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ffmpeg/libavformat/mpegts.c
Michael Niedermayer 23c9925329 libdts support by (Benjamin Zores <ben at geexbox dot org>) 
Originally committed as revision 3310 to svn://svn.ffmpeg.org/ffmpeg/trunk
2004-07-14 01:32:14 +00:00

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/*
* MPEG2 transport stream (aka DVB) demux
* Copyright (c) 2002-2003 Fabrice Bellard.
*
* This library 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 of the License, or (at your option) any later version.
*
* This library 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 this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "avformat.h"
#include "mpegts.h"
//#define DEBUG_SI
//#define DEBUG_SEEK
/* 1.0 second at 24Mbit/s */
#define MAX_SCAN_PACKETS 32000
/* maximum size in which we look for synchronisation if
synchronisation is lost */
#define MAX_RESYNC_SIZE 4096
static int add_pes_stream(MpegTSContext *ts, int pid, int stream_type);
enum MpegTSFilterType {
MPEGTS_PES,
MPEGTS_SECTION,
};
typedef void PESCallback(void *opaque, const uint8_t *buf, int len, int is_start);
typedef struct MpegTSPESFilter {
PESCallback *pes_cb;
void *opaque;
} MpegTSPESFilter;
typedef void SectionCallback(void *opaque, const uint8_t *buf, int len);
typedef void SetServiceCallback(void *opaque, int ret);
typedef struct MpegTSSectionFilter {
int section_index;
int section_h_size;
uint8_t *section_buf;
int check_crc:1;
int end_of_section_reached:1;
SectionCallback *section_cb;
void *opaque;
} MpegTSSectionFilter;
typedef struct MpegTSFilter {
int pid;
int last_cc; /* last cc code (-1 if first packet) */
enum MpegTSFilterType type;
union {
MpegTSPESFilter pes_filter;
MpegTSSectionFilter section_filter;
} u;
} MpegTSFilter;
typedef struct MpegTSService {
int running:1;
int sid;
char *provider_name;
char *name;
} MpegTSService;
struct MpegTSContext {
/* user data */
AVFormatContext *stream;
int raw_packet_size; /* raw packet size, including FEC if present */
int auto_guess; /* if true, all pids are analized to find streams */
int set_service_ret;
int mpeg2ts_raw; /* force raw MPEG2 transport stream output, if possible */
int mpeg2ts_compute_pcr; /* compute exact PCR for each transport stream packet */
/* used to estimate the exact PCR */
int64_t cur_pcr;
int pcr_incr;
int pcr_pid;
/* data needed to handle file based ts */
int stop_parse; /* stop parsing loop */
AVPacket *pkt; /* packet containing av data */
/******************************************/
/* private mpegts data */
/* scan context */
MpegTSFilter *sdt_filter;
int nb_services;
MpegTSService **services;
/* set service context (XXX: allocated it ?) */
SetServiceCallback *set_service_cb;
void *set_service_opaque;
MpegTSFilter *pat_filter;
MpegTSFilter *pmt_filter;
int req_sid;
MpegTSFilter *pids[NB_PID_MAX];
};
static void write_section_data(AVFormatContext *s, MpegTSFilter *tss1,
const uint8_t *buf, int buf_size, int is_start)
{
MpegTSSectionFilter *tss = &tss1->u.section_filter;
int len;
unsigned int crc;
if (is_start) {
memcpy(tss->section_buf, buf, buf_size);
tss->section_index = buf_size;
tss->section_h_size = -1;
tss->end_of_section_reached = 0;
} else {
if (tss->end_of_section_reached)
return;
len = 4096 - tss->section_index;
if (buf_size < len)
len = buf_size;
memcpy(tss->section_buf + tss->section_index, buf, len);
tss->section_index += len;
}
/* compute section length if possible */
if (tss->section_h_size == -1 && tss->section_index >= 3) {
len = (((tss->section_buf[1] & 0xf) << 8) | tss->section_buf[2]) + 3;
if (len > 4096)
return;
tss->section_h_size = len;
}
if (tss->section_h_size != -1 && tss->section_index >= tss->section_h_size) {
if (tss->check_crc) {
crc = mpegts_crc32(tss->section_buf, tss->section_h_size);
if (crc != 0)
goto invalid_crc;
}
tss->section_cb(tss->opaque, tss->section_buf, tss->section_h_size);
