/*
  * Apple HTTP Live Streaming segmenter
  * Copyright (c) 2012, Luca Barbato
  *

  * 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 "config.h"

 #include <float.h>

 #include <stdint.h>

 #if HAVE_UNISTD_H
 #include <unistd.h>
 #endif

 #include "libavutil/avassert.h"

 #include "libavutil/mathematics.h"
 #include "libavutil/parseutils.h"
 #include "libavutil/avstring.h"
 #include "libavutil/opt.h"
 #include "libavutil/log.h"

 #include "libavutil/time_internal.h"

 
 #include "avformat.h"

 #include "avio_internal.h"

 #include "internal.h"

 #include "os_support.h"

 #define KEYSIZE 16
 #define LINE_BUFFER_SIZE 1024
 

 typedef struct HLSSegment {
     char filename[1024];

     char sub_filename[1024];

     double duration; /* in seconds */

     int64_t pos;
     int64_t size;

     char key_uri[LINE_BUFFER_SIZE + 1];
     char iv_string[KEYSIZE*2 + 1];
 

     struct HLSSegment *next;
 } HLSSegment;

 typedef enum HLSFlags {
     // Generate a single media file and use byte ranges in the playlist.
     HLS_SINGLE_FILE = (1 << 0),

     HLS_DELETE_SEGMENTS = (1 << 1),

     HLS_ROUND_DURATIONS = (1 << 2),

     HLS_DISCONT_START = (1 << 3),

     HLS_OMIT_ENDLIST = (1 << 4),

 } HLSFlags;
 

 typedef struct HLSContext {
     const AVClass *class;  // Class for private options.

     unsigned number;

     int64_t sequence;

     int64_t start_sequence;

     AVOutputFormat *oformat;

     AVOutputFormat *vtt_oformat;

     AVFormatContext *avf;

     AVFormatContext *vtt_avf;

     float time;            // Set by a private option.

     int max_nb_segments;   // Set by a private option.

     int  wrap;             // Set by a private option.

     uint32_t flags;        // enum HLSFlags

     char *segment_filename;

     int use_localtime;      ///< flag to expand filename with localtime

     int allowcache;

     int64_t recording_time;
     int has_video;

     int has_subtitle;

     int64_t start_pts;
     int64_t end_pts;

     double duration;      // last segment duration computed so far, in seconds

     int64_t start_pos;    // last segment starting position
     int64_t size;         // last segment size

     int nb_entries;

     int discontinuity_set;

     HLSSegment *segments;
     HLSSegment *last_segment;

     HLSSegment *old_segments;

     char *basename;

     char *vtt_basename;
     char *vtt_m3u8_name;

     char *baseurl;

     char *format_options_str;

     char *vtt_format_options_str;
     char *subtitle_filename;

     AVDictionary *format_options;

 
     char *key_info_file;
     char key_file[LINE_BUFFER_SIZE + 1];
     char key_uri[LINE_BUFFER_SIZE + 1];
     char key_string[KEYSIZE*2 + 1];
     char iv_string[KEYSIZE*2 + 1];

     AVDictionary *vtt_format_options;
 

     char *method;
 

 } HLSContext;
 

 static int hls_delete_old_segments(HLSContext *hls) {
 
     HLSSegment *segment, *previous_segment = NULL;
     float playlist_duration = 0.0f;

     int ret = 0, path_size, sub_path_size;

     char *dirname = NULL, *p, *sub_path;
     char *path = NULL;

 
     segment = hls->segments;
     while (segment) {
         playlist_duration += segment->duration;
         segment = segment->next;
     }
 
     segment = hls->old_segments;
     while (segment) {
         playlist_duration -= segment->duration;
         previous_segment = segment;
         segment = previous_segment->next;
         if (playlist_duration <= -previous_segment->duration) {
             previous_segment->next = NULL;
             break;
         }
     }
 
     if (segment) {
         if (hls->segment_filename) {
             dirname = av_strdup(hls->segment_filename);
         } else {
             dirname = av_strdup(hls->avf->filename);
         }
         if (!dirname) {
             ret = AVERROR(ENOMEM);
             goto fail;
         }
         p = (char *)av_basename(dirname);
         *p = '\0';
     }
 
     while (segment) {
         av_log(hls, AV_LOG_DEBUG, "deleting old segment %s\n",
                                   segment->filename);
         path_size = strlen(dirname) + strlen(segment->filename) + 1;
         path = av_malloc(path_size);
         if (!path) {
             ret = AVERROR(ENOMEM);
             goto fail;
         }

