/*

  * MPEG2 transport stream (aka DVB) muxer

  * Copyright (c) 2003 Fabrice Bellard

  *

  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or

  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either

  * version 2.1 of the License, or (at your option) any later version.

  *

  * FFmpeg is distributed in the hope that it will be useful,

  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public

  * License along with FFmpeg; if not, write to the Free Software

  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

  */

 #include "libavutil/bswap.h"

 #include "libavutil/crc.h"

 #include "libavcodec/mpegvideo.h"

 #include "avformat.h"
 #include "mpegts.h"
 
 /* write DVB SI sections */
 
 /*********************************************/
 /* mpegts section writer */
 
 typedef struct MpegTSSection {
     int pid;
     int cc;
     void (*write_packet)(struct MpegTSSection *s, const uint8_t *packet);
     void *opaque;
 } MpegTSSection;
 

 typedef struct MpegTSService {
     MpegTSSection pmt; /* MPEG2 pmt table context */
     int sid;           /* service ID */
     char *name;
     char *provider_name;
     int pcr_pid;
     int pcr_packet_count;
     int pcr_packet_freq;
 } MpegTSService;
 
 typedef struct MpegTSWrite {
     MpegTSSection pat; /* MPEG2 pat table */
     MpegTSSection sdt; /* MPEG2 sdt table context */
     MpegTSService **services;
     int sdt_packet_count;
     int sdt_packet_freq;
     int pat_packet_count;
     int pat_packet_freq;
     int nb_services;
     int onid;
     int tsid;
     uint64_t cur_pcr;
     int mux_rate;
 } MpegTSWrite;
 

 /* NOTE: 4 bytes must be left at the end for the crc32 */

 static void mpegts_write_section(MpegTSSection *s, uint8_t *buf, int len)

 {

     MpegTSWrite *ts = ((AVFormatContext*)s->opaque)->priv_data;

     unsigned int crc;
     unsigned char packet[TS_PACKET_SIZE];
     const unsigned char *buf_ptr;
     unsigned char *q;
     int first, b, len1, left;
 

     crc = bswap_32(av_crc(av_crc_get_table(AV_CRC_32_IEEE), -1, buf, len - 4));

     buf[len - 4] = (crc >> 24) & 0xff;
     buf[len - 3] = (crc >> 16) & 0xff;
     buf[len - 2] = (crc >> 8) & 0xff;
     buf[len - 1] = (crc) & 0xff;

     /* send each packet */
     buf_ptr = buf;
     while (len > 0) {
         first = (buf == buf_ptr);
         q = packet;
         *q++ = 0x47;
         b = (s->pid >> 8);
         if (first)
             b |= 0x40;
         *q++ = b;
         *q++ = s->pid;
         *q++ = 0x10 | s->cc;

         s->cc = (s->cc + 1) & 0xf;

         if (first)
             *q++ = 0; /* 0 offset */
         len1 = TS_PACKET_SIZE - (q - packet);

         if (len1 > len)

             len1 = len;
         memcpy(q, buf_ptr, len1);
         q += len1;
         /* add known padding data */
         left = TS_PACKET_SIZE - (q - packet);
         if (left > 0)
             memset(q, 0xff, left);
 
         s->write_packet(s, packet);
 
         buf_ptr += len1;
         len -= len1;

 
         ts->cur_pcr += TS_PACKET_SIZE*8*90000LL/ts->mux_rate;

     }
 }
 
 static inline void put16(uint8_t **q_ptr, int val)
 {
     uint8_t *q;
     q = *q_ptr;
     *q++ = val >> 8;
     *q++ = val;
     *q_ptr = q;
 }
 

 static int mpegts_write_section1(MpegTSSection *s, int tid, int id,

                           int version, int sec_num, int last_sec_num,
                           uint8_t *buf, int len)
 {
     uint8_t section[1024], *q;
     unsigned int tot_len;

     tot_len = 3 + 5 + len + 4;
     /* check if not too big */
     if (tot_len > 1024)
         return -1;
 
     q = section;
     *q++ = tid;
     put16(&q, 0xb000 | (len + 5 + 4)); /* 5 byte header + 4 byte CRC */
     put16(&q, id);
     *q++ = 0xc1 | (version << 1); /* current_next_indicator = 1 */
     *q++ = sec_num;
     *q++ = last_sec_num;
     memcpy(q, buf, len);

     mpegts_write_section(s, section, tot_len);
     return 0;
 }
 
 /*********************************************/
 /* mpegts writer */
 
 #define DEFAULT_PMT_START_PID   0x1000
 #define DEFAULT_START_PID       0x0100
 #define DEFAULT_PROVIDER_NAME   "FFmpeg"
 #define DEFAULT_SERVICE_NAME    "Service01"
 
