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ffmpeg/libavformat/ty.c

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/*
* TiVo ty stream demuxer
* Copyright (c) 2005 VLC authors and VideoLAN
* Copyright (c) 2005 by Neal Symms (tivo@freakinzoo.com) - February 2005
* based on code by Christopher Wingert for tivo-mplayer
* tivo(at)wingert.org, February 2003
* Copyright (c) 2017 Paul B Mahol
*
* 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/intreadwrite.h"
#include "libavutil/mem.h"
#include "avformat.h"
#include "demux.h"
#include "internal.h"
#include "mpeg.h"
#define SERIES1_PES_LENGTH 11 /* length of audio PES hdr on S1 */
#define SERIES2_PES_LENGTH 16 /* length of audio PES hdr on S2 */
#define AC3_PES_LENGTH 14 /* length of audio PES hdr for AC3 */
#define VIDEO_PES_LENGTH 16 /* length of video PES header */
#define DTIVO_PTS_OFFSET 6 /* offs into PES for MPEG PTS on DTivo */
#define SA_PTS_OFFSET 9 /* offset into PES for MPEG PTS on SA */
#define AC3_PTS_OFFSET 9 /* offset into PES for AC3 PTS on DTivo */
#define VIDEO_PTS_OFFSET 9 /* offset into PES for video PTS on all */
#define AC3_PKT_LENGTH 1536 /* size of TiVo AC3 pkts (w/o PES hdr) */
static const uint8_t ty_VideoPacket[] = { 0x00, 0x00, 0x01, 0xe0 };
static const uint8_t ty_MPEGAudioPacket[] = { 0x00, 0x00, 0x01, 0xc0 };
static const uint8_t ty_AC3AudioPacket[] = { 0x00, 0x00, 0x01, 0xbd };
#define TIVO_PES_FILEID 0xf5467abd
#define CHUNK_SIZE (128 * 1024)
#define CHUNK_PEEK_COUNT 3 /* number of chunks to probe */
typedef struct TyRecHdr {
int32_t rec_size;
uint8_t ex[2];
uint8_t rec_type;
uint8_t subrec_type;
uint64_t ty_pts; /* TY PTS in the record header */
} TyRecHdr;
typedef enum {
TIVO_TYPE_UNKNOWN,
TIVO_TYPE_SA,
TIVO_TYPE_DTIVO
} TiVo_type;
typedef enum {
TIVO_SERIES_UNKNOWN,
TIVO_SERIES1,
TIVO_SERIES2
} TiVo_series;
typedef enum {
TIVO_AUDIO_UNKNOWN,
TIVO_AUDIO_AC3,
TIVO_AUDIO_MPEG
} TiVo_audio;
typedef struct TYDemuxContext {
unsigned cur_chunk;
unsigned cur_chunk_pos;
int64_t cur_pos;
TiVo_type tivo_type; /* TiVo type (SA / DTiVo) */
TiVo_series tivo_series; /* Series1 or Series2 */
TiVo_audio audio_type; /* AC3 or MPEG */
int pes_length; /* Length of Audio PES header */
int pts_offset; /* offset into audio PES of PTS */
uint8_t pes_buffer[20]; /* holds incomplete pes headers */
int pes_buf_cnt; /* how many bytes in our buffer */
size_t ac3_pkt_size; /* length of ac3 pkt we've seen so far */
uint64_t last_ty_pts; /* last TY timestamp we've seen */
int64_t first_audio_pts;
int64_t last_audio_pts;
int64_t last_video_pts;
TyRecHdr *rec_hdrs; /* record headers array */
int cur_rec; /* current record in this chunk */
int num_recs; /* number of recs in this chunk */
int first_chunk;
uint8_t chunk[CHUNK_SIZE];
} TYDemuxContext;
static int ty_probe(const AVProbeData *p)
{
int i;
for (i = 0; i + 12 < p->buf_size; i += CHUNK_SIZE) {
if (AV_RB32(p->buf + i) == TIVO_PES_FILEID &&
AV_RB32(p->buf + i + 4) == 0x02 &&
AV_RB32(p->buf + i + 8) == CHUNK_SIZE) {
return AVPROBE_SCORE_MAX;
}
}
return 0;
}
static TyRecHdr *parse_chunk_headers(const uint8_t *buf,
int num_recs)
{
TyRecHdr *hdrs, *rec_hdr;
int i;
hdrs = av_calloc(num_recs, sizeof(TyRecHdr));
if (!hdrs)
return NULL;
for (i = 0; i < num_recs; i++) {
const uint8_t *record_header = buf + (i * 16);
rec_hdr = &hdrs[i]; /* for brevity */
