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
 */

/* #define DEBUG */

#include "avformat.h"
#include "avio_internal.h"
#include "internal.h"
#include "libavcodec/internal.h"
#include "libavcodec/raw.h"
#include "libavcodec/bytestream.h"
#include "libavutil/avassert.h"
#include "libavutil/opt.h"
#include "libavutil/dict.h"
#include "libavutil/pixdesc.h"
#include "metadata.h"
#include "id3v2.h"
#include "libavutil/avassert.h"
#include "libavutil/avstring.h"
#include "libavutil/mathematics.h"
#include "libavutil/parseutils.h"
#include "libavutil/time.h"
#include "libavutil/timestamp.h"
#include "riff.h"
#include "audiointerleave.h"
#include "url.h"
#include <stdarg.h>
#if CONFIG_NETWORK
#include "network.h"
#endif

#undef NDEBUG
#include <assert.h>

/**
 * @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;
}

#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(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;
}

/** head of registered input format linked list */
static AVInputFormat *first_iformat = NULL;
/** head of registered output format linked list */
static AVOutputFormat *first_oformat = NULL;

AVInputFormat  *av_iformat_next(AVInputFormat  *f)
{
    if(f) return f->next;
    else  return first_iformat;
}

AVOutputFormat *av_oformat_next(AVOutputFormat *f)
{
    if(f) return f->next;
    else  return first_oformat;
}

void av_register_input_format(AVInputFormat *format)
{
    AVInputFormat **p;
    p = &first_iformat;
    while (*p != NULL) p = &(*p)->next;
    *p = format;
    format->next = NULL;
}

void av_register_output_format(AVOutputFormat *format)
{
    AVOutputFormat **p;
    p = &first_oformat;
    while (*p != NULL) p = &(*p)->next;
    *p = format;
    format->next = NULL;
}

int av_match_ext(const char *filename, const char *extensions)
{
    const char *ext, *p;
    char ext1[32], *q;

    if(!filename)
        return 0;

    ext = strrchr(filename, '.');
    if (ext) {
        ext++;
        p = extensions;
        for(;;) {
            q = ext1;
            while (*p != '\0' && *p != ',' && q-ext1<sizeof(ext1)-1)
                *q++ = *p++;
            *q = '\0';
            if (!av_strcasecmp(ext1, ext))
                return 1;
            if (*p == '\0')
                break;
            p++;
        }
    }
    return 0;
}

static int match_format(const char *name, const char *names)
{
    const char *p;
    int len, namelen;

    if (!name || !names)
        return 0;

    namelen = strlen(name);
    while ((p = strchr(names, ','))) {
        len = FFMAX(p - names, namelen);
        if (!av_strncasecmp(name, names, len))
            return 1;
        names = p+1;
    }
    return !av_strcasecmp(name, names);
}

AVOutputFormat *av_guess_format(const char *short_name, const char *filename,
                                const char *mime_type)
{
    AVOutputFormat *fmt = NULL, *fmt_found;
    int score_max, score;

    /* specific test for image sequences */
#if CONFIG_IMAGE2_MUXER
    if (!short_name && filename &&
        av_filename_number_test(filename) &&
        ff_guess_image2_codec(filename) != AV_CODEC_ID_NONE) {
        return av_guess_format("image2", NULL, NULL);
    }
#endif
    /* Find the proper file type. */
    fmt_found = NULL;
    score_max = 0;
    while ((fmt = av_oformat_next(fmt))) {
        score = 0;
        if (fmt->name && short_name && match_format(short_name, fmt->name))
            score += 100;
        if (fmt->mime_type && mime_type && !strcmp(fmt->mime_type, mime_type))
            score += 10;
        if (filename && fmt->extensions &&
            av_match_ext(filename, fmt->extensions)) {
            score += 5;
        }
        if (score > score_max) {
            score_max = score;
            fmt_found = fmt;
        }
    }
    return fmt_found;
}

enum AVCodecID av_guess_codec(AVOutputFormat *fmt, const char *short_name,
                            const char *filename, const char *mime_type, enum AVMediaType type){
    if(type == AVMEDIA_TYPE_VIDEO){
        enum AVCodecID codec_id= AV_CODEC_ID_NONE;

