text: /*
   * Copyright (c) 2011, 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
   */
  
  /**
   * @file generic segmenter
   * M3U8 specification can be find here:
   * @url{http://tools.ietf.org/id/draft-pantos-http-live-streaming}
   */
  
  #include <float.h>
  #include <time.h>
  
  #include "avformat.h"
  #include "avio_internal.h"
  #include "internal.h"
  
  #include "libavutil/avassert.h"
  #include "libavutil/internal.h"
  #include "libavutil/log.h"
  #include "libavutil/opt.h"
  #include "libavutil/avstring.h"
  #include "libavutil/parseutils.h"
  #include "libavutil/mathematics.h"
  #include "libavutil/time.h"
  #include "libavutil/timecode.h"
  #include "libavutil/time_internal.h"
  #include "libavutil/timestamp.h"
  
  typedef struct SegmentListEntry {
      int index;
      double start_time, end_time;
      int64_t start_pts;
      int64_t offset_pts;
      char *filename;
      struct SegmentListEntry *next;
      int64_t last_duration;
  } SegmentListEntry;
  
  typedef enum {
      LIST_TYPE_UNDEFINED = -1,
      LIST_TYPE_FLAT = 0,
      LIST_TYPE_CSV,
      LIST_TYPE_M3U8,
      LIST_TYPE_EXT, ///< deprecated
      LIST_TYPE_FFCONCAT,
      LIST_TYPE_NB,
  } ListType;
  
  #define SEGMENT_LIST_FLAG_CACHE 1
  #define SEGMENT_LIST_FLAG_LIVE  2
  
  typedef struct SegmentContext {
      const AVClass *class;  /**< Class for private options. */
      int segment_idx;       ///< index of the segment file to write, starting from 0
      int segment_idx_wrap;  ///< number after which the index wraps
      int segment_idx_wrap_nb;  ///< number of time the index has wraped
      int segment_count;     ///< number of segment files already written
      ff_const59 AVOutputFormat *oformat;
      AVFormatContext *avf;
      char *format;              ///< format to use for output segment files
      AVDictionary *format_options;
      char *list;            ///< filename for the segment list file
      int   list_flags;      ///< flags affecting list generation
      int   list_size;       ///< number of entries for the segment list file
  
      int is_nullctx;       ///< whether avf->pb is a nullctx
      int use_clocktime;    ///< flag to cut segments at regular clock time
      int64_t clocktime_offset; //< clock offset for cutting the segments at regular clock time
      int64_t clocktime_wrap_duration; //< wrapping duration considered for starting a new segment
      int64_t last_val;      ///< remember last time for wrap around detection
      int cut_pending;
      int header_written;    ///< whether we've already called avformat_write_header
  
      char *entry_prefix;    ///< prefix to add to list entry filenames
      int list_type;         ///< set the list type
      AVIOContext *list_pb;  ///< list file put-byte context
      int64_t time;          ///< segment duration
      int use_strftime;      ///< flag to expand filename with strftime
      int increment_tc;      ///< flag to increment timecode if found
  
      char *times_str;       ///< segment times specification string
      int64_t *times;        ///< list of segment interval specification
      int nb_times;          ///< number of elments in the times array
  
      char *frames_str;      ///< segment frame numbers specification string
      int *frames;           ///< list of frame number specification
      int nb_frames;         ///< number of elments in the frames array
      int frame_count;       ///< total number of reference frames
      int segment_frame_count; ///< number of reference frames in the segment
  
      int64_t time_delta;
      int  individual_header_trailer; /**< Set by a private option. */
      int  write_header_trailer; /**< Set by a private option. */
      char *header_filename;  ///< filename to write the output header to
  
      int reset_timestamps;  ///< reset timestamps at the beginning of each segment
      int64_t initial_offset;    ///< initial timestamps offset, expressed in microseconds
      char *reference_stream_specifier; ///< reference stream specifier
      int   reference_stream_index;
      int   break_non_keyframes;
      int   write_empty;
  
      int use_rename;
      char temp_list_filename[1024];
  
      SegmentListEntry cur_entry;
      SegmentListEntry *segment_list_entries;
      SegmentListEntry *segment_list_entries_end;
  } SegmentContext;
  
  static void print_csv_escaped_str(AVIOContext *ctx, const char *str)
  {
      int needs_quoting = !!str[strcspn(str, "\",\n\r")];
  
      if (needs_quoting)
          avio_w8(ctx, '"');
  
      for (; *str; str++) {
          if (*str == '"')
              avio_w8(ctx, '"');
          avio_w8(ctx, *str);
      }
      if (needs_quoting)
          avio_w8(ctx, '"');
  }
  
  static int segment_mux_init(AVFormatContext *s)
  {
      SegmentContext *seg = s->priv_data;
      AVFormatContext *oc;
      int i;
      int ret;
  
      ret = avformat_alloc_output_context2(&seg->avf, seg->oformat, NULL, NULL);
      if (ret < 0)
          return ret;
      oc = seg->avf;
  
      oc->interrupt_callback = s->interrupt_callback;
      oc->max_delay          = s->max_delay;
      av_dict_copy(&oc->metadata, s->metadata, 0);
      oc->opaque             = s->opaque;
      oc->io_close           = s->io_close;
      oc->io_open            = s->io_open;
      oc->flags              = s->flags;
  
      for (i = 0; i < s->nb_streams; i++) {
          AVStream *st, *ist = s->streams[i];
          AVCodecParameters *ipar = ist->codecpar, *opar;
  
