/*

  * muxing 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 "avformat.h"
 #include "avio_internal.h"
 #include "internal.h"
 #include "libavcodec/internal.h"
 #include "libavcodec/bytestream.h"
 #include "libavutil/opt.h"
 #include "libavutil/dict.h"
 #include "libavutil/pixdesc.h"

 #include "libavutil/timestamp.h"

 #include "metadata.h"
 #include "id3v2.h"
 #include "libavutil/avassert.h"
 #include "libavutil/avstring.h"

 #include "libavutil/internal.h"

 #include "libavutil/mathematics.h"
 #include "libavutil/parseutils.h"
 #include "libavutil/time.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

  * muxing functions for use within libavformat

  */
 
 /* fraction handling */
 
 /**
  * f = val + (num / den) + 0.5.
  *
  * 'num' is normalized so that it is such as 0 <= num < den.
  *
  * @param f fractional number
  * @param val integer value
  * @param num must be >= 0
  * @param den must be >= 1
  */
 static void frac_init(AVFrac *f, int64_t val, int64_t num, int64_t den)
 {
     num += (den >> 1);
     if (num >= den) {
         val += num / den;
         num  = num % den;
     }
     f->val = val;
     f->num = num;
     f->den = den;
 }
 
 /**
  * Fractional addition to f: f = f + (incr / f->den).
  *
  * @param f fractional number
  * @param incr increment, can be positive or negative
  */
 static void frac_add(AVFrac *f, int64_t incr)
 {
     int64_t num, den;
 
     num = f->num + incr;
     den = f->den;
     if (num < 0) {
         f->val += num / den;
         num     = num % den;
         if (num < 0) {
             num += den;
             f->val--;
         }
     } else if (num >= den) {
         f->val += num / den;
         num     = num % den;
     }
     f->num = num;
 }
 

 AVRational ff_choose_timebase(AVFormatContext *s, AVStream *st, int min_precission)
 {
     AVRational q;
     int j;
 
     if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO) {
         q = (AVRational){1, st->codec->sample_rate};
     } else {
         q = st->codec->time_base;
     }

     for (j=2; j<14; j+= 1+(j>2))

         while (q.den / q.num < min_precission && q.num % j == 0)
             q.num /= j;
     while (q.den / q.num < min_precission && q.den < (1<<24))
         q.den <<= 1;
 
     return q;
 }
 

 int avformat_alloc_output_context2(AVFormatContext **avctx, AVOutputFormat *oformat,
                                    const char *format, const char *filename)
 {
     AVFormatContext *s = avformat_alloc_context();
     int ret = 0;
 
     *avctx = NULL;
     if (!s)
         goto nomem;
 
     if (!oformat) {
         if (format) {
             oformat = av_guess_format(format, NULL, NULL);
             if (!oformat) {
                 av_log(s, AV_LOG_ERROR, "Requested output format '%s' is not a suitable output format\n", format);
                 ret = AVERROR(EINVAL);
                 goto error;
             }
         } else {
             oformat = av_guess_format(NULL, filename, NULL);
             if (!oformat) {
                 ret = AVERROR(EINVAL);
                 av_log(s, AV_LOG_ERROR, "Unable to find a suitable output format for '%s'\n",
                        filename);
                 goto error;
             }
         }
     }
 
     s->oformat = oformat;
     if (s->oformat->priv_data_size > 0) {
         s->priv_data = av_mallocz(s->oformat->priv_data_size);
         if (!s->priv_data)
             goto nomem;
         if (s->oformat->priv_class) {
             *(const AVClass**)s->priv_data= s->oformat->priv_class;
             av_opt_set_defaults(s->priv_data);
         }
     } else
         s->priv_data = NULL;
 
     if (filename)
         av_strlcpy(s->filename, filename, sizeof(s->filename));
     *avctx = s;
     return 0;
 nomem:
     av_log(s, AV_LOG_ERROR, "Out of memory\n");
     ret = AVERROR(ENOMEM);
 error:
     avformat_free_context(s);
     return ret;
 }
 
 #if FF_API_ALLOC_OUTPUT_CONTEXT
 AVFormatContext *avformat_alloc_output_context(const char *format,
                                                AVOutputFormat *oformat, const char *filename)
 {
     AVFormatContext *avctx;
     int ret = avformat_alloc_output_context2(&avctx, oformat, format, filename);
     return ret < 0 ? NULL : avctx;
 }
 #endif
 

 static int validate_codec_tag(AVFormatContext *s, AVStream *st)
 {
     const AVCodecTag *avctag;
     int n;
     enum AVCodecID id = AV_CODEC_ID_NONE;

     int64_t tag  = -1;