#if CONFIG_IMAGE2_MUXER
        if(!strcmp(fmt->name, "image2") || !strcmp(fmt->name, "image2pipe")){
            codec_id= ff_guess_image2_codec(filename);
        }
#endif
        if(codec_id == AV_CODEC_ID_NONE)
            codec_id= fmt->video_codec;
        return codec_id;
    }else if(type == AVMEDIA_TYPE_AUDIO)
        return fmt->audio_codec;
    else if (type == AVMEDIA_TYPE_SUBTITLE)
        return fmt->subtitle_codec;
    else
        return AV_CODEC_ID_NONE;
}

AVInputFormat *av_find_input_format(const char *short_name)
{
    AVInputFormat *fmt = NULL;
    while ((fmt = av_iformat_next(fmt))) {
        if (match_format(short_name, fmt->name))
            return fmt;
    }
    return NULL;
}

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;
}

int av_get_packet(AVIOContext *s, AVPacket *pkt, int size)
{
    int ret;
    int orig_size = size;
    size= ffio_limit(s, size);

    ret= av_new_packet(pkt, size);

    if(ret<0)
        return ret;

    pkt->pos= avio_tell(s);

    ret= avio_read(s, pkt->data, size);
    if(ret<=0)
        av_free_packet(pkt);
    else
        av_shrink_packet(pkt, ret);
    if (pkt->size < orig_size)
        pkt->flags |= AV_PKT_FLAG_CORRUPT;

    return ret;
}

int av_append_packet(AVIOContext *s, AVPacket *pkt, int size)
{
    int ret;
    int old_size;
    if (!pkt->size)
        return av_get_packet(s, pkt, size);
    old_size = pkt->size;
    ret = av_grow_packet(pkt, size);
    if (ret < 0)
        return ret;
    ret = avio_read(s, pkt->data + old_size, size);
    av_shrink_packet(pkt, old_size + FFMAX(ret, 0));
    return ret;
}


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

AVInputFormat *av_probe_input_format3(AVProbeData *pd, int is_opened, int *score_ret)
{
    AVProbeData lpd = *pd;
    AVInputFormat *fmt1 = NULL, *fmt;
    int score, nodat = 0, score_max=0;
    const static uint8_t zerobuffer[AVPROBE_PADDING_SIZE];

    if (!lpd.buf)
        lpd.buf = zerobuffer;

    if (lpd.buf_size > 10 && ff_id3v2_match(lpd.buf, ID3v2_DEFAULT_MAGIC)) {
        int id3len = ff_id3v2_tag_len(lpd.buf);
        if (lpd.buf_size > id3len + 16) {
            lpd.buf += id3len;
            lpd.buf_size -= id3len;
        }else
            nodat = 1;
    }

    fmt = NULL;
    while ((fmt1 = av_iformat_next(fmt1))) {
        if (!is_opened == !(fmt1->flags & AVFMT_NOFILE))
            continue;
        score = 0;
        if (fmt1->read_probe) {
            score = fmt1->read_probe(&lpd);
            if(fmt1->extensions && av_match_ext(lpd.filename, fmt1->extensions))
                score = FFMAX(score, nodat ? AVPROBE_SCORE_MAX/4-1 : 1);
        } else if (fmt1->extensions) {
            if (av_match_ext(lpd.filename, fmt1->extensions)) {
                score = 50;
            }
        }
        if (score > score_max) {
            score_max = score;
            fmt = fmt1;
        }else if (score == score_max)
            fmt = NULL;
    }
    *score_ret= score_max;

    return fmt;
}

AVInputFormat *av_probe_input_format2(AVProbeData *pd, int is_opened, int *score_max)
{
    int score_ret;
    AVInputFormat *fmt= av_probe_input_format3(pd, is_opened, &score_ret);
    if(score_ret > *score_max){
        *score_max= score_ret;
        return fmt;
    }else
        return NULL;
}

AVInputFormat *av_probe_input_format(AVProbeData *pd, int is_opened){
    int score=0;
    return av_probe_input_format2(pd, is_opened, &score);
}