invalid_crc:
tss->end_of_section_reached = 1;
}
}
MpegTSFilter *mpegts_open_section_filter(MpegTSContext *ts, unsigned int pid,
SectionCallback *section_cb, void *opaque,
int check_crc)
{
MpegTSFilter *filter;
MpegTSSectionFilter *sec;
#ifdef DEBUG_SI
printf("Filter: pid=0x%x\n", pid);
#endif
if (pid >= NB_PID_MAX || ts->pids[pid])
return NULL;
filter = av_mallocz(sizeof(MpegTSFilter));
if (!filter)
return NULL;
ts->pids[pid] = filter;
filter->type = MPEGTS_SECTION;
filter->pid = pid;
filter->last_cc = -1;
sec = &filter->u.section_filter;
sec->section_cb = section_cb;
sec->opaque = opaque;
sec->section_buf = av_malloc(MAX_SECTION_SIZE);
sec->check_crc = check_crc;
if (!sec->section_buf) {
av_free(filter);
return NULL;
}
return filter;
}
MpegTSFilter *mpegts_open_pes_filter(MpegTSContext *ts, unsigned int pid,
PESCallback *pes_cb,
void *opaque)
{
MpegTSFilter *filter;
MpegTSPESFilter *pes;
if (pid >= NB_PID_MAX || ts->pids[pid])
return NULL;
filter = av_mallocz(sizeof(MpegTSFilter));
if (!filter)
return NULL;
ts->pids[pid] = filter;
filter->type = MPEGTS_PES;
filter->pid = pid;
filter->last_cc = -1;
pes = &filter->u.pes_filter;
pes->pes_cb = pes_cb;
pes->opaque = opaque;
return filter;
}
void mpegts_close_filter(MpegTSContext *ts, MpegTSFilter *filter)
{
int pid;
pid = filter->pid;
if (filter->type == MPEGTS_SECTION)
av_freep(&filter->u.section_filter.section_buf);
else if (filter->type == MPEGTS_PES)
av_freep(&filter->u.pes_filter.opaque);
av_free(filter);
ts->pids[pid] = NULL;
}
static int analyze(const uint8_t *buf, int size, int packet_size, int *index){
int stat[packet_size];
int i;
int x=0;
int best_score=0;
memset(stat, 0, packet_size*sizeof(int));
for(x=i=0; i<size; i++){
if(buf[i] == 0x47){
stat[x]++;
if(stat[x] > best_score){
best_score= stat[x];
if(index) *index= x;
}
}
x++;
if(x == packet_size) x= 0;
}
return best_score;
}
/* autodetect fec presence. Must have at least 1024 bytes */
static int get_packet_size(const uint8_t *buf, int size)
{
int score, fec_score;
if (size < (TS_FEC_PACKET_SIZE * 5 + 1))
return -1;
score = analyze(buf, size, TS_PACKET_SIZE, NULL);
fec_score= analyze(buf, size, TS_FEC_PACKET_SIZE, NULL);
// av_log(NULL, AV_LOG_DEBUG, "score: %d, fec_score: %d \n", score, fec_score);
if (score > fec_score) return TS_PACKET_SIZE;
else if(score < fec_score) return TS_FEC_PACKET_SIZE;
else return -1;
}
typedef struct SectionHeader {
uint8_t tid;
uint16_t id;
uint8_t version;
uint8_t sec_num;
uint8_t last_sec_num;
} SectionHeader;
static inline int get8(const uint8_t **pp, const uint8_t *p_end)
{
const uint8_t *p;
int c;
p = *pp;
if (p >= p_end)
return -1;
c = *p++;
*pp = p;
return c;
}
static inline int get16(const uint8_t **pp, const uint8_t *p_end)
{
const uint8_t *p;
int c;
p = *pp;
if ((p + 1) >= p_end)
return -1;
c = (p[0] << 8) | p[1];
p += 2;
*pp = p;
return c;
}
/* read and allocate a DVB string preceeded by its length */
static char *getstr8(const uint8_t **pp, const uint8_t *p_end)
{
int len;
const uint8_t *p;
char *str;
p = *pp;
len = get8(&p, p_end);
if (len < 0)
return NULL;
if ((p + len) > p_end)
return NULL;
str = av_malloc(len + 1);
if (!str)
return NULL;
memcpy(str, p, len);
str[len] = '\0';
p += len;
*pp = p;
return str;
}
static int parse_section_header(SectionHeader *h,
const uint8_t **pp, const uint8_t *p_end)
{
int val;
val = get8(pp, p_end);
if (val < 0)
return -1;
h->tid = val;
*pp += 2;
val = get16(pp, p_end);
if (val < 0)
return -1;
h->id = val;
val = get8(pp, p_end);
if (val < 0)
return -1;
h->version = (val >> 1) & 0x1f;
val = get8(pp, p_end);
if (val < 0)
return -1;
h->sec_num = val;
val = get8(pp, p_end);
if (val < 0)
return -1;
h->last_sec_num = val;
return 0;
}
static MpegTSService *new_service(MpegTSContext *ts, int sid,
char *provider_name, char *name)
{
MpegTSService *service;
#ifdef DEBUG_SI
