/*

  * AVI muxer

  * Copyright (c) 2000 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 "internal.h"

 #include "avi.h"

 #include "avio_internal.h"

 #include "riff.h"

 #include "mpegts.h"

 #include "libavformat/avlanguage.h"
 #include "libavutil/avstring.h"

 #include "libavutil/internal.h"

 #include "libavutil/intreadwrite.h"

 #include "libavutil/dict.h"

 #include "libavutil/avassert.h"

 #include "libavutil/timestamp.h"

 #include "libavutil/opt.h"

 #include "libavutil/pixdesc.h"
 #include "libavcodec/raw.h"

 
 /*

  * TODO:

  *  - fill all fields if non streamed (nb_frames for example)
  */
 

 typedef struct AVIIentry {

     unsigned int flags, pos, len;

 } AVIIentry;
 
 #define AVI_INDEX_CLUSTER_SIZE 16384
 
 typedef struct AVIIndex {

     int64_t     indx_start;

     int64_t     audio_strm_offset;

     int         entry;
     int         ents_allocated;

     int         master_odml_riff_id_base;

     AVIIentry** cluster;

 } AVIIndex;
 

 typedef struct AVIContext {

     const AVClass *class;

     int64_t riff_start, movi_list, odml_list;

     int64_t frames_hdr_all;

     int riff_id;

     int write_channel_mask;

 } AVIContext;
 

 typedef struct AVIStream {

     int64_t frames_hdr_strm;

     int64_t audio_strm_length;

     int packet_count;

     int entry;

     int max_size;

     int sample_requested;

     int64_t last_dts;
 

     AVIIndex indexes;

 } AVIStream;

 static int avi_write_packet(AVFormatContext *s, AVPacket *pkt);
 

 static inline AVIIentry *avi_get_ientry(const AVIIndex *idx, int ent_id)

 {
     int cl = ent_id / AVI_INDEX_CLUSTER_SIZE;
     int id = ent_id % AVI_INDEX_CLUSTER_SIZE;
     return &idx->cluster[cl][id];
 }
 

 static int64_t avi_start_new_riff(AVFormatContext *s, AVIOContext *pb,

                                   const char *riff_tag, const char *list_tag)

 {

     AVIContext *avi = s->priv_data;

     int64_t loff;

     int i;

     avi->riff_id++;

     for (i = 0; i < s->nb_streams; i++) {
         AVIStream *avist = s->streams[i]->priv_data;

         avist->indexes.audio_strm_offset = avist->audio_strm_length;

         avist->indexes.entry = 0;
     }

     avi->riff_start = ff_start_tag(pb, "RIFF");

     ffio_wfourcc(pb, riff_tag);

     loff = ff_start_tag(pb, "LIST");

     ffio_wfourcc(pb, list_tag);

     return loff;
 }
 

 static char *avi_stream2fourcc(char *tag, int index, enum AVMediaType type)

 {

     tag[0] = '0' + index / 10;
     tag[1] = '0' + index % 10;

     if (type == AVMEDIA_TYPE_VIDEO) {

         tag[2] = 'd';
         tag[3] = 'c';

     } else if (type == AVMEDIA_TYPE_SUBTITLE) {

         // note: this is not an official code
         tag[2] = 's';
         tag[3] = 'b';

     } else {
         tag[2] = 'w';
         tag[3] = 'b';
     }
     tag[4] = '\0';
     return tag;
 }
 

 static int avi_write_counters(AVFormatContext *s, int riff_id)

 {

     AVIOContext *pb = s->pb;

     AVIContext *avi = s->priv_data;
     int n, au_byterate, au_ssize, au_scale, nb_frames = 0;

     int64_t file_size;

     AVCodecContext *stream;

     file_size = avio_tell(pb);

     for (n = 0; n < s->nb_streams; n++) {
         AVIStream *avist = s->streams[n]->priv_data;

         av_assert0(avist->frames_hdr_strm);

         stream = s->streams[n]->codec;

         avio_seek(pb, avist->frames_hdr_strm, SEEK_SET);

         ff_parse_specific_params(s->streams[n], &au_byterate, &au_ssize, &au_scale);

         if (au_ssize == 0)

             avio_wl32(pb, avist->packet_count);

         else

             avio_wl32(pb, avist->audio_strm_length / au_ssize);

         if (stream->codec_type == AVMEDIA_TYPE_VIDEO)

             nb_frames = FFMAX(nb_frames, avist->packet_count);