          if (!(st = avformat_new_stream(oc, NULL)))
              return AVERROR(ENOMEM);
          ret = ff_stream_encode_params_copy(st, ist);
          if (ret < 0)
              return ret;
          opar = st->codecpar;
          if (!oc->oformat->codec_tag ||
              av_codec_get_id (oc->oformat->codec_tag, ipar->codec_tag) == opar->codec_id ||
              av_codec_get_tag(oc->oformat->codec_tag, ipar->codec_id) <= 0) {
              opar->codec_tag = ipar->codec_tag;
          } else {
              opar->codec_tag = 0;
          }
  #if FF_API_LAVF_AVCTX
  FF_DISABLE_DEPRECATION_WARNINGS
          if (ipar->codec_tag == MKTAG('t','m','c','d'))
              st->codec->time_base = ist->codec->time_base;
  FF_ENABLE_DEPRECATION_WARNINGS
  #endif
      }
  
      return 0;
  }
  
  static int set_segment_filename(AVFormatContext *s)
  {
      SegmentContext *seg = s->priv_data;
      AVFormatContext *oc = seg->avf;
      size_t size;
      int ret;
      char buf[1024];
      char *new_name;
  
      if (seg->segment_idx_wrap)
          seg->segment_idx %= seg->segment_idx_wrap;
      if (seg->use_strftime) {
          time_t now0;
          struct tm *tm, tmpbuf;
          time(&now0);
          tm = localtime_r(&now0, &tmpbuf);
          if (!strftime(buf, sizeof(buf), s->url, tm)) {
              av_log(oc, AV_LOG_ERROR, "Could not get segment filename with strftime\n");
              return AVERROR(EINVAL);
          }
      } else if (av_get_frame_filename(buf, sizeof(buf),
                                       s->url, seg->segment_idx) < 0) {
          av_log(oc, AV_LOG_ERROR, "Invalid segment filename template '%s'\n", s->url);
          return AVERROR(EINVAL);
      }
      new_name = av_strdup(buf);
      if (!new_name)
          return AVERROR(ENOMEM);
      ff_format_set_url(oc, new_name);
  
      /* copy modified name in list entry */
      size = strlen(av_basename(oc->url)) + 1;
      if (seg->entry_prefix)
          size += strlen(seg->entry_prefix);
  
      if ((ret = av_reallocp(&seg->cur_entry.filename, size)) < 0)
          return ret;
      snprintf(seg->cur_entry.filename, size, "%s%s",
               seg->entry_prefix ? seg->entry_prefix : "",
               av_basename(oc->url));
  
      return 0;
  }
  
  static int segment_start(AVFormatContext *s, int write_header)
  {
      SegmentContext *seg = s->priv_data;
      AVFormatContext *oc = seg->avf;
      int err = 0;
  
      if (write_header) {
          avformat_free_context(oc);
          seg->avf = NULL;
          if ((err = segment_mux_init(s)) < 0)
              return err;
          oc = seg->avf;
      }
  
      seg->segment_idx++;
      if ((seg->segment_idx_wrap) && (seg->segment_idx % seg->segment_idx_wrap == 0))
          seg->segment_idx_wrap_nb++;
  
      if ((err = set_segment_filename(s)) < 0)
          return err;
  
      if ((err = s->io_open(s, &oc->pb, oc->url, AVIO_FLAG_WRITE, NULL)) < 0) {
          av_log(s, AV_LOG_ERROR, "Failed to open segment '%s'\n", oc->url);
          return err;
      }
      if (!seg->individual_header_trailer)
          oc->pb->seekable = 0;
  
      if (oc->oformat->priv_class && oc->priv_data)
          av_opt_set(oc->priv_data, "mpegts_flags", "+resend_headers", 0);
  
      if (write_header) {
          AVDictionary *options = NULL;
          av_dict_copy(&options, seg->format_options, 0);
          av_dict_set(&options, "fflags", "-autobsf", 0);
          err = avformat_write_header(oc, &options);
          av_dict_free(&options);
          if (err < 0)
              return err;
      }
  
      seg->segment_frame_count = 0;
      return 0;
  }
  
  static int segment_list_open(AVFormatContext *s)
  {
      SegmentContext *seg = s->priv_data;
      int ret;
  
      snprintf(seg->temp_list_filename, sizeof(seg->temp_list_filename), seg->use_rename ? "%s.tmp" : "%s", seg->list);
      ret = s->io_open(s, &seg->list_pb, seg->temp_list_filename, AVIO_FLAG_WRITE, NULL);
      if (ret < 0) {
          av_log(s, AV_LOG_ERROR, "Failed to open segment list '%s'\n", seg->list);
          return ret;
      }
  
      if (seg->list_type == LIST_TYPE_M3U8 && seg->segment_list_entries) {
          SegmentListEntry *entry;
          double max_duration = 0;
  
          avio_printf(seg->list_pb, "#EXTM3U\n");
          avio_printf(seg->list_pb, "#EXT-X-VERSION:3\n");
          avio_printf(seg->list_pb, "#EXT-X-MEDIA-SEQUENCE:%d\n", seg->segment_list_entries->index);
          avio_printf(seg->list_pb, "#EXT-X-ALLOW-CACHE:%s\n",
                      seg->list_flags & SEGMENT_LIST_FLAG_CACHE ? "YES" : "NO");
  
          av_log(s, AV_LOG_VERBOSE, "EXT-X-MEDIA-SEQUENCE:%d\n",
                 seg->segment_list_entries->index);
  
          for (entry = seg->segment_list_entries; entry; entry = entry->next)
              max_duration = FFMAX(max_duration, entry->end_time - entry->start_time);
          avio_printf(seg->list_pb, "#EXT-X-TARGETDURATION:%"PRId64"\n", (int64_t)ceil(max_duration));
      } else if (seg->list_type == LIST_TYPE_FFCONCAT) {
          avio_printf(seg->list_pb, "ffconcat version 1.0\n");
      }
  
