utils.c

/*
 * various utility functions for use within FFmpeg
 * Copyright (c) 2000, 2001, 2002 Fabrice Bellard
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg 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.
 *
 * FFmpeg 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 FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <stdarg.h>
#include <stdint.h>

#include "config.h"

#include "libavutil/avassert.h"
#include "libavutil/avstring.h"
#include "libavutil/dict.h"
#include "libavutil/internal.h"
#include "libavutil/mathematics.h"
#include "libavutil/opt.h"
#include "libavutil/parseutils.h"
#include "libavutil/pixdesc.h"
#include "libavutil/thread.h"
#include "libavutil/time.h"
#include "libavutil/time_internal.h"
#include "libavutil/timestamp.h"

#include "libavcodec/bytestream.h"
#include "libavcodec/internal.h"
#include "libavcodec/raw.h"

#include "audiointerleave.h"
#include "avformat.h"
#include "avio_internal.h"
#include "id3v2.h"
#include "internal.h"
#include "metadata.h"
#if CONFIG_NETWORK
#include "network.h"
#endif
#include "riff.h"
#include "url.h"

#include "libavutil/ffversion.h"
const char av_format_ffversion[] = "FFmpeg version " FFMPEG_VERSION;

static AVMutex avformat_mutex = AV_MUTEX_INITIALIZER;

/**
 * @file
 * various utility functions for use within FFmpeg
 */

unsigned avformat_version(void)
{
    av_assert0(LIBAVFORMAT_VERSION_MICRO >= 100);
    return LIBAVFORMAT_VERSION_INT;
}

const char *avformat_configuration(void)
{
    return FFMPEG_CONFIGURATION;
}

const char *avformat_license(void)
{
#define LICENSE_PREFIX "libavformat license: "
    return LICENSE_PREFIX FFMPEG_LICENSE + sizeof(LICENSE_PREFIX) - 1;
}

int ff_lock_avformat(void)
{
    return ff_mutex_lock(&avformat_mutex) ? -1 : 0;
}

int ff_unlock_avformat(void)
{
    return ff_mutex_unlock(&avformat_mutex) ? -1 : 0;
}

#define RELATIVE_TS_BASE (INT64_MAX - (1LL<<48))

static int is_relative(int64_t ts) {
    return ts > (RELATIVE_TS_BASE - (1LL<<48));
}

/**
 * Wrap a given time stamp, if there is an indication for an overflow
 *
 * @param st stream
 * @param timestamp the time stamp to wrap
 * @return resulting time stamp
 */
static int64_t wrap_timestamp(const AVStream *st, int64_t timestamp)
{
    if (st->pts_wrap_behavior != AV_PTS_WRAP_IGNORE &&
        st->pts_wrap_reference != AV_NOPTS_VALUE && timestamp != AV_NOPTS_VALUE) {
        if (st->pts_wrap_behavior == AV_PTS_WRAP_ADD_OFFSET &&
            timestamp < st->pts_wrap_reference)
            return timestamp + (1ULL << st->pts_wrap_bits);
        else if (st->pts_wrap_behavior == AV_PTS_WRAP_SUB_OFFSET &&
            timestamp >= st->pts_wrap_reference)
            return timestamp - (1ULL << st->pts_wrap_bits);
    }
    return timestamp;
}

#if FF_API_FORMAT_GET_SET
MAKE_ACCESSORS(AVStream, stream, AVRational, r_frame_rate)
#if FF_API_LAVF_FFSERVER
FF_DISABLE_DEPRECATION_WARNINGS
MAKE_ACCESSORS(AVStream, stream, char *, recommended_encoder_configuration)
FF_ENABLE_DEPRECATION_WARNINGS
#endif
MAKE_ACCESSORS(AVFormatContext, format, AVCodec *, video_codec)
MAKE_ACCESSORS(AVFormatContext, format, AVCodec *, audio_codec)
MAKE_ACCESSORS(AVFormatContext, format, AVCodec *, subtitle_codec)
MAKE_ACCESSORS(AVFormatContext, format, AVCodec *, data_codec)
MAKE_ACCESSORS(AVFormatContext, format, int, metadata_header_padding)
MAKE_ACCESSORS(AVFormatContext, format, void *, opaque)
MAKE_ACCESSORS(AVFormatContext, format, av_format_control_message, control_message_cb)
#if FF_API_OLD_OPEN_CALLBACKS
FF_DISABLE_DEPRECATION_WARNINGS
MAKE_ACCESSORS(AVFormatContext, format, AVOpenCallback, open_cb)
FF_ENABLE_DEPRECATION_WARNINGS
#endif
#endif

int64_t av_stream_get_end_pts(const AVStream *st)
{
    if (st->internal->priv_pts) {
        return st->internal->priv_pts->val;
    } else
        return AV_NOPTS_VALUE;
}