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 },
        { "dts"      , AV_CODEC_ID_DTS       , AVMEDIA_TYPE_AUDIO },
        { "eac3"     , AV_CODEC_ID_EAC3      , AVMEDIA_TYPE_AUDIO },
        { "h264"     , AV_CODEC_ID_H264      , AVMEDIA_TYPE_VIDEO },
        { "loas"     , AV_CODEC_ID_AAC_LATM  , AVMEDIA_TYPE_AUDIO },
        { "m4v"      , AV_CODEC_ID_MPEG4     , AVMEDIA_TYPE_VIDEO },
        { "mp3"      , AV_CODEC_ID_MP3       , AVMEDIA_TYPE_AUDIO },
        { "mpegvideo", AV_CODEC_ID_MPEG2VIDEO, AVMEDIA_TYPE_VIDEO },
        { 0 }
    };
    int score;
    AVInputFormat *fmt = av_probe_input_format3(pd, 1, &score);

    if (fmt && st->request_probe <= score) {
        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)) {
                st->codec->codec_id   = fmt_id_type[i].id;
                st->codec->codec_type = fmt_id_type[i].type;
                break;
            }
        }
    }
    return score;
}

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

int av_demuxer_open(AVFormatContext *ic){
    int err;

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

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

    return 0;
}


/** size of probe buffer, for guessing file type from file contents */
#define PROBE_BUF_MIN 2048
#define PROBE_BUF_MAX (1<<20)

int av_probe_input_buffer(AVIOContext *pb, AVInputFormat **fmt,
                          const char *filename, void *logctx,
                          unsigned int offset, unsigned int max_probe_size)
{
    AVProbeData pd = { filename ? filename : "", NULL, -offset };
    unsigned char *buf = NULL;
    uint8_t *mime_type;
    int ret = 0, probe_size, buf_offset = 0;

    if (!max_probe_size) {
        max_probe_size = PROBE_BUF_MAX;
    } else if (max_probe_size > PROBE_BUF_MAX) {
        max_probe_size = PROBE_BUF_MAX;
    } else if (max_probe_size < PROBE_BUF_MIN) {
        return AVERROR(EINVAL);
    }

    if (offset >= max_probe_size) {
        return AVERROR(EINVAL);
    }

    if (!*fmt && pb->av_class && av_opt_get(pb, "mime_type", AV_OPT_SEARCH_CHILDREN, &mime_type) >= 0 && mime_type) {
        if (!av_strcasecmp(mime_type, "audio/aacp")) {
            *fmt = av_find_input_format("aac");
        }
        av_freep(&mime_type);
    }

    for(probe_size= PROBE_BUF_MIN; probe_size<=max_probe_size && !*fmt;
        probe_size = FFMIN(probe_size<<1, FFMAX(max_probe_size, probe_size+1))) {
        int score = probe_size < max_probe_size ? AVPROBE_SCORE_RETRY : 0;
        void *buftmp;

        if (probe_size < offset) {
            continue;
        }

        /* read probe data */
        buftmp = av_realloc(buf, probe_size + AVPROBE_PADDING_SIZE);
        if(!buftmp){
            av_free(buf);
            return AVERROR(ENOMEM);
        }
        buf=buftmp;
        if ((ret = avio_read(pb, buf + buf_offset, probe_size - buf_offset)) < 0) {
            /* fail if error was not end of file, otherwise, lower score */
            if (ret != AVERROR_EOF) {
                av_free(buf);
                return ret;
            }
            score = 0;
            ret = 0;            /* error was end of file, nothing read */
        }
        pd.buf_size = buf_offset += ret;
        pd.buf = &buf[offset];

        memset(pd.buf + pd.buf_size, 0, AVPROBE_PADDING_SIZE);

        /* guess file format */
        *fmt = av_probe_input_format2(&pd, 1, &score);
        if(*fmt){
            if(score <= AVPROBE_SCORE_RETRY){ //this can only be true in the last iteration
                av_log(logctx, AV_LOG_WARNING, "Format %s detected only with low score of %d, misdetection possible!\n", (*fmt)->name, score);
            }else
                av_log(logctx, AV_LOG_DEBUG, "Format %s probed with size=%d and score=%d\n", (*fmt)->name, probe_size, score);
        }
    }

    if (!*fmt) {
        av_free(buf);
        return AVERROR_INVALIDDATA;
    }

    /* rewind. reuse probe buffer to avoid seeking */
    ret = ffio_rewind_with_probe_data(pb, &buf, pd.buf_size);

    return ret;
}

/* 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_buffer(s->pb, &s->iformat, filename, s, 0, s->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 0;

    if ((ret = avio_open2(&s->pb, filename, AVIO_FLAG_READ | s->avio_flags,
                          &s->interrupt_callback, options)) < 0)
        return ret;
    if (s->iformat)
        return 0;
    return av_probe_input_buffer(s->pb, &s->iformat, filename, s, 0, s->probesize);
}

static AVPacket *add_to_pktbuf(AVPacketList **packet_buffer, AVPacket *pkt,
                               AVPacketList **plast_pktl){
    AVPacketList *pktl = av_mallocz(sizeof(AVPacketList));
    if (!pktl)
        return NULL;