      return ret;
  }
  
  static void segment_list_print_entry(AVIOContext      *list_ioctx,
                                       ListType          list_type,
                                       const SegmentListEntry *list_entry,
                                       void *log_ctx)
  {
      switch (list_type) {
      case LIST_TYPE_FLAT:
          avio_printf(list_ioctx, "%s\n", list_entry->filename);
          break;
      case LIST_TYPE_CSV:
      case LIST_TYPE_EXT:
          print_csv_escaped_str(list_ioctx, list_entry->filename);
          avio_printf(list_ioctx, ",%f,%f\n", list_entry->start_time, list_entry->end_time);
          break;
      case LIST_TYPE_M3U8:
          avio_printf(list_ioctx, "#EXTINF:%f,\n%s\n",
                      list_entry->end_time - list_entry->start_time, list_entry->filename);
          break;
      case LIST_TYPE_FFCONCAT:
      {
          char *buf;
          if (av_escape(&buf, list_entry->filename, NULL, AV_ESCAPE_MODE_AUTO, AV_ESCAPE_FLAG_WHITESPACE) < 0) {
              av_log(log_ctx, AV_LOG_WARNING,
                     "Error writing list entry '%s' in list file\n", list_entry->filename);
              return;
          }
          avio_printf(list_ioctx, "file %s\n", buf);
          av_free(buf);
          break;
      }
      default:
          av_assert0(!"Invalid list type");
      }
  }
  
  static int segment_end(AVFormatContext *s, int write_trailer, int is_last)
  {
      SegmentContext *seg = s->priv_data;
      AVFormatContext *oc = seg->avf;
      int ret = 0;
      AVTimecode tc;
      AVRational rate;
      AVDictionaryEntry *tcr;
      char buf[AV_TIMECODE_STR_SIZE];
      int i;
      int err;
  
      if (!oc || !oc->pb)
          return AVERROR(EINVAL);
  
      av_write_frame(oc, NULL); /* Flush any buffered data (fragmented mp4) */
      if (write_trailer)
          ret = av_write_trailer(oc);
  
      if (ret < 0)
          av_log(s, AV_LOG_ERROR, "Failure occurred when ending segment '%s'\n",
                 oc->url);
  
      if (seg->list) {
          if (seg->list_size || seg->list_type == LIST_TYPE_M3U8) {
              SegmentListEntry *entry = av_mallocz(sizeof(*entry));
              if (!entry) {
                  ret = AVERROR(ENOMEM);
                  goto end;
              }
  
              /* append new element */
              memcpy(entry, &seg->cur_entry, sizeof(*entry));
              entry->filename = av_strdup(entry->filename);
              if (!seg->segment_list_entries)
                  seg->segment_list_entries = seg->segment_list_entries_end = entry;
              else
                  seg->segment_list_entries_end->next = entry;
              seg->segment_list_entries_end = entry;
  
              /* drop first item */
              if (seg->list_size && seg->segment_count >= seg->list_size) {
                  entry = seg->segment_list_entries;
                  seg->segment_list_entries = seg->segment_list_entries->next;
                  av_freep(&entry->filename);
                  av_freep(&entry);
              }
  
              if ((ret = segment_list_open(s)) < 0)
                  goto end;
              for (entry = seg->segment_list_entries; entry; entry = entry->next)
                  segment_list_print_entry(seg->list_pb, seg->list_type, entry, s);
              if (seg->list_type == LIST_TYPE_M3U8 && is_last)
                  avio_printf(seg->list_pb, "#EXT-X-ENDLIST\n");
              ff_format_io_close(s, &seg->list_pb);
              if (seg->use_rename)
                  ff_rename(seg->temp_list_filename, seg->list, s);
          } else {
              segment_list_print_entry(seg->list_pb, seg->list_type, &seg->cur_entry, s);
              avio_flush(seg->list_pb);
          }
      }
  
      av_log(s, AV_LOG_VERBOSE, "segment:'%s' count:%d ended\n",
             seg->avf->url, seg->segment_count);
      seg->segment_count++;
  
      if (seg->increment_tc) {
          tcr = av_dict_get(s->metadata, "timecode", NULL, 0);
          if (tcr) {
              /* search the first video stream */
              for (i = 0; i < s->nb_streams; i++) {
                  if (s->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
                      rate = s->streams[i]->avg_frame_rate;/* Get fps from the video stream */
                      err = av_timecode_init_from_string(&tc, rate, tcr->value, s);
                      if (err < 0) {
                          av_log(s, AV_LOG_WARNING, "Could not increment global timecode, error occurred during timecode creation.\n");
                          break;
                      }
                      tc.start += (int)((seg->cur_entry.end_time - seg->cur_entry.start_time) * av_q2d(rate));/* increment timecode */
                      av_dict_set(&s->metadata, "timecode",
                                  av_timecode_make_string(&tc, buf, 0), 0);
                      break;
                  }
              }
          } else {
              av_log(s, AV_LOG_WARNING, "Could not increment global timecode, no global timecode metadata found.\n");
          }
          for (i = 0; i < s->nb_streams; i++) {
              if (s->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
                  char st_buf[AV_TIMECODE_STR_SIZE];
                  AVTimecode st_tc;
                  AVRational st_rate = s->streams[i]->avg_frame_rate;
                  AVDictionaryEntry *st_tcr = av_dict_get(s->streams[i]->metadata, "timecode", NULL, 0);
                  if (st_tcr) {
                      if ((av_timecode_init_from_string(&st_tc, st_rate, st_tcr->value, s) < 0)) {
                          av_log(s, AV_LOG_WARNING, "Could not increment stream %d timecode, error occurred during timecode creation.\n", i);
                          continue;
                      }
                  st_tc.start += (int)((seg->cur_entry.end_time - seg->cur_entry.start_time) * av_q2d(st_rate));    // increment timecode
                  av_dict_set(&s->streams[i]->metadata, "timecode", av_timecode_make_string(&st_tc, st_buf, 0), 0);
                  }
              }
          }
      }
  
  end:
      ff_format_io_close(oc, &oc->pb);
  
      return ret;
  }
  
  static int parse_times(void *log_ctx, int64_t **times, int *nb_times,
                         const char *times_str)
  {
      char *p;
      int i, ret = 0;
      char *times_str1 = av_strdup(times_str);
      char *saveptr = NULL;
  
      if (!times_str1)
          return AVERROR(ENOMEM);
  