printf("new_service: sid=0x%04x provider='%s' name='%s'\n",
sid, provider_name, name);
#endif
service = av_mallocz(sizeof(MpegTSService));
if (!service)
return NULL;
service->sid = sid;
service->provider_name = provider_name;
service->name = name;
dynarray_add(&ts->services, &ts->nb_services, service);
return service;
}
static void pmt_cb(void *opaque, const uint8_t *section, int section_len)
{
MpegTSContext *ts = opaque;
SectionHeader h1, *h = &h1;
const uint8_t *p, *p_end;
int program_info_length, pcr_pid, pid, stream_type, desc_length;
#ifdef DEBUG_SI
printf("PMT:\n");
av_hex_dump(stdout, (uint8_t *)section, section_len);
#endif
p_end = section + section_len - 4;
p = section;
if (parse_section_header(h, &p, p_end) < 0)
return;
#ifdef DEBUG_SI
printf("sid=0x%x sec_num=%d/%d\n", h->id, h->sec_num, h->last_sec_num);
#endif
if (h->tid != PMT_TID || (ts->req_sid >= 0 && h->id != ts->req_sid) )
return;
pcr_pid = get16(&p, p_end) & 0x1fff;
if (pcr_pid < 0)
return;
ts->pcr_pid = pcr_pid;
#ifdef DEBUG_SI
printf("pcr_pid=0x%x\n", pcr_pid);
#endif
program_info_length = get16(&p, p_end) & 0xfff;
if (program_info_length < 0)
return;
p += program_info_length;
if (p >= p_end)
return;
for(;;) {
stream_type = get8(&p, p_end);
if (stream_type < 0)
break;
pid = get16(&p, p_end) & 0x1fff;
if (pid < 0)
break;
desc_length = get16(&p, p_end) & 0xfff;
if (desc_length < 0)
break;
p += desc_length;
if (p > p_end)
return;
#ifdef DEBUG_SI
printf("stream_type=%d pid=0x%x\n", stream_type, pid);
#endif
/* now create ffmpeg stream */
switch(stream_type) {
case STREAM_TYPE_AUDIO_MPEG1:
case STREAM_TYPE_AUDIO_MPEG2:
case STREAM_TYPE_VIDEO_MPEG1:
case STREAM_TYPE_VIDEO_MPEG2:
case STREAM_TYPE_VIDEO_MPEG4:
case STREAM_TYPE_VIDEO_H264:
case STREAM_TYPE_AUDIO_AAC:
case STREAM_TYPE_AUDIO_AC3:
case STREAM_TYPE_AUDIO_DTS:
add_pes_stream(ts, pid, stream_type);
break;
default:
/* we ignore the other streams */
break;
}
}
/* all parameters are there */
ts->set_service_cb(ts->set_service_opaque, 0);
mpegts_close_filter(ts, ts->pmt_filter);
ts->pmt_filter = NULL;
}
static void pat_cb(void *opaque, const uint8_t *section, int section_len)
{
MpegTSContext *ts = opaque;
SectionHeader h1, *h = &h1;
const uint8_t *p, *p_end;
int sid, pmt_pid;
#ifdef DEBUG_SI
printf("PAT:\n");
av_hex_dump(stdout, (uint8_t *)section, section_len);
#endif
p_end = section + section_len - 4;
p = section;
if (parse_section_header(h, &p, p_end) < 0)
return;
if (h->tid != PAT_TID)
return;
for(;;) {
sid = get16(&p, p_end);
if (sid < 0)
break;
pmt_pid = get16(&p, p_end) & 0x1fff;
if (pmt_pid < 0)
break;
#ifdef DEBUG_SI
printf("sid=0x%x pid=0x%x\n", sid, pmt_pid);
#endif
if (sid == 0x0000) {
/* NIT info */
} else {
if (ts->req_sid == sid) {
ts->pmt_filter = mpegts_open_section_filter(ts, pmt_pid,
pmt_cb, ts, 1);
goto found;
}
}
}
/* not found */
ts->set_service_cb(ts->set_service_opaque, -1);
found:
mpegts_close_filter(ts, ts->pat_filter);
ts->pat_filter = NULL;
}
/* add all services found in the PAT */
static void pat_scan_cb(void *opaque, const uint8_t *section, int section_len)
{
MpegTSContext *ts = opaque;
SectionHeader h1, *h = &h1;
const uint8_t *p, *p_end;
int sid, pmt_pid;
char *provider_name, *name;
char buf[256];
#ifdef DEBUG_SI
printf("PAT:\n");
av_hex_dump(stdout, (uint8_t *)section, section_len);
#endif
p_end = section + section_len - 4;
p = section;
if (parse_section_header(h, &p, p_end) < 0)
return;
if (h->tid != PAT_TID)
return;
for(;;) {
sid = get16(&p, p_end);
if (sid < 0)
break;
pmt_pid = get16(&p, p_end) & 0x1fff;
if (pmt_pid < 0)
break;
#ifdef DEBUG_SI
printf("sid=0x%x pid=0x%x\n", sid, pmt_pid);
#endif
if (sid == 0x0000) {
/* NIT info */
} else {
/* add the service with a dummy name */
snprintf(buf, sizeof(buf), "Service %x\n", sid);
name = av_strdup(buf);
provider_name = av_strdup("");
if (name && provider_name) {
new_service(ts, sid, provider_name, name);
