {
        if (!avc && *stream_type == 's' && demuxer->s_streams[i])
            codec_name = sh_sub_type2str((demuxer->s_streams[i])->type);
        mp_msg(MSGT_DEMUX, MSGL_V, "[lavf] stream %d: %s (%s), -%cid %d",
               i, stream_type, codec_name, *stream_type, stream_id);
        if (lang && lang->value && *stream_type != 'v')
            mp_msg(MSGT_DEMUX, MSGL_V, ", -%clang %s",
                   *stream_type, lang->value);
        if (title && title->value)
            mp_msg(MSGT_DEMUX, MSGL_V, ", %s", title->value);
        mp_msg(MSGT_DEMUX, MSGL_V, "\n");
    }
}

static demuxer_t *demux_open_lavf(demuxer_t *demuxer)
{
    struct MPOpts *opts = demuxer->opts;
    struct lavfdopts *lavfdopts = &opts->lavfdopts;
    AVFormatContext *avfc;
    AVDictionaryEntry *t = NULL;
    lavf_priv_t *priv = demuxer->priv;
    int i;
    char mp_filename[256] = "mp:";

    stream_seek(demuxer->stream, 0);

    avfc = avformat_alloc_context();

    if (lavfdopts->cryptokey)
        parse_cryptokey(avfc, lavfdopts->cryptokey);
    if (matches_avinputformat_name(priv, "avi")) {
        /* for avi libavformat returns the avi timestamps in .dts,
         * some made-up stuff that's not really pts in .pts */
        priv->use_dts = true;
        demuxer->timestamp_type = TIMESTAMP_TYPE_SORT;
    } else {
        if (opts->user_correct_pts != 0)
            avfc->flags |= AVFMT_FLAG_GENPTS;
    }
    if (index_mode == 0)
        avfc->flags |= AVFMT_FLAG_IGNIDX;

    if (lavfdopts->probesize) {
        if (av_opt_set_int(avfc, "probesize", lavfdopts->probesize, 0) < 0)
            mp_msg(MSGT_HEADER, MSGL_ERR,
                   "demux_lavf, couldn't set option probesize to %u\n",
                   lavfdopts->probesize);
    }
    if (lavfdopts->analyzeduration) {
        if (av_opt_set_int(avfc, "analyzeduration",
                           lavfdopts->analyzeduration * AV_TIME_BASE, 0) < 0)
            mp_msg(MSGT_HEADER, MSGL_ERR, "demux_lavf, couldn't set option "
                   "analyzeduration to %u\n", lavfdopts->analyzeduration);
    }

    if (lavfdopts->avopt) {
        if (parse_avopts(avfc, lavfdopts->avopt) < 0) {
            mp_msg(MSGT_HEADER, MSGL_ERR,
                   "Your options /%s/ look like gibberish to me pal\n",
                   lavfdopts->avopt);
            return NULL;
        }
    }

    if (demuxer->stream->url) {
        if (!strncmp(demuxer->stream->url, "ffmpeg://rtsp:", 14))
            av_strlcpy(mp_filename, demuxer->stream->url + 9,
                       sizeof(mp_filename));
        else
            av_strlcat(mp_filename, demuxer->stream->url, sizeof(mp_filename));
    } else
        av_strlcat(mp_filename, "foobar.dummy", sizeof(mp_filename));

    if (!(priv->avif->flags & AVFMT_NOFILE)) {
        priv->pb = avio_alloc_context(priv->buffer, BIO_BUFFER_SIZE, 0,
                                      demuxer, mp_read, NULL, mp_seek);
        priv->pb->read_seek = mp_read_seek;
        priv->pb->seekable = demuxer->stream->end_pos
                 && (demuxer->stream->flags & MP_STREAM_SEEK) == MP_STREAM_SEEK
                ? AVIO_SEEKABLE_NORMAL : 0;
        avfc->pb = priv->pb;
    }

    if (avformat_open_input(&avfc, mp_filename, priv->avif, NULL) < 0) {
        mp_msg(MSGT_HEADER, MSGL_ERR,
               "LAVF_header: avformat_open_input() failed\n");
        return NULL;
    }

    priv->avfc = avfc;

    if (avformat_find_stream_info(avfc, NULL) < 0) {
        mp_msg(MSGT_HEADER, MSGL_ERR,
               "LAVF_header: av_find_stream_info() failed\n");
        return NULL;
    }