  #define FAIL(err) ret = err; goto end
  
      *nb_times = 1;
      for (p = times_str1; *p; p++)
          if (*p == ',')
              (*nb_times)++;
  
      *times = av_malloc_array(*nb_times, sizeof(**times));
      if (!*times) {
          av_log(log_ctx, AV_LOG_ERROR, "Could not allocate forced times array\n");
          FAIL(AVERROR(ENOMEM));
      }
  
      p = times_str1;
      for (i = 0; i < *nb_times; i++) {
          int64_t t;
          char *tstr = av_strtok(p, ",", &saveptr);
          p = NULL;
  
          if (!tstr || !tstr[0]) {
              av_log(log_ctx, AV_LOG_ERROR, "Empty time specification in times list %s\n",
                     times_str);
              FAIL(AVERROR(EINVAL));
          }
  
          ret = av_parse_time(&t, tstr, 1);
          if (ret < 0) {
              av_log(log_ctx, AV_LOG_ERROR,
                     "Invalid time duration specification '%s' in times list %s\n", tstr, times_str);
              FAIL(AVERROR(EINVAL));
          }
          (*times)[i] = t;
  
          /* check on monotonicity */
          if (i && (*times)[i-1] > (*times)[i]) {
              av_log(log_ctx, AV_LOG_ERROR,
                     "Specified time %f is smaller than the last time %f\n",
                     (float)((*times)[i])/1000000, (float)((*times)[i-1])/1000000);
              FAIL(AVERROR(EINVAL));
          }
      }
  
  end:
      av_free(times_str1);
      return ret;
  }
  
  static int parse_frames(void *log_ctx, int **frames, int *nb_frames,
                          const char *frames_str)
  {
      const char *p;
      int i;
  
      *nb_frames = 1;
      for (p = frames_str; *p; p++)
          if (*p == ',')
              (*nb_frames)++;
  
      *frames = av_malloc_array(*nb_frames, sizeof(**frames));
      if (!*frames) {
          av_log(log_ctx, AV_LOG_ERROR, "Could not allocate forced frames array\n");
          return AVERROR(ENOMEM);
      }
  
      p = frames_str;
      for (i = 0; i < *nb_frames; i++) {
          long int f;
          char *tailptr;
  
          if (*p == '\0' || *p == ',') {
              av_log(log_ctx, AV_LOG_ERROR, "Empty frame specification in frame list %s\n",
                     frames_str);
              return AVERROR(EINVAL);
          }
          f = strtol(p, &tailptr, 10);
          if (*tailptr != '\0' && *tailptr != ',' || f <= 0 || f >= INT_MAX) {
              av_log(log_ctx, AV_LOG_ERROR,
                     "Invalid argument '%s', must be a positive integer < INT_MAX\n",
                     p);
              return AVERROR(EINVAL);
          }
          if (*tailptr == ',')
              tailptr++;
          p = tailptr;
          (*frames)[i] = f;
  
          /* check on monotonicity */
          if (i && (*frames)[i-1] > (*frames)[i]) {
              av_log(log_ctx, AV_LOG_ERROR,
                     "Specified frame %d is smaller than the last frame %d\n",
                     (*frames)[i], (*frames)[i-1]);
              return AVERROR(EINVAL);
          }
      }
  
      return 0;
  }
  
  static int open_null_ctx(AVIOContext **ctx)
  {
      int buf_size = 32768;
      uint8_t *buf = av_malloc(buf_size);
      if (!buf)
          return AVERROR(ENOMEM);
      *ctx = avio_alloc_context(buf, buf_size, AVIO_FLAG_WRITE, NULL, NULL, NULL, NULL);
      if (!*ctx) {
          av_free(buf);
          return AVERROR(ENOMEM);
      }
      return 0;
  }
  
  static void close_null_ctxp(AVIOContext **pb)
  {
      av_freep(&(*pb)->buffer);
      avio_context_free(pb);
  }
  
  static int select_reference_stream(AVFormatContext *s)
  {
      SegmentContext *seg = s->priv_data;
      int ret, i;
  
      seg->reference_stream_index = -1;
      if (!strcmp(seg->reference_stream_specifier, "auto")) {
          /* select first index of type with highest priority */
          int type_index_map[AVMEDIA_TYPE_NB];
          static const enum AVMediaType type_priority_list[] = {
              AVMEDIA_TYPE_VIDEO,
              AVMEDIA_TYPE_AUDIO,
              AVMEDIA_TYPE_SUBTITLE,
              AVMEDIA_TYPE_DATA,
              AVMEDIA_TYPE_ATTACHMENT
          };
          enum AVMediaType type;
  
          for (i = 0; i < AVMEDIA_TYPE_NB; i++)
              type_index_map[i] = -1;
  
          /* select first index for each type */
          for (i = 0; i < s->nb_streams; i++) {
              type = s->streams[i]->codecpar->codec_type;
              if ((unsigned)type < AVMEDIA_TYPE_NB && type_index_map[type] == -1
                  /* ignore attached pictures/cover art streams */
                  && !(s->streams[i]->disposition & AV_DISPOSITION_ATTACHED_PIC))
                  type_index_map[type] = i;
          }
  
          for (i = 0; i < FF_ARRAY_ELEMS(type_priority_list); i++) {
              type = type_priority_list[i];
              if ((seg->reference_stream_index = type_index_map[type]) >= 0)
                  break;
          }
      } else {
          for (i = 0; i < s->nb_streams; i++) {
              ret = avformat_match_stream_specifier(s, s->streams[i],
                                                    seg->reference_stream_specifier);
              if (ret < 0)
                  return ret;
              if (ret > 0) {
                  seg->reference_stream_index = i;
                  break;
              }
          }
      }
  