     }

     if (riff_id == 1) {

         av_assert0(avi->frames_hdr_all);

         avio_seek(pb, avi->frames_hdr_all, SEEK_SET);

         avio_wl32(pb, nb_frames);

     }

     avio_seek(pb, file_size, SEEK_SET);

 
     return 0;
 }
 

 static void write_odml_master(AVFormatContext *s, int stream_index)
 {
     AVIOContext *pb = s->pb;
     AVStream *st = s->streams[stream_index];
     AVCodecContext *enc = st->codec;
     AVIStream *avist = st->priv_data;
     unsigned char tag[5];
     int j;
 
     /* Starting to lay out AVI OpenDML master index.
         * We want to make it JUNK entry for now, since we'd
         * like to get away without making AVI an OpenDML one
         * for compatibility reasons. */
     avist->indexes.indx_start = ff_start_tag(pb, "JUNK");
     avio_wl16(pb, 4);   /* wLongsPerEntry */
     avio_w8(pb, 0);     /* bIndexSubType (0 == frame index) */
     avio_w8(pb, 0);     /* bIndexType (0 == AVI_INDEX_OF_INDEXES) */
     avio_wl32(pb, 0);   /* nEntriesInUse (will fill out later on) */
     ffio_wfourcc(pb, avi_stream2fourcc(tag, stream_index, enc->codec_type));
                         /* dwChunkId */
     avio_wl64(pb, 0);   /* dwReserved[3] */

     avio_wl32(pb, 0);   /* Must be 0.    */

     for (j = 0; j < AVI_MASTER_INDEX_SIZE * 2; j++)
         avio_wl64(pb, 0);
     ff_end_tag(pb, avist->indexes.indx_start);
 }
 

 static int avi_write_header(AVFormatContext *s)
 {

     AVIContext *avi = s->priv_data;

     AVIOContext *pb = s->pb;

     int bitrate, n, i, nb_frames, au_byterate, au_ssize, au_scale;

     AVCodecContext *video_enc;

     AVStream *video_st = NULL;

     int64_t list1, list2, strh, strf;

     AVDictionaryEntry *t = NULL;

     int padding;

     if (s->nb_streams > AVI_MAX_STREAM_COUNT) {
         av_log(s, AV_LOG_ERROR, "AVI does not support >%d streams\n",
                AVI_MAX_STREAM_COUNT);

         return AVERROR(EINVAL);

     }
 

     for (n = 0; n < s->nb_streams; n++) {
         s->streams[n]->priv_data = av_mallocz(sizeof(AVIStream));
         if (!s->streams[n]->priv_data)

             return AVERROR(ENOMEM);
     }
 

     /* header list */

     avi->riff_id = 0;

     list1 = avi_start_new_riff(s, pb, "AVI ", "hdrl");

 
     /* avi header */

     ffio_wfourcc(pb, "avih");

     avio_wl32(pb, 14 * 4);

     bitrate = 0;
 
     video_enc = NULL;

     for (n = 0; n < s->nb_streams; n++) {

         AVCodecContext *codec = s->streams[n]->codec;
         bitrate += codec->bit_rate;

         if (codec->codec_type == AVMEDIA_TYPE_VIDEO) {

             video_enc = codec;

             video_st = s->streams[n];
         }

     }

     nb_frames = 0;
 