} else {
av_freep(&name);
av_freep(&provider_name);
}
}
}
ts->stop_parse = 1;
/* remove filter */
mpegts_close_filter(ts, ts->pat_filter);
ts->pat_filter = NULL;
}
void mpegts_set_service(MpegTSContext *ts, int sid,
SetServiceCallback *set_service_cb, void *opaque)
{
ts->set_service_cb = set_service_cb;
ts->set_service_opaque = opaque;
ts->req_sid = sid;
ts->pat_filter = mpegts_open_section_filter(ts, PAT_PID,
pat_cb, ts, 1);
}
static void sdt_cb(void *opaque, const uint8_t *section, int section_len)
{
MpegTSContext *ts = opaque;
SectionHeader h1, *h = &h1;
const uint8_t *p, *p_end, *desc_list_end, *desc_end;
int onid, val, sid, desc_list_len, desc_tag, desc_len, service_type;
char *name, *provider_name;
#ifdef DEBUG_SI
printf("SDT:\n");
av_hex_dump(stdout, (uint8_t *)section, section_len);
#endif
p_end = section + section_len - 4;
p = section;
if (parse_section_header(h, &p, p_end) < 0)
return;
if (h->tid != SDT_TID)
return;
onid = get16(&p, p_end);
if (onid < 0)
return;
val = get8(&p, p_end);
if (val < 0)
return;
for(;;) {
sid = get16(&p, p_end);
if (sid < 0)
break;
val = get8(&p, p_end);
if (val < 0)
break;
desc_list_len = get16(&p, p_end) & 0xfff;
if (desc_list_len < 0)
break;
desc_list_end = p + desc_list_len;
if (desc_list_end > p_end)
break;
for(;;) {
desc_tag = get8(&p, desc_list_end);
if (desc_tag < 0)
break;
desc_len = get8(&p, desc_list_end);
desc_end = p + desc_len;
if (desc_end > desc_list_end)
break;
#ifdef DEBUG_SI
printf("tag: 0x%02x len=%d\n", desc_tag, desc_len);
#endif
switch(desc_tag) {
case 0x48:
service_type = get8(&p, p_end);
if (service_type < 0)
break;
provider_name = getstr8(&p, p_end);
if (!provider_name)
break;
name = getstr8(&p, p_end);
if (!name)
break;
new_service(ts, sid, provider_name, name);
break;
default:
break;
}
p = desc_end;
}
p = desc_list_end;
}
ts->stop_parse = 1;
/* remove filter */
mpegts_close_filter(ts, ts->sdt_filter);
ts->sdt_filter = NULL;
}
/* scan services in a transport stream by looking at the SDT */
void mpegts_scan_sdt(MpegTSContext *ts)
{
ts->sdt_filter = mpegts_open_section_filter(ts, SDT_PID,
sdt_cb, ts, 1);
}
/* scan services in a transport stream by looking at the PAT (better
than nothing !) */
void mpegts_scan_pat(MpegTSContext *ts)
{
ts->pat_filter = mpegts_open_section_filter(ts, PAT_PID,
pat_scan_cb, ts, 1);
}
/* TS stream handling */
enum MpegTSState {
MPEGTS_HEADER = 0,
MPEGTS_PESHEADER_FILL,
MPEGTS_PAYLOAD,
MPEGTS_SKIP,
};
/* enough for PES header + length */
#define PES_START_SIZE 9
#define MAX_PES_HEADER_SIZE (9 + 255)
typedef struct PESContext {
int pid;
int stream_type;
MpegTSContext *ts;
AVFormatContext *stream;
AVStream *st;
enum MpegTSState state;
/* used to get the format */
int data_index;
int total_size;
int pes_header_size;
int64_t pts, dts;
uint8_t header[MAX_PES_HEADER_SIZE];
} PESContext;
static int64_t get_pts(const uint8_t *p)
{
int64_t pts;
int val;
pts = (int64_t)((p[0] >> 1) & 0x07) << 30;
val = (p[1] << 8) | p[2];
pts |= (int64_t)(val >> 1) << 15;
val = (p[3] << 8) | p[4];
pts |= (int64_t)(val >> 1);
return pts;
}
/* return non zero if a packet could be constructed */
static void mpegts_push_data(void *opaque,
const uint8_t *buf, int buf_size, int is_start)
{
PESContext *pes = opaque;
MpegTSContext *ts = pes->ts;
AVStream *st;
const uint8_t *p;
int len, code, codec_type, codec_id;
if (is_start) {
pes->state = MPEGTS_HEADER;
pes->data_index = 0;
}
p = buf;
while (buf_size > 0) {
switch(pes->state) {
case MPEGTS_HEADER:
len = PES_START_SIZE - pes->data_index;
if (len > buf_size)
len = buf_size;
memcpy(pes->header + pes->data_index, p, len);
pes->data_index += len;
p += len;
buf_size -= len;
if (pes->data_index == PES_START_SIZE) {
/* we got all the PES or section header. We can now
decide */
#if 0
av_hex_dump(pes->header, pes->data_index);
#endif