 
     /**
      * Check that tag + id is in the table
      * If neither is in the table -> OK
      * If tag is in the table with another id -> FAIL
      * If id is in the table with another tag -> FAIL unless strict < normal
      */
     for (n = 0; s->oformat->codec_tag[n]; n++) {
         avctag = s->oformat->codec_tag[n];
         while (avctag->id != AV_CODEC_ID_NONE) {
             if (avpriv_toupper4(avctag->tag) == avpriv_toupper4(st->codec->codec_tag)) {
                 id = avctag->id;
                 if (id == st->codec->codec_id)
                     return 1;
             }
             if (avctag->id == st->codec->codec_id)
                 tag = avctag->tag;
             avctag++;
         }
     }
     if (id != AV_CODEC_ID_NONE)
         return 0;

     if (tag >= 0 && (st->codec->strict_std_compliance >= FF_COMPLIANCE_NORMAL))

         return 0;
     return 1;
 }
 

 
 static int init_muxer(AVFormatContext *s, AVDictionary **options)

 {
     int ret = 0, i;
     AVStream *st;
     AVDictionary *tmp = NULL;

     AVCodecContext *codec = NULL;
     AVOutputFormat *of = s->oformat;

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

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

     if (s->priv_data && s->oformat->priv_class && *(const AVClass**)s->priv_data==s->oformat->priv_class &&
         (ret = av_opt_set_dict(s->priv_data, &tmp)) < 0)
         goto fail;

 
     // some sanity checks

     if (s->nb_streams == 0 && !(of->flags & AVFMT_NOSTREAMS)) {

         av_log(s, AV_LOG_ERROR, "No streams to mux were specified\n");

         ret = AVERROR(EINVAL);
         goto fail;
     }
 
     for (i = 0; i < s->nb_streams; i++) {

         st    = s->streams[i];
         codec = st->codec;

         switch (codec->codec_type) {

         case AVMEDIA_TYPE_AUDIO:

             if (codec->sample_rate <= 0) {

                 av_log(s, AV_LOG_ERROR, "sample rate not set\n");
                 ret = AVERROR(EINVAL);
                 goto fail;
             }

             if (!codec->block_align)
                 codec->block_align = codec->channels *
                                      av_get_bits_per_sample(codec->codec_id) >> 3;

             break;
         case AVMEDIA_TYPE_VIDEO:

             if (codec->time_base.num <= 0 ||
                 codec->time_base.den <= 0) { //FIXME audio too?

                 av_log(s, AV_LOG_ERROR, "time base not set\n");
                 ret = AVERROR(EINVAL);
                 goto fail;
             }

 
             if ((codec->width <= 0 || codec->height <= 0) &&
                 !(of->flags & AVFMT_NODIMENSIONS)) {

                 av_log(s, AV_LOG_ERROR, "dimensions not set\n");
                 ret = AVERROR(EINVAL);
                 goto fail;
             }

             if (av_cmp_q(st->sample_aspect_ratio, codec->sample_aspect_ratio)
                 && FFABS(av_q2d(st->sample_aspect_ratio) - av_q2d(codec->sample_aspect_ratio)) > 0.004*av_q2d(st->sample_aspect_ratio)

             ) {

                 if (st->sample_aspect_ratio.num != 0 &&
                     st->sample_aspect_ratio.den != 0 &&
                     codec->sample_aspect_ratio.den != 0 &&
                     codec->sample_aspect_ratio.den != 0) {
                     av_log(s, AV_LOG_ERROR, "Aspect ratio mismatch between muxer "

                            "(%d/%d) and encoder layer (%d/%d)\n",
                            st->sample_aspect_ratio.num, st->sample_aspect_ratio.den,
                            codec->sample_aspect_ratio.num,
                            codec->sample_aspect_ratio.den);

                     ret = AVERROR(EINVAL);
                     goto fail;
                 }

             }
             break;
         }
 

         if (of->codec_tag) {

             if (   codec->codec_tag
                 && codec->codec_id == AV_CODEC_ID_RAWVIDEO
                 && (   av_codec_get_tag(of->codec_tag, codec->codec_id) == 0
                     || av_codec_get_tag(of->codec_tag, codec->codec_id) == MKTAG('r', 'a', 'w', ' '))
                 && !validate_codec_tag(s, st)) {

                 // the current rawvideo encoding system ends up setting

                 // the wrong codec_tag for avi/mov, we override it here

                 codec->codec_tag = 0;