     // TODO: should be avg_frame_rate
     if (video_st)
         avio_wl32(pb, (uint32_t) (INT64_C(1000000) * video_st->time_base.num /
                                   video_st->time_base.den));

     else

         avio_wl32(pb, 0);
     avio_wl32(pb, bitrate / 8); /* XXX: not quite exact */
     avio_wl32(pb, 0); /* padding */

     if (!pb->seekable)

         avio_wl32(pb, AVIF_TRUSTCKTYPE | AVIF_ISINTERLEAVED);  /* flags */

     else

         avio_wl32(pb, AVIF_TRUSTCKTYPE | AVIF_HASINDEX | AVIF_ISINTERLEAVED);  /* flags */

     avi->frames_hdr_all = avio_tell(pb); /* remember this offset to fill later */

     avio_wl32(pb, nb_frames); /* nb frames, filled later */
     avio_wl32(pb, 0); /* initial frame */
     avio_wl32(pb, s->nb_streams); /* nb streams */
     avio_wl32(pb, 1024 * 1024); /* suggested buffer size */

     if (video_enc) {

         avio_wl32(pb, video_enc->width);
         avio_wl32(pb, video_enc->height);

     } else {

         avio_wl32(pb, 0);
         avio_wl32(pb, 0);

     }

     avio_wl32(pb, 0); /* reserved */
     avio_wl32(pb, 0); /* reserved */
     avio_wl32(pb, 0); /* reserved */
     avio_wl32(pb, 0); /* reserved */

     /* stream list */

     for (i = 0; i < n; i++) {

         AVStream *st = s->streams[i];
         AVCodecContext *enc = st->codec;
         AVIStream *avist = st->priv_data;

         list2 = ff_start_tag(pb, "LIST");

         ffio_wfourcc(pb, "strl");

         /* stream generic header */

         strh = ff_start_tag(pb, "strh");

         switch (enc->codec_type) {

         case AVMEDIA_TYPE_SUBTITLE:

             // XSUB subtitles behave like video tracks, other subtitles
             // are not (yet) supported.

             if (enc->codec_id != AV_CODEC_ID_XSUB) {

                 av_log(s, AV_LOG_ERROR,
                        "Subtitle streams other than DivX XSUB are not supported by the AVI muxer.\n");

                 return AVERROR_PATCHWELCOME;
             }

         case AVMEDIA_TYPE_VIDEO:
             ffio_wfourcc(pb, "vids");
             break;
         case AVMEDIA_TYPE_AUDIO:
             ffio_wfourcc(pb, "auds");
             break;
 //      case AVMEDIA_TYPE_TEXT:
 //          ffio_wfourcc(pb, "txts");
 //          break;
         case AVMEDIA_TYPE_DATA:
             ffio_wfourcc(pb, "dats");
             break;

         }

         if (enc->codec_type == AVMEDIA_TYPE_VIDEO ||
             enc->codec_id == AV_CODEC_ID_XSUB)
             avio_wl32(pb, enc->codec_tag);

         else

             avio_wl32(pb, 1);
         avio_wl32(pb, 0); /* flags */
         avio_wl16(pb, 0); /* priority */
         avio_wl16(pb, 0); /* language */
         avio_wl32(pb, 0); /* initial frame */

         ff_parse_specific_params(st, &au_byterate, &au_ssize, &au_scale);

         if (   enc->codec_type == AVMEDIA_TYPE_VIDEO
             && enc->codec_id != AV_CODEC_ID_XSUB

             && au_byterate > 1000LL*au_scale) {
             au_byterate = 600;
             au_scale    = 1;
         }

         avpriv_set_pts_info(st, 64, au_scale, au_byterate);
         if (enc->codec_id == AV_CODEC_ID_XSUB)

             au_scale = au_byterate = 0;
 

         avio_wl32(pb, au_scale); /* scale */
         avio_wl32(pb, au_byterate); /* rate */

         avio_wl32(pb, 0); /* start */

         /* remember this offset to fill later */
         avist->frames_hdr_strm = avio_tell(pb);

         if (!pb->seekable)

