PeerStreamer

/*

 * 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 "libavutil/opt.h"

#include "libavcodec/mpegvideo.h"

#include "avformat.h"

#include "internal.h"

#include "mpegts.h"

#include "adts.h"

#define PCR_TIME_BASE 27000000

/* 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_period;

} MpegTSService;

typedef struct MpegTSWrite {

    MpegTSSection pat; /* MPEG2 pat table */

    MpegTSSection sdt; /* MPEG2 sdt table context */

    MpegTSService **services;

    int sdt_packet_count;

    int sdt_packet_period;

    int pat_packet_count;

    int pat_packet_period;

    int nb_services;

    int onid;

    int tsid;

    int64_t first_pcr;

    int mux_rate; ///< set to 1 when VBR

    int transport_stream_id;

    int original_network_id;

    int service_id;

    int pmt_start_pid;

    int start_pid;

} MpegTSWrite;

static const AVOption options[] = {

    { "mpegts_transport_stream_id", "Set transport_stream_id field.",

      offsetof(MpegTSWrite, transport_stream_id), FF_OPT_TYPE_INT, 0x0001, 0x0001, 0xffff, AV_OPT_FLAG_ENCODING_PARAM},

    { "mpegts_original_network_id", "Set original_network_id field.",

      offsetof(MpegTSWrite, original_network_id), FF_OPT_TYPE_INT, 0x0001, 0x0001, 0xffff, AV_OPT_FLAG_ENCODING_PARAM},

    { "mpegts_service_id", "Set service_id field.",

      offsetof(MpegTSWrite, service_id), FF_OPT_TYPE_INT, 0x0001, 0x0001, 0xffff, AV_OPT_FLAG_ENCODING_PARAM},

    { "mpegts_pmt_start_pid", "Set the first pid of the PMT.",

      offsetof(MpegTSWrite, pmt_start_pid), FF_OPT_TYPE_INT, 0x1000, 0x1000, 0x1f00, AV_OPT_FLAG_ENCODING_PARAM},

    { "mpegts_start_pid", "Set the first pid.",

      offsetof(MpegTSWrite, start_pid), FF_OPT_TYPE_INT, 0x0100, 0x0100, 0x0f00, AV_OPT_FLAG_ENCODING_PARAM},

    { NULL },

};

static const AVClass mpegts_muxer_class = {

    "MPEGTS muxer",

    av_default_item_name,

    options,

    LIBAVUTIL_VERSION_INT,

};

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

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

{

    unsigned int crc;

    unsigned char packet[TS_PACKET_SIZE];

    const unsigned char *buf_ptr;

    unsigned char *q;

    int first, b, len1, left;

    crc = av_bswap32(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;

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

        *q++ = 0x10 | s->cc;

        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;

    }

}

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;

    /* reserved_future_use field must be set to 1 for SDT */

    unsigned int flags = tid == SDT_TID ? 0xf000 : 0xb000;

    tot_len = 3 + 5 + len + 4;

    /* check if not too big */

    if (tot_len > 1024)

        return -1;

    q = section;

    *q++ = tid;

    put16(&q, flags | (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_PROVIDER_NAME   "FFmpeg"

#define DEFAULT_SERVICE_NAME    "Service01"

/* 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;

    int first_pts_check; ///< first pts check needed

    int64_t payload_pts;

    int64_t payload_dts;

    uint8_t payload[DEFAULT_PES_PAYLOAD_SIZE];

    ADTSContext *adts;

} 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_AAC_LATM:

            stream_type = STREAM_TYPE_AUDIO_AAC_LATM;

            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 AVMEDIA_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 AVMEDIA_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) */

                if(st->codec->extradata_size == 4) {

                    memcpy(q, st->codec->extradata, 4);

                    q += 4;

                } else {

                    put16(&q, 1); /* page id */

                    put16(&q, 1); /* ancillary page id */

                }

            }

            break;

        case AVMEDIA_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 = ts->pmt_start_pid + ts->nb_services;

    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, *pcr_st = NULL;

    AVMetadataTag *title, *provider;

    int i, j;

    const char *service_name;

    const char *provider_name;

    int *pids;

    ts->tsid = ts->transport_stream_id;

    ts->onid = ts->original_network_id;