 /* default network id, transport stream and service identifiers */
 #define DEFAULT_ONID            0x0001
 #define DEFAULT_TSID            0x0001
 #define DEFAULT_SID             0x0001
 
 /* a PES packet header is generated every DEFAULT_PES_HEADER_FREQ packets */
 #define DEFAULT_PES_HEADER_FREQ 16

 #define DEFAULT_PES_PAYLOAD_SIZE ((DEFAULT_PES_HEADER_FREQ - 1) * 184 + 170)

 
 /* we retransmit the SI info at this rate */
 #define SDT_RETRANS_TIME 500
 #define PAT_RETRANS_TIME 100

 #define PCR_RETRANS_TIME 20

 
 typedef struct MpegTSWriteStream {

     struct MpegTSService *service;

     int pid; /* stream associated pid */
     int cc;

     int payload_index;
     int64_t payload_pts;

     int64_t payload_dts;

     uint8_t payload[DEFAULT_PES_PAYLOAD_SIZE];

 } MpegTSWriteStream;
 
 static void mpegts_write_pat(AVFormatContext *s)
 {
     MpegTSWrite *ts = s->priv_data;
     MpegTSService *service;
     uint8_t data[1012], *q;
     int i;

     q = data;
     for(i = 0; i < ts->nb_services; i++) {
         service = ts->services[i];
         put16(&q, service->sid);
         put16(&q, 0xe000 | service->pmt.pid);
     }
     mpegts_write_section1(&ts->pat, PAT_TID, ts->tsid, 0, 0, 0,
                           data, q - data);
 }
 
 static void mpegts_write_pmt(AVFormatContext *s, MpegTSService *service)
 {
     //    MpegTSWrite *ts = s->priv_data;
     uint8_t data[1012], *q, *desc_length_ptr, *program_info_length_ptr;
     int val, stream_type, i;
 
     q = data;
     put16(&q, 0xe000 | service->pcr_pid);
 
     program_info_length_ptr = q;
     q += 2; /* patched after */
 
     /* put program info here */
 
     val = 0xf000 | (q - program_info_length_ptr - 2);
     program_info_length_ptr[0] = val >> 8;
     program_info_length_ptr[1] = val;

     for(i = 0; i < s->nb_streams; i++) {
         AVStream *st = s->streams[i];
         MpegTSWriteStream *ts_st = st->priv_data;

         AVMetadataTag *lang = av_metadata_get(st->metadata, "language", NULL,0);

         switch(st->codec->codec_id) {

         case CODEC_ID_MPEG1VIDEO:
         case CODEC_ID_MPEG2VIDEO:
             stream_type = STREAM_TYPE_VIDEO_MPEG2;

             break;

         case CODEC_ID_MPEG4:
             stream_type = STREAM_TYPE_VIDEO_MPEG4;
             break;
         case CODEC_ID_H264:
             stream_type = STREAM_TYPE_VIDEO_H264;
             break;

         case CODEC_ID_DIRAC:
             stream_type = STREAM_TYPE_VIDEO_DIRAC;
             break;

         case CODEC_ID_MP2:
         case CODEC_ID_MP3:

             stream_type = STREAM_TYPE_AUDIO_MPEG1;

             break;

         case CODEC_ID_AAC:
             stream_type = STREAM_TYPE_AUDIO_AAC;
             break;
         case CODEC_ID_AC3:
             stream_type = STREAM_TYPE_AUDIO_AC3;
             break;

         default:
             stream_type = STREAM_TYPE_PRIVATE_DATA;
             break;
         }
         *q++ = stream_type;
         put16(&q, 0xe000 | ts_st->pid);
         desc_length_ptr = q;
         q += 2; /* patched after */
 