             /* FIXME: this may be broken, but who cares */
             avio_wl32(pb, AVI_MAX_RIFF_SIZE);

         else

             avio_wl32(pb, 0);  /* length, XXX: filled later */

         /* suggested buffer size, is set to largest chunk size in avi_write_trailer */

         if (enc->codec_type == AVMEDIA_TYPE_VIDEO)

             avio_wl32(pb, 1024 * 1024);

         else if (enc->codec_type == AVMEDIA_TYPE_AUDIO)

             avio_wl32(pb, 12 * 1024);

         else

             avio_wl32(pb, 0);
         avio_wl32(pb, -1); /* quality */
         avio_wl32(pb, au_ssize); /* sample size */
         avio_wl32(pb, 0);

         avio_wl16(pb, enc->width);
         avio_wl16(pb, enc->height);

         ff_end_tag(pb, strh);

         if (enc->codec_type != AVMEDIA_TYPE_DATA) {

             int ret, flags;

             enum AVPixelFormat pix_fmt;

             strf = ff_start_tag(pb, "strf");

             switch (enc->codec_type) {

             case AVMEDIA_TYPE_SUBTITLE:
                 /* XSUB subtitles behave like video tracks, other subtitles
                  * are not (yet) supported. */

                 if (enc->codec_id != AV_CODEC_ID_XSUB)

                     break;
             case AVMEDIA_TYPE_VIDEO:

                 /* WMP expects RGB 5:5:5 rawvideo in avi to have bpp set to 16. */

                 if (  !enc->codec_tag
                     && enc->codec_id == AV_CODEC_ID_RAWVIDEO
                     && enc->pix_fmt == AV_PIX_FMT_RGB555LE
                     && enc->bits_per_coded_sample == 15)
                     enc->bits_per_coded_sample = 16;
                 ff_put_bmp_header(pb, enc, ff_codec_bmp_tags, 0, 0);

                 pix_fmt = avpriv_find_pix_fmt(avpriv_pix_fmt_bps_avi,

                                               enc->bits_per_coded_sample);
                 if (   !enc->codec_tag
                     && enc->codec_id == AV_CODEC_ID_RAWVIDEO
                     && enc->pix_fmt != pix_fmt
                     && enc->pix_fmt != AV_PIX_FMT_NONE)

                     av_log(s, AV_LOG_ERROR, "%s rawvideo cannot be written to avi, output file will be unreadable\n",

                           av_get_pix_fmt_name(enc->pix_fmt));

                 break;
             case AVMEDIA_TYPE_AUDIO:

                 flags = (avi->write_channel_mask == 0) ? FF_PUT_WAV_HEADER_SKIP_CHANNELMASK : 0;
                 if ((ret = ff_put_wav_header(pb, enc, flags)) < 0)

                     return ret;

                 break;
             default:

                 av_log(s, AV_LOG_ERROR,
                     "Invalid or not supported codec type '%s' found in the input\n",

                     (char *)av_x_if_null(av_get_media_type_string(enc->codec_type), "?"));

                 return AVERROR(EINVAL);

             }

             ff_end_tag(pb, strf);

             if ((t = av_dict_get(st->metadata, "title", NULL, 0))) {

                 ff_riff_write_info_tag(s->pb, "strn", t->value);
                 t = NULL;
             }

             if (enc->codec_id == AV_CODEC_ID_XSUB

             && (t = av_dict_get(s->streams[i]->metadata, "language", NULL, 0))) {
                 const char* langstr = av_convert_lang_to(t->value, AV_LANG_ISO639_1);
                 t = NULL;
                 if (langstr) {
                     char* str = av_asprintf("Subtitle - %s-xx;02", langstr);

                     if (!str)
                         return AVERROR(ENOMEM);

                     ff_riff_write_info_tag(s->pb, "strn", str);
                     av_free(str);
                 }

             }
         }

         if (pb->seekable) {

             write_odml_master(s, i);

         }

         if (enc->codec_type == AVMEDIA_TYPE_VIDEO   &&
             st->sample_aspect_ratio.num > 0 &&
             st->sample_aspect_ratio.den > 0) {

             int vprp       = ff_start_tag(pb, "vprp");

             AVRational dar = av_mul_q(st->sample_aspect_ratio,
                                       (AVRational) { enc->width,
                                                      enc->height });

             int num, den;
             av_reduce(&num, &den, dar.num, dar.den, 0xFFFF);
 

             avio_wl32(pb, 0); // video format   = unknown
             avio_wl32(pb, 0); // video standard = unknown