    /* allocate a single DVB service */

    title = av_metadata_get(s->metadata, "service_name", NULL, 0);

    if (!title)

        title = av_metadata_get(s->metadata, "title", NULL, 0);

    service_name = title ? title->value : DEFAULT_SERVICE_NAME;

    provider = av_metadata_get(s->metadata, "service_provider", NULL, 0);

    provider_name = provider ? provider->value : DEFAULT_PROVIDER_NAME;

    service = mpegts_add_service(ts, ts->service_id, provider_name, service_name);

    service->pmt.write_packet = section_write_packet;

    service->pmt.opaque = s;

    service->pmt.cc = 15;

    ts->pat.pid = PAT_PID;

    ts->pat.cc = 15; // Initialize at 15 so that it wraps and be equal to 0 for the first packet we write

    ts->pat.write_packet = section_write_packet;

    ts->pat.opaque = s;

    ts->sdt.pid = SDT_PID;

    ts->sdt.cc = 15;

    ts->sdt.write_packet = section_write_packet;

    ts->sdt.opaque = s;

    pids = av_malloc(s->nb_streams * sizeof(*pids));

    if (!pids)

        return AVERROR(ENOMEM);

    /* assign pids to each stream */

    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;

        /* MPEG pid values < 16 are reserved. Applications which set st->id in

         * this range are assigned a calculated pid. */

        if (st->id < 16) {

            ts_st->pid = ts->start_pid + i;

        } else if (st->id < 0x1FFF) {

            ts_st->pid = st->id;

        } else {

            av_log(s, AV_LOG_ERROR, "Invalid stream id %d, must be less than 8191\n", st->id);

            goto fail;

        }

        if (ts_st->pid == service->pmt.pid) {

            av_log(s, AV_LOG_ERROR, "Duplicate stream id %d\n", ts_st->pid);

            goto fail;

        }

        for (j = 0; j < i; j++)

            if (pids[j] == ts_st->pid) {

                av_log(s, AV_LOG_ERROR, "Duplicate stream id %d\n", ts_st->pid);

                goto fail;

            }

        pids[i] = ts_st->pid;

        ts_st->payload_pts = AV_NOPTS_VALUE;

        ts_st->payload_dts = AV_NOPTS_VALUE;

        ts_st->first_pts_check = 1;

        ts_st->cc = 15;

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

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

            service->pcr_pid == 0x1fff) {

            service->pcr_pid = ts_st->pid;

            pcr_st = st;

        }

        if (st->codec->codec_id == CODEC_ID_AAC &&

            st->codec->extradata_size > 0) {

            ts_st->adts = av_mallocz(sizeof(*ts_st->adts));

            if (!ts_st->adts)

                return AVERROR(ENOMEM);

            if (ff_adts_decode_extradata(s, ts_st->adts, st->codec->extradata,

                                         st->codec->extradata_size) < 0)

                return -1;

        }

    }

    av_free(pids);

    /* if no video stream, use the first stream as PCR */

    if (service->pcr_pid == 0x1fff && s->nb_streams > 0) {

        pcr_st = s->streams[0];

        ts_st = pcr_st->priv_data;

        service->pcr_pid = ts_st->pid;

    }

    ts->mux_rate = s->mux_rate ? s->mux_rate : 1;

    if (ts->mux_rate > 1) {

        service->pcr_packet_period = (ts->mux_rate * PCR_RETRANS_TIME) /

            (TS_PACKET_SIZE * 8 * 1000);

        ts->sdt_packet_period      = (ts->mux_rate * SDT_RETRANS_TIME) /

            (TS_PACKET_SIZE * 8 * 1000);

        ts->pat_packet_period      = (ts->mux_rate * PAT_RETRANS_TIME) /

            (TS_PACKET_SIZE * 8 * 1000);

        ts->first_pcr = av_rescale(s->max_delay, PCR_TIME_BASE, AV_TIME_BASE);

    } else {

        /* Arbitrary values, PAT/PMT could be written on key frames */

        ts->sdt_packet_period = 200;

        ts->pat_packet_period = 40;

        if (pcr_st->codec->codec_type == AVMEDIA_TYPE_AUDIO) {

            if (!pcr_st->codec->frame_size) {

                av_log(s, AV_LOG_WARNING, "frame size not set\n");

                service->pcr_packet_period =

                    pcr_st->codec->sample_rate/(10*512);

            } else {

                service->pcr_packet_period =

                    pcr_st->codec->sample_rate/(10*pcr_st->codec->frame_size);

            }

        } else {

            // max delta PCR 0.1s

            service->pcr_packet_period =

                pcr_st->codec->time_base.den/(10*pcr_st->codec->time_base.num);