struct AVCodecParserContext *av_stream_get_parser(const AVStream *st)
{
    return st->parser;
}

void av_format_inject_global_side_data(AVFormatContext *s)
{
    int i;
    s->internal->inject_global_side_data = 1;
    for (i = 0; i < s->nb_streams; i++) {
        AVStream *st = s->streams[i];
        st->inject_global_side_data = 1;
    }
}

int ff_copy_whiteblacklists(AVFormatContext *dst, const AVFormatContext *src)
{
    av_assert0(!dst->codec_whitelist &&
               !dst->format_whitelist &&
               !dst->protocol_whitelist &&
               !dst->protocol_blacklist);
    dst-> codec_whitelist = av_strdup(src->codec_whitelist);
    dst->format_whitelist = av_strdup(src->format_whitelist);
    dst->protocol_whitelist = av_strdup(src->protocol_whitelist);
    dst->protocol_blacklist = av_strdup(src->protocol_blacklist);
    if (   (src-> codec_whitelist && !dst-> codec_whitelist)
        || (src->  format_whitelist && !dst->  format_whitelist)
        || (src->protocol_whitelist && !dst->protocol_whitelist)
        || (src->protocol_blacklist && !dst->protocol_blacklist)) {
        av_log(dst, AV_LOG_ERROR, "Failed to duplicate black/whitelist\n");
        return AVERROR(ENOMEM);
    }
    return 0;
}

static const AVCodec *find_decoder(AVFormatContext *s, const AVStream *st, enum AVCodecID codec_id)
{
#if FF_API_LAVF_AVCTX
FF_DISABLE_DEPRECATION_WARNINGS
    if (st->codec->codec)
        return st->codec->codec;
FF_ENABLE_DEPRECATION_WARNINGS
#endif

    switch (st->codecpar->codec_type) {
    case AVMEDIA_TYPE_VIDEO:
        if (s->video_codec)    return s->video_codec;
        break;
    case AVMEDIA_TYPE_AUDIO:
        if (s->audio_codec)    return s->audio_codec;
        break;
    case AVMEDIA_TYPE_SUBTITLE:
        if (s->subtitle_codec) return s->subtitle_codec;
        break;
    }

    return avcodec_find_decoder(codec_id);
}

static const AVCodec *find_probe_decoder(AVFormatContext *s, const AVStream *st, enum AVCodecID codec_id)
{
    const AVCodec *codec;

#if CONFIG_H264_DECODER
    /* Other parts of the code assume this decoder to be used for h264,
     * so force it if possible. */
    if (codec_id == AV_CODEC_ID_H264)
        return avcodec_find_decoder_by_name("h264");
#endif

    codec = find_decoder(s, st, codec_id);
    if (!codec)
        return NULL;

    if (codec->capabilities & AV_CODEC_CAP_AVOID_PROBING) {
        const AVCodec *probe_codec = NULL;
        while (probe_codec = av_codec_next(probe_codec)) {
            if (probe_codec->id == codec_id &&
                    av_codec_is_decoder(probe_codec) &&
                    !(probe_codec->capabilities & (AV_CODEC_CAP_AVOID_PROBING | AV_CODEC_CAP_EXPERIMENTAL))) {
                return probe_codec;
            }
        }
    }

    return codec;
}

#if FF_API_FORMAT_GET_SET
int av_format_get_probe_score(const AVFormatContext *s)
{
    return s->probe_score;
}
#endif

/* an arbitrarily chosen "sane" max packet size -- 50M */
#define SANE_CHUNK_SIZE (50000000)

int ffio_limit(AVIOContext *s, int size)
{
    if (s->maxsize>= 0) {
        int64_t remaining= s->maxsize - avio_tell(s);
        if (remaining < size) {
            int64_t newsize = avio_size(s);
            if (!s->maxsize || s->maxsize<newsize)
                s->maxsize = newsize - !newsize;
            remaining= s->maxsize - avio_tell(s);
            remaining= FFMAX(remaining, 0);
        }

        if (s->maxsize>= 0 && remaining+1 < size) {
            av_log(NULL, remaining ? AV_LOG_ERROR : AV_LOG_DEBUG, "Truncating packet of size %d to %"PRId64"\n", size, remaining+1);
            size = remaining+1;
        }
    }
    return size;
}

/* Read the data in sane-sized chunks and append to pkt.
 * Return the number of bytes read or an error. */
static int append_packet_chunked(AVIOContext *s, AVPacket *pkt, int size)
{
    int64_t orig_pos   = pkt->pos; // av_grow_packet might reset pos
    int orig_size      = pkt->size;
    int ret;

    do {
        int prev_size = pkt->size;
        int read_size;