rec_hdr->rec_type = record_header[3];
rec_hdr->subrec_type = record_header[2] & 0x0f;
if ((record_header[0] & 0x80) == 0x80) {
uint8_t b1, b2;
/* marker bit 2 set, so read extended data */
b1 = (((record_header[0] & 0x0f) << 4) |
((record_header[1] & 0xf0) >> 4));
b2 = (((record_header[1] & 0x0f) << 4) |
((record_header[2] & 0xf0) >> 4));
rec_hdr->ex[0] = b1;
rec_hdr->ex[1] = b2;
rec_hdr->rec_size = 0;
rec_hdr->ty_pts = 0;
} else {
rec_hdr->rec_size = (record_header[0] << 8 |
record_header[1]) << 4 |
(record_header[2] >> 4);
rec_hdr->ty_pts = AV_RB64(&record_header[8]);
}
}
return hdrs;
}
static int find_es_header(const uint8_t *header,
const uint8_t *buffer, int search_len)
{
int count;
for (count = 0; count < search_len; count++) {
if (!memcmp(&buffer[count], header, 4))
return count;
}
return -1;
}
static int analyze_chunk(AVFormatContext *s, const uint8_t *chunk)
{
TYDemuxContext *ty = s->priv_data;
int num_recs, i;
TyRecHdr *hdrs;
int num_6e0, num_be0, num_9c0, num_3c0;
/* skip if it's a Part header */
if (AV_RB32(&chunk[0]) == TIVO_PES_FILEID)
return 0;
/* number of records in chunk (we ignore high order byte;
* rarely are there > 256 chunks & we don't need that many anyway) */
num_recs = chunk[0];
if (num_recs < 5) {
/* try again with the next chunk. Sometimes there are dead ones */
return 0;
}
chunk += 4; /* skip past rec count & SEQ bytes */
ff_dlog(s, "probe: chunk has %d recs\n", num_recs);
hdrs = parse_chunk_headers(chunk, num_recs);
if (!hdrs)
return AVERROR(ENOMEM);
/* scan headers.
* 1. check video packets. Presence of 0x6e0 means S1.
* No 6e0 but have be0 means S2.
* 2. probe for audio 0x9c0 vs 0x3c0 (AC3 vs Mpeg)
* If AC-3, then we have DTivo.
* If MPEG, search for PTS offset. This will determine SA vs. DTivo.
*/
num_6e0 = num_be0 = num_9c0 = num_3c0 = 0;
for (i = 0; i < num_recs; i++) {
switch (hdrs[i].subrec_type << 8 | hdrs[i].rec_type) {
case 0x6e0:
num_6e0++;
break;
case 0xbe0:
num_be0++;
break;
case 0x3c0:
num_3c0++;
break;
case 0x9c0:
num_9c0++;
break;
}
}
ff_dlog(s, "probe: chunk has %d 0x6e0 recs, %d 0xbe0 recs.\n",
num_6e0, num_be0);
/* set up our variables */
if (num_6e0 > 0) {
ff_dlog(s, "detected Series 1 Tivo\n");
ty->tivo_series = TIVO_SERIES1;
ty->pes_length = SERIES1_PES_LENGTH;
} else if (num_be0 > 0) {
ff_dlog(s, "detected Series 2 Tivo\n");
ty->tivo_series = TIVO_SERIES2;
ty->pes_length = SERIES2_PES_LENGTH;
}
if (num_9c0 > 0) {
ff_dlog(s, "detected AC-3 Audio (DTivo)\n");
ty->audio_type = TIVO_AUDIO_AC3;
ty->tivo_type = TIVO_TYPE_DTIVO;
ty->pts_offset = AC3_PTS_OFFSET;
ty->pes_length = AC3_PES_LENGTH;
} else if (num_3c0 > 0) {
ty->audio_type = TIVO_AUDIO_MPEG;
ff_dlog(s, "detected MPEG Audio\n");
}
/* if tivo_type still unknown, we can check PTS location
* in MPEG packets to determine tivo_type */
if (ty->tivo_type == TIVO_TYPE_UNKNOWN) {
uint32_t data_offset = 16 * num_recs;
for (i = 0; i < num_recs; i++) {
if (data_offset + hdrs[i].rec_size > CHUNK_SIZE)
break;
if ((hdrs[i].subrec_type << 8 | hdrs[i].rec_type) == 0x3c0 && hdrs[i].rec_size > 15) {
/* first make sure we're aligned */
int pes_offset = find_es_header(ty_MPEGAudioPacket,
&chunk[data_offset], 5);
if (pes_offset >= 0) {
/* pes found. on SA, PES has hdr data at offset 6, not PTS. */
if ((chunk[data_offset + 6 + pes_offset] & 0x80) == 0x80) {
/* S1SA or S2(any) Mpeg Audio (PES hdr, not a PTS start) */