    /* Add metadata. */
    while ((t = av_dict_get(avfc->metadata, "", t,
                            AV_DICT_IGNORE_SUFFIX)))
        demux_info_add(demuxer, t->key, t->value);

    for (i = 0; i < avfc->nb_chapters; i++) {
        AVChapter *c = avfc->chapters[i];
        uint64_t start = av_rescale_q(c->start, c->time_base,
                                      (AVRational){1, 1000000000});
        uint64_t end   = av_rescale_q(c->end, c->time_base,
                                      (AVRational){1, 1000000000});
        t = av_dict_get(c->metadata, "title", NULL, 0);
        demuxer_add_chapter(demuxer, t ? bstr0(t->value) : bstr0(NULL),
                            start, end);
    }

    for (i = 0; i < avfc->nb_streams; i++)
        handle_stream(demuxer, avfc, i);
    priv->nb_streams_last = avfc->nb_streams;

    if (avfc->nb_programs) {
        int p;
        for (p = 0; p < avfc->nb_programs; p++) {
            AVProgram *program = avfc->programs[p];
            t = av_dict_get(program->metadata, "title", NULL, 0);
            mp_msg(MSGT_HEADER, MSGL_INFO, "LAVF: Program %d %s\n",
                   program->id, t ? t->value : "");
            mp_msg(MSGT_IDENTIFY, MSGL_V, "PROGRAM_ID=%d\n", program->id);
        }
    }

    mp_msg(MSGT_HEADER, MSGL_V, "LAVF: %d audio and %d video streams found\n",
           priv->audio_streams, priv->video_streams);
    mp_msg(MSGT_HEADER, MSGL_V, "LAVF: build %d\n", LIBAVFORMAT_BUILD);
    demuxer->audio->id = -2;  // wait for higher-level code to select track
    if (!priv->video_streams) {
        if (!priv->audio_streams) {
            mp_msg(MSGT_HEADER, MSGL_ERR,
                   "LAVF: no audio or video headers found - broken file?\n");
            return NULL;
        }
        demuxer->video->id = -2; // audio-only
    }

    // disabled because unreliable per-stream bitrate values returned
    // by libavformat trigger this heuristic incorrectly and break things
#if 0
    /* libavformat sets bitrate for mpeg based on pts at start and end
     * of file, which fails for files with pts resets. So calculate our
     * own bitrate estimate. */
    if (priv->avif->flags & AVFMT_TS_DISCONT) {
        for (int i = 0; i < avfc->nb_streams; i++)
            priv->bitrate += avfc->streams[i]->codec->bit_rate;
        /* pts-based is more accurate if there are no resets; try to make
         * a somewhat reasonable guess */
        if (!avfc->duration || avfc->duration == AV_NOPTS_VALUE
            || priv->bitrate && (avfc->bit_rate < priv->bitrate / 2
                                 || avfc->bit_rate > priv->bitrate * 2))
            priv->seek_by_bytes = true;
        if (!priv->bitrate)
            priv->bitrate = 1440000;
    }
#endif
    demuxer->accurate_seek = !priv->seek_by_bytes;

    return demuxer;
}

static void check_internet_radio_hack(struct demuxer *demuxer)
{
    struct lavf_priv *priv = demuxer->priv;
    struct AVFormatContext *avfc = priv->avfc;

    if (!matches_avinputformat_name(priv, "ogg"))
        return;
    if (priv->nb_streams_last == avfc->nb_streams)
        return;
    if (avfc->nb_streams - priv->nb_streams_last == 1
        && priv->video_streams == 0 && priv->sub_streams == 0
        && demuxer->a_streams[priv->audio_streams - 1]->format == 0x566f // vorbis
        && (priv->audio_streams == 2 || priv->internet_radio_hack)
        && demuxer->a_streams[0]->format == 0x566f) {
        // extradata match could be checked but would require parsing
        // headers, as the comment section will vary
        if (!priv->internet_radio_hack) {
            mp_msg(MSGT_DEMUX, MSGL_V,
                   "[lavf] enabling internet ogg radio hack\n");
        }
        priv->internet_radio_hack = true;
        // use new per-track metadata as global metadata
        AVDictionaryEntry *t = NULL;
        AVStream *stream = avfc->streams[avfc->nb_streams - 1];
        while ((t = av_dict_get(stream->metadata, "", t,
                                AV_DICT_IGNORE_SUFFIX)))
            demux_info_add(demuxer, t->key, t->value);
    } else {
        if (priv->internet_radio_hack)
            mp_tmsg(MSGT_DEMUX, MSGL_WARN, "[lavf] Internet radio ogg hack "
                    "was enabled, but stream characteristics changed.\n"
                    "This may or may not work.\n");
        priv->internet_radio_hack = false;
    }
}