             // TODO: should be avg_frame_rate

             avio_wl32(pb, (2LL*st->time_base.den + st->time_base.num - 1) / (2LL * st->time_base.num));

             avio_wl32(pb, enc->width);
             avio_wl32(pb, enc->height);

             avio_wl16(pb, den);
             avio_wl16(pb, num);

             avio_wl32(pb, enc->width);
             avio_wl32(pb, enc->height);

             avio_wl32(pb, 1); // progressive FIXME

             avio_wl32(pb, enc->height);
             avio_wl32(pb, enc->width);
             avio_wl32(pb, enc->height);
             avio_wl32(pb, enc->width);

             avio_wl32(pb, 0);
             avio_wl32(pb, 0);
 
             avio_wl32(pb, 0);
             avio_wl32(pb, 0);

             ff_end_tag(pb, vprp);

         }
 

         ff_end_tag(pb, list2);

     }

     if (pb->seekable) {

         /* AVI could become an OpenDML one, if it grows beyond 2Gb range */

         avi->odml_list = ff_start_tag(pb, "JUNK");

         ffio_wfourcc(pb, "odml");
         ffio_wfourcc(pb, "dmlh");

         avio_wl32(pb, 248);

         for (i = 0; i < 248; i += 4)
             avio_wl32(pb, 0);

         ff_end_tag(pb, avi->odml_list);

     }

     ff_end_tag(pb, list1);

     ff_riff_write_info(s);

 
     padding = s->metadata_header_padding;
     if (padding < 0)
         padding = 1016;
 

     /* some padding for easier tag editing */

     if (padding) {

         list2 = ff_start_tag(pb, "JUNK");
         for (i = padding; i > 0; i -= 4)
             avio_wl32(pb, 0);
         ff_end_tag(pb, list2);

     }

     avi->movi_list = ff_start_tag(pb, "LIST");

     ffio_wfourcc(pb, "movi");

     avio_flush(pb);

 
     return 0;
 }
 

 static void update_odml_entry(AVFormatContext *s, int stream_index, int64_t ix, int size)

 {
     AVIOContext *pb = s->pb;
     AVIContext *avi = s->priv_data;
     AVIStream *avist = s->streams[stream_index]->priv_data;
     int64_t pos;
     int au_byterate, au_ssize, au_scale;
 
     avio_flush(pb);
     pos = avio_tell(pb);
 
     /* Updating one entry in the AVI OpenDML master index */
     avio_seek(pb, avist->indexes.indx_start - 8, SEEK_SET);
     ffio_wfourcc(pb, "indx");             /* enabling this entry */
     avio_skip(pb, 8);

     avio_wl32(pb, avi->riff_id - avist->indexes.master_odml_riff_id_base);          /* nEntriesInUse */
     avio_skip(pb, 16 * (avi->riff_id - avist->indexes.master_odml_riff_id_base));

     avio_wl64(pb, ix);                    /* qwOffset */

     avio_wl32(pb, size);                  /* dwSize */

     ff_parse_specific_params(s->streams[stream_index], &au_byterate, &au_ssize, &au_scale);
     if (s->streams[stream_index]->codec->codec_type == AVMEDIA_TYPE_AUDIO && au_ssize > 0) {
         uint32_t audio_segm_size = (avist->audio_strm_length - avist->indexes.audio_strm_offset);
         if ((audio_segm_size % au_ssize > 0) && !avist->sample_requested) {
             avpriv_request_sample(s, "OpenDML index duration for audio packets with partial frames");
             avist->sample_requested = 1;
         }
         avio_wl32(pb, audio_segm_size / au_ssize);  /* dwDuration (sample count) */
     } else
         avio_wl32(pb, avist->indexes.entry);  /* dwDuration (packet count) */
 
     avio_seek(pb, pos, SEEK_SET);
 }
 

 static int avi_write_ix(AVFormatContext *s)
 {

     AVIOContext *pb = s->pb;