        /* When the caller requests a lot of data, limit it to the amount
         * left in file or SANE_CHUNK_SIZE when it is not known. */
        read_size = size;
        if (read_size > SANE_CHUNK_SIZE/10) {
            read_size = ffio_limit(s, read_size);
            // If filesize/maxsize is unknown, limit to SANE_CHUNK_SIZE
            if (s->maxsize < 0)
                read_size = FFMIN(read_size, SANE_CHUNK_SIZE);
        }

        ret = av_grow_packet(pkt, read_size);
        if (ret < 0)
            break;

        ret = avio_read(s, pkt->data + prev_size, read_size);
        if (ret != read_size) {
            av_shrink_packet(pkt, prev_size + FFMAX(ret, 0));
            break;
        }

        size -= read_size;
    } while (size > 0);
    if (size > 0)
        pkt->flags |= AV_PKT_FLAG_CORRUPT;

    pkt->pos = orig_pos;
    if (!pkt->size)
        av_packet_unref(pkt);
    return pkt->size > orig_size ? pkt->size - orig_size : ret;
}

int av_get_packet(AVIOContext *s, AVPacket *pkt, int size)
{
    av_init_packet(pkt);
    pkt->data = NULL;
    pkt->size = 0;
    pkt->pos  = avio_tell(s);

    return append_packet_chunked(s, pkt, size);
}

int av_append_packet(AVIOContext *s, AVPacket *pkt, int size)
{
    if (!pkt->size)
        return av_get_packet(s, pkt, size);
    return append_packet_chunked(s, pkt, size);
}

int av_filename_number_test(const char *filename)
{
    char buf[1024];
    return filename &&
           (av_get_frame_filename(buf, sizeof(buf), filename, 1) >= 0);
}

static int set_codec_from_probe_data(AVFormatContext *s, AVStream *st,
                                     AVProbeData *pd)
{
    static const struct {
        const char *name;
        enum AVCodecID id;
        enum AVMediaType type;
    } fmt_id_type[] = {
        { "aac",       AV_CODEC_ID_AAC,        AVMEDIA_TYPE_AUDIO },
        { "ac3",       AV_CODEC_ID_AC3,        AVMEDIA_TYPE_AUDIO },
        { "aptx",      AV_CODEC_ID_APTX,       AVMEDIA_TYPE_AUDIO },
        { "dts",       AV_CODEC_ID_DTS,        AVMEDIA_TYPE_AUDIO },
        { "dvbsub",    AV_CODEC_ID_DVB_SUBTITLE,AVMEDIA_TYPE_SUBTITLE },
        { "dvbtxt",    AV_CODEC_ID_DVB_TELETEXT,AVMEDIA_TYPE_SUBTITLE },
        { "eac3",      AV_CODEC_ID_EAC3,       AVMEDIA_TYPE_AUDIO },
        { "h264",      AV_CODEC_ID_H264,       AVMEDIA_TYPE_VIDEO },
        { "hevc",      AV_CODEC_ID_HEVC,       AVMEDIA_TYPE_VIDEO },
        { "loas",      AV_CODEC_ID_AAC_LATM,   AVMEDIA_TYPE_AUDIO },
        { "m4v",       AV_CODEC_ID_MPEG4,      AVMEDIA_TYPE_VIDEO },
        { "mjpeg_2000",AV_CODEC_ID_JPEG2000,   AVMEDIA_TYPE_VIDEO },
        { "mp3",       AV_CODEC_ID_MP3,        AVMEDIA_TYPE_AUDIO },
        { "mpegvideo", AV_CODEC_ID_MPEG2VIDEO, AVMEDIA_TYPE_VIDEO },
        { "truehd",    AV_CODEC_ID_TRUEHD,     AVMEDIA_TYPE_AUDIO },
        { 0 }
    };
    int score;
    AVInputFormat *fmt = av_probe_input_format3(pd, 1, &score);

    if (fmt) {
        int i;
        av_log(s, AV_LOG_DEBUG,
               "Probe with size=%d, packets=%d detected %s with score=%d\n",
               pd->buf_size, MAX_PROBE_PACKETS - st->probe_packets,
               fmt->name, score);
        for (i = 0; fmt_id_type[i].name; i++) {
            if (!strcmp(fmt->name, fmt_id_type[i].name)) {
                if (fmt_id_type[i].type != AVMEDIA_TYPE_AUDIO &&
                    st->codecpar->sample_rate)
                    continue;
                if (st->request_probe > score &&
                    st->codecpar->codec_id != fmt_id_type[i].id)
                    continue;
                st->codecpar->codec_id   = fmt_id_type[i].id;
                st->codecpar->codec_type = fmt_id_type[i].type;
                st->internal->need_context_update = 1;
#if FF_API_LAVF_AVCTX
FF_DISABLE_DEPRECATION_WARNINGS
                st->codec->codec_type = st->codecpar->codec_type;
                st->codec->codec_id   = st->codecpar->codec_id;
FF_ENABLE_DEPRECATION_WARNINGS
#endif
                return score;
            }
        }
    }
    return 0;
}

