diff options
Diffstat (limited to 'libavformat/mpegts.c')
| -rw-r--r-- | libavformat/mpegts.c | 316 |
1 files changed, 316 insertions, 0 deletions
diff --git a/libavformat/mpegts.c b/libavformat/mpegts.c new file mode 100644 index 0000000000..2947d960e8 --- /dev/null +++ b/libavformat/mpegts.c @@ -0,0 +1,316 @@ +/* + * MPEG2 transport stream (aka DVB) demux + * Copyright (c) 2002 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" + +#define TS_FEC_PACKET_SIZE 204 +#define TS_PACKET_SIZE 188 +#define NB_PID_MAX 8192 + +enum MpegTSState { + MPEGTS_HEADER = 0, + MPEGTS_PESHEADER_FILL, + MPEGTS_PESHEADER_FLAGS, + MPEGTS_PESHEADER_SIZE, + MPEGTS_PESHEADER_READ, + MPEGTS_PAYLOAD, + MPEGTS_SKIP, +}; + +/* enough for PES header + length */ +#define MAX_HEADER_SIZE 6 + +typedef struct MpegTSStream { + int pid; + enum MpegTSState state; + int last_cc; /* last cc code (-1 if first packet) */ + /* used to get the format */ + int header_size; + int payload_size; + int pes_header_size; + AVStream *st; + unsigned char header[MAX_HEADER_SIZE]; +} MpegTSStream; + +typedef struct MpegTSContext { + int raw_packet_size; /* raw packet size, including FEC if present */ + MpegTSStream *pids[NB_PID_MAX]; +} MpegTSContext; + +/* autodetect fec presence. Must have at least 1024 bytes */ +static int get_packet_size(const unsigned char *buf, int size) +{ + int i; + + if (size < (TS_FEC_PACKET_SIZE * 5 + 1)) + return -1; + for(i=0;i<5;i++) { + if (buf[i * TS_PACKET_SIZE] != 0x47) + goto try_fec; + } + return TS_PACKET_SIZE; + try_fec: + for(i=0;i<5;i++) { + if (buf[i * TS_FEC_PACKET_SIZE] != 0x47) + return -1; + } + return TS_FEC_PACKET_SIZE; +} + +static int mpegts_probe(AVProbeData *p) +{ + int size; + size = get_packet_size(p->buf, p->buf_size); + if (size < 0) + return 0; + return AVPROBE_SCORE_MAX; +} + +static int mpegts_read_header(AVFormatContext *s, + AVFormatParameters *ap) +{ + MpegTSContext *ts = s->priv_data; + ByteIOContext *pb = &s->pb; + unsigned char buf[1024]; + int len; + INT64 pos; + + /* 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; + /* go again to the start */ + url_fseek(pb, pos, SEEK_SET); + return 0; + fail: + return -1; +} + +/* return non zero if a packet could be constructed */ +static int mpegts_push_data(AVFormatContext *s, MpegTSStream *tss, + AVPacket *pkt, + const unsigned char *buf, int buf_size, int is_start) +{ + AVStream *st; + const unsigned char *p; + int len, code, codec_type, codec_id; + + if (is_start) { + tss->state = MPEGTS_HEADER; + tss->header_size = 0; + } + p = buf; + while (buf_size > 0) { + len = buf_size; + switch(tss->state) { + case MPEGTS_HEADER: + if (len > MAX_HEADER_SIZE - tss->header_size) + len = MAX_HEADER_SIZE - tss->header_size; + memcpy(tss->header, p, len); + tss->header_size += len; + p += len; + buf_size -= len; + if (tss->header_size == MAX_HEADER_SIZE) { + /* we got all the PES or section header. We can now + decide */ +#if 0 + av_hex_dump(tss->header, tss->header_size); +#endif + if (tss->header[0] == 0x00 && tss->header[1] == 0x00 && + tss->header[2] == 0x01) { + /* it must be an mpeg2 PES stream */ + /* XXX: add AC3 support */ + code = tss->header[3] | 0x100; + if (!