         /* write optional descriptors here */

         switch(st->codec->codec_type) {

         case CODEC_TYPE_AUDIO:

             if (lang && strlen(lang->value) == 3) {

                 *q++ = 0x0a; /* ISO 639 language descriptor */
                 *q++ = 4;

                 *q++ = lang->value[0];
                 *q++ = lang->value[1];
                 *q++ = lang->value[2];

                 *q++ = 0; /* undefined type */
             }
             break;
         case CODEC_TYPE_SUBTITLE:
             {
                 const char *language;

                 language = lang && strlen(lang->value)==3 ? lang->value : "eng";

                 *q++ = 0x59;
                 *q++ = 8;
                 *q++ = language[0];
                 *q++ = language[1];
                 *q++ = language[2];
                 *q++ = 0x10; /* normal subtitles (0x20 = if hearing pb) */
                 put16(&q, 1); /* page id */
                 put16(&q, 1); /* ancillary page id */
             }
             break;

         case CODEC_TYPE_VIDEO:
             if (stream_type == STREAM_TYPE_VIDEO_DIRAC) {
                 *q++ = 0x05; /*MPEG-2 registration descriptor*/
                 *q++ = 4;
                 *q++ = 'd';
                 *q++ = 'r';
                 *q++ = 'a';
                 *q++ = 'c';
             }
             break;

         }

 
         val = 0xf000 | (q - desc_length_ptr - 2);
         desc_length_ptr[0] = val >> 8;
         desc_length_ptr[1] = val;
     }
     mpegts_write_section1(&service->pmt, PMT_TID, service->sid, 0, 0, 0,
                           data, q - data);

 }

 
 /* NOTE: str == NULL is accepted for an empty string */
 static void putstr8(uint8_t **q_ptr, const char *str)
 {
     uint8_t *q;
     int len;
 
     q = *q_ptr;
     if (!str)
         len = 0;
     else
         len = strlen(str);
     *q++ = len;
     memcpy(q, str, len);
     q += len;
     *q_ptr = q;
 }
 
 static void mpegts_write_sdt(AVFormatContext *s)
 {
     MpegTSWrite *ts = s->priv_data;
     MpegTSService *service;
     uint8_t data[1012], *q, *desc_list_len_ptr, *desc_len_ptr;
     int i, running_status, free_ca_mode, val;

     q = data;
     put16(&q, ts->onid);
     *q++ = 0xff;
     for(i = 0; i < ts->nb_services; i++) {
         service = ts->services[i];
         put16(&q, service->sid);
         *q++ = 0xfc | 0x00; /* currently no EIT info */
         desc_list_len_ptr = q;
         q += 2;
         running_status = 4; /* running */
         free_ca_mode = 0;
 
         /* write only one descriptor for the service name and provider */
         *q++ = 0x48;
         desc_len_ptr = q;
         q++;
         *q++ = 0x01; /* digital television service */
         putstr8(&q, service->provider_name);
         putstr8(&q, service->name);
         desc_len_ptr[0] = q - desc_len_ptr - 1;
 
         /* fill descriptor length */

         val = (running_status << 13) | (free_ca_mode << 12) |

             (q - desc_list_len_ptr - 2);
         desc_list_len_ptr[0] = val >> 8;
         desc_list_len_ptr[1] = val;
     }
     mpegts_write_section1(&ts->sdt, SDT_TID, ts->tsid, 0, 0, 0,
                           data, q - data);
 }
 

 static MpegTSService *mpegts_add_service(MpegTSWrite *ts,
                                          int sid,
                                          const char *provider_name,

                                          const char *name)
 {
     MpegTSService *service;
 
     service = av_mallocz(sizeof(MpegTSService));
     if (!service)
         return NULL;
     service->pmt.pid = DEFAULT_PMT_START_PID + ts->nb_services - 1;
     service->sid = sid;
     service->provider_name = av_strdup(provider_name);
     service->name = av_strdup(name);
     service->pcr_pid = 0x1fff;
     dynarray_add(&ts->services, &ts->nb_services, service);
     return service;
 }
 
 static void section_write_packet(MpegTSSection *s, const uint8_t *packet)
 {
     AVFormatContext *ctx = s->opaque;

     put_buffer(ctx->pb, packet, TS_PACKET_SIZE);