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

    /* add the packet in the buffered packet list */
    *plast_pktl = pktl;
    pktl->pkt= *pkt;
    return &pktl->pkt;
}

void avformat_queue_attached_pictures(AVFormatContext *s)
{
    int i;
    for (i = 0; i < s->nb_streams; i++)
        if (s->streams[i]->disposition & AV_DISPOSITION_ATTACHED_PIC &&
            s->streams[i]->discard < AVDISCARD_ALL) {
            AVPacket copy = s->streams[i]->attached_pic;
            copy.destruct = NULL;
            add_to_pktbuf(&s->raw_packet_buffer, &copy, &s->raw_packet_buffer_end);
        }
}

int avformat_open_input(AVFormatContext **ps, const char *filename, AVInputFormat *fmt, AVDictionary **options)
{
    AVFormatContext *s = *ps;
    int 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 ((ret = av_opt_set_dict(s, &tmp)) < 0)
        goto fail;

    if ((ret = init_input(s, filename, &tmp)) < 0)
        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;
    av_strlcpy(s->filename, filename ? filename : "", sizeof(s->filename));

    /* 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(s, 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 (id3v2_extra_meta) {
        if (!strcmp(s->iformat->name, "mp3")) {
            if((ret = ff_id3v2_parse_apic(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);

    avformat_queue_attached_pictures(s);

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

    s->raw_packet_buffer_remaining_size = RAW_PACKET_BUFFER_SIZE;

    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_close(s->pb);
    avformat_free_context(s);
    *ps = NULL;
    return ret;
}

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

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

static void 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)
                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->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->codec->codec_id != AV_CODEC_ID_NONE && score > AVPROBE_SCORE_RETRY)
                || end){
                pd->buf_size=0;
                av_freep(&pd->buf);
                st->request_probe= -1;
                if(st->codec->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);
        }
    }
}

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

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

        if (pktl) {
            *pkt = pktl->pkt;
            st = s->streams[pkt->stream_index];
            if(st->request_probe <= 0){
                s->raw_packet_buffer = pktl->next;
                s->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) {
            if (!pktl || ret == AVERROR(EAGAIN))
                return ret;
            for (i = 0; i < s->nb_streams; i++) {
                st = s->streams[i];
                if (st->probe_packets) {
                    probe_codec(s, st, NULL);
                }
                av_assert0(st->request_probe <= 0);
            }
            continue;
        }

        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_free_packet(pkt);
            continue;
        }

        if(!(s->flags & AVFMT_FLAG_KEEP_SIDE_DATA))
            av_packet_merge_side_data(pkt);

        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];
        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;

        add_to_pktbuf(&s->raw_packet_buffer, pkt, &s->raw_packet_buffer_end);
        s->raw_packet_buffer_remaining_size -= pkt->size;

        probe_codec(s, st, pkt);
    }
}

#if FF_API_READ_PACKET
int av_read_packet(AVFormatContext *s, AVPacket *pkt)
{
    return ff_read_packet(s, pkt);
}
#endif


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

static int determinable_frame_size(AVCodecContext *avctx)
{
    if (/*avctx->codec_id == AV_CODEC_ID_AAC ||*/
        avctx->codec_id == AV_CODEC_ID_MP1 ||
        avctx->codec_id == AV_CODEC_ID_MP2 ||
        avctx->codec_id == AV_CODEC_ID_MP3/* ||
        avctx->codec_id == AV_CODEC_ID_CELT*/)
        return 1;
    return 0;
}

/**
 * Get the number of samples of an audio frame. Return -1 on error.
 */
int ff_get_audio_frame_size(AVCodecContext *enc, int size, int mux)
{
    int frame_size;

    /* give frame_size priority if demuxing */
    if (!mux && enc->frame_size > 1)
        return enc->frame_size;

    if ((frame_size = av_get_audio_frame_duration(enc, size)) > 0)
        return frame_size;

    /* fallback to using frame_size if muxing */
    if (enc->frame_size > 1)
        return enc->frame_size;