/************************************************************/
/* input media file */

int av_demuxer_open(AVFormatContext *ic) {
    int err;

    if (ic->format_whitelist && av_match_list(ic->iformat->name, ic->format_whitelist, ',') <= 0) {
        av_log(ic, AV_LOG_ERROR, "Format not on whitelist \'%s\'\n", ic->format_whitelist);
        return AVERROR(EINVAL);
    }

    if (ic->iformat->read_header) {
        err = ic->iformat->read_header(ic);
        if (err < 0)
            return err;
    }

    if (ic->pb && !ic->internal->data_offset)
        ic->internal->data_offset = avio_tell(ic->pb);

    return 0;
}

/* Open input file and probe the format if necessary. */
static int init_input(AVFormatContext *s, const char *filename,
                      AVDictionary **options)
{
    int ret;
    AVProbeData pd = { filename, NULL, 0 };
    int score = AVPROBE_SCORE_RETRY;

    if (s->pb) {
        s->flags |= AVFMT_FLAG_CUSTOM_IO;
        if (!s->iformat)
            return av_probe_input_buffer2(s->pb, &s->iformat, filename,
                                         s, 0, s->format_probesize);
        else if (s->iformat->flags & AVFMT_NOFILE)
            av_log(s, AV_LOG_WARNING, "Custom AVIOContext makes no sense and "
                                      "will be ignored with AVFMT_NOFILE format.\n");
        return 0;
    }

    if ((s->iformat && s->iformat->flags & AVFMT_NOFILE) ||
        (!s->iformat && (s->iformat = av_probe_input_format2(&pd, 0, &score))))
        return score;

    if ((ret = s->io_open(s, &s->pb, filename, AVIO_FLAG_READ | s->avio_flags, options)) < 0)
        return ret;

    if (s->iformat)
        return 0;
    return av_probe_input_buffer2(s->pb, &s->iformat, filename,
                                 s, 0, s->format_probesize);
}

int ff_packet_list_put(AVPacketList **packet_buffer,
                       AVPacketList **plast_pktl,
                       AVPacket      *pkt, int flags)
{
    AVPacketList *pktl = av_mallocz(sizeof(AVPacketList));
    int ret;

    if (!pktl)
        return AVERROR(ENOMEM);

    if (flags & FF_PACKETLIST_FLAG_REF_PACKET) {
        if ((ret = av_packet_ref(&pktl->pkt, pkt)) < 0) {
            av_free(pktl);
            return ret;
        }
    } else {
        // TODO: Adapt callers in this file so the line below can use
        //       av_packet_move_ref() to effectively move the reference
        //       to the list.
        pktl->pkt = *pkt;
    }

    if (*packet_buffer)
        (*plast_pktl)->next = pktl;
    else
        *packet_buffer = pktl;

    /* Add the packet in the buffered packet list. */
    *plast_pktl = pktl;
    return 0;
}

int avformat_queue_attached_pictures(AVFormatContext *s)
{
    int i, ret;
    for (i = 0; i < s->nb_streams; i++)
        if (s->streams[i]->disposition & AV_DISPOSITION_ATTACHED_PIC &&
            s->streams[i]->discard < AVDISCARD_ALL) {
            if (s->streams[i]->attached_pic.size <= 0) {
                av_log(s, AV_LOG_WARNING,
                    "Attached picture on stream %d has invalid size, "
                    "ignoring\n", i);
                continue;
            }

            ret = ff_packet_list_put(&s->internal->raw_packet_buffer,
                                     &s->internal->raw_packet_buffer_end,
                                     &s->streams[i]->attached_pic,
                                     FF_PACKETLIST_FLAG_REF_PACKET);
            if (ret < 0)
                return ret;
        }
    return 0;
}

static int update_stream_avctx(AVFormatContext *s)
{
    int i, ret;
    for (i = 0; i < s->nb_streams; i++) {
        AVStream *st = s->streams[i];

        if (!st->internal->need_context_update)
            continue;

        /* close parser, because it depends on the codec */
        if (st->parser && st->internal->avctx->codec_id != st->codecpar->codec_id) {
            av_parser_close(st->parser);
            st->parser = NULL;
        }

        /* update internal codec context, for the parser */
        ret = avcodec_parameters_to_context(st->internal->avctx, st->codecpar);
        if (ret < 0)
            return ret;