if (ty->tivo_series == TIVO_SERIES1)
ff_dlog(s, "detected Stand-Alone Tivo\n");
ty->tivo_type = TIVO_TYPE_SA;
ty->pts_offset = SA_PTS_OFFSET;
} else {
if (ty->tivo_series == TIVO_SERIES1)
ff_dlog(s, "detected DirecTV Tivo\n");
ty->tivo_type = TIVO_TYPE_DTIVO;
ty->pts_offset = DTIVO_PTS_OFFSET;
}
break;
}
}
data_offset += hdrs[i].rec_size;
}
}
av_free(hdrs);
return 0;
}
static int ty_read_header(AVFormatContext *s)
{
TYDemuxContext *ty = s->priv_data;
AVIOContext *pb = s->pb;
AVStream *st, *ast;
int i, ret = 0;
ty->first_audio_pts = AV_NOPTS_VALUE;
ty->last_audio_pts = AV_NOPTS_VALUE;
ty->last_video_pts = AV_NOPTS_VALUE;
for (i = 0; i < CHUNK_PEEK_COUNT; i++) {
avio_read(pb, ty->chunk, CHUNK_SIZE);
ret = analyze_chunk(s, ty->chunk);
if (ret < 0)
return ret;
if (ty->tivo_series != TIVO_SERIES_UNKNOWN &&
ty->audio_type != TIVO_AUDIO_UNKNOWN &&
ty->tivo_type != TIVO_TYPE_UNKNOWN)
break;
}
if (ty->tivo_series == TIVO_SERIES_UNKNOWN ||
ty->audio_type == TIVO_AUDIO_UNKNOWN ||
ty->tivo_type == TIVO_TYPE_UNKNOWN)
return AVERROR(EIO);
st = avformat_new_stream(s, NULL);
if (!st)
return AVERROR(ENOMEM);
st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
st->codecpar->codec_id = AV_CODEC_ID_MPEG2VIDEO;
ffstream(st)->need_parsing = AVSTREAM_PARSE_FULL_RAW;
avpriv_set_pts_info(st, 64, 1, 90000);
ast = avformat_new_stream(s, NULL);
if (!ast)
return AVERROR(ENOMEM);
ast->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
if (ty->audio_type == TIVO_AUDIO_MPEG) {
ast->codecpar->codec_id = AV_CODEC_ID_MP2;
ffstream(ast)->need_parsing = AVSTREAM_PARSE_FULL_RAW;
} else {
ast->codecpar->codec_id = AV_CODEC_ID_AC3;
}
avpriv_set_pts_info(ast, 64, 1, 90000);
ty->first_chunk = 1;
avio_seek(pb, 0, SEEK_SET);
return 0;
}
static int get_chunk(AVFormatContext *s)
{
TYDemuxContext *ty = s->priv_data;
AVIOContext *pb = s->pb;
int read_size, num_recs;
ff_dlog(s, "parsing ty chunk #%d\n", ty->cur_chunk);
/* if we have left-over filler space from the last chunk, get that */
if (avio_feof(pb))
return AVERROR_EOF;
/* read the TY packet header */
read_size = avio_read(pb, ty->chunk, CHUNK_SIZE);
ty->cur_chunk++;
if ((read_size < 4) || (AV_RB32(ty->chunk) == 0)) {
return AVERROR_EOF;
}
/* check if it's a PART Header */
if (AV_RB32(ty->chunk) == TIVO_PES_FILEID) {
/* skip master chunk and read new chunk */
return get_chunk(s);
}
/* number of records in chunk (8- or 16-bit number) */
if (ty->chunk[3] & 0x80) {
/* 16 bit rec cnt */
ty->num_recs = num_recs = (ty->chunk[1] << 8) + ty->chunk[0];
} else {
/* 8 bit reclen - TiVo 1.3 format */
ty->num_recs = num_recs = ty->chunk[0];
}
ty->cur_rec = 0;
ty->first_chunk = 0;
ff_dlog(s, "chunk has %d records\n", num_recs);
ty->cur_chunk_pos = 4;
av_freep(&ty->rec_hdrs);
if (num_recs * 16 >= CHUNK_SIZE - 4)
return AVERROR_INVALIDDATA;
ty->rec_hdrs = parse_chunk_headers(ty->chunk + 4, num_recs);
if (!ty->rec_hdrs)
return AVERROR(ENOMEM);
ty->cur_chunk_pos += 16 * num_recs;
return 0;
}
static int demux_video(AVFormatContext *s, TyRecHdr *rec_hdr, AVPacket *pkt)
{
TYDemuxContext *ty = s->priv_data;
const int subrec_type = rec_hdr->subrec_type;
const int64_t rec_size = rec_hdr->rec_size;
int es_offset1, ret;
int got_packet = 0;
if (subrec_type != 0x02 && subrec_type != 0x0c &&
subrec_type != 0x08 && rec_size > 4) {
/* get the PTS from this packet if it has one.