             }

             if (codec->codec_tag) {

                 if (!validate_codec_tag(s, st)) {

                     char tagbuf[32], tagbuf2[32];

                     av_get_codec_tag_string(tagbuf, sizeof(tagbuf), codec->codec_tag);

                     av_get_codec_tag_string(tagbuf2, sizeof(tagbuf2), av_codec_get_tag(s->oformat->codec_tag, codec->codec_id));

                     av_log(s, AV_LOG_ERROR,

                            "Tag %s/0x%08x incompatible with output codec id '%d' (%s)\n",

                            tagbuf, codec->codec_tag, codec->codec_id, tagbuf2);

                     ret = AVERROR_INVALIDDATA;
                     goto fail;
                 }
             } else

                 codec->codec_tag = av_codec_get_tag(of->codec_tag, codec->codec_id);

         }
 

         if (of->flags & AVFMT_GLOBALHEADER &&
             !(codec->flags & CODEC_FLAG_GLOBAL_HEADER))
             av_log(s, AV_LOG_WARNING,
                    "Codec for stream %d does not use global headers "
                    "but container format requires global headers\n", i);

 
         if (codec->codec_type != AVMEDIA_TYPE_ATTACHMENT)
             s->internal->nb_interleaved_streams++;

     }
 

     if (!s->priv_data && of->priv_data_size > 0) {
         s->priv_data = av_mallocz(of->priv_data_size);

         if (!s->priv_data) {
             ret = AVERROR(ENOMEM);
             goto fail;
         }

         if (of->priv_class) {
             *(const AVClass **)s->priv_data = of->priv_class;

             av_opt_set_defaults(s->priv_data);
             if ((ret = av_opt_set_dict(s->priv_data, &tmp)) < 0)
                 goto fail;
         }
     }
 
     /* set muxer identification string */
     if (s->nb_streams && !(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT)) {
         av_dict_set(&s->metadata, "encoder", LIBAVFORMAT_IDENT, 0);

     } else {
         av_dict_set(&s->metadata, "encoder", NULL, 0);

     }
 

     if (options) {
          av_dict_free(options);
          *options = tmp;

     }
 

     return 0;
 
 fail:
     av_dict_free(&tmp);
     return ret;
 }
 
 static int init_pts(AVFormatContext *s)
 {
     int i;
     AVStream *st;
 

     /* init PTS generation */
     for (i = 0; i < s->nb_streams; i++) {
         int64_t den = AV_NOPTS_VALUE;
         st = s->streams[i];
 
         switch (st->codec->codec_type) {
         case AVMEDIA_TYPE_AUDIO:
             den = (int64_t)st->time_base.num * st->codec->sample_rate;
             break;
         case AVMEDIA_TYPE_VIDEO:
             den = (int64_t)st->time_base.num * st->codec->time_base.den;
             break;
         default:
             break;
         }
         if (den != AV_NOPTS_VALUE) {

             if (den <= 0)
                 return AVERROR_INVALIDDATA;
 

             frac_init(&st->pts, 0, 0, den);
         }
     }
 

     return 0;
 }
 
 int avformat_write_header(AVFormatContext *s, AVDictionary **options)
 {
     int ret = 0;
 
     if (ret = init_muxer(s, options))
         return ret;
 
     if (s->oformat->write_header) {
         ret = s->oformat->write_header(s);

         if (ret >= 0 && s->pb && s->pb->error < 0)
             ret = s->pb->error;

         if (ret < 0)
             return ret;

     }

     if ((ret = init_pts(s)) < 0)

         return ret;
 

     if (s->avoid_negative_ts < 0) {
         if (s->oformat->flags & (AVFMT_TS_NEGATIVE | AVFMT_NOTIMESTAMPS)) {
             s->avoid_negative_ts = 0;
         } else
             s->avoid_negative_ts = 1;
     }
 

     return 0;
 }
 

 #define AV_PKT_FLAG_UNCODED_FRAME 0x2000
 
 /* Note: using sizeof(AVFrame) from outside lavu is unsafe in general, but
    it is only being used internally to this file as a consistency check.
    The value is chosen to be very unlikely to appear on its own and to cause
    immediate failure if used anywhere as a real size. */
 #define UNCODED_FRAME_PACKET_SIZE (INT_MIN / 3 * 2 + (int)sizeof(AVFrame))
 
 

 //FIXME merge with compute_pkt_fields
 static int compute_pkt_fields2(AVFormatContext *s, AVStream *st, AVPacket *pkt)
 {

     int delay = FFMAX(st->codec->has_b_frames, st->codec->max_b_frames > 0);

     int num, den, frame_size, i;
 

     av_dlog(s, "compute_pkt_fields2: pts:%s dts:%s cur_dts:%s b:%d size:%d st:%d\n",
             av_ts2str(pkt->pts), av_ts2str(pkt->dts), av_ts2str(st->cur_dts), delay, pkt->size, pkt->stream_index);