 }
 
 static int mpegts_write_header(AVFormatContext *s)
 {
     MpegTSWrite *ts = s->priv_data;
     MpegTSWriteStream *ts_st;
     MpegTSService *service;
     AVStream *st;

     AVMetadataTag *title;

     int i, total_bit_rate;

     const char *service_name;

     uint64_t sdt_size, pat_pmt_size, pos;

     ts->tsid = DEFAULT_TSID;
     ts->onid = DEFAULT_ONID;
     /* allocate a single DVB service */

     title = av_metadata_get(s->metadata, "title", NULL, 0);
     service_name = title ? title->value : DEFAULT_SERVICE_NAME;

     service = mpegts_add_service(ts, DEFAULT_SID,

                                  DEFAULT_PROVIDER_NAME, service_name);

     service->pmt.write_packet = section_write_packet;
     service->pmt.opaque = s;
 
     ts->pat.pid = PAT_PID;
     ts->pat.cc = 0;
     ts->pat.write_packet = section_write_packet;
     ts->pat.opaque = s;
 
     ts->sdt.pid = SDT_PID;
     ts->sdt.cc = 0;
     ts->sdt.write_packet = section_write_packet;
     ts->sdt.opaque = s;
 
     /* assign pids to each stream */
     total_bit_rate = 0;
     for(i = 0;i < s->nb_streams; i++) {
         st = s->streams[i];
         ts_st = av_mallocz(sizeof(MpegTSWriteStream));
         if (!ts_st)
             goto fail;
         st->priv_data = ts_st;

         ts_st->service = service;

         ts_st->pid = DEFAULT_START_PID + i;

         ts_st->payload_pts = AV_NOPTS_VALUE;

         ts_st->payload_dts = AV_NOPTS_VALUE;

         /* update PCR pid by using the first video stream */

         if (st->codec->codec_type == CODEC_TYPE_VIDEO &&

             service->pcr_pid == 0x1fff)
             service->pcr_pid = ts_st->pid;

         total_bit_rate += st->codec->bit_rate;

     }

     /* if no video stream, use the first stream as PCR */
     if (service->pcr_pid == 0x1fff && s->nb_streams > 0) {
         ts_st = s->streams[0]->priv_data;
         service->pcr_pid = ts_st->pid;
     }
 

     if (total_bit_rate <= 8 * 1024)
         total_bit_rate = 8 * 1024;

     service->pcr_packet_freq = (total_bit_rate * PCR_RETRANS_TIME) /

         (TS_PACKET_SIZE * 8 * 1000);

     ts->sdt_packet_freq = (total_bit_rate * SDT_RETRANS_TIME) /

         (TS_PACKET_SIZE * 8 * 1000);

     ts->pat_packet_freq = (total_bit_rate * PAT_RETRANS_TIME) /

         (TS_PACKET_SIZE * 8 * 1000);
 

     ts->mux_rate = 1; // avoid div by 0

     /* write info at the start of the file, so that it will be fast to
        find them */

     pos = url_ftell(s->pb);

     mpegts_write_sdt(s);

     sdt_size = url_ftell(s->pb) - pos;
     pos = url_ftell(s->pb);

     mpegts_write_pat(s);
     for(i = 0; i < ts->nb_services; i++) {
         mpegts_write_pmt(s, ts->services[i]);
     }

     pat_pmt_size = url_ftell(s->pb) - pos;
 
     total_bit_rate +=
         total_bit_rate * 25 / (8 * DEFAULT_PES_PAYLOAD_SIZE) + /* PES header size */
         total_bit_rate * 4 / (8 * TS_PACKET_SIZE) +            /* TS  header size */
         SDT_RETRANS_TIME * sdt_size +                          /* SDT size */
         PAT_RETRANS_TIME * pat_pmt_size +                      /* PAT+PMT size */
         PCR_RETRANS_TIME * 8;                                  /* PCR size */
 
     av_log(s, AV_LOG_DEBUG, "muxrate %d freq sdt %d pat %d\n",
            total_bit_rate, ts->sdt_packet_freq, ts->pat_packet_freq);
 
     if (s->mux_rate)
         ts->mux_rate = s->mux_rate;
     else
         ts->mux_rate = total_bit_rate;
 