static int destroy_avpacket(void *pkt)
{
    av_free_packet(pkt);
    return 0;
}

static int demux_lavf_fill_buffer(demuxer_t *demux, demux_stream_t *dsds)
{
    lavf_priv_t *priv = demux->priv;
    demux_packet_t *dp;
    demux_stream_t *ds;
    int id;
    mp_msg(MSGT_DEMUX, MSGL_DBG2, "demux_lavf_fill_buffer()\n");

    demux->filepos = stream_tell(demux->stream);

    AVPacket *pkt = talloc(NULL, AVPacket);
    if (av_read_frame(priv->avfc, pkt) < 0) {
        talloc_free(pkt);
        return 0;
    }
    talloc_set_destructor(pkt, destroy_avpacket);

    // handle any new streams that might have been added
    for (id = priv->nb_streams_last; id < priv->avfc->nb_streams; id++)
        handle_stream(demux, priv->avfc, id);
    check_internet_radio_hack(demux);

    priv->nb_streams_last = priv->avfc->nb_streams;

    id = pkt->stream_index;

    if (id == demux->audio->id || priv->internet_radio_hack) {
        // audio
        ds = demux->audio;
        if (!ds->sh) {
            ds->sh = demux->a_streams[id];
            mp_msg(MSGT_DEMUX, MSGL_V, "Auto-selected LAVF audio ID = %d\n",
                   ds->id);
        }
    } else if (id == demux->video->id) {
        // video
        ds = demux->video;
        if (!ds->sh) {
            ds->sh = demux->v_streams[id];
            mp_msg(MSGT_DEMUX, MSGL_V, "Auto-selected LAVF video ID = %d\n",
                   ds->id);
        }
    } else if (id == demux->sub->id) {
        // subtitle
        ds = demux->sub;
        sub_utf8 = 1;
    } else {
        talloc_free(pkt);
        return 1;
    }

    // If the packet has pointers to temporary fields that could be
    // overwritten/freed by next av_read_frame(), copy them to persistent
    // allocations so we can safely queue the packet for any length of time.
    if (av_dup_packet(pkt) < 0)
        abort();
    dp = new_demux_packet_fromdata(pkt->data, pkt->size);
    dp->avpacket = pkt;

    int64_t ts = priv->use_dts ? pkt->dts : pkt->pts;
    if (ts != AV_NOPTS_VALUE) {
        dp->pts = ts * av_q2d(priv->avfc->streams[id]->time_base);
        priv->last_pts = dp->pts * AV_TIME_BASE;
        // always set duration for subtitles, even if AV_PKT_FLAG_KEY isn't set,
        // otherwise they will stay on screen to long if e.g. ASS is demuxed
        // from mkv
        if ((ds == demux->sub || (pkt->flags & AV_PKT_FLAG_KEY)) &&
            pkt->convergence_duration > 0)
            dp->duration = pkt->convergence_duration *
                av_q2d(priv->avfc->streams[id]->time_base);
    }
    dp->pos = demux->filepos;
    dp->keyframe = pkt->flags & AV_PKT_FLAG_KEY;
    // append packet to DS stream:
    ds_add_packet(ds, dp);
    return 1;
}

static void demux_seek_lavf(demuxer_t *demuxer, float rel_seek_secs,
                            float audio_delay, int flags)
{
    lavf_priv_t *priv = demuxer->priv;
    int avsflags = 0;
    mp_msg(MSGT_DEMUX, MSGL_DBG2, "demux_seek_lavf(%p, %f, %f, %d)\n",
           demuxer, rel_seek_secs, audio_delay, flags);