 
     /* duration field */
     if (pkt->duration == 0) {
         ff_compute_frame_duration(&num, &den, st, NULL, pkt);
         if (den && num) {
             pkt->duration = av_rescale(1, num * (int64_t)st->time_base.den * st->codec->ticks_per_frame, den * (int64_t)st->time_base.num);
         }
     }
 
     if (pkt->pts == AV_NOPTS_VALUE && pkt->dts != AV_NOPTS_VALUE && delay == 0)
         pkt->pts = pkt->dts;
 
     //XXX/FIXME this is a temporary hack until all encoders output pts
     if ((pkt->pts == 0 || pkt->pts == AV_NOPTS_VALUE) && pkt->dts == AV_NOPTS_VALUE && !delay) {

         static int warned;
         if (!warned) {
             av_log(s, AV_LOG_WARNING, "Encoder did not produce proper pts, making some up.\n");
             warned = 1;
         }

         pkt->dts =
 //        pkt->pts= st->cur_dts;
             pkt->pts = st->pts.val;
     }
 
     //calculate dts from pts
     if (pkt->pts != AV_NOPTS_VALUE && pkt->dts == AV_NOPTS_VALUE && delay <= MAX_REORDER_DELAY) {
         st->pts_buffer[0] = pkt->pts;
         for (i = 1; i < delay + 1 && st->pts_buffer[i] == AV_NOPTS_VALUE; i++)
             st->pts_buffer[i] = pkt->pts + (i - delay - 1) * pkt->duration;
         for (i = 0; i<delay && st->pts_buffer[i] > st->pts_buffer[i + 1]; i++)
             FFSWAP(int64_t, st->pts_buffer[i], st->pts_buffer[i + 1]);
 
         pkt->dts = st->pts_buffer[0];
     }
 
     if (st->cur_dts && st->cur_dts != AV_NOPTS_VALUE &&
         ((!(s->oformat->flags & AVFMT_TS_NONSTRICT) &&
           st->cur_dts >= pkt->dts) || st->cur_dts > pkt->dts)) {
         av_log(s, AV_LOG_ERROR,

                "Application provided invalid, non monotonically increasing dts to muxer in stream %d: %s >= %s\n",
                st->index, av_ts2str(st->cur_dts), av_ts2str(pkt->dts));

         return AVERROR(EINVAL);
     }
     if (pkt->dts != AV_NOPTS_VALUE && pkt->pts != AV_NOPTS_VALUE && pkt->pts < pkt->dts) {

         av_log(s, AV_LOG_ERROR, "pts (%s) < dts (%s) in stream %d\n",
                av_ts2str(pkt->pts), av_ts2str(pkt->dts), st->index);

         return AVERROR(EINVAL);
     }
 

     av_dlog(s, "av_write_frame: pts2:%s dts2:%s\n",
             av_ts2str(pkt->pts), av_ts2str(pkt->dts));

     st->cur_dts = pkt->dts;
     st->pts.val = pkt->dts;
 
     /* update pts */
     switch (st->codec->codec_type) {
     case AVMEDIA_TYPE_AUDIO:

         frame_size = (pkt->flags & AV_PKT_FLAG_UNCODED_FRAME) ?
                      ((AVFrame *)pkt->data)->nb_samples :
                      ff_get_audio_frame_size(st->codec, pkt->size, 1);

 
         /* HACK/FIXME, we skip the initial 0 size packets as they are most
          * likely equal to the encoder delay, but it would be better if we
          * had the real timestamps from the encoder */
         if (frame_size >= 0 && (pkt->size || st->pts.num != st->pts.den >> 1 || st->pts.val)) {
             frac_add(&st->pts, (int64_t)st->time_base.den * frame_size);
         }
         break;
     case AVMEDIA_TYPE_VIDEO:
         frac_add(&st->pts, (int64_t)st->time_base.den * st->codec->time_base.num);
         break;
     default:
         break;
     }
     return 0;
 }
 

 /**

  * Make timestamps non negative, move side data from payload to internal struct, call muxer, and restore
  * sidedata.
  *

  * FIXME: this function should NEVER get undefined pts/dts beside when the
  * AVFMT_NOTIMESTAMPS is set.
  * Those additional safety checks should be dropped once the correct checks
  * are set in the callers.