         av_strlcpy(path, dirname, path_size);
         av_strlcat(path, segment->filename, path_size);
         if (unlink(path) < 0) {
             av_log(hls, AV_LOG_ERROR, "failed to delete old segment %s: %s\n",
                                      path, strerror(errno));
         }

         if (segment->sub_filename[0] != '\0') {
             sub_path_size = strlen(dirname) + strlen(segment->sub_filename) + 1;
             sub_path = av_malloc(sub_path_size);
             if (!sub_path) {
                 ret = AVERROR(ENOMEM);
                 goto fail;
             }
 
             av_strlcpy(sub_path, dirname, sub_path_size);
             av_strlcat(sub_path, segment->sub_filename, sub_path_size);
             if (unlink(sub_path) < 0) {
                 av_log(hls, AV_LOG_ERROR, "failed to delete old segment %s: %s\n",
                                          sub_path, strerror(errno));
             }
             av_free(sub_path);

         }

         av_freep(&path);

         previous_segment = segment;
         segment = previous_segment->next;
         av_free(previous_segment);
     }
 
 fail:

     av_free(path);

     av_free(dirname);
 
     return ret;
 }
 

 static int hls_encryption_start(AVFormatContext *s)
 {
     HLSContext *hls = s->priv_data;
     int ret;
     AVIOContext *pb;
     uint8_t key[KEYSIZE];
 

     if ((ret = s->io_open(s, &pb, hls->key_info_file, AVIO_FLAG_READ, NULL)) < 0) {

         av_log(hls, AV_LOG_ERROR,
                 "error opening key info file %s\n", hls->key_info_file);
         return ret;
     }
 
     ff_get_line(pb, hls->key_uri, sizeof(hls->key_uri));
     hls->key_uri[strcspn(hls->key_uri, "\r\n")] = '\0';
 
     ff_get_line(pb, hls->key_file, sizeof(hls->key_file));
     hls->key_file[strcspn(hls->key_file, "\r\n")] = '\0';
 
     ff_get_line(pb, hls->iv_string, sizeof(hls->iv_string));
     hls->iv_string[strcspn(hls->iv_string, "\r\n")] = '\0';
 

     ff_format_io_close(s, &pb);

 
     if (!*hls->key_uri) {
         av_log(hls, AV_LOG_ERROR, "no key URI specified in key info file\n");
         return AVERROR(EINVAL);
     }
 
     if (!*hls->key_file) {
         av_log(hls, AV_LOG_ERROR, "no key file specified in key info file\n");
         return AVERROR(EINVAL);
     }
 

     if ((ret = s->io_open(s, &pb, hls->key_file, AVIO_FLAG_READ, NULL)) < 0) {

         av_log(hls, AV_LOG_ERROR, "error opening key file %s\n", hls->key_file);
         return ret;
     }
 
     ret = avio_read(pb, key, sizeof(key));

     ff_format_io_close(s, &pb);

     if (ret != sizeof(key)) {
         av_log(hls, AV_LOG_ERROR, "error reading key file %s\n", hls->key_file);
         if (ret >= 0 || ret == AVERROR_EOF)
             ret = AVERROR(EINVAL);
         return ret;
     }
     ff_data_to_hex(hls->key_string, key, sizeof(key), 0);
 
     return 0;
 }
 

 static int hls_mux_init(AVFormatContext *s)
 {
     HLSContext *hls = s->priv_data;
     AVFormatContext *oc;

     AVFormatContext *vtt_oc = NULL;

     int i, ret;

     ret = avformat_alloc_output_context2(&hls->avf, hls->oformat, NULL, NULL);
     if (ret < 0)
         return ret;
     oc = hls->avf;

 
     oc->oformat            = hls->oformat;
     oc->interrupt_callback = s->interrupt_callback;

     oc->max_delay          = s->max_delay;

     oc->opaque             = s->opaque;
     oc->io_open            = s->io_open;
     oc->io_close           = s->io_close;

     av_dict_copy(&oc->metadata, s->metadata, 0);

     if(hls->vtt_oformat) {
         ret = avformat_alloc_output_context2(&hls->vtt_avf, hls->vtt_oformat, NULL, NULL);
         if (ret < 0)
             return ret;
         vtt_oc          = hls->vtt_avf;
         vtt_oc->oformat = hls->vtt_oformat;
         av_dict_copy(&vtt_oc->metadata, s->metadata, 0);
     }
 

     for (i = 0; i < s->nb_streams; i++) {
         AVStream *st;

