mpegts.c

/*
 * 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;