if (pes->header[0] == 0x00 && pes->header[1] == 0x00 &&
pes->header[2] == 0x01) {
/* it must be an mpeg2 PES stream */
code = pes->header[3] | 0x100;
if (!((code >= 0x1c0 && code <= 0x1df) ||
(code >= 0x1e0 && code <= 0x1ef) ||
(code == 0x1bd)))
goto skip;
if (!pes->st) {
/* allocate stream */
switch(pes->stream_type){
case STREAM_TYPE_AUDIO_MPEG1:
case STREAM_TYPE_AUDIO_MPEG2:
codec_type = CODEC_TYPE_AUDIO;
codec_id = CODEC_ID_MP3;
break;
case STREAM_TYPE_VIDEO_MPEG1:
case STREAM_TYPE_VIDEO_MPEG2:
codec_type = CODEC_TYPE_VIDEO;
codec_id = CODEC_ID_MPEG2VIDEO;
break;
case STREAM_TYPE_VIDEO_MPEG4:
codec_type = CODEC_TYPE_VIDEO;
codec_id = CODEC_ID_MPEG4;
break;
case STREAM_TYPE_VIDEO_H264:
codec_type = CODEC_TYPE_VIDEO;
codec_id = CODEC_ID_H264;
break;
case STREAM_TYPE_AUDIO_AAC:
codec_type = CODEC_TYPE_AUDIO;
codec_id = CODEC_ID_AAC;
break;
case STREAM_TYPE_AUDIO_AC3:
codec_type = CODEC_TYPE_AUDIO;
codec_id = CODEC_ID_AC3;
break;
case STREAM_TYPE_AUDIO_DTS:
codec_type = CODEC_TYPE_AUDIO;
codec_id = CODEC_ID_DTS;
break;
default:
if (code >= 0x1c0 && code <= 0x1df) {
codec_type = CODEC_TYPE_AUDIO;
codec_id = CODEC_ID_MP2;
} else if (code == 0x1bd) {
codec_type = CODEC_TYPE_AUDIO;
codec_id = CODEC_ID_AC3;
} else {
codec_type = CODEC_TYPE_VIDEO;
codec_id = CODEC_ID_MPEG1VIDEO;
}
break;
}
st = av_new_stream(pes->stream, pes->pid);
if (st) {
av_set_pts_info(st, 60, 1, 90000);
st->priv_data = pes;
st->codec.codec_type = codec_type;
st->codec.codec_id = codec_id;
st->need_parsing = 1;
pes->st = st;
}
}
pes->state = MPEGTS_PESHEADER_FILL;
pes->total_size = (pes->header[4] << 8) | pes->header[5];
/* NOTE: a zero total size means the PES size is
unbounded */
if (pes->total_size)
pes->total_size += 6;
pes->pes_header_size = pes->header[8] + 9;
} else {
/* otherwise, it should be a table */
/* skip packet */
skip:
pes->state = MPEGTS_SKIP;
continue;
}
}
break;
/**********************************************/
/* PES packing parsing */
case MPEGTS_PESHEADER_FILL:
len = pes->pes_header_size - pes->data_index;
if (len > buf_size)
len = buf_size;
memcpy(pes->header + pes->data_index, p, len);
pes->data_index += len;
p += len;
buf_size -= len;
if (pes->data_index == pes->pes_header_size) {
const uint8_t *r;
unsigned int flags;
flags = pes->header[7];
r = pes->header + 9;
pes->pts = AV_NOPTS_VALUE;
pes->dts = AV_NOPTS_VALUE;
if ((flags & 0xc0) == 0x80) {
pes->pts = get_pts(r);
r += 5;
} else if ((flags & 0xc0) == 0xc0) {
pes->pts = get_pts(r);
r += 5;
pes->dts = get_pts(r);
r += 5;
}
/* we got the full header. We parse it and get the payload */
pes->state = MPEGTS_PAYLOAD;
}
break;
case MPEGTS_PAYLOAD:
if (pes->total_size) {
len = pes->total_size - pes->data_index;
if (len > buf_size)
len = buf_size;
} else {
len = buf_size;
}
if (len > 0) {
AVPacket *pkt = ts->pkt;
if (pes->st && av_new_packet(pkt, len) == 0) {
memcpy(pkt->data, p, len);
pkt->stream_index = pes->st->index;
pkt->pts = pes->pts;
pkt->dts = pes->dts;
/* reset pts values */
pes->pts = AV_NOPTS_VALUE;
pes->dts = AV_NOPTS_VALUE;
ts->stop_parse = 1;
return;
}
}
buf_size = 0;
break;
case MPEGTS_SKIP:
buf_size = 0;
break;
}
}
}
static int add_pes_stream(MpegTSContext *ts, int pid, int stream_type)
{
MpegTSFilter *tss;
PESContext *pes;
/* if no pid found, then add a pid context */
pes = av_mallocz(sizeof(PESContext));
if (!pes)
return -1;
pes->ts = ts;
pes->stream = ts->stream;
pes->pid = pid;
pes->stream_type = stream_type;
tss = mpegts_open_pes_filter(ts, pid, mpegts_push_data, pes);
if (!tss) {
av_free(pes);
return -1;
}
return 0;
}
/* handle one TS packet */
static void handle_packet(MpegTSContext *ts, const uint8_t *packet)
{
AVFormatContext *s = ts->stream;
MpegTSFilter *tss;
int len, pid, cc, cc_ok, afc, is_start;
const uint8_t *p, *p_end;
pid = ((packet[1] & 0x1f) << 8) | packet[2];
is_start = packet[1] & 0x40;
tss = ts->pids[pid];
if (ts->auto_guess && tss == NULL && is_start) {