  */

 static int write_packet(AVFormatContext *s, AVPacket *pkt)

 {

     int ret, did_split;

     if (s->output_ts_offset) {
         AVStream *st = s->streams[pkt->stream_index];
         int64_t offset = av_rescale_q(s->output_ts_offset, AV_TIME_BASE_Q, st->time_base);
 
         if (pkt->dts != AV_NOPTS_VALUE)
             pkt->dts += offset;
         if (pkt->pts != AV_NOPTS_VALUE)
             pkt->pts += offset;
     }
 

     if (s->avoid_negative_ts > 0) {
         AVStream *st = s->streams[pkt->stream_index];

         int64_t offset = st->mux_ts_offset;

         if ((pkt->dts < 0 || s->avoid_negative_ts == 2) && pkt->dts != AV_NOPTS_VALUE && !s->offset) {

             s->offset = -pkt->dts;
             s->offset_timebase = st->time_base;

         }

         if (s->offset && !offset) {
             offset = st->mux_ts_offset =

                 av_rescale_q_rnd(s->offset,
                                  s->offset_timebase,
                                  st->time_base,
                                  AV_ROUND_UP);
         }
 
         if (pkt->dts != AV_NOPTS_VALUE)

             pkt->dts += offset;

         if (pkt->pts != AV_NOPTS_VALUE)

             pkt->pts += offset;

 
         av_assert2(pkt->dts == AV_NOPTS_VALUE || pkt->dts >= 0);

     }
 

     did_split = av_packet_split_side_data(pkt);

     if ((pkt->flags & AV_PKT_FLAG_UNCODED_FRAME)) {
         AVFrame *frame = (AVFrame *)pkt->data;
         av_assert0(pkt->size == UNCODED_FRAME_PACKET_SIZE);
         ret = s->oformat->write_uncoded_frame(s, pkt->stream_index, &frame, 0);
         av_frame_free(&frame);
     } else {
         ret = s->oformat->write_packet(s, pkt);
     }

     if (s->flush_packets && s->pb && ret >= 0 && s->flags & AVFMT_FLAG_FLUSH_PACKETS)

         avio_flush(s->pb);

     if (did_split)
         av_packet_merge_side_data(pkt);

     return ret;
 }
 

 static int check_packet(AVFormatContext *s, AVPacket *pkt)
 {
     if (!pkt)
         return 0;
 
     if (pkt->stream_index < 0 || pkt->stream_index >= s->nb_streams) {
         av_log(s, AV_LOG_ERROR, "Invalid packet stream index: %d\n",
                pkt->stream_index);
         return AVERROR(EINVAL);
     }
 
     if (s->streams[pkt->stream_index]->codec->codec_type == AVMEDIA_TYPE_ATTACHMENT) {
         av_log(s, AV_LOG_ERROR, "Received a packet for an attachment stream.\n");
         return AVERROR(EINVAL);
     }
 
     return 0;
 }
 

 int av_write_frame(AVFormatContext *s, AVPacket *pkt)
 {
     int ret;
 

     ret = check_packet(s, pkt);
     if (ret < 0)
         return ret;
 

     if (!pkt) {

         if (s->oformat->flags & AVFMT_ALLOW_FLUSH) {

             ret = s->oformat->write_packet(s, NULL);

             if (s->flush_packets && s->pb && s->pb->error >= 0)
                 avio_flush(s->pb);

             if (ret >= 0 && s->pb && s->pb->error < 0)
                 ret = s->pb->error;
             return ret;
         }

         return 1;
     }
 
     ret = compute_pkt_fields2(s, s->streams[pkt->stream_index], pkt);
 
     if (ret < 0 && !(s->oformat->flags & AVFMT_NOTIMESTAMPS))
         return ret;
 

     ret = write_packet(s, pkt);

     if (ret >= 0 && s->pb && s->pb->error < 0)
         ret = s->pb->error;

 
     if (ret >= 0)
         s->streams[pkt->stream_index]->nb_frames++;
     return ret;
 }
 

 #define CHUNK_START 0x1000
 
 int ff_interleave_add_packet(AVFormatContext *s, AVPacket *pkt,

                               int (*compare)(AVFormatContext *, AVPacket *, AVPacket *))
 {
     AVPacketList **next_point, *this_pktl;

     AVStream *st   = s->streams[pkt->stream_index];
     int chunked    = s->max_chunk_size || s->max_chunk_duration;

     int ret;

 
     this_pktl      = av_mallocz(sizeof(AVPacketList));

     if (!this_pktl)
         return AVERROR(ENOMEM);

     this_pktl->pkt = *pkt;