     // adjust pcr
     ts->cur_pcr /= ts->mux_rate;
 

     put_flush_packet(s->pb);

 
     return 0;
 
  fail:
     for(i = 0;i < s->nb_streams; i++) {
         st = s->streams[i];
         av_free(st->priv_data);
     }
     return -1;
 }
 
 /* send SDT, PAT and PMT tables regulary */
 static void retransmit_si_info(AVFormatContext *s)
 {
     MpegTSWrite *ts = s->priv_data;
     int i;
 
     if (++ts->sdt_packet_count == ts->sdt_packet_freq) {
         ts->sdt_packet_count = 0;
         mpegts_write_sdt(s);
     }
     if (++ts->pat_packet_count == ts->pat_packet_freq) {
         ts->pat_packet_count = 0;
         mpegts_write_pat(s);
         for(i = 0; i < ts->nb_services; i++) {
             mpegts_write_pmt(s, ts->services[i]);
         }
     }
 }
 

 static void write_pts(uint8_t *q, int fourbits, int64_t pts)
 {
     int val;
 
     val = fourbits << 4 | (((pts >> 30) & 0x07) << 1) | 1;
     *q++ = val;
     val = (((pts >> 15) & 0x7fff) << 1) | 1;
     *q++ = val >> 8;
     *q++ = val;
     val = (((pts) & 0x7fff) << 1) | 1;
     *q++ = val >> 8;
     *q++ = val;
 }
 

 /* NOTE: pes_data contains all the PES packet */
 static void mpegts_write_pes(AVFormatContext *s, AVStream *st,
                              const uint8_t *payload, int payload_size,

                              int64_t pts, int64_t dts)

 {
     MpegTSWriteStream *ts_st = st->priv_data;

     MpegTSWrite *ts = s->priv_data;

     uint8_t buf[TS_PACKET_SIZE];

     uint8_t *q;

     int val, is_start, len, header_len, write_pcr, private_code, flags;

     int afc_len, stuffing_len;
     int64_t pcr = -1; /* avoid warning */

     is_start = 1;
     while (payload_size > 0) {
         retransmit_si_info(s);

         write_pcr = 0;
         if (ts_st->pid == ts_st->service->pcr_pid) {
             ts_st->service->pcr_packet_count++;

             if (ts_st->service->pcr_packet_count >=

                 ts_st->service->pcr_packet_freq) {
                 ts_st->service->pcr_packet_count = 0;
                 write_pcr = 1;
             }
         }
 

         /* prepare packet header */
         q = buf;
         *q++ = 0x47;
         val = (ts_st->pid >> 8);
         if (is_start)
             val |= 0x40;
         *q++ = val;
         *q++ = ts_st->pid;

         *q++ = 0x10 | ts_st->cc | (write_pcr ? 0x20 : 0);

         ts_st->cc = (ts_st->cc + 1) & 0xf;

         if (write_pcr) {

             // add 11, pcr references the last byte of program clock reference base
             pcr = ts->cur_pcr + (4+7)*8*90000LL / ts->mux_rate;

             if (dts != AV_NOPTS_VALUE && dts < pcr)
                 av_log(s, AV_LOG_WARNING, "dts < pcr, TS is invalid\n");

             *q++ = 7; /* AFC length */
             *q++ = 0x10; /* flags: PCR present */
             *q++ = pcr >> 25;
             *q++ = pcr >> 17;
             *q++ = pcr >> 9;
             *q++ = pcr >> 1;
             *q++ = (pcr & 1) << 7;
             *q++ = 0;
         }

         if (is_start) {

             int pes_extension = 0;

             /* write PES header */
             *q++ = 0x00;
             *q++ = 0x00;
             *q++ = 0x01;

             private_code = 0;

             if (st->codec->codec_type == CODEC_TYPE_VIDEO) {

                 if (st->codec->codec_id == CODEC_ID_DIRAC) {
                     *q++ = 0xfd;
                 } else
                     *q++ = 0xe0;

             } else if (st->codec->codec_type == CODEC_TYPE_AUDIO &&
                        (st->codec->codec_id == CODEC_ID_MP2 ||
                         st->codec->codec_id == CODEC_ID_MP3)) {

                 *q++ = 0xc0;