add_pes_stream(ts, pid, 0);
tss = ts->pids[pid];
}
if (!tss)
return;
/* continuity check (currently not used) */
cc = (packet[3] & 0xf);
cc_ok = (tss->last_cc < 0) || ((((tss->last_cc + 1) & 0x0f) == cc));
tss->last_cc = cc;
/* skip adaptation field */
afc = (packet[3] >> 4) & 3;
p = packet + 4;
if (afc == 0) /* reserved value */
return;
if (afc == 2) /* adaptation field only */
return;
if (afc == 3) {
/* skip adapation field */
p += p[0] + 1;
}
/* if past the end of packet, ignore */
p_end = packet + TS_PACKET_SIZE;
if (p >= p_end)
return;
if (tss->type == MPEGTS_SECTION) {
if (is_start) {
/* pointer field present */
len = *p++;
if (p + len > p_end)
return;
if (len && cc_ok) {
/* write remaning section bytes */
write_section_data(s, tss,
p, len, 0);
}
p += len;
if (p < p_end) {
write_section_data(s, tss,
p, p_end - p, 1);
}
} else {
if (cc_ok) {
write_section_data(s, tss,
p, p_end - p, 0);
}
}
} else {
tss->u.pes_filter.pes_cb(tss->u.pes_filter.opaque,
p, p_end - p, is_start);
}
}
/* XXX: try to find a better synchro over several packets (use
get_packet_size() ?) */
static int mpegts_resync(ByteIOContext *pb)
{
int c, i;
for(i = 0;i < MAX_RESYNC_SIZE; i++) {
c = url_fgetc(pb);
if (c < 0)
return -1;
if (c == 0x47) {
url_fseek(pb, -1, SEEK_CUR);
return 0;
}
}
/* no sync found */
return -1;
}
/* return -1 if error or EOF. Return 0 if OK. */
static int read_packet(ByteIOContext *pb, uint8_t *buf, int raw_packet_size)
{
int skip, len;
for(;;) {
len = get_buffer(pb, buf, TS_PACKET_SIZE);
if (len != TS_PACKET_SIZE)
return AVERROR_IO;
/* check paquet sync byte */
if (buf[0] != 0x47) {
/* find a new packet start */
url_fseek(pb, -TS_PACKET_SIZE, SEEK_CUR);
if (mpegts_resync(pb) < 0)
return AVERROR_INVALIDDATA;
else
continue;
} else {
skip = raw_packet_size - TS_PACKET_SIZE;
if (skip > 0)
url_fskip(pb, skip);
break;
}
}
return 0;
}
static int handle_packets(MpegTSContext *ts, int nb_packets)
{
AVFormatContext *s = ts->stream;
ByteIOContext *pb = &s->pb;
uint8_t packet[TS_PACKET_SIZE];
int packet_num, ret;
ts->stop_parse = 0;
packet_num = 0;
for(;;) {
if (ts->stop_parse)
break;
packet_num++;
if (nb_packets != 0 && packet_num >= nb_packets)
break;
ret = read_packet(pb, packet, ts->raw_packet_size);
if (ret != 0)
return ret;
handle_packet(ts, packet);
}
return 0;
}
static int mpegts_probe(AVProbeData *p)
{
#if 1
const int size= p->buf_size;
int score, fec_score;
#define CHECK_COUNT 10
if (size < (TS_FEC_PACKET_SIZE * CHECK_COUNT))
return -1;
score = analyze(p->buf, TS_PACKET_SIZE *CHECK_COUNT, TS_PACKET_SIZE, NULL);
fec_score= analyze(p->buf, TS_FEC_PACKET_SIZE*CHECK_COUNT, TS_FEC_PACKET_SIZE, NULL);
// av_log(NULL, AV_LOG_DEBUG, "score: %d, fec_score: %d \n", score, fec_score);
// we need a clear definition for the returned score otherwise things will become messy sooner or later
if (score > fec_score && score > 6) return AVPROBE_SCORE_MAX + score - CHECK_COUNT;
else if( fec_score > 6) return AVPROBE_SCORE_MAX + fec_score - CHECK_COUNT;
else return -1;
#else
/* only use the extension for safer guess */
if (match_ext(p->filename, "ts"))
return AVPROBE_SCORE_MAX;
else
return 0;
#endif
}
void set_service_cb(void *opaque, int ret)
{
MpegTSContext *ts = opaque;
ts->set_service_ret = ret;
ts->stop_parse = 1;
}
/* return the 90 kHz PCR and the extension for the 27 MHz PCR. return
(-1) if not available */
static int parse_pcr(int64_t *ppcr_high, int *ppcr_low,
const uint8_t *packet)
{
int afc, len, flags;
const uint8_t *p;
unsigned int v;
afc = (packet[3] >> 4) & 3;
if (afc <= 1)
return -1;
p = packet + 4;
len = p[0];
p++;
if (len == 0)
return -1;
flags = *p++;
len--;
if (!(flags & 0x10))
return -1;
if (len < 6)
return -1;
v = (p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3];
*ppcr_high = ((int64_t)v << 1) | (p[4] >> 7);
*ppcr_low = ((p[4] & 1) << 8) | p[5];
return 0;