 #if FF_API_DESTRUCT_PACKET

 FF_DISABLE_DEPRECATION_WARNINGS

     pkt->destruct  = NULL;           // do not free original but only the copy

 FF_ENABLE_DEPRECATION_WARNINGS

 #endif
     pkt->buf       = NULL;

     if ((pkt->flags & AV_PKT_FLAG_UNCODED_FRAME)) {
         av_assert0(pkt->size == UNCODED_FRAME_PACKET_SIZE);
         av_assert0(((AVFrame *)pkt->data)->buf);
     } else {

         // duplicate the packet if it uses non-allocated memory
         if ((ret = av_dup_packet(&this_pktl->pkt)) < 0) {
             av_free(this_pktl);
             return ret;
         }

         av_copy_packet_side_data(&this_pktl->pkt, &this_pktl->pkt); // copy side data
     }

 
     if (s->streams[pkt->stream_index]->last_in_packet_buffer) {

         next_point = &(st->last_in_packet_buffer->next);
     } else {

         next_point = &s->packet_buffer;

     }

     if (chunked) {
         uint64_t max= av_rescale_q_rnd(s->max_chunk_duration, AV_TIME_BASE_Q, st->time_base, AV_ROUND_UP);

         st->interleaver_chunk_size     += pkt->size;
         st->interleaver_chunk_duration += pkt->duration;

         if (   (s->max_chunk_size && st->interleaver_chunk_size > s->max_chunk_size)
             || (max && st->interleaver_chunk_duration           > max)) {

             st->interleaver_chunk_size      = 0;

             this_pktl->pkt.flags |= CHUNK_START;

             if (max && st->interleaver_chunk_duration > max) {
                 int64_t syncoffset = (st->codec->codec_type == AVMEDIA_TYPE_VIDEO)*max/2;
                 int64_t syncto = av_rescale(pkt->dts + syncoffset, 1, max)*max - syncoffset;
 
                 st->interleaver_chunk_duration += (pkt->dts - syncto)/8 - max;
             } else
                 st->interleaver_chunk_duration = 0;

         }

     }
     if (*next_point) {
         if (chunked && !(this_pktl->pkt.flags & CHUNK_START))
             goto next_non_null;

         if (compare(s, &s->packet_buffer_end->pkt, pkt)) {

             while (   *next_point
                    && ((chunked && !((*next_point)->pkt.flags&CHUNK_START))
                        || !compare(s, &(*next_point)->pkt, pkt)))

                 next_point = &(*next_point)->next;

             if (*next_point)
                 goto next_non_null;

         } else {
             next_point = &(s->packet_buffer_end->next);
         }
     }

     av_assert1(!*next_point);

 
     s->packet_buffer_end = this_pktl;
 next_non_null:
 
     this_pktl->next = *next_point;
 
     s->streams[pkt->stream_index]->last_in_packet_buffer =
         *next_point                                      = this_pktl;

     return 0;

 }
 

 static int interleave_compare_dts(AVFormatContext *s, AVPacket *next,
                                   AVPacket *pkt)

 {
     AVStream *st  = s->streams[pkt->stream_index];
     AVStream *st2 = s->streams[next->stream_index];
     int comp      = av_compare_ts(next->dts, st2->time_base, pkt->dts,
                                   st->time_base);

     if (s->audio_preload && ((st->codec->codec_type == AVMEDIA_TYPE_AUDIO) != (st2->codec->codec_type == AVMEDIA_TYPE_AUDIO))) {
         int64_t ts = av_rescale_q(pkt ->dts, st ->time_base, AV_TIME_BASE_Q) - s->audio_preload*(st ->codec->codec_type == AVMEDIA_TYPE_AUDIO);
         int64_t ts2= av_rescale_q(next->dts, st2->time_base, AV_TIME_BASE_Q) - s->audio_preload*(st2->codec->codec_type == AVMEDIA_TYPE_AUDIO);
         if (ts == ts2) {
             ts= ( pkt ->dts* st->time_base.num*AV_TIME_BASE - s->audio_preload*(int64_t)(st ->codec->codec_type == AVMEDIA_TYPE_AUDIO)* st->time_base.den)*st2->time_base.den
                -( next->dts*st2->time_base.num*AV_TIME_BASE - s->audio_preload*(int64_t)(st2->codec->codec_type == AVMEDIA_TYPE_AUDIO)*st2->time_base.den)* st->time_base.den;
             ts2=0;
         }
         comp= (ts>ts2) - (ts<ts2);
     }

 
     if (comp == 0)
         return pkt->stream_index < next->stream_index;
     return comp > 0;
 }
 
 int ff_interleave_packet_per_dts(AVFormatContext *s, AVPacket *out,
                                  AVPacket *pkt, int flush)
 {
     AVPacketList *pktl;

     int stream_count = 0, noninterleaved_count = 0;
     int i, ret;

 
     if (pkt) {

         ret = ff_interleave_add_packet(s, pkt, interleave_compare_dts);

         if (ret < 0)
             return ret;