#if FF_API_LAVF_AVCTX
FF_DISABLE_DEPRECATION_WARNINGS
        /* update deprecated public codec context */
        ret = avcodec_parameters_to_context(st->codec, st->codecpar);
        if (ret < 0)
            return ret;
FF_ENABLE_DEPRECATION_WARNINGS
#endif

        st->internal->need_context_update = 0;
    }
    return 0;
}


int avformat_open_input(AVFormatContext **ps, const char *filename,
                        AVInputFormat *fmt, AVDictionary **options)
{
    AVFormatContext *s = *ps;
    int i, ret = 0;
    AVDictionary *tmp = NULL;
    ID3v2ExtraMeta *id3v2_extra_meta = NULL;

    if (!s && !(s = avformat_alloc_context()))
        return AVERROR(ENOMEM);
    if (!s->av_class) {
        av_log(NULL, AV_LOG_ERROR, "Input context has not been properly allocated by avformat_alloc_context() and is not NULL either\n");
        return AVERROR(EINVAL);
    }
    if (fmt)
        s->iformat = fmt;

    if (options)
        av_dict_copy(&tmp, *options, 0);

    if (s->pb) // must be before any goto fail
        s->flags |= AVFMT_FLAG_CUSTOM_IO;

    if ((ret = av_opt_set_dict(s, &tmp)) < 0)
        goto fail;

    if (!(s->url = av_strdup(filename ? filename : ""))) {
        ret = AVERROR(ENOMEM);
        goto fail;
    }

#if FF_API_FORMAT_FILENAME
FF_DISABLE_DEPRECATION_WARNINGS
    av_strlcpy(s->filename, filename ? filename : "", sizeof(s->filename));
FF_ENABLE_DEPRECATION_WARNINGS
#endif
    if ((ret = init_input(s, filename, &tmp)) < 0)
        goto fail;
    s->probe_score = ret;

    if (!s->protocol_whitelist && s->pb && s->pb->protocol_whitelist) {
        s->protocol_whitelist = av_strdup(s->pb->protocol_whitelist);
        if (!s->protocol_whitelist) {
            ret = AVERROR(ENOMEM);
            goto fail;
        }
    }

    if (!s->protocol_blacklist && s->pb && s->pb->protocol_blacklist) {
        s->protocol_blacklist = av_strdup(s->pb->protocol_blacklist);
        if (!s->protocol_blacklist) {
            ret = AVERROR(ENOMEM);
            goto fail;
        }
    }

    if (s->format_whitelist && av_match_list(s->iformat->name, s->format_whitelist, ',') <= 0) {
        av_log(s, AV_LOG_ERROR, "Format not on whitelist \'%s\'\n", s->format_whitelist);
        ret = AVERROR(EINVAL);
        goto fail;
    }

    avio_skip(s->pb, s->skip_initial_bytes);

    /* Check filename in case an image number is expected. */
    if (s->iformat->flags & AVFMT_NEEDNUMBER) {
        if (!av_filename_number_test(filename)) {
            ret = AVERROR(EINVAL);
            goto fail;
        }
    }

    s->duration = s->start_time = AV_NOPTS_VALUE;

    /* Allocate private data. */
    if (s->iformat->priv_data_size > 0) {
        if (!(s->priv_data = av_mallocz(s->iformat->priv_data_size))) {
            ret = AVERROR(ENOMEM);
            goto fail;
        }
        if (s->iformat->priv_class) {
            *(const AVClass **) s->priv_data = s->iformat->priv_class;
            av_opt_set_defaults(s->priv_data);
            if ((ret = av_opt_set_dict(s->priv_data, &tmp)) < 0)
                goto fail;
        }
    }

    /* e.g. AVFMT_NOFILE formats will not have a AVIOContext */
    if (s->pb)
        ff_id3v2_read_dict(s->pb, &s->internal->id3v2_meta, ID3v2_DEFAULT_MAGIC, &id3v2_extra_meta);


    if (!(s->flags&AVFMT_FLAG_PRIV_OPT) && s->iformat->read_header)
        if ((ret = s->iformat->read_header(s)) < 0)
            goto fail;

    if (!s->metadata) {
        s->metadata = s->internal->id3v2_meta;
        s->internal->id3v2_meta = NULL;
    } else if (s->internal->id3v2_meta) {
        int level = AV_LOG_WARNING;
        if (s->error_recognition & AV_EF_COMPLIANT)
            level = AV_LOG_ERROR;
        av_log(s, level, "Discarding ID3 tags because more suitable tags were found.\n");
        av_dict_free(&s->internal->id3v2_meta);
        if (s->error_recognition & AV_EF_EXPLODE)
            return AVERROR_INVALIDDATA;
    }