* on S1, only 0x06 has PES. On S2, however, most all do.
* Do NOT Pass the PES Header to the MPEG2 codec */
es_offset1 = find_es_header(ty_VideoPacket, ty->chunk + ty->cur_chunk_pos, 5);
if (es_offset1 != -1) {
ty->last_video_pts = ff_parse_pes_pts(
ty->chunk + ty->cur_chunk_pos + es_offset1 + VIDEO_PTS_OFFSET);
if (subrec_type != 0x06) {
/* if we found a PES, and it's not type 6, then we're S2 */
/* The packet will have video data (& other headers) so we
* chop out the PES header and send the rest */
if (rec_size >= VIDEO_PES_LENGTH + es_offset1) {
int size = rec_hdr->rec_size - VIDEO_PES_LENGTH - es_offset1;
ty->cur_chunk_pos += VIDEO_PES_LENGTH + es_offset1;
if ((ret = av_new_packet(pkt, size)) < 0)
return ret;
memcpy(pkt->data, ty->chunk + ty->cur_chunk_pos, size);
ty->cur_chunk_pos += size;
pkt->stream_index = 0;
got_packet = 1;
} else {
ff_dlog(s, "video rec type 0x%02x has short PES"
" (%"PRId64" bytes)\n", subrec_type, rec_size);
/* nuke this block; it's too short, but has PES marker */
ty->cur_chunk_pos += rec_size;
return 0;
}
}
}
}
if (subrec_type == 0x06) {
/* type 6 (S1 DTivo) has no data, so we're done */
ty->cur_chunk_pos += rec_size;
return 0;
}
if (!got_packet) {
if ((ret = av_new_packet(pkt, rec_size)) < 0)
return ret;
memcpy(pkt->data, ty->chunk + ty->cur_chunk_pos, rec_size);
ty->cur_chunk_pos += rec_size;
pkt->stream_index = 0;
got_packet = 1;
}
/* if it's not a continue blk, then set PTS */
if (subrec_type != 0x02) {
if (subrec_type == 0x0c && pkt->size >= 6)
pkt->data[5] |= 0x08;
if (subrec_type == 0x07) {
ty->last_ty_pts = rec_hdr->ty_pts;
} else {
/* yes I know this is a cheap hack. It's the timestamp
used for display and skipping fwd/back, so it
doesn't have to be accurate to the millisecond.
I adjust it here by roughly one 1/30 sec. Yes it
will be slightly off for UK streams, but it's OK.
*/
ty->last_ty_pts += 35000000;
//ty->last_ty_pts += 33366667;
}
/* set PTS for this block before we send */
if (ty->last_video_pts > AV_NOPTS_VALUE) {
pkt->pts = ty->last_video_pts;
/* PTS gets used ONCE.
