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239 lines
7.5 KiB
C
239 lines
7.5 KiB
C
/*
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* TechnoTrend PVA (.pva) demuxer
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* Copyright (c) 2007, 2008 Ivo van Poorten
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "avformat.h"
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#include "internal.h"
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#include "mpeg.h"
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#define PVA_MAX_PAYLOAD_LENGTH 0x17f8
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#define PVA_VIDEO_PAYLOAD 0x01
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#define PVA_AUDIO_PAYLOAD 0x02
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#define PVA_MAGIC (('A' << 8) + 'V')
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typedef struct PVAContext {
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int continue_pes;
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} PVAContext;
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static int pva_check(const uint8_t *p) {
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int length = AV_RB16(p + 6);
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if (AV_RB16(p) != PVA_MAGIC || !p[2] || p[2] > 2 || p[4] != 0x55 ||
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(p[5] & 0xe0) || length > PVA_MAX_PAYLOAD_LENGTH)
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return -1;
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return length + 8;
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}
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static int pva_probe(const AVProbeData * pd) {
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const unsigned char *buf = pd->buf;
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int len = pva_check(buf);
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if (len < 0)
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return 0;
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if (pd->buf_size >= len + 8 &&
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pva_check(buf + len) >= 0)
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return AVPROBE_SCORE_EXTENSION;
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return AVPROBE_SCORE_MAX / 4;
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}
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static int pva_read_header(AVFormatContext *s) {
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AVStream *st;
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if (!(st = avformat_new_stream(s, NULL)))
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return AVERROR(ENOMEM);
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st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
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st->codecpar->codec_id = AV_CODEC_ID_MPEG2VIDEO;
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st->need_parsing = AVSTREAM_PARSE_FULL;
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avpriv_set_pts_info(st, 32, 1, 90000);
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av_add_index_entry(st, 0, 0, 0, 0, AVINDEX_KEYFRAME);
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if (!(st = avformat_new_stream(s, NULL)))
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return AVERROR(ENOMEM);
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st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
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st->codecpar->codec_id = AV_CODEC_ID_MP2;
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st->need_parsing = AVSTREAM_PARSE_FULL;
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avpriv_set_pts_info(st, 33, 1, 90000);
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av_add_index_entry(st, 0, 0, 0, 0, AVINDEX_KEYFRAME);
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/* the parameters will be extracted from the compressed bitstream */
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return 0;
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}
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#define pva_log if (read_packet) av_log
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static int read_part_of_packet(AVFormatContext *s, int64_t *pts,
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int *len, int *strid, int read_packet) {
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AVIOContext *pb = s->pb;
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PVAContext *pvactx = s->priv_data;
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int syncword, streamid, reserved, flags, length, pts_flag;
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int64_t pva_pts = AV_NOPTS_VALUE, startpos;
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int ret;
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recover:
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startpos = avio_tell(pb);
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syncword = avio_rb16(pb);
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streamid = avio_r8(pb);
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avio_r8(pb); /* counter not used */
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reserved = avio_r8(pb);
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flags = avio_r8(pb);
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length = avio_rb16(pb);
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pts_flag = flags & 0x10;
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if (syncword != PVA_MAGIC) {
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pva_log(s, AV_LOG_ERROR, "invalid syncword\n");
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return AVERROR(EIO);
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}
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if (streamid != PVA_VIDEO_PAYLOAD && streamid != PVA_AUDIO_PAYLOAD) {
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pva_log(s, AV_LOG_ERROR, "invalid streamid\n");
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return AVERROR(EIO);
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}
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if (reserved != 0x55) {
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pva_log(s, AV_LOG_WARNING, "expected reserved byte to be 0x55\n");
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}
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if (length > PVA_MAX_PAYLOAD_LENGTH) {
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pva_log(s, AV_LOG_ERROR, "invalid payload length %u\n", length);
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return AVERROR(EIO);
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}
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if (streamid == PVA_VIDEO_PAYLOAD && pts_flag) {
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pva_pts = avio_rb32(pb);
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length -= 4;
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} else if (streamid == PVA_AUDIO_PAYLOAD) {
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/* PVA Audio Packets either start with a signaled PES packet or
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* are a continuation of the previous PES packet. New PES packets
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* always start at the beginning of a PVA Packet, never somewhere in