}
static int mpegts_read_header(AVFormatContext *s,
AVFormatParameters *ap)
{
MpegTSContext *ts = s->priv_data;
ByteIOContext *pb = &s->pb;
uint8_t buf[1024];
int len, sid, i;
int64_t pos;
MpegTSService *service;
if (ap) {
ts->mpeg2ts_raw = ap->mpeg2ts_raw;
ts->mpeg2ts_compute_pcr = ap->mpeg2ts_compute_pcr;
}
/* read the first 1024 bytes to get packet size */
pos = url_ftell(pb);
len = get_buffer(pb, buf, sizeof(buf));
if (len != sizeof(buf))
goto fail;
ts->raw_packet_size = get_packet_size(buf, sizeof(buf));
if (ts->raw_packet_size <= 0)
goto fail;
ts->stream = s;
ts->auto_guess = 0;
if (!ts->mpeg2ts_raw) {
/* normal demux */
if (!ts->auto_guess) {
ts->set_service_ret = -1;
/* first do a scaning to get all the services */
url_fseek(pb, pos, SEEK_SET);
mpegts_scan_sdt(ts);
handle_packets(ts, MAX_SCAN_PACKETS);
if (ts->nb_services <= 0) {
/* no SDT found, we try to look at the PAT */
/* First remove the SDT filters from each PID */
int i;
for (i=0; i < NB_PID_MAX; i++) {
if (ts->pids[i])
mpegts_close_filter(ts, ts->pids[i]);
}
url_fseek(pb, pos, SEEK_SET);
mpegts_scan_pat(ts);
handle_packets(ts, MAX_SCAN_PACKETS);
}
if (ts->nb_services <= 0) {
/* raw transport stream */
ts->auto_guess = 1;
s->ctx_flags |= AVFMTCTX_NOHEADER;
goto do_pcr;
}
/* tune to first service found */
for(i=0; i<ts->nb_services && ts->set_service_ret; i++){
service = ts->services[i];
sid = service->sid;
#ifdef DEBUG_SI
printf("tuning to '%s'\n", service->name);
#endif
/* now find the info for the first service if we found any,
otherwise try to filter all PATs */
url_fseek(pb, pos, SEEK_SET);
mpegts_set_service(ts, sid, set_service_cb, ts);
handle_packets(ts, MAX_SCAN_PACKETS);
}
/* if could not find service, exit */
if (ts->set_service_ret != 0)
return -1;
#ifdef DEBUG_SI
printf("tuning done\n");
#endif
}
s->ctx_flags |= AVFMTCTX_NOHEADER;
} else {
AVStream *st;
int pcr_pid, pid, nb_packets, nb_pcrs, ret, pcr_l;
int64_t pcrs[2], pcr_h;
int packet_count[2];
uint8_t packet[TS_PACKET_SIZE];
/* only read packets */
do_pcr:
st = av_new_stream(s, 0);
if (!st)
goto fail;
av_set_pts_info(st, 60, 1, 27000000);
st->codec.codec_type = CODEC_TYPE_DATA;
st->codec.codec_id = CODEC_ID_MPEG2TS;
/* we iterate until we find two PCRs to estimate the bitrate */
pcr_pid = -1;
nb_pcrs = 0;
nb_packets = 0;
for(;;) {
ret = read_packet(&s->pb, packet, ts->raw_packet_size);
if (ret < 0)
return -1;
pid = ((packet[1] & 0x1f) << 8) | packet[2];
if ((pcr_pid == -1 || pcr_pid == pid) &&
parse_pcr(&pcr_h, &pcr_l, packet) == 0) {
pcr_pid = pid;
packet_count[nb_pcrs] = nb_packets;
pcrs[nb_pcrs] = pcr_h * 300 + pcr_l;
nb_pcrs++;
if (nb_pcrs >= 2)
break;
}
nb_packets++;
}
ts->pcr_pid = pcr_pid;
/* NOTE1: the bitrate is computed without the FEC */
/* NOTE2: it is only the bitrate of the start of the stream */
ts->pcr_incr = (pcrs[1] - pcrs[0]) / (packet_count[1] - packet_count[0]);
ts->cur_pcr = pcrs[0] - ts->pcr_incr * packet_count[0];
s->bit_rate = (TS_PACKET_SIZE * 8) * 27e6 / ts->pcr_incr;
st->codec.bit_rate = s->bit_rate;
st->start_time = ts->cur_pcr * 1000000.0 / 27.0e6;
#if 0
printf("start=%0.3f pcr=%0.3f incr=%d\n",
st->start_time / 1000000.0, pcrs[0] / 27e6, ts->pcr_incr);
#endif
}
url_fseek(pb, pos, SEEK_SET);
return 0;
fail:
return -1;
}
#define MAX_PACKET_READAHEAD ((128 * 1024) / 188)
static int mpegts_raw_read_packet(AVFormatContext *s,
AVPacket *pkt)
{
MpegTSContext *ts = s->priv_data;
int ret, i;
int64_t pcr_h, next_pcr_h, pos;
int pcr_l, next_pcr_l;
uint8_t pcr_buf[12];
if (av_new_packet(pkt, TS_PACKET_SIZE) < 0)
return -ENOMEM;
ret = read_packet(&s->pb, pkt->data, ts->raw_packet_size);
if (ret < 0) {
av_free_packet(pkt);
return ret;
}
if (ts->mpeg2ts_compute_pcr) {
/* compute exact PCR for each packet */
if (parse_pcr(&pcr_h, &pcr_l, pkt->data) == 0) {
/* we read the next PCR (XXX: optimize it by using a bigger buffer */