             } else {
                 *q++ = 0xbd;

                 if (st->codec->codec_type == CODEC_TYPE_SUBTITLE) {

                     private_code = 0x20;
                 }
             }

             header_len = 0;
             flags = 0;
             if (pts != AV_NOPTS_VALUE) {
                 header_len += 5;
                 flags |= 0x80;
             }

             if (dts != AV_NOPTS_VALUE && dts != pts) {

                 header_len += 5;
                 flags |= 0x40;
             }

             if (st->codec->codec_type == CODEC_TYPE_VIDEO &&
                 st->codec->codec_id == CODEC_ID_DIRAC) {
                 /* set PES_extension_flag */
                 pes_extension = 1;
                 flags |= 0x01;
 
                 /*
                 * One byte for PES2 extension flag +
                 * one byte for extension length +
                 * one byte for extension id
                 */
                 header_len += 3;
             }

             len = payload_size + header_len + 3;

             if (private_code != 0)

                 len++;

             *q++ = len >> 8;
             *q++ = len;

             val = 0x80;
             /* data alignment indicator is required for subtitle data */

             if (st->codec->codec_type == CODEC_TYPE_SUBTITLE)

                 val |= 0x04;
             *q++ = val;

             *q++ = flags;
             *q++ = header_len;

             if (pts != AV_NOPTS_VALUE) {

                 write_pts(q, flags >> 6, pts);
                 q += 5;
             }

             if (dts != AV_NOPTS_VALUE && dts != pts) {

                 write_pts(q, 1, dts);
                 q += 5;

             }

             if (pes_extension && st->codec->codec_id == CODEC_ID_DIRAC) {
                 flags = 0x01;  /* set PES_extension_flag_2 */
                 *q++ = flags;
                 *q++ = 0x80 | 0x01;  /* marker bit + extension length */
                 /*
                 * Set the stream id extension flag bit to 0 and
                 * write the extended stream id
                 */
                 *q++ = 0x00 | 0x60;
             }

             if (private_code != 0)
                 *q++ = private_code;

             is_start = 0;

         }

         /* header size */
         header_len = q - buf;
         /* data len */
         len = TS_PACKET_SIZE - header_len;

         if (len > payload_size)
             len = payload_size;

         stuffing_len = TS_PACKET_SIZE - header_len - len;
         if (stuffing_len > 0) {
             /* add stuffing with AFC */
             if (buf[3] & 0x20) {
                 /* stuffing already present: increase its size */
                 afc_len = buf[4] + 1;
                 memmove(buf + 4 + afc_len + stuffing_len,

                         buf + 4 + afc_len,

                         header_len - (4 + afc_len));
                 buf[4] += stuffing_len;
                 memset(buf + 4 + afc_len, 0xff, stuffing_len);
             } else {
                 /* add stuffing */
                 memmove(buf + 4 + stuffing_len, buf + 4, header_len - 4);
                 buf[3] |= 0x20;
                 buf[4] = stuffing_len - 1;
                 if (stuffing_len >= 2) {
                     buf[5] = 0x00;
                     memset(buf + 6, 0xff, stuffing_len - 2);
                 }
             }
         }
         memcpy(buf + TS_PACKET_SIZE - len, payload, len);

         payload += len;
         payload_size -= len;

         put_buffer(s->pb, buf, TS_PACKET_SIZE);

         ts->cur_pcr += TS_PACKET_SIZE*8*90000LL/ts->mux_rate;

     }

     put_flush_packet(s->pb);

 }
 

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

 {

     AVStream *st = s->streams[pkt->stream_index];
     int size= pkt->size;
     uint8_t *buf= pkt->data;

     uint8_t *data= NULL;