     AVIContext *avi = s->priv_data;

     char tag[5];
     char ix_tag[] = "ix00";

     int i, j;

     av_assert0(pb->seekable);

     for (i = 0; i < s->nb_streams; i++) {
         AVIStream *avist = s->streams[i]->priv_data;
         if (avi->riff_id - avist->indexes.master_odml_riff_id_base == AVI_MASTER_INDEX_SIZE) {
             int64_t pos;
             int size = 8+2+1+1+4+8+4+4+16*AVI_MASTER_INDEX_SIZE;
 
             pos = avio_tell(pb);
             update_odml_entry(s, i, pos, size);
             write_odml_master(s, i);
             av_assert1(avio_tell(pb) - pos == size);
             avist->indexes.master_odml_riff_id_base = avi->riff_id - 1;
         }
         av_assert0(avi->riff_id - avist->indexes.master_odml_riff_id_base < AVI_MASTER_INDEX_SIZE);

     }

     for (i = 0; i < s->nb_streams; i++) {
         AVIStream *avist = s->streams[i]->priv_data;

         int64_t ix;

 
         avi_stream2fourcc(tag, i, s->streams[i]->codec->codec_type);
         ix_tag[3] = '0' + i;
 
         /* Writing AVI OpenDML leaf index chunk */
         ix = avio_tell(pb);
         ffio_wfourcc(pb, ix_tag);      /* ix?? */
         avio_wl32(pb, avist->indexes.entry * 8 + 24);
         /* chunk size */
         avio_wl16(pb, 2);           /* wLongsPerEntry */
         avio_w8(pb, 0);             /* bIndexSubType (0 == frame index) */
         avio_w8(pb, 1);             /* bIndexType (1 == AVI_INDEX_OF_CHUNKS) */
         avio_wl32(pb, avist->indexes.entry);
         /* nEntriesInUse */
         ffio_wfourcc(pb, tag);         /* dwChunkId */
         avio_wl64(pb, avi->movi_list); /* qwBaseOffset */
         avio_wl32(pb, 0);              /* dwReserved_3 (must be 0) */
 
         for (j = 0; j < avist->indexes.entry; j++) {
             AVIIentry *ie = avi_get_ientry(&avist->indexes, j);
             avio_wl32(pb, ie->pos + 8);
             avio_wl32(pb, ((uint32_t) ie->len & ~0x80000000) |

                           (ie->flags & 0x10 ? 0 : 0x80000000));

         }
 

         update_odml_entry(s, i, ix, avio_tell(pb) - ix);

     }
     return 0;
 }
 
 static int avi_write_idx1(AVFormatContext *s)

 {

     AVIOContext *pb = s->pb;

     AVIContext *avi = s->priv_data;

     int64_t idx_chunk;

     int i;

     char tag[5];

     if (pb->seekable) {

         AVIStream *avist;

         AVIIentry *ie = 0, *tie;

         int empty, stream_id = -1;
 

         idx_chunk = ff_start_tag(pb, "idx1");

         for (i = 0; i < s->nb_streams; i++) {
             avist        = s->streams[i]->priv_data;
             avist->entry = 0;

         }
 

         do {
             empty = 1;

             for (i = 0; i < s->nb_streams; i++) {
                 avist = s->streams[i]->priv_data;
                 if (avist->indexes.entry <= avist->entry)
                     continue;
 
                 tie = avi_get_ientry(&avist->indexes, avist->entry);
                 if (empty || tie->pos < ie->pos) {
                     ie        = tie;
                     stream_id = i;
                 }
                 empty = 0;

             }
             if (!empty) {

                 avist = s->streams[stream_id]->priv_data;

                 avi_stream2fourcc(tag, stream_id,

                                   s->streams[stream_id]->codec->codec_type);

                 ffio_wfourcc(pb, tag);

                 avio_wl32(pb, ie->flags);
                 avio_wl32(pb, ie->pos);
                 avio_wl32(pb, ie->len);

                 avist->entry++;

             }
         } while (!empty);

         ff_end_tag(pb, idx_chunk);

         avi_write_counters(s, avi->riff_id);

