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ffmpeg/libavformat/pva.c

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/*
* TechnoTrend PVA (.pva) demuxer
* Copyright (c) 2007, 2008 Ivo van Poorten
*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "avformat.h"
#include "internal.h"
#include "mpeg.h"
#define PVA_MAX_PAYLOAD_LENGTH 0x17f8
#define PVA_VIDEO_PAYLOAD 0x01
#define PVA_AUDIO_PAYLOAD 0x02
#define PVA_MAGIC (('A' << 8) + 'V')
typedef struct {
int continue_pes;
} PVAContext;
static int pva_probe(AVProbeData * pd) {
unsigned char *buf = pd->buf;
if (AV_RB16(buf) == PVA_MAGIC && buf[2] && buf[2] < 3 && buf[4] == 0x55)
return AVPROBE_SCORE_MAX / 2;
return 0;
}
static int pva_read_header(AVFormatContext *s) {
AVStream *st;
if (!(st = avformat_new_stream(s, NULL)))
return AVERROR(ENOMEM);
st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
st->codec->codec_id = AV_CODEC_ID_MPEG2VIDEO;
st->need_parsing = AVSTREAM_PARSE_FULL;
avpriv_set_pts_info(st, 32, 1, 90000);
av_add_index_entry(st, 0, 0, 0, 0, AVINDEX_KEYFRAME);
if (!(st = avformat_new_stream(s, NULL)))
return AVERROR(ENOMEM);
st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
st->codec->codec_id = AV_CODEC_ID_MP2;
st->need_parsing = AVSTREAM_PARSE_FULL;
avpriv_set_pts_info(st, 33, 1, 90000);
av_add_index_entry(st, 0, 0, 0, 0, AVINDEX_KEYFRAME);
/* the parameters will be extracted from the compressed bitstream */
return 0;
}
#define pva_log if (read_packet) av_log
static int read_part_of_packet(AVFormatContext *s, int64_t *pts,
int *len, int *strid, int read_packet) {
AVIOContext *pb = s->pb;
PVAContext *pvactx = s->priv_data;
int syncword, streamid, reserved, flags, length, pts_flag;
int64_t pva_pts = AV_NOPTS_VALUE, startpos;
recover:
startpos = avio_tell(pb);
syncword = avio_rb16(pb);
streamid = avio_r8(pb);
avio_r8(pb); /* counter not used */
reserved = avio_r8(pb);
flags = avio_r8(pb);
length = avio_rb16(pb);
pts_flag = flags & 0x10;
if (syncword != PVA_MAGIC) {
pva_log(s, AV_LOG_ERROR, "invalid syncword\n");
return AVERROR(EIO);
}
if (streamid != PVA_VIDEO_PAYLOAD && streamid != PVA_AUDIO_PAYLOAD) {
pva_log(s, AV_LOG_ERROR, "invalid streamid\n");
return AVERROR(EIO);
}
if (reserved != 0x55) {
pva_log(s, AV_LOG_WARNING, "expected reserved byte to be 0x55\n");
}
if (length > PVA_MAX_PAYLOAD_LENGTH) {
pva_log(s, AV_LOG_ERROR, "invalid payload length %u\n", length);
return AVERROR(EIO);
}
if (streamid == PVA_VIDEO_PAYLOAD && pts_flag) {
pva_pts = avio_rb32(pb);
length -= 4;
} else if (streamid == PVA_AUDIO_PAYLOAD) {
/* PVA Audio Packets either start with a signaled PES packet or
* are a continuation of the previous PES packet. New PES packets
* always start at the beginning of a PVA Packet, never somewhere in
* the middle. */
if (!pvactx->continue_pes) {
int pes_signal, pes_header_data_length, pes_packet_length,
pes_flags;
unsigned char pes_header_data[256];
pes_signal = avio_rb24(pb);
avio_r8(pb);
pes_packet_length = avio_rb16(pb);
pes_flags = avio_rb16(pb);
pes_header_data_length = avio_r8(pb);
if (pes_signal != 1) {
pva_log(s, AV_LOG_WARNING, "expected signaled PES packet, "
"trying to recover\n");
avio_skip(pb, length - 9);
if (!read_packet)
return AVERROR(EIO);
goto recover;
}
avio_read(pb, pes_header_data, pes_header_data_length);
length -= 9 + pes_header_data_length;
pes_packet_length -= 3 + pes_header_data_length;
pvactx->continue_pes = pes_packet_length;
if (pes_flags & 0x80 && (pes_header_data[0] & 0xf0) == 0x20)
pva_pts = ff_parse_pes_pts(pes_header_data);
}
pvactx->continue_pes -= length;
if (pvactx->continue_pes < 0) {
pva_log(s, AV_LOG_WARNING, "audio data corruption\n");
pvactx->continue_pes = 0;
}
}
if (pva_pts != AV_NOPTS_VALUE)
av_add_index_entry(s->streams[streamid-1], startpos, pva_pts, 0, 0, AVINDEX_KEYFRAME);
*pts = pva_pts;
*len = length;
*strid = streamid;
return 0;
}
static int pva_read_packet(AVFormatContext *s, AVPacket *pkt) {
AVIOContext *pb = s->pb;
int64_t pva_pts;
int ret, length, streamid;
if (read_part_of_packet(s, &pva_pts, &length, &streamid, 1) < 0 ||
(ret = av_get_packet(pb, pkt, length)) <= 0)
return AVERROR(EIO);
pkt->stream_index = streamid - 1;
pkt->pts = pva_pts;
return ret;
}
static int64_t pva_read_timestamp(struct AVFormatContext *s, int stream_index,
int64_t *pos, int64_t pos_limit) {
AVIOContext *pb = s->pb;
PVAContext *pvactx = s->priv_data;
int length, streamid;
int64_t res = AV_NOPTS_VALUE;
pos_limit = FFMIN(*pos+PVA_MAX_PAYLOAD_LENGTH*8, (uint64_t)*pos+pos_limit);
while (*pos < pos_limit) {
res = AV_NOPTS_VALUE;
avio_seek(pb, *pos, SEEK_SET);
pvactx->continue_pes = 0;
if (read_part_of_packet(s, &res, &length, &streamid, 0)) {
(*pos)++;
continue;
}
if (streamid - 1 != stream_index || res == AV_NOPTS_VALUE) {
*pos = avio_tell(pb) + length;
continue;
}
break;
}
pvactx->continue_pes = 0;
return res;
}
AVInputFormat ff_pva_demuxer = {
.name = "pva",
.long_name = NULL_IF_CONFIG_SMALL("TechnoTrend PVA"),
.priv_data_size = sizeof(PVAContext),
.read_probe = pva_probe,
.read_header = pva_read_header,
.read_packet = pva_read_packet,
.read_timestamp = pva_read_timestamp,
};
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