     MpegTSWriteStream *ts_st = st->priv_data;

     int len, max_payload_size;

     const uint8_t *access_unit_index = NULL;

     const uint64_t delay = av_rescale(s->max_delay, 90000, AV_TIME_BASE);

     int64_t dts = AV_NOPTS_VALUE, pts = AV_NOPTS_VALUE;
 
     if (pkt->pts != AV_NOPTS_VALUE)
         pts = pkt->pts + delay;
     if (pkt->dts != AV_NOPTS_VALUE)
         dts = pkt->dts + delay;

     if (st->codec->codec_type == CODEC_TYPE_SUBTITLE) {

         /* for subtitle, a single PES packet must be generated */

         mpegts_write_pes(s, st, buf, size, pts, AV_NOPTS_VALUE);

         return 0;
     }

     if (st->codec->codec_id == CODEC_ID_DIRAC) {
         /* for Dirac, a single PES packet must be generated */

         mpegts_write_pes(s, st, buf, size, pts, dts);

         return 0;
     }

     max_payload_size = DEFAULT_PES_PAYLOAD_SIZE;

     if (st->codec->codec_id == CODEC_ID_MPEG2VIDEO ||
         st->codec->codec_id == CODEC_ID_MPEG1VIDEO) {
         const uint8_t *p = pkt->data;
         const uint8_t *end = pkt->data+pkt->size;
         uint32_t state = -1;
         while (p < end) {
             p = ff_find_start_code(p, end, &state);
             if (state == PICTURE_START_CODE) {
                 access_unit_index = p - 4;
                 break;
             }
         }

     } if (st->codec->codec_id == CODEC_ID_H264) {
         if (pkt->size < 5 || AV_RB32(pkt->data) != 0x0000001) {
             av_log(s, AV_LOG_ERROR, "h264 bitstream malformated\n");
             return -1;
         }
         if (pkt->data[4] != 0x09) { // AUD NAL
             data = av_malloc(pkt->size+6);
             if (!data)
                 return -1;
             memcpy(data+6, pkt->data, pkt->size);
             AV_WB32(data, 0x00000001);
             data[4] = 0x09;
             data[5] = 0xe0; // any slice type
             buf  = data;
             size = pkt->size+6;
         }
         access_unit_index = buf;

     } else {

         access_unit_index = pkt->data;
     }
 
     if (!access_unit_index) {
         av_log(s, AV_LOG_ERROR, "error, could not find access unit start\n");
         return -1;
     }
 

     while (size > 0) {

         len = max_payload_size - ts_st->payload_index;

         if (len > size)
             len = size;
         memcpy(ts_st->payload + ts_st->payload_index, buf, len);
         buf += len;
         size -= len;
         ts_st->payload_index += len;

         if (access_unit_index && access_unit_index < buf &&
             ts_st->payload_pts == AV_NOPTS_VALUE &&
             ts_st->payload_dts == AV_NOPTS_VALUE) {

             ts_st->payload_dts = dts;
             ts_st->payload_pts = pts;

         }

         if (ts_st->payload_index >= max_payload_size) {

             mpegts_write_pes(s, st, ts_st->payload, ts_st->payload_index,

                              ts_st->payload_pts, ts_st->payload_dts);

             ts_st->payload_pts = AV_NOPTS_VALUE;

             ts_st->payload_dts = AV_NOPTS_VALUE;

             ts_st->payload_index = 0;

             access_unit_index = NULL; // unset access unit to avoid setting pts/dts again

         }
     }

 
     av_free(data);
 

     return 0;
 }
 
 static int mpegts_write_end(AVFormatContext *s)
 {
     MpegTSWrite *ts = s->priv_data;
     MpegTSWriteStream *ts_st;
     MpegTSService *service;
     AVStream *st;
     int i;
 
     /* flush current packets */
     for(i = 0; i < s->nb_streams; i++) {
         st = s->streams[i];
         ts_st = st->priv_data;

         if (ts_st->payload_index > 0) {
             mpegts_write_pes(s, st, ts_st->payload, ts_st->payload_index,

                              ts_st->payload_pts, ts_st->payload_dts);

         }
     }

     put_flush_packet(s->pb);

     for(i = 0; i < ts->nb_services; i++) {
         service = ts->services[i];
         av_freep(&service->provider_name);
         av_freep(&service->name);
         av_free(service);
     }
     av_free(ts->services);
 
     return 0;
 }
 

 AVOutputFormat mpegts_muxer = {

     "mpegts",

     NULL_IF_CONFIG_SMALL("MPEG-2 transport stream format"),

     "video/x-mpegts",

     "ts,m2t",

     sizeof(MpegTSWrite),
     CODEC_ID_MP2,

     CODEC_ID_MPEG2VIDEO,

     mpegts_write_header,
     mpegts_write_packet,
     mpegts_write_end,
 };