     }
     return 0;
 }
 

 static int write_skip_frames(AVFormatContext *s, int stream_index, int64_t dts)
 {
     AVIStream *avist    = s->streams[stream_index]->priv_data;
     AVCodecContext *enc = s->streams[stream_index]->codec;
 

     ff_dlog(s, "dts:%s packet_count:%d stream_index:%d\n", av_ts2str(dts), avist->packet_count, stream_index);

     while (enc->block_align == 0 && dts != AV_NOPTS_VALUE &&
            dts > avist->packet_count && enc->codec_id != AV_CODEC_ID_XSUB && avist->packet_count) {
         AVPacket empty_packet;
 
         if (dts - avist->packet_count > 60000) {
             av_log(s, AV_LOG_ERROR, "Too large number of skipped frames %"PRId64" > 60000\n", dts - avist->packet_count);
             return AVERROR(EINVAL);
         }
 
         av_init_packet(&empty_packet);
         empty_packet.size         = 0;
         empty_packet.data         = NULL;
         empty_packet.stream_index = stream_index;
         avi_write_packet(s, &empty_packet);

         ff_dlog(s, "dup dts:%s packet_count:%d\n", av_ts2str(dts), avist->packet_count);

     }
 
     return 0;
 }
 

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

 {
     unsigned char tag[5];

     unsigned int flags = 0;
     const int stream_index = pkt->stream_index;
     int size               = pkt->size;
     AVIContext *avi     = s->priv_data;
     AVIOContext *pb     = s->pb;
     AVIStream *avist    = s->streams[stream_index]->priv_data;
     AVCodecContext *enc = s->streams[stream_index]->codec;

     int ret;

     if (enc->codec_id == AV_CODEC_ID_H264 && enc->codec_tag == MKTAG('H','2','6','4') && pkt->size) {

         ret = ff_check_h264_startcode(s, s->streams[stream_index], pkt);

         if (ret < 0)
             return ret;
     }

     if ((ret = write_skip_frames(s, stream_index, pkt->dts)) < 0)
         return ret;

     if (pkt->dts != AV_NOPTS_VALUE)
         avist->last_dts = pkt->dts + pkt->duration;
 

     avist->packet_count++;

     // Make sure to put an OpenDML chunk when the file size exceeds the limits

     if (pb->seekable &&

         (avio_tell(pb) - avi->riff_start > AVI_MAX_RIFF_SIZE)) {

         avi_write_ix(s);

         ff_end_tag(pb, avi->movi_list);

         if (avi->riff_id == 1)
             avi_write_idx1(s);

         ff_end_tag(pb, avi->riff_start);

         avi->movi_list = avi_start_new_riff(s, pb, "AVIX", "movi");

     }

     avi_stream2fourcc(tag, stream_index, enc->codec_type);

     if (pkt->flags & AV_PKT_FLAG_KEY)

         flags = 0x10;

     if (enc->codec_type == AVMEDIA_TYPE_AUDIO)
         avist->audio_strm_length += size;

     if (s->pb->seekable) {

         AVIIndex *idx = &avist->indexes;

         int cl = idx->entry / AVI_INDEX_CLUSTER_SIZE;
         int id = idx->entry % AVI_INDEX_CLUSTER_SIZE;

         if (idx->ents_allocated <= idx->entry) {

             idx->cluster = av_realloc_f(idx->cluster, sizeof(void*), cl+1);

             if (!idx->cluster) {

                 idx->ents_allocated = 0;

                 idx->entry          = 0;

                 return AVERROR(ENOMEM);

             }

             idx->cluster[cl] =
                 av_malloc(AVI_INDEX_CLUSTER_SIZE * sizeof(AVIIentry));

             if (!idx->cluster[cl])

                 return AVERROR(ENOMEM);

             idx->ents_allocated += AVI_INDEX_CLUSTER_SIZE;
         }

         idx->cluster[cl][id].flags = flags;

         idx->cluster[cl][id].pos   = avio_tell(pb) - avi->movi_list;
         idx->cluster[cl][id].len   = size;

         avist->max_size = FFMAX(avist->max_size, size);

         idx->entry++;