      if (seg->reference_stream_index < 0) {
          av_log(s, AV_LOG_ERROR, "Could not select stream matching identifier '%s'\n",
                 seg->reference_stream_specifier);
          return AVERROR(EINVAL);
      }
  
      return 0;
  }
  
  static void seg_free(AVFormatContext *s)
  {
      SegmentContext *seg = s->priv_data;
      SegmentListEntry *cur;
  
      ff_format_io_close(s, &seg->list_pb);
      if (seg->avf) {
          if (seg->is_nullctx)
              close_null_ctxp(&seg->avf->pb);
          else
              ff_format_io_close(s, &seg->avf->pb);
          avformat_free_context(seg->avf);
          seg->avf = NULL;
      }
      av_freep(&seg->times);
      av_freep(&seg->frames);
      av_freep(&seg->cur_entry.filename);
  
      cur = seg->segment_list_entries;
      while (cur) {
          SegmentListEntry *next = cur->next;
          av_freep(&cur->filename);
          av_free(cur);
          cur = next;
      }
  }
  
  static int seg_init(AVFormatContext *s)
  {
      SegmentContext *seg = s->priv_data;
      AVFormatContext *oc = seg->avf;
      AVDictionary *options = NULL;
      int ret;
      int i;
  
      seg->segment_count = 0;
      if (!seg->write_header_trailer)
          seg->individual_header_trailer = 0;
  
      if (seg->header_filename) {
          seg->write_header_trailer = 1;
          seg->individual_header_trailer = 0;
      }
  
      if (seg->initial_offset > 0) {
          av_log(s, AV_LOG_WARNING, "NOTE: the option initial_offset is deprecated,"
                 "you can use output_ts_offset instead of it\n");
      }
  
      if ((seg->time != 2000000) + !!seg->times_str + !!seg->frames_str > 1) {
          av_log(s, AV_LOG_ERROR,
                 "segment_time, segment_times, and segment_frames options "
                 "are mutually exclusive, select just one of them\n");
          return AVERROR(EINVAL);
      }
  
      if (seg->times_str) {
          if ((ret = parse_times(s, &seg->times, &seg->nb_times, seg->times_str)) < 0)
              return ret;
      } else if (seg->frames_str) {
          if ((ret = parse_frames(s, &seg->frames, &seg->nb_frames, seg->frames_str)) < 0)
              return ret;
      } else {
          if (seg->use_clocktime) {
              if (seg->time <= 0) {
                  av_log(s, AV_LOG_ERROR, "Invalid negative segment_time with segment_atclocktime option set\n");
                  return AVERROR(EINVAL);
              }
              seg->clocktime_offset = seg->time - (seg->clocktime_offset % seg->time);
          }
      }
  
      if (seg->list) {
          if (seg->list_type == LIST_TYPE_UNDEFINED) {
              if      (av_match_ext(seg->list, "csv" )) seg->list_type = LIST_TYPE_CSV;
              else if (av_match_ext(seg->list, "ext" )) seg->list_type = LIST_TYPE_EXT;
              else if (av_match_ext(seg->list, "m3u8")) seg->list_type = LIST_TYPE_M3U8;
              else if (av_match_ext(seg->list, "ffcat,ffconcat")) seg->list_type = LIST_TYPE_FFCONCAT;
              else                                      seg->list_type = LIST_TYPE_FLAT;
          }
          if (!seg->list_size && seg->list_type != LIST_TYPE_M3U8) {
              if ((ret = segment_list_open(s)) < 0)
                  return ret;
          } else {
              const char *proto = avio_find_protocol_name(seg->list);
              seg->use_rename = proto && !strcmp(proto, "file");
          }
      }
  
      if (seg->list_type == LIST_TYPE_EXT)
          av_log(s, AV_LOG_WARNING, "'ext' list type option is deprecated in favor of 'csv'\n");
  
      if ((ret = select_reference_stream(s)) < 0)
          return ret;
      av_log(s, AV_LOG_VERBOSE, "Selected stream id:%d type:%s\n",
             seg->reference_stream_index,
             av_get_media_type_string(s->streams[seg->reference_stream_index]->codecpar->codec_type));
  
      seg->oformat = av_guess_format(seg->format, s->url, NULL);
  
      if (!seg->oformat)
          return AVERROR_MUXER_NOT_FOUND;
      if (seg->oformat->flags & AVFMT_NOFILE) {
          av_log(s, AV_LOG_ERROR, "format %s not supported.\n",
                 seg->oformat->name);
          return AVERROR(EINVAL);
      }
  
      if ((ret = segment_mux_init(s)) < 0)
          return ret;
  
      if ((ret = set_segment_filename(s)) < 0)
          return ret;
      oc = seg->avf;
  
      if (seg->write_header_trailer) {
          if ((ret = s->io_open(s, &oc->pb,
                                seg->header_filename ? seg->header_filename : oc->url,
                                AVIO_FLAG_WRITE, NULL)) < 0) {
              av_log(s, AV_LOG_ERROR, "Failed to open segment '%s'\n", oc->url);
              return ret;
          }
          if (!seg->individual_header_trailer)
              oc->pb->seekable = 0;
      } else {
          if ((ret = open_null_ctx(&oc->pb)) < 0)
              return ret;
          seg->is_nullctx = 1;
      }
  
      av_dict_copy(&options, seg->format_options, 0);
      av_dict_set(&options, "fflags", "-autobsf", 0);
      ret = avformat_init_output(oc, &options);
      if (av_dict_count(options)) {
          av_log(s, AV_LOG_ERROR,
                 "Some of the provided format options are not recognized\n");
          av_dict_free(&options);
          return AVERROR(EINVAL);
      }
      av_dict_free(&options);
  
      if (ret < 0) {
          return ret;
      }
      seg->segment_frame_count = 0;
  