((code >= 0x1c0 && code <= 0x1df) || + (code >= 0x1e0 && code <= 0x1ef))) + goto skip; + if (!tss->st) { + /* allocate stream */ + if (code >= 0x1c0 && code <= 0x1df) { + codec_type = CODEC_TYPE_AUDIO; + codec_id = CODEC_ID_MP2; + } else { + codec_type = CODEC_TYPE_VIDEO; + codec_id = CODEC_ID_MPEG1VIDEO; + } + st = av_new_stream(s, tss->pid); + if (st) { + st->priv_data = tss; + st->codec.codec_type = codec_type; + st->codec.codec_id = codec_id; + tss->st = st; + } + } + tss->state = MPEGTS_PESHEADER_FILL; + tss->payload_size = (tss->header[4] << 8) | tss->header[5]; + if (tss->payload_size == 0) + tss->payload_size = 65536; + } else { + /* otherwise, it should be a table */ + /* skip packet */ + skip: + tss->state = MPEGTS_SKIP; + continue; + } + } + break; + /**********************************************/ + /* PES packing parsing */ + case MPEGTS_PESHEADER_FILL: + /* skip filling */ + code = *p++; + buf_size--; + tss->payload_size--; + if (code != 0xff) { + if ((code & 0xc0) != 0x80) + goto skip; + tss->state = MPEGTS_PESHEADER_FLAGS; + } + break; + case MPEGTS_PESHEADER_FLAGS: + code = *p++; + buf_size--; + tss->payload_size--; + tss->state = MPEGTS_PESHEADER_SIZE; + break; + case MPEGTS_PESHEADER_SIZE: + tss->pes_header_size = *p++; + buf_size--; + tss->payload_size--; + tss->state = MPEGTS_PESHEADER_READ; + break; + case MPEGTS_PESHEADER_READ: + /* currently we do nothing except skipping */ + if (len > tss->pes_header_size) + len = tss->pes_header_size; + p += len; + buf_size -= len; + tss->pes_header_size -= len; + tss->payload_size -= len; + if (tss->pes_header_size == 0) + tss->state = MPEGTS_PAYLOAD; + break; + case MPEGTS_PAYLOAD: + if (len > tss->payload_size) + len = tss->payload_size; + if (len > 0) { + if (tss->st && av_new_packet(pkt, buf_size) == 0) { + memcpy(pkt->data, p, buf_size); + pkt->stream_index = tss->st->index; + return 1; + } + tss->payload_size -= len; + } + buf_size = 0; + break; + case MPEGTS_SKIP: + buf_size = 0; + break; + } + } + return 0; +} + +static int mpegts_read_packet(AVFormatContext *s, + AVPacket *pkt) +{ + MpegTSContext *ts = s->priv_data; + MpegTSStream *tss; + ByteIOContext *pb = &s->pb; + unsigned char packet[TS_FEC_PACKET_SIZE]; + int len, pid, cc, cc_ok, afc; + const unsigned char *p; + + for(;;) { + len = get_buffer(pb, packet, ts->raw_packet_size); + if (len != ts->raw_packet_size) + return AVERROR_IO; + /* check paquet sync byte */ + /* XXX: accept to resync ? */ + if (packet[0] != 0x47) + return AVERROR_INVALIDDATA; + + pid = ((packet[1] & 0x1f) << 8) | packet[2]; + tss = ts->pids[pid]; + if (tss == NULL) { + /* if no pid found, then add a pid context */ + tss = av_mallocz(sizeof(MpegTSStream)); + if (!tss) + continue; + ts->pids[pid] = tss; + tss->pid = pid; + tss->last_cc = -1; + // printf("new pid=0x%x\n", pid); + } + + /* 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 */ + continue; + if (afc == 2) /* adaptation field only */ + continue; + if (afc == 3) { + /* skip adapation field */ + p += p[0] + 1; + } + /* if past the end of packet, ignore */ + if (p >= packet + TS_PACKET_SIZE) + continue; + + if (mpegts_push_data(s, tss, pkt, p, TS_PACKET_SIZE - (p - packet), + packet[1] & 0x40)) + break; + } + return 0; +} + +static int mpegts_read_close(AVFormatContext *s) +{ + MpegTSContext *ts = s->priv_data; + int i; + for(i=0;i<NB_PID_MAX;i++) + av_free(ts->pids[i]); + return 0; +} + +AVInputFormat mpegts_demux = { + "mpegts", + "MPEG2 transport stream format", + sizeof(MpegTSContext), + mpegts_probe, + mpegts_read_header, + mpegts_read_packet, + mpegts_read_close, + .flags = AVFMT_NOHEADER | AVFMT_SHOW_IDS, +}; + +int mpegts_init(void) +{ + av_register_input_format(&mpegts_demux); + return 0; +} |