         AVFormatContext *loc;
         if (s->streams[i]->codec->codec_type == AVMEDIA_TYPE_SUBTITLE)
             loc = vtt_oc;
         else
             loc = oc;
 
         if (!(st = avformat_new_stream(loc, NULL)))

             return AVERROR(ENOMEM);
         avcodec_copy_context(st->codec, s->streams[i]->codec);
         st->sample_aspect_ratio = s->streams[i]->sample_aspect_ratio;

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

     }

     hls->start_pos = 0;

 
     return 0;
 }
 

 /* Create a new segment and append it to the segment list */

 static int hls_append_segment(HLSContext *hls, double duration, int64_t pos,
                               int64_t size)

 {

     HLSSegment *en = av_malloc(sizeof(*en));

     int ret;

 
     if (!en)
         return AVERROR(ENOMEM);
 

     av_strlcpy(en->filename, av_basename(hls->avf->filename), sizeof(en->filename));

     if(hls->has_subtitle)
         av_strlcpy(en->sub_filename, av_basename(hls->vtt_avf->filename), sizeof(en->sub_filename));

     else
         en->sub_filename[0] = '\0';

     en->duration = duration;

     en->pos      = pos;
     en->size     = size;

     en->next     = NULL;
 

     if (hls->key_info_file) {
         av_strlcpy(en->key_uri, hls->key_uri, sizeof(en->key_uri));
         av_strlcpy(en->iv_string, hls->iv_string, sizeof(en->iv_string));
     }
 

     if (!hls->segments)
         hls->segments = en;

     else

         hls->last_segment->next = en;

     hls->last_segment = en;

     if (hls->max_nb_segments && hls->nb_entries >= hls->max_nb_segments) {
         en = hls->segments;
         hls->segments = en->next;

         if (en && hls->flags & HLS_DELETE_SEGMENTS &&
                 !(hls->flags & HLS_SINGLE_FILE || hls->wrap)) {
             en->next = hls->old_segments;
             hls->old_segments = en;
             if ((ret = hls_delete_old_segments(hls)) < 0)
                 return ret;
         } else
             av_free(en);

     } else
         hls->nb_entries++;

     hls->sequence++;
 

     return 0;
 }
 

 static void hls_free_segments(HLSSegment *p)

 {

     HLSSegment *en;

 
     while(p) {
         en = p;
         p = p->next;
         av_free(en);
     }
 }
 

 static void set_http_options(AVDictionary **options, HLSContext *c)
 {
     if (c->method)
         av_dict_set(options, "method", c->method, 0);
 }
 

 static int hls_window(AVFormatContext *s, int last)
 {
     HLSContext *hls = s->priv_data;

     HLSSegment *en;

     int target_duration = 0;

     int ret = 0;

     AVIOContext *out = NULL;

     AVIOContext *sub_out = NULL;

     char temp_filename[1024];

     int64_t sequence = FFMAX(hls->start_sequence, hls->sequence - hls->nb_entries);

     int version = hls->flags & HLS_SINGLE_FILE ? 4 : 3;

     const char *proto = avio_find_protocol_name(s->filename);
     int use_rename = proto && !strcmp(proto, "file");

     static unsigned warned_non_file;

     char *key_uri = NULL;
     char *iv_string = NULL;

     AVDictionary *options = NULL;

 
     if (!use_rename && !warned_non_file++)
         av_log(s, AV_LOG_ERROR, "Cannot use rename on non file protocol, this may lead to races and temporarly partial files\n");

     set_http_options(&options, hls);

     snprintf(temp_filename, sizeof(temp_filename), use_rename ? "%s.tmp" : "%s", s->filename);

     if ((ret = s->io_open(s, &out, temp_filename, AVIO_FLAG_WRITE, NULL)) < 0)

         goto fail;
 

     for (en = hls->segments; en; en = en->next) {

         if (target_duration < en->duration)

             target_duration = ceil(en->duration);

     }
 

     hls->discontinuity_set = 0;

     avio_printf(out, "#EXTM3U\n");
     avio_printf(out, "#EXT-X-VERSION:%d\n", version);

     if (hls->allowcache == 0 || hls->allowcache == 1) {

         avio_printf(out, "#EXT-X-ALLOW-CACHE:%s\n", hls->allowcache == 0 ? "NO" : "YES");