      av_assert0(s->nb_streams == oc->nb_streams);
      if (ret == AVSTREAM_INIT_IN_WRITE_HEADER) {
          ret = avformat_write_header(oc, NULL);
          if (ret < 0)
              return ret;
          seg->header_written = 1;
      }
  
      for (i = 0; i < s->nb_streams; i++) {
          AVStream *inner_st  = oc->streams[i];
          AVStream *outer_st = s->streams[i];
          avpriv_set_pts_info(outer_st, inner_st->pts_wrap_bits, inner_st->time_base.num, inner_st->time_base.den);
      }
  
      if (oc->avoid_negative_ts > 0 && s->avoid_negative_ts < 0)
          s->avoid_negative_ts = 1;
  
      return ret;
  }
  
  static int seg_write_header(AVFormatContext *s)
  {
      SegmentContext *seg = s->priv_data;
      AVFormatContext *oc = seg->avf;
      int ret;
  
      if (!seg->header_written) {
          ret = avformat_write_header(oc, NULL);
          if (ret < 0)
              return ret;
      }
  
      if (!seg->write_header_trailer || seg->header_filename) {
          if (seg->header_filename) {
              av_write_frame(oc, NULL);
              ff_format_io_close(oc, &oc->pb);
          } else {
              close_null_ctxp(&oc->pb);
              seg->is_nullctx = 0;
          }
          if ((ret = oc->io_open(oc, &oc->pb, oc->url, AVIO_FLAG_WRITE, NULL)) < 0)
              return ret;
          if (!seg->individual_header_trailer)
              oc->pb->seekable = 0;
      }
  
      return 0;
  }
  
  static int seg_write_packet(AVFormatContext *s, AVPacket *pkt)
  {
      SegmentContext *seg = s->priv_data;
      AVStream *st = s->streams[pkt->stream_index];
      int64_t end_pts = INT64_MAX, offset;
      int start_frame = INT_MAX;
      int ret;
      struct tm ti;
      int64_t usecs;
      int64_t wrapped_val;
  
      if (!seg->avf || !seg->avf->pb)
          return AVERROR(EINVAL);
  
      if (!st->codecpar->extradata_size) {
          buffer_size_t pkt_extradata_size;
          uint8_t *pkt_extradata = av_packet_get_side_data(pkt, AV_PKT_DATA_NEW_EXTRADATA, &pkt_extradata_size);
          if (pkt_extradata && pkt_extradata_size > 0) {
              ret = ff_alloc_extradata(st->codecpar, pkt_extradata_size);
              if (ret < 0) {
                  av_log(s, AV_LOG_WARNING, "Unable to add extradata to stream. Output segments may be invalid.\n");
                  goto calc_times;
              }
              memcpy(st->codecpar->extradata, pkt_extradata, pkt_extradata_size);
          }
      }
  
  calc_times:
      if (seg->times) {
          end_pts = seg->segment_count < seg->nb_times ?
              seg->times[seg->segment_count] : INT64_MAX;
      } else if (seg->frames) {
          start_frame = seg->segment_count < seg->nb_frames ?
              seg->frames[seg->segment_count] : INT_MAX;
      } else {
          if (seg->use_clocktime) {
              int64_t avgt = av_gettime();
              time_t sec = avgt / 1000000;
              localtime_r(&sec, &ti);
              usecs = (int64_t)(ti.tm_hour * 3600 + ti.tm_min * 60 + ti.tm_sec) * 1000000 + (avgt % 1000000);
              wrapped_val = (usecs + seg->clocktime_offset) % seg->time;
              if (wrapped_val < seg->last_val && wrapped_val < seg->clocktime_wrap_duration)
                  seg->cut_pending = 1;
              seg->last_val = wrapped_val;
          } else {
              end_pts = seg->time * (seg->segment_count + 1);
          }
      }
  
      ff_dlog(s, "packet stream:%d pts:%s pts_time:%s duration_time:%s is_key:%d frame:%d\n",
              pkt->stream_index, av_ts2str(pkt->pts), av_ts2timestr(pkt->pts, &st->time_base),
              av_ts2timestr(pkt->duration, &st->time_base),
              pkt->flags & AV_PKT_FLAG_KEY,
              pkt->stream_index == seg->reference_stream_index ? seg->frame_count : -1);
  
      if (pkt->stream_index == seg->reference_stream_index &&
          (pkt->flags & AV_PKT_FLAG_KEY || seg->break_non_keyframes) &&
          (seg->segment_frame_count > 0 || seg->write_empty) &&
          (seg->cut_pending || seg->frame_count >= start_frame ||
           (pkt->pts != AV_NOPTS_VALUE &&
            av_compare_ts(pkt->pts, st->time_base,
                          end_pts - seg->time_delta, AV_TIME_BASE_Q) >= 0))) {
          /* sanitize end time in case last packet didn't have a defined duration */
          if (seg->cur_entry.last_duration == 0)
              seg->cur_entry.end_time = (double)pkt->pts * av_q2d(st->time_base);
  
          if ((ret = segment_end(s, seg->individual_header_trailer, 0)) < 0)
              goto fail;
  
          if ((ret = segment_start(s, seg->individual_header_trailer)) < 0)
              goto fail;
  
          seg->cut_pending = 0;
          seg->cur_entry.index = seg->segment_idx + seg->segment_idx_wrap * seg->segment_idx_wrap_nb;
          seg->cur_entry.start_time = (double)pkt->pts * av_q2d(st->time_base);
          seg->cur_entry.start_pts = av_rescale_q(pkt->pts, st->time_base, AV_TIME_BASE_Q);
          seg->cur_entry.end_time = seg->cur_entry.start_time;
  
          if (seg->times || (!seg->frames && !seg->use_clocktime) && seg->write_empty)
              goto calc_times;
      }
  