     }

     avio_write(pb, tag, 4);
     avio_wl32(pb, size);
     avio_write(pb, pkt->data, size);

     if (size & 1)

         avio_w8(pb, 0);

 
     return 0;
 }
 
 static int avi_write_trailer(AVFormatContext *s)
 {
     AVIContext *avi = s->priv_data;

     AVIOContext *pb = s->pb;

     int res = 0;

     int i, j, n, nb_frames;

     int64_t file_size;

     for (i = 0; i < s->nb_streams; i++) {
         AVIStream *avist = s->streams[i]->priv_data;
         write_skip_frames(s, i, avist->last_dts);
     }
 

     if (pb->seekable) {

         if (avi->riff_id == 1) {

             ff_end_tag(pb, avi->movi_list);

             res = avi_write_idx1(s);

             ff_end_tag(pb, avi->riff_start);

         } else {
             avi_write_ix(s);

             ff_end_tag(pb, avi->movi_list);
             ff_end_tag(pb, avi->riff_start);

             file_size = avio_tell(pb);

             avio_seek(pb, avi->odml_list - 8, SEEK_SET);

             ffio_wfourcc(pb, "LIST"); /* Making this AVI OpenDML one */

             avio_skip(pb, 16);

             for (n = nb_frames = 0; n < s->nb_streams; n++) {

                 AVCodecContext *stream = s->streams[n]->codec;

                 AVIStream *avist       = s->streams[n]->priv_data;

                 if (stream->codec_type == AVMEDIA_TYPE_VIDEO) {

                     if (nb_frames < avist->packet_count)
                         nb_frames = avist->packet_count;

                 } else {

                     if (stream->codec_id == AV_CODEC_ID_MP2 ||
                         stream->codec_id == AV_CODEC_ID_MP3)

                         nb_frames += avist->packet_count;

                 }
             }

             avio_wl32(pb, nb_frames);

             avio_seek(pb, file_size, SEEK_SET);

             avi_write_counters(s, avi->riff_id);
         }

     }

     for (i = 0; i < s->nb_streams; i++) {
         AVIStream *avist = s->streams[i]->priv_data;
         for (j = 0; j < avist->indexes.ents_allocated / AVI_INDEX_CLUSTER_SIZE; j++)

             av_freep(&avist->indexes.cluster[j]);

         av_freep(&avist->indexes.cluster);
         avist->indexes.ents_allocated = avist->indexes.entry = 0;

         if (pb->seekable) {
             avio_seek(pb, avist->frames_hdr_strm + 4, SEEK_SET);
             avio_wl32(pb, avist->max_size);
         }

     }

     return res;

 }
 

 #define OFFSET(x) offsetof(AVIContext, x)
 #define ENC AV_OPT_FLAG_ENCODING_PARAM
 static const AVOption options[] = {
     { "write_channel_mask", "write channel mask into wave format header", OFFSET(write_channel_mask), AV_OPT_TYPE_BOOL, { .i64 = 1 }, 0, 1, ENC },
     { NULL },
 };
 
 static const AVClass avi_muxer_class = {
     .class_name = "AVI muxer",
     .item_name  = av_default_item_name,
     .option     = options,
     .version    = LIBAVUTIL_VERSION_INT,
 };
 

 AVOutputFormat ff_avi_muxer = {

     .name           = "avi",
     .long_name      = NULL_IF_CONFIG_SMALL("AVI (Audio Video Interleaved)"),
     .mime_type      = "video/x-msvideo",
     .extensions     = "avi",
     .priv_data_size = sizeof(AVIContext),
     .audio_codec    = CONFIG_LIBMP3LAME ? AV_CODEC_ID_MP3 : AV_CODEC_ID_AC3,
     .video_codec    = AV_CODEC_ID_MPEG4,
     .write_header   = avi_write_header,
     .write_packet   = avi_write_packet,
     .write_trailer  = avi_write_trailer,
     .codec_tag      = (const AVCodecTag * const []) {

         ff_codec_bmp_tags, ff_codec_wav_tags, 0
     },

     .priv_class     = &avi_muxer_class,

 };