     }

     avio_printf(out, "#EXT-X-TARGETDURATION:%d\n", target_duration);
     avio_printf(out, "#EXT-X-MEDIA-SEQUENCE:%"PRId64"\n", sequence);

     av_log(s, AV_LOG_VERBOSE, "EXT-X-MEDIA-SEQUENCE:%"PRId64"\n",

            sequence);

     if((hls->flags & HLS_DISCONT_START) && sequence==hls->start_sequence && hls->discontinuity_set==0 ){
         avio_printf(out, "#EXT-X-DISCONTINUITY\n");
         hls->discontinuity_set = 1;
     }

     for (en = hls->segments; en; en = en->next) {

         if (hls->key_info_file && (!key_uri || strcmp(en->key_uri, key_uri) ||
                                     av_strcasecmp(en->iv_string, iv_string))) {
             avio_printf(out, "#EXT-X-KEY:METHOD=AES-128,URI=\"%s\"", en->key_uri);
             if (*en->iv_string)
                 avio_printf(out, ",IV=0x%s", en->iv_string);
             avio_printf(out, "\n");
             key_uri = en->key_uri;
             iv_string = en->iv_string;
         }
 

         if (hls->flags & HLS_ROUND_DURATIONS)

             avio_printf(out, "#EXTINF:%ld,\n",  lrint(en->duration));

         else
             avio_printf(out, "#EXTINF:%f,\n", en->duration);

         if (hls->flags & HLS_SINGLE_FILE)

              avio_printf(out, "#EXT-X-BYTERANGE:%"PRIi64"@%"PRIi64"\n",

                          en->size, en->pos);

         if (hls->baseurl)

             avio_printf(out, "%s", hls->baseurl);
         avio_printf(out, "%s\n", en->filename);

     }
 

     if (last && (hls->flags & HLS_OMIT_ENDLIST)==0)

         avio_printf(out, "#EXT-X-ENDLIST\n");

     if( hls->vtt_m3u8_name ) {

         if ((ret = s->io_open(s, &sub_out, hls->vtt_m3u8_name, AVIO_FLAG_WRITE, &options)) < 0)

             goto fail;
         avio_printf(sub_out, "#EXTM3U\n");
         avio_printf(sub_out, "#EXT-X-VERSION:%d\n", version);
         if (hls->allowcache == 0 || hls->allowcache == 1) {
             avio_printf(sub_out, "#EXT-X-ALLOW-CACHE:%s\n", hls->allowcache == 0 ? "NO" : "YES");
         }
         avio_printf(sub_out, "#EXT-X-TARGETDURATION:%d\n", target_duration);
         avio_printf(sub_out, "#EXT-X-MEDIA-SEQUENCE:%"PRId64"\n", sequence);
 
         av_log(s, AV_LOG_VERBOSE, "EXT-X-MEDIA-SEQUENCE:%"PRId64"\n",
                sequence);
 
         for (en = hls->segments; en; en = en->next) {
             avio_printf(sub_out, "#EXTINF:%f,\n", en->duration);
             if (hls->flags & HLS_SINGLE_FILE)
                  avio_printf(sub_out, "#EXT-X-BYTERANGE:%"PRIi64"@%"PRIi64"\n",
                          en->size, en->pos);
             if (hls->baseurl)
                 avio_printf(sub_out, "%s", hls->baseurl);
             avio_printf(sub_out, "%s\n", en->sub_filename);
         }
 
         if (last)
             avio_printf(sub_out, "#EXT-X-ENDLIST\n");
 
     }
 

 fail:

     av_dict_free(&options);

     ff_format_io_close(s, &out);

     ff_format_io_close(s, &sub_out);

     if (ret >= 0 && use_rename)

         ff_rename(temp_filename, s->filename, s);

     return ret;
 }
 
 static int hls_start(AVFormatContext *s)
 {
     HLSContext *c = s->priv_data;
     AVFormatContext *oc = c->avf;

     AVFormatContext *vtt_oc = c->vtt_avf;