     }
 

     for (i = 0; i < s->nb_streams; i++) {
         if (s->streams[i]->last_in_packet_buffer) {
             ++stream_count;
         } else if (s->streams[i]->codec->codec_type == AVMEDIA_TYPE_SUBTITLE) {
             ++noninterleaved_count;
         }
     }

     if (s->internal->nb_interleaved_streams == stream_count)

         flush = 1;

     if (s->max_interleave_delta > 0 && s->packet_buffer && !flush) {
         AVPacket *top_pkt = &s->packet_buffer->pkt;
         int64_t delta_dts = INT64_MIN;
         int64_t top_dts = av_rescale_q(top_pkt->dts,
                                        s->streams[top_pkt->stream_index]->time_base,
                                        AV_TIME_BASE_Q);
 
         for (i = 0; i < s->nb_streams; i++) {
             int64_t last_dts;
             const AVPacketList *last = s->streams[i]->last_in_packet_buffer;
 
             if (!last)
                 continue;
 
             last_dts = av_rescale_q(last->pkt.dts,
                                     s->streams[i]->time_base,
                                     AV_TIME_BASE_Q);
             delta_dts = FFMAX(delta_dts, last_dts - top_dts);

         }

 
         if (delta_dts > s->max_interleave_delta) {
             av_log(s, AV_LOG_DEBUG,
                    "Delay between the first packet and last packet in the "
                    "muxing queue is %"PRId64" > %"PRId64": forcing output\n",
                    delta_dts, s->max_interleave_delta);

             flush = 1;
         }
     }

     if (stream_count && flush) {
         AVStream *st;

         pktl = s->packet_buffer;
         *out = pktl->pkt;

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

 
         s->packet_buffer = pktl->next;
         if (!s->packet_buffer)
             s->packet_buffer_end = NULL;
 

         if (st->last_in_packet_buffer == pktl)
             st->last_in_packet_buffer = NULL;

         av_freep(&pktl);

         return 1;
     } else {
         av_init_packet(out);
         return 0;
     }
 }
 
 /**
  * Interleave an AVPacket correctly so it can be muxed.
  * @param out the interleaved packet will be output here
  * @param in the input packet
  * @param flush 1 if no further packets are available as input and all
  *              remaining packets should be output
  * @return 1 if a packet was output, 0 if no packet could be output,
  *         < 0 if an error occurred
  */
 static int interleave_packet(AVFormatContext *s, AVPacket *out, AVPacket *in, int flush)
 {
     if (s->oformat->interleave_packet) {
         int ret = s->oformat->interleave_packet(s, out, in, flush);
         if (in)
             av_free_packet(in);
         return ret;
     } else
         return ff_interleave_packet_per_dts(s, out, in, flush);
 }
 
 int av_interleaved_write_frame(AVFormatContext *s, AVPacket *pkt)
 {
     int ret, flush = 0;
 

     ret = check_packet(s, pkt);
     if (ret < 0)

         goto fail;

     if (pkt) {
         AVStream *st = s->streams[pkt->stream_index];
 
         //FIXME/XXX/HACK drop zero sized packets

         if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO && pkt->size == 0) {
             ret = 0;
             goto fail;
         }

         av_dlog(s, "av_interleaved_write_frame size:%d dts:%s pts:%s\n",
                 pkt->size, av_ts2str(pkt->dts), av_ts2str(pkt->pts));

         if ((ret = compute_pkt_fields2(s, st, pkt)) < 0 && !(s->oformat->flags & AVFMT_NOTIMESTAMPS))

             goto fail;

         if (pkt->dts == AV_NOPTS_VALUE && !(s->oformat->flags & AVFMT_NOTIMESTAMPS)) {
             ret = AVERROR(EINVAL);
             goto fail;
         }

     } else {
         av_dlog(s, "av_interleaved_write_frame FLUSH\n");
         flush = 1;
     }
 
     for (;; ) {
         AVPacket opkt;
         int ret = interleave_packet(s, &opkt, pkt, flush);

         if (pkt) {
             memset(pkt, 0, sizeof(*pkt));
             av_init_packet(pkt);
             pkt = NULL;
         }

         if (ret <= 0) //FIXME cleanup needed for ret<0 ?
             return ret;
 

         ret = write_packet(s, &opkt);

         if (ret >= 0)
             s->streams[opkt.stream_index]->nb_frames++;
 
         av_free_packet(&opkt);
 
         if (ret < 0)
             return ret;

         if(s->pb && s->pb->error)
             return s->pb->error;