    //For WMA we currently have no other means to calculate duration thus we
    //do it here by assuming CBR, which is true for all known cases.
    if(!mux && enc->bit_rate>0 && size>0 && enc->sample_rate>0 && enc->block_align>1) {
        if (enc->codec_id == AV_CODEC_ID_WMAV1 || enc->codec_id == AV_CODEC_ID_WMAV2)
            return  ((int64_t)size * 8 * enc->sample_rate) / enc->bit_rate;
    }

    return -1;
}


/**
 * Return the frame duration in seconds. Return 0 if not available.
 */
void ff_compute_frame_duration(int *pnum, int *pden, AVStream *st,
                               AVCodecParserContext *pc, AVPacket *pkt)
{
    int frame_size;

    *pnum = 0;
    *pden = 0;
    switch(st->codec->codec_type) {
    case AVMEDIA_TYPE_VIDEO:
        if (st->r_frame_rate.num && !pc) {
            *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(st->codec->time_base.num*1000LL > st->codec->time_base.den){
            *pnum = st->codec->time_base.num;
            *pden = st->codec->time_base.den;
            if (pc && pc->repeat_pict) {
                if (*pnum > INT_MAX / (1 + pc->repeat_pict))
                    *pden /= 1 + pc->repeat_pict;
                else
                    *pnum *= 1 + pc->repeat_pict;
            }
            //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->codec->ticks_per_frame>1 && !pc){
                *pnum = *pden = 0;
            }
        }
        break;
    case AVMEDIA_TYPE_AUDIO:
        frame_size = ff_get_audio_frame_size(st->codec, pkt->size, 0);
        if (frame_size <= 0 || st->codec->sample_rate <= 0)
            break;
        *pnum = frame_size;
        *pden = st->codec->sample_rate;
        break;
    default:
        break;
    }
}

static int is_intra_only(AVCodecContext *enc){
    const AVCodecDescriptor *desc;

    if(enc->codec_type != AVMEDIA_TYPE_VIDEO)
        return 1;

    desc = av_codec_get_codec_descriptor(enc);
    if (!desc) {
        desc = avcodec_descriptor_get(enc->codec_id);
        av_codec_set_codec_descriptor(enc, desc);
    }
    if (desc)
        return !!(desc->props & AV_CODEC_PROP_INTRA_ONLY);
    return 0;
}

static int has_decode_delay_been_guessed(AVStream *st)
{
    if(st->codec->codec_id != AV_CODEC_ID_H264) return 1;
    if(!st->info) // if we have left find_stream_info then nb_decoded_frames wont increase anymore for stream copy
        return 1;
#if CONFIG_H264_DECODER
    if(st->codec->has_b_frames &&
       avpriv_h264_has_num_reorder_frames(st->codec) == st->codec->has_b_frames)
        return 1;
#endif
    if(st->codec->has_b_frames<3)
        return st->nb_decoded_frames >= 7;
    else if(st->codec->has_b_frames<4)
        return st->nb_decoded_frames >= 18;
    else
        return st->nb_decoded_frames >= 20;
}

static AVPacketList *get_next_pkt(AVFormatContext *s, AVStream *st, AVPacketList *pktl)
{
    if (pktl->next)
        return pktl->next;
    if (pktl == s->parse_queue_end)
        return s->packet_buffer;
    return NULL;
}

static int update_wrap_reference(AVFormatContext *s, AVStream *st, int stream_index)
{
    if (s->correct_ts_overflow && st->pts_wrap_bits < 63 &&
        st->pts_wrap_reference == AV_NOPTS_VALUE && st->first_dts != AV_NOPTS_VALUE) {
        int i;

        // reference time stamp should be 60 s before first time stamp
        int64_t pts_wrap_reference = st->first_dts - 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
        int pts_wrap_behavior = (st->first_dts < (1LL<<st->pts_wrap_bits) - (1LL<<st->pts_wrap_bits-3)) ||
            (st->first_dts < (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;

        AVProgram *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++) {
                    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;
    }
    return 0;
}

static void update_initial_timestamps(AVFormatContext *s, int stream_index,
                                      int64_t dts, int64_t pts, AVPacket *pkt)
{
    AVStream *st= s->streams[stream_index];
    AVPacketList *pktl= s->parse_queue ? s->parse_queue : s->packet_buffer;
    int64_t pts_buffer[MAX_REORDER_DELAY+1];
    int64_t shift;
    int i, delay;