* Any subsequent frames we get BEFORE next PES
* header will have their PTS computed in the codec */
ty->last_video_pts = AV_NOPTS_VALUE;
}
}
return got_packet;
}
static int check_sync_pes(AVFormatContext *s, AVPacket *pkt,
int32_t offset, int32_t rec_len)
{
TYDemuxContext *ty = s->priv_data;
if (offset < 0 || offset + ty->pes_length > rec_len) {
/* entire PES header not present */
ff_dlog(s, "PES header at %"PRId32" not complete in record. storing.\n", offset);
/* save the partial pes header */
if (offset < 0) {
/* no header found, fake some 00's (this works, believe me) */
memset(ty->pes_buffer, 0, 4);
ty->pes_buf_cnt = 4;
if (rec_len > 4)
ff_dlog(s, "PES header not found in record of %"PRId32" bytes!\n", rec_len);
return -1;
}
/* copy the partial pes header we found */
memcpy(ty->pes_buffer, pkt->data + offset, rec_len - offset);
ty->pes_buf_cnt = rec_len - offset;
if (offset > 0) {
/* PES Header was found, but not complete, so trim the end of this record */
pkt->size -= rec_len - offset;
return 1;
}
return -1; /* partial PES, no audio data */
}
/* full PES header present, extract PTS */
ty->last_audio_pts = ff_parse_pes_pts(&pkt->data[ offset + ty->pts_offset]);
if (ty->first_audio_pts == AV_NOPTS_VALUE)
ty->first_audio_pts = ty->last_audio_pts;
pkt->pts = ty->last_audio_pts;
memmove(pkt->data + offset, pkt->data + offset + ty->pes_length, rec_len - ty->pes_length);
pkt->size -= ty->pes_length;
return 0;
}
static int demux_audio(AVFormatContext *s, TyRecHdr *rec_hdr, AVPacket *pkt)
{
TYDemuxContext *ty = s->priv_data;
const int subrec_type = rec_hdr->subrec_type;
const int64_t rec_size = rec_hdr->rec_size;
int es_offset1, ret;
if (subrec_type == 2) {
int need = 0;
/* SA or DTiVo Audio Data, no PES (continued block)
* ================================================
*/
/* continue PES if previous was incomplete */
if (ty->pes_buf_cnt > 0) {
need = ty->pes_length - ty->pes_buf_cnt;
ff_dlog(s, "continuing PES header\n");
/* do we have enough data to complete? */
if (need >= rec_size) {
/* don't have complete PES hdr; save what we have and return */
memcpy(ty->pes_buffer + ty->pes_buf_cnt, ty->chunk + ty->cur_chunk_pos, rec_size);
ty->cur_chunk_pos += rec_size;
ty->pes_buf_cnt += rec_size;
return 0;
}
/* we have enough; reconstruct this frame with the new hdr */
memcpy(ty->pes_buffer + ty->pes_buf_cnt, ty->chunk + ty->cur_chunk_pos, need);
ty->cur_chunk_pos += need;
/* get the PTS out of this PES header (MPEG or AC3) */
if (ty->audio_type == TIVO_AUDIO_MPEG) {
es_offset1 = find_es_header(ty_MPEGAudioPacket,
ty->pes_buffer, 5);
} else {
es_offset1 = find_es_header(ty_AC3AudioPacket,
ty->pes_buffer, 5);
}
if (es_offset1 < 0) {
ff_dlog(s, "Can't find audio PES header in packet.\n");
} else {
ty->last_audio_pts = ff_parse_pes_pts(
&ty->pes_buffer[es_offset1 + ty->pts_offset]);
pkt->pts = ty->last_audio_pts;
}
ty->pes_buf_cnt = 0;
}
if ((ret = av_new_packet(pkt, rec_size - need)) < 0)
return ret;
memcpy(pkt->data, ty->chunk + ty->cur_chunk_pos, rec_size - need);
ty->cur_chunk_pos += rec_size - need;
pkt->stream_index = 1;
/* S2 DTivo has AC3 packets with 2 padding bytes at end. This is
* not allowed in the AC3 spec and will cause problems. So here
* we try to trim things. */
/* Also, S1 DTivo has alternating short / long AC3 packets. That
* is, one packet is short (incomplete) and the next packet has
* the first one's missing data, plus all of its own. Strange. */
if (ty->audio_type == TIVO_AUDIO_AC3 &&
ty->tivo_series == TIVO_SERIES2) {
if (ty->ac3_pkt_size + pkt->size > AC3_PKT_LENGTH) {
pkt->size -= 2;
ty->ac3_pkt_size = 0;
} else {
ty->ac3_pkt_size += pkt->size;
}
}
} else if (subrec_type == 0x03) {
if ((ret = av_new_packet(pkt, rec_size)) < 0)
return ret;
memcpy(pkt->data, ty->chunk + ty->cur_chunk_pos, rec_size);
ty->cur_chunk_pos += rec_size;
pkt->stream_index = 1;
/* MPEG Audio with PES Header, either SA or DTiVo */
/* ================================================ */
es_offset1 = find_es_header(ty_MPEGAudioPacket, pkt->data, 5);
/* SA PES Header, No Audio Data */
/* ================================================ */
if ((es_offset1 == 0) && (rec_size == 16)) {
ty->last_audio_pts = ff_parse_pes_pts(&pkt->data[SA_PTS_OFFSET]);
if (ty->first_audio_pts == AV_NOPTS_VALUE)
ty->first_audio_pts = ty->last_audio_pts;
av_packet_unref(pkt);
return 0;
}
/* DTiVo Audio with PES Header */
/* ================================================ */
/* Check for complete PES */
if (check_sync_pes(s, pkt, es_offset1, rec_size) == -1) {
/* partial PES header found, nothing else.