    if (id3v2_extra_meta) {
        if (!strcmp(s->iformat->name, "mp3") || !strcmp(s->iformat->name, "aac") ||
            !strcmp(s->iformat->name, "tta")) {
            if ((ret = ff_id3v2_parse_apic(s, &id3v2_extra_meta)) < 0)
                goto fail;
            if ((ret = ff_id3v2_parse_chapters(s, &id3v2_extra_meta)) < 0)
                goto fail;
            if ((ret = ff_id3v2_parse_priv(s, &id3v2_extra_meta)) < 0)
                goto fail;
        } else
            av_log(s, AV_LOG_DEBUG, "demuxer does not support additional id3 data, skipping\n");
    }
    ff_id3v2_free_extra_meta(&id3v2_extra_meta);

    if ((ret = avformat_queue_attached_pictures(s)) < 0)
        goto fail;

    if (!(s->flags&AVFMT_FLAG_PRIV_OPT) && s->pb && !s->internal->data_offset)
        s->internal->data_offset = avio_tell(s->pb);

    s->internal->raw_packet_buffer_remaining_size = RAW_PACKET_BUFFER_SIZE;

    update_stream_avctx(s);

    for (i = 0; i < s->nb_streams; i++)
        s->streams[i]->internal->orig_codec_id = s->streams[i]->codecpar->codec_id;

    if (options) {
        av_dict_free(options);
        *options = tmp;
    }
    *ps = s;
    return 0;

fail:
    ff_id3v2_free_extra_meta(&id3v2_extra_meta);
    av_dict_free(&tmp);
    if (s->pb && !(s->flags & AVFMT_FLAG_CUSTOM_IO))
        avio_closep(&s->pb);
    avformat_free_context(s);
    *ps = NULL;
    return ret;
}

/*******************************************************/

static void force_codec_ids(AVFormatContext *s, AVStream *st)
{
    switch (st->codecpar->codec_type) {
    case AVMEDIA_TYPE_VIDEO:
        if (s->video_codec_id)
            st->codecpar->codec_id = s->video_codec_id;
        break;
    case AVMEDIA_TYPE_AUDIO:
        if (s->audio_codec_id)
            st->codecpar->codec_id = s->audio_codec_id;
        break;
    case AVMEDIA_TYPE_SUBTITLE:
        if (s->subtitle_codec_id)
            st->codecpar->codec_id = s->subtitle_codec_id;
        break;
    case AVMEDIA_TYPE_DATA:
        if (s->data_codec_id)
            st->codecpar->codec_id = s->data_codec_id;
        break;
    }
}

static int probe_codec(AVFormatContext *s, AVStream *st, const AVPacket *pkt)
{
    if (st->request_probe>0) {
        AVProbeData *pd = &st->probe_data;
        int end;
        av_log(s, AV_LOG_DEBUG, "probing stream %d pp:%d\n", st->index, st->probe_packets);
        --st->probe_packets;

        if (pkt) {
            uint8_t *new_buf = av_realloc(pd->buf, pd->buf_size+pkt->size+AVPROBE_PADDING_SIZE);
            if (!new_buf) {
                av_log(s, AV_LOG_WARNING,
                       "Failed to reallocate probe buffer for stream %d\n",
                       st->index);
                goto no_packet;
            }
            pd->buf = new_buf;
            memcpy(pd->buf + pd->buf_size, pkt->data, pkt->size);
            pd->buf_size += pkt->size;
            memset(pd->buf + pd->buf_size, 0, AVPROBE_PADDING_SIZE);
        } else {
no_packet:
            st->probe_packets = 0;
            if (!pd->buf_size) {
                av_log(s, AV_LOG_WARNING,
                       "nothing to probe for stream %d\n", st->index);
            }
        }

        end=    s->internal->raw_packet_buffer_remaining_size <= 0
                || st->probe_packets<= 0;

        if (end || av_log2(pd->buf_size) != av_log2(pd->buf_size - pkt->size)) {
            int score = set_codec_from_probe_data(s, st, pd);
            if (    (st->codecpar->codec_id != AV_CODEC_ID_NONE && score > AVPROBE_SCORE_STREAM_RETRY)
                || end) {
                pd->buf_size = 0;
                av_freep(&pd->buf);
                st->request_probe = -1;
                if (st->codecpar->codec_id != AV_CODEC_ID_NONE) {
                    av_log(s, AV_LOG_DEBUG, "probed stream %d\n", st->index);
                } else
                    av_log(s, AV_LOG_WARNING, "probed stream %d failed\n", st->index);
            }
            force_codec_ids(s, st);
        }
    }
    return 0;
}

static int update_wrap_reference(AVFormatContext *s, AVStream *st, int stream_index, AVPacket *pkt)
{
    int64_t ref = pkt->dts;
    int i, pts_wrap_behavior;
    int64_t pts_wrap_reference;
    AVProgram *first_program;

    if (ref == AV_NOPTS_VALUE)
        ref = pkt->pts;
    if (st->pts_wrap_reference != AV_NOPTS_VALUE || st->pts_wrap_bits >= 63 || ref == AV_NOPTS_VALUE || !s->correct_ts_overflow)
        return 0;
    ref &= (1LL << st->pts_wrap_bits)-1;