      if (pkt->stream_index == seg->reference_stream_index) {
          if (pkt->pts != AV_NOPTS_VALUE)
              seg->cur_entry.end_time =
                  FFMAX(seg->cur_entry.end_time, (double)(pkt->pts + pkt->duration) * av_q2d(st->time_base));
          seg->cur_entry.last_duration = pkt->duration;
      }
  
      if (seg->segment_frame_count == 0) {
          av_log(s, AV_LOG_VERBOSE, "segment:'%s' starts with packet stream:%d pts:%s pts_time:%s frame:%d\n",
                 seg->avf->url, pkt->stream_index,
                 av_ts2str(pkt->pts), av_ts2timestr(pkt->pts, &st->time_base), seg->frame_count);
      }
  
      av_log(s, AV_LOG_DEBUG, "stream:%d start_pts_time:%s pts:%s pts_time:%s dts:%s dts_time:%s",
             pkt->stream_index,
             av_ts2timestr(seg->cur_entry.start_pts, &AV_TIME_BASE_Q),
             av_ts2str(pkt->pts), av_ts2timestr(pkt->pts, &st->time_base),
             av_ts2str(pkt->dts), av_ts2timestr(pkt->dts, &st->time_base));
  
      /* compute new timestamps */
      offset = av_rescale_q(seg->initial_offset - (seg->reset_timestamps ? seg->cur_entry.start_pts : 0),
                            AV_TIME_BASE_Q, st->time_base);
      if (pkt->pts != AV_NOPTS_VALUE)
          pkt->pts += offset;
      if (pkt->dts != AV_NOPTS_VALUE)
          pkt->dts += offset;
  
      av_log(s, AV_LOG_DEBUG, " -> pts:%s pts_time:%s dts:%s dts_time:%s\n",
             av_ts2str(pkt->pts), av_ts2timestr(pkt->pts, &st->time_base),
             av_ts2str(pkt->dts), av_ts2timestr(pkt->dts, &st->time_base));
  
      ret = ff_write_chained(seg->avf, pkt->stream_index, pkt, s,
                             seg->initial_offset || seg->reset_timestamps || seg->avf->oformat->interleave_packet);
  
  fail:
      if (pkt->stream_index == seg->reference_stream_index) {
          seg->frame_count++;
          seg->segment_frame_count++;
      }
  
      return ret;
  }
  
  static int seg_write_trailer(struct AVFormatContext *s)
  {
      SegmentContext *seg = s->priv_data;
      AVFormatContext *oc = seg->avf;
      int ret;
  
      if (!oc)
          return 0;
  
      if (!seg->write_header_trailer) {
          if ((ret = segment_end(s, 0, 1)) < 0)
              return ret;
          if ((ret = open_null_ctx(&oc->pb)) < 0)
              return ret;
          seg->is_nullctx = 1;
          ret = av_write_trailer(oc);
      } else {
          ret = segment_end(s, 1, 1);
      }
      return ret;
  }
  
  static int seg_check_bitstream(struct AVFormatContext *s, const AVPacket *pkt)
  {
      SegmentContext *seg = s->priv_data;
      AVFormatContext *oc = seg->avf;
      if (oc->oformat->check_bitstream) {
          int ret = oc->oformat->check_bitstream(oc, pkt);
          if (ret == 1) {
              AVStream *st = s->streams[pkt->stream_index];
              AVStream *ost = oc->streams[pkt->stream_index];
              st->internal->bsfc = ost->internal->bsfc;
              ost->internal->bsfc = NULL;
          }
          return ret;
      }
      return 1;
  }
  
  #define OFFSET(x) offsetof(SegmentContext, x)
  #define E AV_OPT_FLAG_ENCODING_PARAM
  static const AVOption options[] = {
      { "reference_stream",  "set reference stream", OFFSET(reference_stream_specifier), AV_OPT_TYPE_STRING, {.str = "auto"}, 0, 0, E },
      { "segment_format",    "set container format used for the segments", OFFSET(format),  AV_OPT_TYPE_STRING, {.str = NULL},  0, 0,       E },
      { "segment_format_options", "set list of options for the container format used for the segments", OFFSET(format_options), AV_OPT_TYPE_DICT, {.str = NULL}, 0, 0, E },
      { "segment_list",      "set the segment list filename",              OFFSET(list),    AV_OPT_TYPE_STRING, {.str = NULL},  0, 0,       E },
      { "segment_header_filename", "write a single file containing the header", OFFSET(header_filename), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, E },
  
      { "segment_list_flags","set flags affecting segment list generation", OFFSET(list_flags), AV_OPT_TYPE_FLAGS, {.i64 = SEGMENT_LIST_FLAG_CACHE }, 0, UINT_MAX, E, "list_flags"},
      { "cache",             "allow list caching",                                    0, AV_OPT_TYPE_CONST, {.i64 = SEGMENT_LIST_FLAG_CACHE }, INT_MIN, INT_MAX,   E, "list_flags"},
      { "live",              "enable live-friendly list generation (useful for HLS)", 0, AV_OPT_TYPE_CONST, {.i64 = SEGMENT_LIST_FLAG_LIVE }, INT_MIN, INT_MAX,    E, "list_flags"},
  
      { "segment_list_size", "set the maximum number of playlist entries", OFFSET(list_size), AV_OPT_TYPE_INT,  {.i64 = 0},     0, INT_MAX, E },
  
