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FFmpeg/libavformat/mpegtsenc.c

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/*
* 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 "avformat.h"
#include "crc.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;
/* 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 = bswap_32(av_crc(av_crc04C11DB7, -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;
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;
uint8_t payload[DEFAULT_PES_PAYLOAD_SIZE];
} MpegTSWriteStream;
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;
} MpegTSWrite;
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;
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_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 (strlen(st->language) == 3) {
*q++ = 0x0a; /* ISO 639 language descriptor */
*q++ = 4;
*q++ = st->language[0];
*q++ = st->language[1];
*q++ = st->language[2];
*q++ = 0; /* undefined type */
}
break;
case CODEC_TYPE_SUBTITLE:
{
const char *language;
language = st->language;
if (strlen(language) != 3)
language = "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;
}
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;
int i, total_bit_rate;
const char *service_name;
ts->tsid = DEFAULT_TSID;
ts->onid = DEFAULT_ONID;
/* allocate a single DVB service */
service_name = s->title;
if (service_name[0] == '\0')
service_name = 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;
/* 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);
#if 0
printf("%d %d %d\n",
total_bit_rate, ts->sdt_packet_freq, ts->pat_packet_freq);
#endif
/* write info at the start of the file, so that it will be fast to
find them */
mpegts_write_sdt(s);
mpegts_write_pat(s);
for(i = 0; i < ts->nb_services; i++) {
mpegts_write_pmt(s, ts->services[i]);
}
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]);
}
}
}
/* 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)
{
MpegTSWriteStream *ts_st = st->priv_data;
uint8_t buf[TS_PACKET_SIZE];
uint8_t *q;
int val, is_start, len, header_len, write_pcr, private_code;
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;
/* XXX: this is incorrect, but at least we have a PCR
value */
pcr = pts;
}
}
/* 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) {
*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) {
/* write PES header */
*q++ = 0x00;
*q++ = 0x00;
*q++ = 0x01;
private_code = 0;
if (st->codec->codec_type == CODEC_TYPE_VIDEO) {
*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;
}
}
if (pts != AV_NOPTS_VALUE)
header_len = 8;
else
header_len = 3;
if (private_code != 0)
header_len++;
len = payload_size + header_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;
if (pts != AV_NOPTS_VALUE) {
*q++ = 0x80; /* PTS only */
*q++ = 0x05; /* header len */
val = (0x02 << 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;
} else {
*q++ = 0x00;
*q++ = 0x00;
}
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;
MpegTSWriteStream *ts_st = st->priv_data;
int len, max_payload_size;
if (st->codec->codec_type == CODEC_TYPE_SUBTITLE) {
/* for subtitle, a single PES packet must be generated */
mpegts_write_pes(s, st, buf, size, pkt->pts);
return 0;
}
max_payload_size = DEFAULT_PES_PAYLOAD_SIZE;
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 (ts_st->payload_pts == AV_NOPTS_VALUE)
ts_st->payload_pts = pkt->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_pts = AV_NOPTS_VALUE;
ts_st->payload_index = 0;
}
}
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);
}
}
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",
"MPEG2 transport stream format",
"video/x-mpegts",
"ts",
sizeof(MpegTSWrite),
CODEC_ID_MP2,
CODEC_ID_MPEG2VIDEO,
mpegts_write_header,
mpegts_write_packet,
mpegts_write_end,
};