* we're done. */
av_packet_unref(pkt);
return 0;
}
} else if (subrec_type == 0x04) {
/* SA Audio with no PES Header */
/* ================================================ */
if ((ret = av_new_packet(pkt, rec_size)) < 0)
return ret;
memcpy(pkt->data, ty->chunk + ty->cur_chunk_pos, rec_size);
ty->cur_chunk_pos += rec_size;
pkt->stream_index = 1;
pkt->pts = ty->last_audio_pts;
} else if (subrec_type == 0x09) {
if ((ret = av_new_packet(pkt, rec_size)) < 0)
return ret;
memcpy(pkt->data, ty->chunk + ty->cur_chunk_pos, rec_size);
ty->cur_chunk_pos += rec_size ;
pkt->stream_index = 1;
/* DTiVo AC3 Audio Data with PES Header */
/* ================================================ */
es_offset1 = find_es_header(ty_AC3AudioPacket, pkt->data, 5);
/* Check for complete PES */
if (check_sync_pes(s, pkt, es_offset1, rec_size) == -1) {
/* partial PES header found, nothing else. we're done. */
av_packet_unref(pkt);
return 0;
}
/* S2 DTivo has invalid long AC3 packets */
if (ty->tivo_series == TIVO_SERIES2) {
if (pkt->size > AC3_PKT_LENGTH) {
pkt->size -= 2;
ty->ac3_pkt_size = 0;
} else {
ty->ac3_pkt_size = pkt->size;
}
}
} else {
/* Unsupported/Unknown */
ty->cur_chunk_pos += rec_size;
return 0;
}
return 1;
}
static int ty_read_packet(AVFormatContext *s, AVPacket *pkt)
{
TYDemuxContext *ty = s->priv_data;
AVIOContext *pb = s->pb;
TyRecHdr *rec;
int64_t rec_size = 0;
int ret = 0;
if (avio_feof(pb))
return AVERROR_EOF;
while (ret <= 0) {
if (!ty->rec_hdrs || ty->first_chunk || ty->cur_rec >= ty->num_recs) {
if (get_chunk(s) < 0 || ty->num_recs <= 0)
return AVERROR_EOF;
}
rec = &ty->rec_hdrs[ty->cur_rec];
rec_size = rec->rec_size;
ty->cur_rec++;
if (rec_size <= 0)
continue;
if (ty->cur_chunk_pos + rec->rec_size > CHUNK_SIZE)
return AVERROR_INVALIDDATA;
if (avio_feof(pb))
return AVERROR_EOF;
switch (rec->rec_type) {
case VIDEO_ID:
ret = demux_video(s, rec, pkt);
break;
case AUDIO_ID:
ret = demux_audio(s, rec, pkt);
break;
default:
ff_dlog(s, "Invalid record type 0x%02x\n", rec->rec_type);
case 0x01:
case 0x02:
case 0x03: /* TiVo data services */
case 0x05: /* unknown, but seen regularly */
ty->cur_chunk_pos += rec->rec_size;
break;
}
}
return 0;
}
static int ty_read_close(AVFormatContext *s)
{
TYDemuxContext *ty = s->priv_data;
av_freep(&ty->rec_hdrs);
return 0;
}
const FFInputFormat ff_ty_demuxer = {
.p.name = "ty",
.p.long_name = NULL_IF_CONFIG_SMALL("TiVo TY Stream"),
.p.extensions = "ty,ty+",
.p.flags = AVFMT_TS_DISCONT,
.priv_data_size = sizeof(TYDemuxContext),
.read_probe = ty_probe,
.read_header = ty_read_header,
.read_packet = ty_read_packet,
.read_close = ty_read_close,
};
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