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- /*
- * TechnoTrend PVA (.pva) demuxer
- * Copyright (c) 2007, 2008 Ivo van Poorten
- *
- * 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 "avformat.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, AVFormatParameters *ap) {
- AVStream *st;
- if (!(st = av_new_stream(s, 0)))
- return AVERROR(ENOMEM);
- st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
- st->codec->codec_id = CODEC_ID_MPEG2VIDEO;
- st->need_parsing = AVSTREAM_PARSE_FULL;
- av_set_pts_info(st, 32, 1, 90000);
- av_add_index_entry(st, 0, 0, 0, 0, AVINDEX_KEYFRAME);
- if (!(st = av_new_stream(s, 1)))
- return AVERROR(ENOMEM);
- st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
- st->codec->codec_id = CODEC_ID_MP2;
- st->need_parsing = AVSTREAM_PARSE_FULL;
- av_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 file and stream format"),
- .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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