     AVDictionary *options = NULL;
     char *filename, iv_string[KEYSIZE*2 + 1];

     int err = 0;
 

     if (c->flags & HLS_SINGLE_FILE) {

         av_strlcpy(oc->filename, c->basename,
                    sizeof(oc->filename));

         if (c->vtt_basename)
             av_strlcpy(vtt_oc->filename, c->vtt_basename,
                   sizeof(vtt_oc->filename));
     } else {

         if (c->use_localtime) {
             time_t now0;
             struct tm *tm, tmpbuf;
             time(&now0);
             tm = localtime_r(&now0, &tmpbuf);
             if (!strftime(oc->filename, sizeof(oc->filename), c->basename, tm)) {
                 av_log(oc, AV_LOG_ERROR, "Could not get segment filename with use_localtime\n");
                 return AVERROR(EINVAL);
             }
        } else if (av_get_frame_filename(oc->filename, sizeof(oc->filename),

                                   c->basename, c->wrap ? c->sequence % c->wrap : c->sequence) < 0) {

             av_log(oc, AV_LOG_ERROR, "Invalid segment filename template '%s' you can try use -use_localtime 1 with it\n", c->basename);

             return AVERROR(EINVAL);
         }

         if( c->vtt_basename) {
             if (av_get_frame_filename(vtt_oc->filename, sizeof(vtt_oc->filename),
                               c->vtt_basename, c->wrap ? c->sequence % c->wrap : c->sequence) < 0) {
                 av_log(vtt_oc, AV_LOG_ERROR, "Invalid segment filename template '%s'\n", c->vtt_basename);
                 return AVERROR(EINVAL);
             }
        }
     }

     c->number++;

     set_http_options(&options, c);
 

     if (c->key_info_file) {
         if ((err = hls_encryption_start(s)) < 0)

             goto fail;

         if ((err = av_dict_set(&options, "encryption_key", c->key_string, 0))
                 < 0)

             goto fail;

         err = av_strlcpy(iv_string, c->iv_string, sizeof(iv_string));
         if (!err)
             snprintf(iv_string, sizeof(iv_string), "%032"PRIx64, c->sequence);
         if ((err = av_dict_set(&options, "encryption_iv", iv_string, 0)) < 0)

            goto fail;

 
         filename = av_asprintf("crypto:%s", oc->filename);
         if (!filename) {

             err = AVERROR(ENOMEM);
             goto fail;

         }

         err = s->io_open(s, &oc->pb, filename, AVIO_FLAG_WRITE, &options);

         av_free(filename);
         av_dict_free(&options);
         if (err < 0)
             return err;
     } else

         if ((err = s->io_open(s, &oc->pb, oc->filename, AVIO_FLAG_WRITE, &options)) < 0)

             goto fail;

     if (c->vtt_basename) {

         set_http_options(&options, c);

         if ((err = s->io_open(s, &vtt_oc->pb, vtt_oc->filename, AVIO_FLAG_WRITE, &options)) < 0)

             goto fail;

     }

     av_dict_free(&options);

     /* We only require one PAT/PMT per segment. */
     if (oc->oformat->priv_class && oc->priv_data) {
         char period[21];
 
         snprintf(period, sizeof(period), "%d", (INT_MAX / 2) - 1);
 

         av_opt_set(oc->priv_data, "mpegts_flags", "resend_headers", 0);

         av_opt_set(oc->priv_data, "sdt_period", period, 0);
         av_opt_set(oc->priv_data, "pat_period", period, 0);
     }

     if (c->vtt_basename) {
         err = avformat_write_header(vtt_oc,NULL);
         if (err < 0)
             return err;
     }

     return 0;

 fail:
     av_dict_free(&options);
 
     return err;

 }
 
 static int hls_write_header(AVFormatContext *s)
 {
     HLSContext *hls = s->priv_data;
     int ret, i;
     char *p;
     const char *pattern = "%d.ts";

     const char *pattern_localtime_fmt = "-%s.ts";

     const char *vtt_pattern = "%d.vtt";

     AVDictionary *options = NULL;

     int basename_size;

     int vtt_basename_size;

     hls->sequence       = hls->start_sequence;

     hls->recording_time = hls->time * AV_TIME_BASE;

     hls->start_pts      = AV_NOPTS_VALUE;
 

     if (hls->format_options_str) {
         ret = av_dict_parse_string(&hls->format_options, hls->format_options_str, "=", ":", 0);
         if (ret < 0) {
             av_log(s, AV_LOG_ERROR, "Could not parse format options list '%s'\n", hls->format_options_str);
             goto fail;
         }
     }
 