    // reference time stamp should be 60 s before first time stamp
    pts_wrap_reference = ref - av_rescale(60, st->time_base.den, st->time_base.num);
    // if first time stamp is not more than 1/8 and 60s before the wrap point, subtract rather than add wrap offset
    pts_wrap_behavior = (ref < (1LL << st->pts_wrap_bits) - (1LL << st->pts_wrap_bits-3)) ||
        (ref < (1LL << st->pts_wrap_bits) - av_rescale(60, st->time_base.den, st->time_base.num)) ?
        AV_PTS_WRAP_ADD_OFFSET : AV_PTS_WRAP_SUB_OFFSET;

    first_program = av_find_program_from_stream(s, NULL, stream_index);

    if (!first_program) {
        int default_stream_index = av_find_default_stream_index(s);
        if (s->streams[default_stream_index]->pts_wrap_reference == AV_NOPTS_VALUE) {
            for (i = 0; i < s->nb_streams; i++) {
                if (av_find_program_from_stream(s, NULL, i))
                    continue;
                s->streams[i]->pts_wrap_reference = pts_wrap_reference;
                s->streams[i]->pts_wrap_behavior = pts_wrap_behavior;
            }
        }
        else {
            st->pts_wrap_reference = s->streams[default_stream_index]->pts_wrap_reference;
            st->pts_wrap_behavior = s->streams[default_stream_index]->pts_wrap_behavior;
        }
    }
    else {
        AVProgram *program = first_program;
        while (program) {
            if (program->pts_wrap_reference != AV_NOPTS_VALUE) {
                pts_wrap_reference = program->pts_wrap_reference;
                pts_wrap_behavior = program->pts_wrap_behavior;
                break;
            }
            program = av_find_program_from_stream(s, program, stream_index);
        }

        // update every program with differing pts_wrap_reference
        program = first_program;
        while (program) {
            if (program->pts_wrap_reference != pts_wrap_reference) {
                for (i = 0; i<program->nb_stream_indexes; i++) {
                    s->streams[program->stream_index[i]]->pts_wrap_reference = pts_wrap_reference;
                    s->streams[program->stream_index[i]]->pts_wrap_behavior = pts_wrap_behavior;
                }

                program->pts_wrap_reference = pts_wrap_reference;
                program->pts_wrap_behavior = pts_wrap_behavior;
            }
            program = av_find_program_from_stream(s, program, stream_index);
        }
    }
    return 1;
}

int ff_read_packet(AVFormatContext *s, AVPacket *pkt)
{
    int ret, i, err;
    AVStream *st;

    for (;;) {
        AVPacketList *pktl = s->internal->raw_packet_buffer;

        if (pktl) {
            *pkt = pktl->pkt;
            st   = s->streams[pkt->stream_index];
            if (s->internal->raw_packet_buffer_remaining_size <= 0)
                if ((err = probe_codec(s, st, NULL)) < 0)
                    return err;
            if (st->request_probe <= 0) {
                s->internal->raw_packet_buffer                 = pktl->next;
                s->internal->raw_packet_buffer_remaining_size += pkt->size;
                av_free(pktl);
                return 0;
            }
        }

        pkt->data = NULL;
        pkt->size = 0;
        av_init_packet(pkt);
        ret = s->iformat->read_packet(s, pkt);
        if (ret < 0) {
            /* Some demuxers return FFERROR_REDO when they consume
               data and discard it (ignored streams, junk, extradata).
               We must re-call the demuxer to get the real packet. */
            if (ret == FFERROR_REDO)
                continue;
            if (!pktl || ret == AVERROR(EAGAIN))
                return ret;
            for (i = 0; i < s->nb_streams; i++) {
                st = s->streams[i];
                if (st->probe_packets || st->request_probe > 0)
                    if ((err = probe_codec(s, st, NULL)) < 0)
                        return err;
                av_assert0(st->request_probe <= 0);
            }
            continue;
        }

        err = av_packet_make_refcounted(pkt);
        if (err < 0)
            return err;

        if ((s->flags & AVFMT_FLAG_DISCARD_CORRUPT) &&
            (pkt->flags & AV_PKT_FLAG_CORRUPT)) {
            av_log(s, AV_LOG_WARNING,
                   "Dropped corrupted packet (stream = %d)\n",
                   pkt->stream_index);
            av_packet_unref(pkt);
            continue;
        }