    if (priv->seek_by_bytes) {
        int64_t pos = demuxer->filepos;
        rel_seek_secs *= priv->bitrate / 8;
        pos += rel_seek_secs;
        av_seek_frame(priv->avfc, -1, pos, AVSEEK_FLAG_BYTE);
        return;
    }

    if (flags & SEEK_ABSOLUTE)
        priv->last_pts = 0;
    else if (rel_seek_secs < 0)
        avsflags = AVSEEK_FLAG_BACKWARD;
    if (flags & SEEK_FORWARD)
        avsflags = 0;
    else if (flags & SEEK_BACKWARD)
        avsflags = AVSEEK_FLAG_BACKWARD;
    if (flags & SEEK_FACTOR) {
        if (priv->avfc->duration == 0 || priv->avfc->duration == AV_NOPTS_VALUE)
            return;
        priv->last_pts += rel_seek_secs * priv->avfc->duration;
    } else
        priv->last_pts += rel_seek_secs * AV_TIME_BASE;
    if (av_seek_frame(priv->avfc, -1, priv->last_pts, avsflags) < 0) {
        avsflags ^= AVSEEK_FLAG_BACKWARD;
        av_seek_frame(priv->avfc, -1, priv->last_pts, avsflags);
    }
}

static int demux_lavf_control(demuxer_t *demuxer, int cmd, void *arg)
{
    lavf_priv_t *priv = demuxer->priv;

    switch (cmd) {
    case DEMUXER_CTRL_CORRECT_PTS:
        return DEMUXER_CTRL_OK;
    case DEMUXER_CTRL_GET_TIME_LENGTH:
        if (priv->seek_by_bytes) {
            /* Our bitrate estimate may be better than would be used in
             * otherwise similar fallback code at higher level */
            if (demuxer->movi_end <= 0)
                return DEMUXER_CTRL_DONTKNOW;
            *(double *)arg = (demuxer->movi_end - demuxer->movi_start) * 8 /
                             priv->bitrate;
            return DEMUXER_CTRL_GUESS;
        }
        if (priv->avfc->duration == 0 || priv->avfc->duration == AV_NOPTS_VALUE)
            return DEMUXER_CTRL_DONTKNOW;

        *((double *)arg) = (double)priv->avfc->duration / AV_TIME_BASE;
        return DEMUXER_CTRL_OK;

    case DEMUXER_CTRL_GET_PERCENT_POS:
        if (priv->seek_by_bytes)
            return DEMUXER_CTRL_DONTKNOW;  // let it use the fallback code
        if (priv->avfc->duration == 0 || priv->avfc->duration == AV_NOPTS_VALUE)
            return DEMUXER_CTRL_DONTKNOW;

        *((int *)arg) = (int)((priv->last_pts - priv->avfc->start_time) * 100 /
                              priv->avfc->duration);
        return DEMUXER_CTRL_OK;
    case DEMUXER_CTRL_SWITCH_AUDIO:
    case DEMUXER_CTRL_SWITCH_VIDEO:
    {
        int id = *((int *)arg);
        int newid = -2;
        int i, curridx = -1;
        int nstreams, *pstreams;
        demux_stream_t *ds;

        if (cmd == DEMUXER_CTRL_SWITCH_VIDEO) {
            ds = demuxer->video;
            nstreams = priv->video_streams;
            pstreams = priv->vstreams;
        } else {
            ds = demuxer->audio;
            nstreams = priv->audio_streams;
            pstreams = priv->astreams;
        }
        for (i = 0; i < nstreams; i++) {
            if (pstreams[i] == ds->id) {  //current stream id
                curridx = i;
                break;
            }
        }

        if (id == -1) {       // next track
            i = (curridx + 2) % (nstreams + 1) - 1;
            if (i >= 0)
                newid = pstreams[i];
        } else if (id >= 0 && id < nstreams) {       // select track by id
            i = id;
            newid = pstreams[i];
        } else       // no sound
            i = -1;