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

         hls->has_video +=
             s->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO;

         hls->has_subtitle +=
             s->streams[i]->codec->codec_type == AVMEDIA_TYPE_SUBTITLE;
     }

 
     if (hls->has_video > 1)
         av_log(s, AV_LOG_WARNING,
                "More than a single video stream present, "
                "expect issues decoding it.\n");
 
     hls->oformat = av_guess_format("mpegts", NULL, NULL);
 
     if (!hls->oformat) {
         ret = AVERROR_MUXER_NOT_FOUND;
         goto fail;
     }
 

     if(hls->has_subtitle) {
         hls->vtt_oformat = av_guess_format("webvtt", NULL, NULL);
         if (!hls->oformat) {
             ret = AVERROR_MUXER_NOT_FOUND;
             goto fail;
         }
     }
 

     if (hls->segment_filename) {
         hls->basename = av_strdup(hls->segment_filename);
         if (!hls->basename) {
             ret = AVERROR(ENOMEM);
             goto fail;
         }
     } else {
         if (hls->flags & HLS_SINGLE_FILE)
             pattern = ".ts";

         if (hls->use_localtime) {
             basename_size = strlen(s->filename) + strlen(pattern_localtime_fmt) + 1;
         } else {
             basename_size = strlen(s->filename) + strlen(pattern) + 1;
         }

         hls->basename = av_malloc(basename_size);
         if (!hls->basename) {
             ret = AVERROR(ENOMEM);
             goto fail;
         }

         av_strlcpy(hls->basename, s->filename, basename_size);

         p = strrchr(hls->basename, '.');
         if (p)
             *p = '\0';

         if (hls->use_localtime) {
             av_strlcat(hls->basename, pattern_localtime_fmt, basename_size);
         } else {
             av_strlcat(hls->basename, pattern, basename_size);
         }

     }

     if(hls->has_subtitle) {
 
         if (hls->flags & HLS_SINGLE_FILE)
             vtt_pattern = ".vtt";
         vtt_basename_size = strlen(s->filename) + strlen(vtt_pattern) + 1;
         hls->vtt_basename = av_malloc(vtt_basename_size);
         if (!hls->vtt_basename) {
             ret = AVERROR(ENOMEM);
             goto fail;
         }
         hls->vtt_m3u8_name = av_malloc(vtt_basename_size);
         if (!hls->vtt_m3u8_name ) {
             ret = AVERROR(ENOMEM);
             goto fail;
         }
         av_strlcpy(hls->vtt_basename, s->filename, vtt_basename_size);
         p = strrchr(hls->vtt_basename, '.');
         if (p)
             *p = '\0';
 
         if( hls->subtitle_filename ) {
             strcpy(hls->vtt_m3u8_name, hls->subtitle_filename);
         } else {
             strcpy(hls->vtt_m3u8_name, hls->vtt_basename);
             av_strlcat(hls->vtt_m3u8_name, "_vtt.m3u8", vtt_basename_size);
         }
         av_strlcat(hls->vtt_basename, vtt_pattern, vtt_basename_size);
     }
 

     if ((ret = hls_mux_init(s)) < 0)
         goto fail;
 
     if ((ret = hls_start(s)) < 0)
         goto fail;
 

     av_dict_copy(&options, hls->format_options, 0);
     ret = avformat_write_header(hls->avf, &options);
     if (av_dict_count(options)) {
         av_log(s, AV_LOG_ERROR, "Some of provided format options in '%s' are not recognized\n", hls->format_options_str);
         ret = AVERROR(EINVAL);

         goto fail;

     }

     //av_assert0(s->nb_streams == hls->avf->nb_streams);

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

         AVStream *inner_st;

         AVStream *outer_st = s->streams[i];

         if (outer_st->codec->codec_type != AVMEDIA_TYPE_SUBTITLE)
             inner_st = hls->avf->streams[i];
         else if (hls->vtt_avf)
             inner_st = hls->vtt_avf->streams[0];
         else {

             /* We have a subtitle stream, when the user does not want one */

             inner_st = NULL;
             continue;
         }

         avpriv_set_pts_info(outer_st, inner_st->pts_wrap_bits, inner_st->time_base.num, inner_st->time_base.den);

     }

 fail:

 
     av_dict_free(&options);

     if (ret < 0) {

         av_freep(&hls->basename);

         av_freep(&hls->vtt_basename);

         if (hls->avf)
             avformat_free_context(hls->avf);

         if (hls->vtt_avf)
             avformat_free_context(hls->vtt_avf);
 