        if (pkt->stream_index >= (unsigned)s->nb_streams) {
            av_log(s, AV_LOG_ERROR, "Invalid stream index %d\n", pkt->stream_index);
            continue;
        }

        st = s->streams[pkt->stream_index];

        if (update_wrap_reference(s, st, pkt->stream_index, pkt) && st->pts_wrap_behavior == AV_PTS_WRAP_SUB_OFFSET) {
            // correct first time stamps to negative values
            if (!is_relative(st->first_dts))
                st->first_dts = wrap_timestamp(st, st->first_dts);
            if (!is_relative(st->start_time))
                st->start_time = wrap_timestamp(st, st->start_time);
            if (!is_relative(st->cur_dts))
                st->cur_dts = wrap_timestamp(st, st->cur_dts);
        }

        pkt->dts = wrap_timestamp(st, pkt->dts);
        pkt->pts = wrap_timestamp(st, pkt->pts);

        force_codec_ids(s, st);

        /* TODO: audio: time filter; video: frame reordering (pts != dts) */
        if (s->use_wallclock_as_timestamps)
            pkt->dts = pkt->pts = av_rescale_q(av_gettime(), AV_TIME_BASE_Q, st->time_base);

        if (!pktl && st->request_probe <= 0)
            return ret;

        err = ff_packet_list_put(&s->internal->raw_packet_buffer,
                                 &s->internal->raw_packet_buffer_end,
                                 pkt, 0);
        if (err)
            return err;
        s->internal->raw_packet_buffer_remaining_size -= pkt->size;

        if ((err = probe_codec(s, st, pkt)) < 0)
            return err;
    }
}


/**********************************************************/

static int determinable_frame_size(AVCodecContext *avctx)
{
    switch(avctx->codec_id) {
    case AV_CODEC_ID_MP1:
    case AV_CODEC_ID_MP2:
    case AV_CODEC_ID_MP3:
    case AV_CODEC_ID_CODEC2:
        return 1;
    }

    return 0;
}

/**
 * Return the frame duration in seconds. Return 0 if not available.
 */
void ff_compute_frame_duration(AVFormatContext *s, int *pnum, int *pden, AVStream *st,
                               AVCodecParserContext *pc, AVPacket *pkt)
{
    AVRational codec_framerate = s->iformat ? st->internal->avctx->framerate :
                                              av_mul_q(av_inv_q(st->internal->avctx->time_base), (AVRational){1, st->internal->avctx->ticks_per_frame});
    int frame_size, sample_rate;

#if FF_API_LAVF_AVCTX
FF_DISABLE_DEPRECATION_WARNINGS
    if ((!codec_framerate.den || !codec_framerate.num) && st->codec->time_base.den && st->codec->time_base.num)
        codec_framerate = av_mul_q(av_inv_q(st->codec->time_base), (AVRational){1, st->codec->ticks_per_frame});
FF_ENABLE_DEPRECATION_WARNINGS
#endif

    *pnum = 0;
    *pden = 0;
    switch (st->codecpar->codec_type) {
    case AVMEDIA_TYPE_VIDEO:
        if (st->r_frame_rate.num && !pc && s->iformat) {
            *pnum = st->r_frame_rate.den;
            *pden = st->r_frame_rate.num;
        } else if (st->time_base.num * 1000LL > st->time_base.den) {
            *pnum = st->time_base.num;
            *pden = st->time_base.den;
        } else if (codec_framerate.den * 1000LL > codec_framerate.num) {
            av_assert0(st->internal->avctx->ticks_per_frame);
            av_reduce(pnum, pden,
                      codec_framerate.den,
                      codec_framerate.num * (int64_t)st->internal->avctx->ticks_per_frame,
                      INT_MAX);

            if (pc && pc->repeat_pict) {
                av_assert0(s->iformat); // this may be wrong for interlaced encoding but its not used for that case
                av_reduce(pnum, pden,
                          (*pnum) * (1LL + pc->repeat_pict),
                          (*pden),
                          INT_MAX);
            }
            /* If this codec can be interlaced or progressive then we need
             * a parser to compute duration of a packet. Thus if we have
             * no parser in such case leave duration undefined. */
            if (st->internal->avctx->ticks_per_frame > 1 && !pc)
                *pnum = *pden = 0;
        }
        break;
    case AVMEDIA_TYPE_AUDIO:
        if (st->internal->avctx_inited) {
            frame_size = av_get_audio_frame_duration(st->internal->avctx, pkt->size);
            sample_rate = st->internal->avctx->sample_rate;
        } else {
            frame_size = av_get_audio_frame_duration2(st->codecpar, pkt->size);
            sample_rate = st->codecpar->sample_rate;
        }