pos = url_ftell(&s->pb);
for(i = 0; i < MAX_PACKET_READAHEAD; i++) {
url_fseek(&s->pb, pos + i * ts->raw_packet_size, SEEK_SET);
get_buffer(&s->pb, pcr_buf, 12);
if (parse_pcr(&next_pcr_h, &next_pcr_l, pcr_buf) == 0) {
/* XXX: not precise enough */
ts->pcr_incr = ((next_pcr_h - pcr_h) * 300 + (next_pcr_l - pcr_l)) /
(i + 1);
break;
}
}
url_fseek(&s->pb, pos, SEEK_SET);
/* no next PCR found: we use previous increment */
ts->cur_pcr = pcr_h * 300 + pcr_l;
}
pkt->pts = ts->cur_pcr;
pkt->duration = ts->pcr_incr;
ts->cur_pcr += ts->pcr_incr;
}
pkt->stream_index = 0;
return 0;
}
static int mpegts_read_packet(AVFormatContext *s,
AVPacket *pkt)
{
MpegTSContext *ts = s->priv_data;
if (!ts->mpeg2ts_raw) {
ts->pkt = pkt;
return handle_packets(ts, 0);
} else {
return mpegts_raw_read_packet(s, pkt);
}
}
static int mpegts_read_close(AVFormatContext *s)
{
MpegTSContext *ts = s->priv_data;
int i;
for(i=0;i<NB_PID_MAX;i++)
if (ts->pids[i]) mpegts_close_filter(ts, ts->pids[i]);
return 0;
}
static int64_t mpegts_get_pcr(AVFormatContext *s, int stream_index,
int64_t *ppos, int64_t pos_limit)
{
MpegTSContext *ts = s->priv_data;
int64_t pos, timestamp;
uint8_t buf[TS_PACKET_SIZE];
int pcr_l, pid;
const int find_next= 1;
pos = ((*ppos + ts->raw_packet_size - 1) / ts->raw_packet_size) * ts->raw_packet_size;
if (find_next) {
for(;;) {
url_fseek(&s->pb, pos, SEEK_SET);
if (get_buffer(&s->pb, buf, TS_PACKET_SIZE) != TS_PACKET_SIZE)
return AV_NOPTS_VALUE;
pid = ((buf[1] & 0x1f) << 8) | buf[2];
if (pid == ts->pcr_pid &&
parse_pcr(&timestamp, &pcr_l, buf) == 0) {
break;
}
pos += ts->raw_packet_size;
}
} else {
for(;;) {
pos -= ts->raw_packet_size;
if (pos < 0)
return AV_NOPTS_VALUE;
url_fseek(&s->pb, pos, SEEK_SET);
if (get_buffer(&s->pb, buf, TS_PACKET_SIZE) != TS_PACKET_SIZE)
return AV_NOPTS_VALUE;
pid = ((buf[1] & 0x1f) << 8) | buf[2];
if (pid == ts->pcr_pid &&
parse_pcr(&timestamp, &pcr_l, buf) == 0) {
break;
}
}
}
*ppos = pos;
return timestamp;
}
static int read_seek(AVFormatContext *s, int stream_index, int64_t target_ts){
MpegTSContext *ts = s->priv_data;
uint8_t buf[TS_PACKET_SIZE];
int64_t pos;
if(av_seek_frame_binary(s, stream_index, target_ts) < 0)
return -1;
pos= url_ftell(&s->pb);
for(;;) {
url_fseek(&s->pb, pos, SEEK_SET);
if (get_buffer(&s->pb, buf, TS_PACKET_SIZE) != TS_PACKET_SIZE)
return -1;
// pid = ((buf[1] & 0x1f) << 8) | buf[2];
if(buf[1] & 0x40) break;
pos += ts->raw_packet_size;
}
url_fseek(&s->pb, pos, SEEK_SET);
return 0;
}
/**************************************************************/
/* parsing functions - called from other demuxers such as RTP */
MpegTSContext *mpegts_parse_open(AVFormatContext *s)
{
MpegTSContext *ts;
ts = av_mallocz(sizeof(MpegTSContext));
if (!ts)
return NULL;
/* no stream case, currently used by RTP */
ts->raw_packet_size = TS_PACKET_SIZE;
ts->stream = s;
ts->auto_guess = 1;
return ts;
}
/* return the consumed length if a packet was output, or -1 if no
packet is output */
int mpegts_parse_packet(MpegTSContext *ts, AVPacket *pkt,
const uint8_t *buf, int len)
{
int len1;
len1 = len;
ts->pkt = pkt;
ts->stop_parse = 0;
for(;;) {
if (ts->stop_parse)
break;
if (len < TS_PACKET_SIZE)
return -1;
if (buf[0] != 0x47) {
buf++;
len--;
} else {
handle_packet(ts, buf);
buf += TS_PACKET_SIZE;
len -= TS_PACKET_SIZE;
}
}
return len1 - len;
}
void mpegts_parse_close(MpegTSContext *ts)
{
int i;
for(i=0;i<NB_PID_MAX;i++)
av_free(ts->pids[i]);
av_free(ts);
}
AVInputFormat mpegts_demux = {
"mpegts",
"MPEG2 transport stream format",
sizeof(MpegTSContext),
mpegts_probe,
mpegts_read_header,
mpegts_read_packet,
mpegts_read_close,
read_seek,
mpegts_get_pcr,
.flags = AVFMT_SHOW_IDS,
};
int mpegts_init(void)
{
av_register_input_format(&mpegts_demux);
#ifdef CONFIG_ENCODERS
av_register_output_format(&mpegts_mux);
#endif
return 0;
}
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