     }
     return ret;
 }
 
 static int hls_write_packet(AVFormatContext *s, AVPacket *pkt)
 {
     HLSContext *hls = s->priv_data;

     AVFormatContext *oc = NULL;

     AVStream *st = s->streams[pkt->stream_index];
     int64_t end_pts = hls->recording_time * hls->number;

     int is_ref_pkt = 1;

     int ret, can_split = 1;

     int stream_index = 0;

     if( st->codec->codec_type == AVMEDIA_TYPE_SUBTITLE ) {
         oc = hls->vtt_avf;
         stream_index = 0;
     } else {
         oc = hls->avf;
         stream_index = pkt->stream_index;
     }

     if (hls->start_pts == AV_NOPTS_VALUE) {
         hls->start_pts = pkt->pts;
         hls->end_pts   = pkt->pts;
     }
 

     if (hls->has_video) {
         can_split = st->codec->codec_type == AVMEDIA_TYPE_VIDEO &&
                     pkt->flags & AV_PKT_FLAG_KEY;

         is_ref_pkt = st->codec->codec_type == AVMEDIA_TYPE_VIDEO;

     }

     if (pkt->pts == AV_NOPTS_VALUE)
         is_ref_pkt = can_split = 0;

     if (is_ref_pkt)

         hls->duration = (double)(pkt->pts - hls->end_pts)
                                    * st->time_base.num / st->time_base.den;

     if (can_split && av_compare_ts(pkt->pts - hls->start_pts, st->time_base,
                                    end_pts, AV_TIME_BASE_Q) >= 0) {

         int64_t new_start_pos;
         av_write_frame(oc, NULL); /* Flush any buffered data */
 
         new_start_pos = avio_tell(hls->avf->pb);
         hls->size = new_start_pos - hls->start_pos;
         ret = hls_append_segment(hls, hls->duration, hls->start_pos, hls->size);
         hls->start_pos = new_start_pos;

         if (ret < 0)

             return ret;
 

         hls->end_pts = pkt->pts;

         hls->duration = 0;

         if (hls->flags & HLS_SINGLE_FILE) {
             if (hls->avf->oformat->priv_class && hls->avf->priv_data)
                 av_opt_set(hls->avf->priv_data, "mpegts_flags", "resend_headers", 0);
             hls->number++;
         } else {

             ff_format_io_close(s, &oc->pb);

             if (hls->vtt_avf)

                 ff_format_io_close(s, &hls->vtt_avf->pb);

             ret = hls_start(s);
         }

         if (ret < 0)

             return ret;
 

         if( st->codec->codec_type == AVMEDIA_TYPE_SUBTITLE )
             oc = hls->vtt_avf;
         else

         oc = hls->avf;
 
         if ((ret = hls_window(s, 0)) < 0)
             return ret;
     }
 

     ret = ff_write_chained(oc, stream_index, pkt, s, 0);

 
     return ret;
 }
 
 static int hls_write_trailer(struct AVFormatContext *s)
 {
     HLSContext *hls = s->priv_data;
     AVFormatContext *oc = hls->avf;

     AVFormatContext *vtt_oc = hls->vtt_avf;

 
     av_write_trailer(oc);

     if (oc->pb) {
         hls->size = avio_tell(hls->avf->pb) - hls->start_pos;

         ff_format_io_close(s, &oc->pb);

         hls_append_segment(hls, hls->duration, hls->start_pos, hls->size);
     }

 
     if (vtt_oc) {
         if (vtt_oc->pb)
             av_write_trailer(vtt_oc);
         hls->size = avio_tell(hls->vtt_avf->pb) - hls->start_pos;

         ff_format_io_close(s, &vtt_oc->pb);

     }

     av_freep(&hls->basename);

     avformat_free_context(oc);

 
     if (vtt_oc) {
         av_freep(&hls->vtt_basename);
         av_freep(&hls->vtt_m3u8_name);
         avformat_free_context(vtt_oc);
     }
 

     hls->avf = NULL;

     hls_window(s, 1);
 

     hls_free_segments(hls->segments);
     hls_free_segments(hls->old_segments);

     return 0;
 }
 
 #define OFFSET(x) offsetof(HLSContext, x)
 #define E AV_OPT_FLAG_ENCODING_PARAM
 static const AVOption options[] = {