      { "segment_list_type", "set the segment list type",                  OFFSET(list_type), AV_OPT_TYPE_INT,  {.i64 = LIST_TYPE_UNDEFINED}, -1, LIST_TYPE_NB-1, E, "list_type" },
      { "flat", "flat format",     0, AV_OPT_TYPE_CONST, {.i64=LIST_TYPE_FLAT }, INT_MIN, INT_MAX, E, "list_type" },
      { "csv",  "csv format",      0, AV_OPT_TYPE_CONST, {.i64=LIST_TYPE_CSV  }, INT_MIN, INT_MAX, E, "list_type" },
      { "ext",  "extended format", 0, AV_OPT_TYPE_CONST, {.i64=LIST_TYPE_EXT  }, INT_MIN, INT_MAX, E, "list_type" },
      { "ffconcat", "ffconcat format", 0, AV_OPT_TYPE_CONST, {.i64=LIST_TYPE_FFCONCAT }, INT_MIN, INT_MAX, E, "list_type" },
      { "m3u8", "M3U8 format",     0, AV_OPT_TYPE_CONST, {.i64=LIST_TYPE_M3U8 }, INT_MIN, INT_MAX, E, "list_type" },
      { "hls", "Apple HTTP Live Streaming compatible", 0, AV_OPT_TYPE_CONST, {.i64=LIST_TYPE_M3U8 }, INT_MIN, INT_MAX, E, "list_type" },
  
      { "segment_atclocktime",      "set segment to be cut at clocktime",  OFFSET(use_clocktime), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, E},
      { "segment_clocktime_offset", "set segment clocktime offset",        OFFSET(clocktime_offset), AV_OPT_TYPE_DURATION, {.i64 = 0}, 0, 86400000000LL, E},
      { "segment_clocktime_wrap_duration", "set segment clocktime wrapping duration", OFFSET(clocktime_wrap_duration), AV_OPT_TYPE_DURATION, {.i64 = INT64_MAX}, 0, INT64_MAX, E},
      { "segment_time",      "set segment duration",                       OFFSET(time),AV_OPT_TYPE_DURATION, {.i64 = 2000000}, INT64_MIN, INT64_MAX,       E },
      { "segment_time_delta","set approximation value used for the segment times", OFFSET(time_delta), AV_OPT_TYPE_DURATION, {.i64 = 0}, 0, INT64_MAX, E },
      { "segment_times",     "set segment split time points",              OFFSET(times_str),AV_OPT_TYPE_STRING,{.str = NULL},  0, 0,       E },
      { "segment_frames",    "set segment split frame numbers",            OFFSET(frames_str),AV_OPT_TYPE_STRING,{.str = NULL},  0, 0,       E },
      { "segment_wrap",      "set number after which the index wraps",     OFFSET(segment_idx_wrap), AV_OPT_TYPE_INT, {.i64 = 0}, 0, INT_MAX, E },
      { "segment_list_entry_prefix", "set base url prefix for segments", OFFSET(entry_prefix), AV_OPT_TYPE_STRING,  {.str = NULL}, 0, 0, E },
      { "segment_start_number", "set the sequence number of the first segment", OFFSET(segment_idx), AV_OPT_TYPE_INT, {.i64 = 0}, 0, INT_MAX, E },
      { "segment_wrap_number", "set the number of wrap before the first segment", OFFSET(segment_idx_wrap_nb), AV_OPT_TYPE_INT, {.i64 = 0}, 0, INT_MAX, E },
      { "strftime",          "set filename expansion with strftime at segment creation", OFFSET(use_strftime), AV_OPT_TYPE_BOOL, {.i64 = 0 }, 0, 1, E },
      { "increment_tc", "increment timecode between each segment", OFFSET(increment_tc), AV_OPT_TYPE_BOOL, {.i64 = 0 }, 0, 1, E },
      { "break_non_keyframes", "allow breaking segments on non-keyframes", OFFSET(break_non_keyframes), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, E },
  
      { "individual_header_trailer", "write header/trailer to each segment", OFFSET(individual_header_trailer), AV_OPT_TYPE_BOOL, {.i64 = 1}, 0, 1, E },
      { "write_header_trailer", "write a header to the first segment and a trailer to the last one", OFFSET(write_header_trailer), AV_OPT_TYPE_BOOL, {.i64 = 1}, 0, 1, E },
      { "reset_timestamps", "reset timestamps at the beginning of each segment", OFFSET(reset_timestamps), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, E },
      { "initial_offset", "set initial timestamp offset", OFFSET(initial_offset), AV_OPT_TYPE_DURATION, {.i64 = 0}, -INT64_MAX, INT64_MAX, E },
      { "write_empty_segments", "allow writing empty 'filler' segments", OFFSET(write_empty), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, E },
      { NULL },
  };
  
  #if CONFIG_SEGMENT_MUXER
  static const AVClass seg_class = {
      .class_name = "segment muxer",
      .item_name  = av_default_item_name,
      .option     = options,
      .version    = LIBAVUTIL_VERSION_INT,
  };
  
  AVOutputFormat ff_segment_muxer = {
      .name           = "segment",
      .long_name      = NULL_IF_CONFIG_SMALL("segment"),
      .priv_data_size = sizeof(SegmentContext),
      .flags          = AVFMT_NOFILE|AVFMT_GLOBALHEADER,
      .init           = seg_init,
      .write_header   = seg_write_header,
      .write_packet   = seg_write_packet,
      .write_trailer  = seg_write_trailer,
      .deinit         = seg_free,
      .check_bitstream = seg_check_bitstream,
      .priv_class     = &seg_class,
  };
  #endif
  
  #if CONFIG_STREAM_SEGMENT_MUXER
  static const AVClass sseg_class = {
      .class_name = "stream_segment muxer",
      .item_name  = av_default_item_name,
      .option     = options,
      .version    = LIBAVUTIL_VERSION_INT,
  };
  
  AVOutputFormat ff_stream_segment_muxer = {
      .name           = "stream_segment,ssegment",
      .long_name      = NULL_IF_CONFIG_SMALL("streaming segment muxer"),
      .priv_data_size = sizeof(SegmentContext),
      .flags          = AVFMT_NOFILE,
      .init           = seg_init,
      .write_header   = seg_write_header,
      .write_packet   = seg_write_packet,
      .write_trailer  = seg_write_trailer,
      .deinit         = seg_free,
      .check_bitstream = seg_check_bitstream,
      .priv_class     = &sseg_class,
  };
  #endif
  