        if (i == curridx) {
            *(int *) arg = curridx < 0 ? -2 : curridx;
            return DEMUXER_CTRL_OK;
        } else {
            ds_free_packs(ds);
            if (ds->id >= 0)
                priv->avfc->streams[ds->id]->discard = AVDISCARD_ALL;
            ds->id = newid;
            *(int *) arg = i < 0 ? -2 : i;
            if (newid >= 0)
                priv->avfc->streams[newid]->discard = AVDISCARD_NONE;
            return DEMUXER_CTRL_OK;
        }
    }
    case DEMUXER_CTRL_IDENTIFY_PROGRAM:
    {
        demux_program_t *prog = arg;
        AVProgram *program;
        int p, i;
        int start;

        prog->vid = prog->aid = prog->sid = -2;
        if (priv->avfc->nb_programs < 1)
            return DEMUXER_CTRL_DONTKNOW;

        if (prog->progid == -1) {
            p = 0;
            while (p < priv->avfc->nb_programs && priv->avfc->programs[p]->id != priv->cur_program)
                p++;
            p = (p + 1) % priv->avfc->nb_programs;
        } else {
            for (i = 0; i < priv->avfc->nb_programs; i++)
                if (priv->avfc->programs[i]->id == prog->progid)
                    break;
            if (i == priv->avfc->nb_programs)
                return DEMUXER_CTRL_DONTKNOW;
            p = i;
        }
        start = p;
redo:
        program = priv->avfc->programs[p];
        for (i = 0; i < program->nb_stream_indexes; i++) {
            switch (priv->avfc->streams[program->stream_index[i]]->codec->codec_type) {
            case AVMEDIA_TYPE_VIDEO:
                if (prog->vid == -2)
                    prog->vid = program->stream_index[i];
                break;
            case AVMEDIA_TYPE_AUDIO:
                if (prog->aid == -2)
                    prog->aid = program->stream_index[i];
                break;
            case AVMEDIA_TYPE_SUBTITLE:
                if (prog->sid == -2 && priv->avfc->streams[program->stream_index[i]]->codec->codec_id == CODEC_ID_TEXT)
                    prog->sid = program->stream_index[i];
                break;
            }
        }
        if (prog->aid >= 0 && prog->aid < MAX_A_STREAMS &&
            demuxer->a_streams[prog->aid]) {
            sh_audio_t *sh = demuxer->a_streams[prog->aid];
            prog->aid = sh->aid;
        } else
            prog->aid = -2;
        if (prog->vid >= 0 && prog->vid < MAX_V_STREAMS &&
            demuxer->v_streams[prog->vid]) {
            sh_video_t *sh = demuxer->v_streams[prog->vid];
            prog->vid = sh->vid;
        } else
            prog->vid = -2;
        if (prog->progid == -1 && prog->vid == -2 && prog->aid == -2) {
            p = (p + 1) % priv->avfc->nb_programs;
            if (p == start)
                return DEMUXER_CTRL_DONTKNOW;
            goto redo;
        }
        priv->cur_program = prog->progid = program->id;
        return DEMUXER_CTRL_OK;
    }
    default:
        return DEMUXER_CTRL_NOTIMPL;
    }
}

static void demux_close_lavf(demuxer_t *demuxer)
{
    lavf_priv_t *priv = demuxer->priv;
    if (priv) {
        if (priv->avfc) {
            av_freep(&priv->avfc->key);
            avformat_close_input(&priv->avfc);
        }
        av_freep(&priv->pb);
        free(priv);
        demuxer->priv = NULL;
    }
}


const demuxer_desc_t demuxer_desc_lavf = {
    "libavformat demuxer",
    "lavf",
    "libavformat",
    "Michael Niedermayer",
    "supports many formats, requires libavformat",
    DEMUXER_TYPE_LAVF,
    0, // Check after other demuxer
    lavf_check_file,
    demux_lavf_fill_buffer,
    demux_open_lavf,
    demux_close_lavf,
    demux_seek_lavf,
    demux_lavf_control
};

const demuxer_desc_t demuxer_desc_lavf_preferred = {
    "libavformat preferred demuxer",
    "lavfpref",
    "libavformat",
    "Michael Niedermayer",
    "supports many formats, requires libavformat",
    DEMUXER_TYPE_LAVF_PREFERRED,
    1,
    lavf_check_preferred_file,
    demux_lavf_fill_buffer,
    demux_open_lavf,
    demux_close_lavf,
    demux_seek_lavf,
    demux_lavf_control
};