        }

    }

    // output a PCR as soon as possible

    service->pcr_packet_count = service->pcr_packet_period;

    ts->pat_packet_count = ts->pat_packet_period-1;

    ts->sdt_packet_count = ts->sdt_packet_period-1;

    if (ts->mux_rate == 1)

        av_log(s, AV_LOG_INFO, "muxrate VBR, ");

    else

        av_log(s, AV_LOG_INFO, "muxrate %d, ", ts->mux_rate);

    av_log(s, AV_LOG_INFO, "pcr every %d pkts, "

           "sdt every %d, pat/pmt every %d pkts\n",

           service->pcr_packet_period,

           ts->sdt_packet_period, ts->pat_packet_period);

    put_flush_packet(s->pb);

    return 0;

 fail:

    av_free(pids);

    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_period) {

        ts->sdt_packet_count = 0;

        mpegts_write_sdt(s);

    }

    if (++ts->pat_packet_count == ts->pat_packet_period) {

        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 int64_t get_pcr(const MpegTSWrite *ts, ByteIOContext *pb)

{

    return av_rescale(url_ftell(pb) + 11, 8 * PCR_TIME_BASE, ts->mux_rate) +

           ts->first_pcr;

}

static uint8_t* write_pcr_bits(uint8_t *buf, int64_t pcr)

{

    int64_t pcr_low = pcr % 300, pcr_high = pcr / 300;

    *buf++ = pcr_high >> 25;

    *buf++ = pcr_high >> 17;

    *buf++ = pcr_high >> 9;

    *buf++ = pcr_high >> 1;

    *buf++ = pcr_high << 7 | pcr_low >> 8 | 0x7e;

    *buf++ = pcr_low;

    return buf;

}

/* Write a single null transport stream packet */

static void mpegts_insert_null_packet(AVFormatContext *s)

{

    uint8_t *q;

    uint8_t buf[TS_PACKET_SIZE];

    q = buf;

    *q++ = 0x47;

    *q++ = 0x00 | 0x1f;

    *q++ = 0xff;

    *q++ = 0x10;

    memset(q, 0x0FF, TS_PACKET_SIZE - (q - buf));

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

}

/* Write a single transport stream packet with a PCR and no payload */

static void mpegts_insert_pcr_only(AVFormatContext *s, AVStream *st)

{

    MpegTSWrite *ts = s->priv_data;

    MpegTSWriteStream *ts_st = st->priv_data;

    uint8_t *q;

    uint8_t buf[TS_PACKET_SIZE];

    q = buf;

    *q++ = 0x47;

    *q++ = ts_st->pid >> 8;

    *q++ = ts_st->pid;

    *q++ = 0x20 | ts_st->cc;   /* Adaptation only */

    /* Continuity Count field does not increment (see 13818-1 section 2.4.3.3) */

    *q++ = TS_PACKET_SIZE - 5; /* Adaptation Field Length */

    *q++ = 0x10;               /* Adaptation flags: PCR present */

    /* PCR coded into 6 bytes */

    q = write_pcr_bits(q, get_pcr(ts, s->pb));

    /* stuffing bytes */

    memset(q, 0xFF, TS_PACKET_SIZE - (q - buf));

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

}

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;

}

/* Add a pes header to the front of payload, and segment into an integer number of

 * ts packets. The final ts packet is padded using an over-sized adaptation header

 * to exactly fill the last ts packet.

 * NOTE: 'payload' contains a complete PES payload.

 */

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 */

    int64_t delay = av_rescale(s->max_delay, 90000, AV_TIME_BASE);

    is_start = 1;

    while (payload_size > 0) {

        retransmit_si_info(s);

        write_pcr = 0;

        if (ts_st->pid == ts_st->service->pcr_pid) {

            if (ts->mux_rate > 1 || is_start) // VBR pcr period is based on frames

                ts_st->service->pcr_packet_count++;

            if (ts_st->service->pcr_packet_count >=

                ts_st->service->pcr_packet_period) {

                ts_st->service->pcr_packet_count = 0;

                write_pcr = 1;

            }

        }

        if (ts->mux_rate > 1 && dts != AV_NOPTS_VALUE &&

            (dts - get_pcr(ts, s->pb)/300) > delay) {

            /* pcr insert gets priority over null packet insert */

            if (write_pcr)

                mpegts_insert_pcr_only(s, st);

            else

                mpegts_insert_null_packet(s);

            continue; /* recalculate write_pcr and possibly retransmit si_info */

        }

        /* prepare packet header */

        q = buf;

        *q++ = 0x47;

        val = (ts_st->pid >> 8);

        if (is_start)

            val |= 0x40;