     {"start_number",  "set first number in the sequence",        OFFSET(start_sequence),AV_OPT_TYPE_INT64,  {.i64 = 0},     0, INT64_MAX, E},

     {"hls_time",      "set segment length in seconds",           OFFSET(time),    AV_OPT_TYPE_FLOAT,  {.dbl = 2},     0, FLT_MAX, E},

     {"hls_list_size", "set maximum number of playlist entries",  OFFSET(max_nb_segments),    AV_OPT_TYPE_INT,    {.i64 = 5},     0, INT_MAX, E},

     {"hls_ts_options","set hls mpegts list of options for the container format used for hls", OFFSET(format_options_str), AV_OPT_TYPE_STRING, {.str = NULL},  0, 0,    E},

     {"hls_vtt_options","set hls vtt list of options for the container format used for hls", OFFSET(vtt_format_options_str), AV_OPT_TYPE_STRING, {.str = NULL},  0, 0,    E},

     {"hls_wrap",      "set number after which the index wraps",  OFFSET(wrap),    AV_OPT_TYPE_INT,    {.i64 = 0},     0, INT_MAX, E},

     {"hls_allow_cache", "explicitly set whether the client MAY (1) or MUST NOT (0) cache media segments", OFFSET(allowcache), AV_OPT_TYPE_INT, {.i64 = -1}, INT_MIN, INT_MAX, E},

     {"hls_base_url",  "url to prepend to each playlist entry",   OFFSET(baseurl), AV_OPT_TYPE_STRING, {.str = NULL},  0, 0,       E},

     {"hls_segment_filename", "filename template for segment files", OFFSET(segment_filename),   AV_OPT_TYPE_STRING, {.str = NULL},            0,       0,         E},

     {"hls_key_info_file",    "file with key URI and key file path", OFFSET(key_info_file),      AV_OPT_TYPE_STRING, {.str = NULL},            0,       0,         E},

     {"hls_subtitle_path",     "set path of hls subtitles", OFFSET(subtitle_filename), AV_OPT_TYPE_STRING, {.str = NULL},  0, 0,    E},

     {"hls_flags",     "set flags affecting HLS playlist and media file generation", OFFSET(flags), AV_OPT_TYPE_FLAGS, {.i64 = 0 }, 0, UINT_MAX, E, "flags"},
     {"single_file",   "generate a single media file indexed with byte ranges", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_SINGLE_FILE }, 0, UINT_MAX,   E, "flags"},

     {"delete_segments", "delete segment files that are no longer part of the playlist", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_DELETE_SEGMENTS }, 0, UINT_MAX,   E, "flags"},

     {"round_durations", "round durations in m3u8 to whole numbers", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_ROUND_DURATIONS }, 0, UINT_MAX,   E, "flags"},

     {"discont_start", "start the playlist with a discontinuity tag", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_DISCONT_START }, 0, UINT_MAX,   E, "flags"},

     {"omit_endlist", "Do not append an endlist when ending stream", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_OMIT_ENDLIST }, 0, UINT_MAX,   E, "flags"},

     { "use_localtime", "set filename expansion with strftime at segment creation", OFFSET(use_localtime), AV_OPT_TYPE_BOOL, {.i64 = 0 }, 0, 1, E },

     {"method", "set the HTTP method", OFFSET(method), AV_OPT_TYPE_STRING, {.str = NULL},  0, 0,    E},

     { NULL },
 };
 
 static const AVClass hls_class = {
     .class_name = "hls muxer",
     .item_name  = av_default_item_name,
     .option     = options,
     .version    = LIBAVUTIL_VERSION_INT,
 };
 
 
 AVOutputFormat ff_hls_muxer = {
     .name           = "hls",

     .long_name      = NULL_IF_CONFIG_SMALL("Apple HTTP Live Streaming"),

     .extensions     = "m3u8",
     .priv_data_size = sizeof(HLSContext),

     .audio_codec    = AV_CODEC_ID_AAC,
     .video_codec    = AV_CODEC_ID_H264,

     .subtitle_codec = AV_CODEC_ID_WEBVTT,

     .flags          = AVFMT_NOFILE | AVFMT_ALLOW_FLUSH,
     .write_header   = hls_write_header,
     .write_packet   = hls_write_packet,
     .write_trailer  = hls_write_trailer,
     .priv_class     = &hls_class,
 };