/*
  * 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 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

     char *time_str;        ///< segment duration specification string
     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);

         opar = st->codecpar;
         avcodec_parameters_copy(opar, ipar);

         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;

         }

         st->sample_aspect_ratio = ist->sample_aspect_ratio;
         st->time_base           = ist->time_base;
         st->avg_frame_rate      = ist->avg_frame_rate;

         st->disposition         = ist->disposition;

 #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

         av_dict_copy(&st->metadata, ist->metadata, 0);

     }
 
     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 greater than the following 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)
 {
     char *p;
     int i, ret = 0;
     char *frames_str1 = av_strdup(frames_str);
     char *saveptr = NULL;
 
     if (!frames_str1)
         return AVERROR(ENOMEM);
 
 #define FAIL(err) ret = err; goto end
 
     *nb_frames = 1;
     for (p = frames_str1; *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");
         FAIL(AVERROR(ENOMEM));
     }
 
     p = frames_str1;
     for (i = 0; i < *nb_frames; i++) {
         long int f;
         char *tailptr;
         char *fstr = av_strtok(p, ",", &saveptr);
 
         p = NULL;
         if (!fstr) {
             av_log(log_ctx, AV_LOG_ERROR, "Empty frame specification in frame list %s\n",
                    frames_str);
             FAIL(AVERROR(EINVAL));
         }
         f = strtol(fstr, &tailptr, 10);
         if (*tailptr || f <= 0 || f >= INT_MAX) {
             av_log(log_ctx, AV_LOG_ERROR,
                    "Invalid argument '%s', must be a positive integer <= INT64_MAX\n",
                    fstr);
             FAIL(AVERROR(EINVAL));
         }
         (*frames)[i] = f;
 
         /* check on monotonicity */
         if (i && (*frames)[i-1] > (*frames)[i]) {
             av_log(log_ctx, AV_LOG_ERROR,
                    "Specified frame %d is greater than the following frame %d\n",
                    (*frames)[i], (*frames)[i-1]);
             FAIL(AVERROR(EINVAL));
         }
     }
 
 end:
     av_free(frames_str1);
     return ret;
 }
 

 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;

     ff_format_io_close(seg->avf, &seg->list_pb);

     avformat_free_context(seg->avf);
     seg->avf = NULL;
 }
 

 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_str + !!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 {
         /* set default value if not specified */
         if (!seg->time_str)
             seg->time_str = av_strdup("2");
         if ((ret = av_parse_time(&seg->time, seg->time_str, 1)) < 0) {
             av_log(s, AV_LOG_ERROR,
                    "Invalid time duration specification '%s' for segment_time option\n",
                    seg->time_str);
             return ret;
         }

         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;

     }

     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) {

         ff_format_io_close(oc, &oc->pb);

         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, i;

 
     if (!seg->header_written) {

         for (i = 0; i < s->nb_streams; i++) {
             AVStream *st = oc->streams[i];
             AVCodecParameters *ipar, *opar;
 
             ipar = s->streams[i]->codecpar;
             opar = oc->streams[i]->codecpar;
             avcodec_parameters_copy(opar, ipar);
             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;
             }
             st->sample_aspect_ratio = s->streams[i]->sample_aspect_ratio;
             st->time_base = s->streams[i]->time_base;
         }

         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);
         }

         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) {
         int pkt_extradata_size = 0;
         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;

     SegmentListEntry *cur, *next;

     int ret = 0;
 
     if (!oc)
         goto fail;

     if (!seg->write_header_trailer) {

         if ((ret = segment_end(s, 0, 1)) < 0)

             goto fail;

         if ((ret = open_null_ctx(&oc->pb)) < 0)
             goto fail;

         ret = av_write_trailer(oc);

         close_null_ctxp(&oc->pb);

     } else {

         ret = segment_end(s, 1, 1);

     }

 fail:

     if (seg->list)

         ff_format_io_close(s, &seg->list_pb);

 
     av_opt_free(seg);

     av_freep(&seg->times);

     av_freep(&seg->frames);

     av_freep(&seg->cur_entry.filename);

     cur = seg->segment_list_entries;
     while (cur) {
         next = cur->next;

         av_freep(&cur->filename);

         av_free(cur);
         cur = next;
     }
 

     avformat_free_context(oc);

     seg->avf = NULL;

     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_str),AV_OPT_TYPE_STRING, {.str = NULL},  0, 0,       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