     }

 fail:
     av_packet_unref(pkt);
     return ret;

 }
 
 int av_write_trailer(AVFormatContext *s)
 {
     int ret, i;
 
     for (;; ) {
         AVPacket pkt;
         ret = interleave_packet(s, &pkt, NULL, 1);
         if (ret < 0) //FIXME cleanup needed for ret<0 ?
             goto fail;
         if (!ret)
             break;
 

         ret = write_packet(s, &pkt);

         if (ret >= 0)
             s->streams[pkt.stream_index]->nb_frames++;
 
         av_free_packet(&pkt);
 
         if (ret < 0)
             goto fail;

         if(s->pb && s->pb->error)
             goto fail;

     }
 
     if (s->oformat->write_trailer)
         ret = s->oformat->write_trailer(s);
 
 fail:

     if (s->pb)
        avio_flush(s->pb);
     if (ret == 0)
        ret = s->pb ? s->pb->error : 0;

     for (i = 0; i < s->nb_streams; i++) {
         av_freep(&s->streams[i]->priv_data);
         av_freep(&s->streams[i]->index_entries);
     }
     if (s->oformat->priv_class)
         av_opt_free(s->priv_data);
     av_freep(&s->priv_data);
     return ret;
 }

 
 int av_get_output_timestamp(struct AVFormatContext *s, int stream,
                             int64_t *dts, int64_t *wall)
 {
     if (!s->oformat || !s->oformat->get_output_timestamp)
         return AVERROR(ENOSYS);
     s->oformat->get_output_timestamp(s, stream, dts, wall);
     return 0;

 }

 int ff_write_chained(AVFormatContext *dst, int dst_stream, AVPacket *pkt,
                      AVFormatContext *src)
 {
     AVPacket local_pkt;
 
     local_pkt = *pkt;
     local_pkt.stream_index = dst_stream;
     if (pkt->pts != AV_NOPTS_VALUE)
         local_pkt.pts = av_rescale_q(pkt->pts,
                                      src->streams[pkt->stream_index]->time_base,
                                      dst->streams[dst_stream]->time_base);
     if (pkt->dts != AV_NOPTS_VALUE)
         local_pkt.dts = av_rescale_q(pkt->dts,
                                      src->streams[pkt->stream_index]->time_base,
                                      dst->streams[dst_stream]->time_base);

     if (pkt->duration)
         local_pkt.duration = av_rescale_q(pkt->duration,
                                           src->streams[pkt->stream_index]->time_base,
                                           dst->streams[dst_stream]->time_base);

     return av_write_frame(dst, &local_pkt);
 }

 
 static int av_write_uncoded_frame_internal(AVFormatContext *s, int stream_index,
                                            AVFrame *frame, int interleaved)
 {
     AVPacket pkt, *pktp;
 
     av_assert0(s->oformat);
     if (!s->oformat->write_uncoded_frame)
         return AVERROR(ENOSYS);
 
     if (!frame) {
         pktp = NULL;
     } else {
         pktp = &pkt;
         av_init_packet(&pkt);
         pkt.data = (void *)frame;
         pkt.size         = UNCODED_FRAME_PACKET_SIZE;
         pkt.pts          =
         pkt.dts          = frame->pts;
         pkt.duration     = av_frame_get_pkt_duration(frame);
         pkt.stream_index = stream_index;
         pkt.flags |= AV_PKT_FLAG_UNCODED_FRAME;
     }
 
     return interleaved ? av_interleaved_write_frame(s, pktp) :
                          av_write_frame(s, pktp);
 }
 
 int av_write_uncoded_frame(AVFormatContext *s, int stream_index,
                            AVFrame *frame)
 {
     return av_write_uncoded_frame_internal(s, stream_index, frame, 0);
 }
 
 int av_interleaved_write_uncoded_frame(AVFormatContext *s, int stream_index,
                                        AVFrame *frame)
 {
     return av_write_uncoded_frame_internal(s, stream_index, frame, 1);
 }
 
 int av_write_uncoded_frame_query(AVFormatContext *s, int stream_index)
 {
     av_assert0(s->oformat);
     if (!s->oformat->write_uncoded_frame)
         return AVERROR(ENOSYS);
     return s->oformat->write_uncoded_frame(s, stream_index, NULL,
                                            AV_WRITE_UNCODED_FRAME_QUERY);
 }