        *q++ = val;

        *q++ = ts_st->pid;

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

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

        if (write_pcr) {

            // add 11, pcr references the last byte of program clock reference base

            if (ts->mux_rate > 1)

                pcr = get_pcr(ts, s->pb);

            else

                pcr = (dts - delay)*300;

            if (dts != AV_NOPTS_VALUE && dts < pcr / 300)

                av_log(s, AV_LOG_WARNING, "dts < pcr, TS is invalid\n");

            *q++ = 7; /* AFC length */

            *q++ = 0x10; /* flags: PCR present */

            q = write_pcr_bits(q, pcr);

        }

        if (is_start) {

            int pes_extension = 0;

            /* write PES header */

            *q++ = 0x00;

            *q++ = 0x00;

            *q++ = 0x01;

            private_code = 0;

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

                if (st->codec->codec_id == CODEC_ID_DIRAC) {

                    *q++ = 0xfd;

                } else

                    *q++ = 0xe0;

            } else if (st->codec->codec_type == AVMEDIA_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 == AVMEDIA_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 && pts != AV_NOPTS_VALUE && dts != pts) {

                header_len += 5;

                flags |= 0x40;

            }

            if (st->codec->codec_type == AVMEDIA_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++;

            if (len > 0xffff)

                len = 0;

            *q++ = len >> 8;

            *q++ = len;

            val = 0x80;

            /* data alignment indicator is required for subtitle data */

            if (st->codec->codec_type == AVMEDIA_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 && pts != 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);

    }

    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;

    const uint64_t delay = av_rescale(s->max_delay, 90000, AV_TIME_BASE)*2;

    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 (ts_st->first_pts_check && pts == AV_NOPTS_VALUE) {

        av_log(s, AV_LOG_ERROR, "first pts value must set\n");

        return -1;

    }

    ts_st->first_pts_check = 0;

    if (st->codec->codec_id == CODEC_ID_H264) {

        const uint8_t *p = buf, *buf_end = p+size;

        uint32_t state = -1;

        if (pkt->size < 5 || AV_RB32(pkt->data) != 0x0000001) {

            av_log(s, AV_LOG_ERROR, "h264 bitstream malformated, "

                   "no startcode found, use -vbsf h264_mp4toannexb\n");

            return -1;

        }

        do {

            p = ff_find_start_code(p, buf_end, &state);

            //av_log(s, AV_LOG_INFO, "nal %d\n", state & 0x1f);

        } while (p < buf_end && (state & 0x1f) != 9 &&

                 (state & 0x1f) != 5 && (state & 0x1f) != 1);

        if ((state & 0x1f) != 9) { // 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] = 0xf0; // any slice type (0xe) + rbsp stop one bit

            buf  = data;

            size = pkt->size+6;

        }

    } else if (st->codec->codec_id == CODEC_ID_AAC) {

        if (pkt->size < 2)

            return -1;

        if ((AV_RB16(pkt->data) & 0xfff0) != 0xfff0) {

            ADTSContext *adts = ts_st->adts;

            int new_size;

            if (!adts) {

                av_log(s, AV_LOG_ERROR, "aac bitstream not in adts format "

                       "and extradata missing\n");

                return -1;

            }

            new_size = ADTS_HEADER_SIZE+adts->pce_size+pkt->size;

            if ((unsigned)new_size >= INT_MAX)

                return -1;

            data = av_malloc(new_size);

            if (!data)

                return AVERROR(ENOMEM);

            ff_adts_write_frame_header(adts, data, pkt->size, adts->pce_size);

            if (adts->pce_size) {

                memcpy(data+ADTS_HEADER_SIZE, adts->pce_data, adts->pce_size);

                adts->pce_size = 0;

            }

            memcpy(data+ADTS_HEADER_SIZE+adts->pce_size, pkt->data, pkt->size);

            buf = data;

            size = new_size;

        }

    }

    if (st->codec->codec_type != AVMEDIA_TYPE_AUDIO) {

        // for video and subtitle, write a single pes packet

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

        av_free(data);

        return 0;

    }

    if (ts_st->payload_index + size > DEFAULT_PES_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_index = 0;

    }

    if (!ts_st->payload_index) {

        ts_st->payload_pts = pts;

        ts_st->payload_dts = dts;

    }

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

    ts_st->payload_index += size;

    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);

        }

        av_freep(&ts_st->adts);

    }

    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 ff_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,

    .priv_class = &mpegts_muxer_class,

};