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* the middle. */
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if (!pvactx->continue_pes) {
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int pes_signal, pes_header_data_length, pes_packet_length,
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pes_flags;
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unsigned char pes_header_data[256];
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pes_signal = avio_rb24(pb);
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avio_r8(pb);
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pes_packet_length = avio_rb16(pb);
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pes_flags = avio_rb16(pb);
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pes_header_data_length = avio_r8(pb);
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if (avio_feof(pb)) {
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return AVERROR_EOF;
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}
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if (pes_signal != 1 || pes_header_data_length == 0) {
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pva_log(s, AV_LOG_WARNING, "expected non empty signaled PES packet, "
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"trying to recover\n");
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avio_skip(pb, length - 9);
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if (!read_packet)
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return AVERROR(EIO);
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goto recover;
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}
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ret = avio_read(pb, pes_header_data, pes_header_data_length);
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if (ret != pes_header_data_length)
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return ret < 0 ? ret : AVERROR_INVALIDDATA;
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length -= 9 + pes_header_data_length;
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pes_packet_length -= 3 + pes_header_data_length;
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pvactx->continue_pes = pes_packet_length;
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if (pes_flags & 0x80 && (pes_header_data[0] & 0xf0) == 0x20) {
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if (pes_header_data_length < 5) {
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pva_log(s, AV_LOG_ERROR, "header too short\n");
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avio_skip(pb, length);
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return AVERROR_INVALIDDATA;
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}
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pva_pts = ff_parse_pes_pts(pes_header_data);
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}
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}
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pvactx->continue_pes -= length;
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if (pvactx->continue_pes < 0) {
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pva_log(s, AV_LOG_WARNING, "audio data corruption\n");
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pvactx->continue_pes = 0;
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}
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}
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if (pva_pts != AV_NOPTS_VALUE)
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av_add_index_entry(s->streams[streamid-1], startpos, pva_pts, 0, 0, AVINDEX_KEYFRAME);
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*pts = pva_pts;
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*len = length;
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*strid = streamid;
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return 0;
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}
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static int pva_read_packet(AVFormatContext *s, AVPacket *pkt) {
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AVIOContext *pb = s->pb;
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int64_t pva_pts;
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int ret, length, streamid;
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if (read_part_of_packet(s, &pva_pts, &length, &streamid, 1) < 0 ||
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(ret = av_get_packet(pb, pkt, length)) <= 0)
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return AVERROR(EIO);
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pkt->stream_index = streamid - 1;
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pkt->pts = pva_pts;
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return ret;
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}
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static int64_t pva_read_timestamp(struct AVFormatContext *s, int stream_index,
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int64_t *pos, int64_t pos_limit) {
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AVIOContext *pb = s->pb;
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PVAContext *pvactx = s->priv_data;
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int length, streamid;
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int64_t res = AV_NOPTS_VALUE;
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pos_limit = FFMIN(*pos+PVA_MAX_PAYLOAD_LENGTH*8, (uint64_t)*pos+pos_limit);
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while (*pos < pos_limit) {
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res = AV_NOPTS_VALUE;
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avio_seek(pb, *pos, SEEK_SET);
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pvactx->continue_pes = 0;
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if (read_part_of_packet(s, &res, &length, &streamid, 0)) {
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(*pos)++;
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continue;
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}
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if (streamid - 1 != stream_index || res == AV_NOPTS_VALUE) {
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*pos = avio_tell(pb) + length;
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continue;
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}
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break;
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}
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pvactx->continue_pes = 0;
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return res;
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}
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AVInputFormat ff_pva_demuxer = {
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.name = "pva",
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.long_name = NULL_IF_CONFIG_SMALL("TechnoTrend PVA"),
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.priv_data_size = sizeof(PVAContext),
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.read_probe = pva_probe,
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.read_header = pva_read_header,
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.read_packet = pva_read_packet,
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.read_timestamp = pva_read_timestamp,
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};
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