1/* 2 * TechnoTrend PVA (.pva) demuxer 3 * Copyright (c) 2007, 2008 Ivo van Poorten 4 * 5 * This file is part of Libav. 6 * 7 * Libav is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU Lesser General Public 9 * License as published by the Free Software Foundation; either 10 * version 2.1 of the License, or (at your option) any later version. 11 * 12 * Libav is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 * Lesser General Public License for more details. 16 * 17 * You should have received a copy of the GNU Lesser General Public 18 * License along with Libav; if not, write to the Free Software 19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 20 */ 21 22#include "avformat.h" 23#include "internal.h" 24#include "mpeg.h" 25 26#define PVA_MAX_PAYLOAD_LENGTH 0x17f8 27#define PVA_VIDEO_PAYLOAD 0x01 28#define PVA_AUDIO_PAYLOAD 0x02 29#define PVA_MAGIC (('A' << 8) + 'V') 30 31typedef struct { 32 int continue_pes; 33} PVAContext; 34 35static int pva_probe(AVProbeData * pd) { 36 unsigned char *buf = pd->buf; 37 38 if (AV_RB16(buf) == PVA_MAGIC && buf[2] && buf[2] < 3 && buf[4] == 0x55) 39 return AVPROBE_SCORE_MAX / 2; 40 41 return 0; 42} 43 44static int pva_read_header(AVFormatContext *s, AVFormatParameters *ap) { 45 AVStream *st; 46 47 if (!(st = avformat_new_stream(s, NULL))) 48 return AVERROR(ENOMEM); 49 st->codec->codec_type = AVMEDIA_TYPE_VIDEO; 50 st->codec->codec_id = CODEC_ID_MPEG2VIDEO; 51 st->need_parsing = AVSTREAM_PARSE_FULL; 52 avpriv_set_pts_info(st, 32, 1, 90000); 53 av_add_index_entry(st, 0, 0, 0, 0, AVINDEX_KEYFRAME); 54 55 if (!(st = avformat_new_stream(s, NULL))) 56 return AVERROR(ENOMEM); 57 st->codec->codec_type = AVMEDIA_TYPE_AUDIO; 58 st->codec->codec_id = CODEC_ID_MP2; 59 st->need_parsing = AVSTREAM_PARSE_FULL; 60 avpriv_set_pts_info(st, 33, 1, 90000); 61 av_add_index_entry(st, 0, 0, 0, 0, AVINDEX_KEYFRAME); 62 63 /* the parameters will be extracted from the compressed bitstream */ 64 return 0; 65} 66 67#define pva_log if (read_packet) av_log 68 69static int read_part_of_packet(AVFormatContext *s, int64_t *pts, 70 int *len, int *strid, int read_packet) { 71 AVIOContext *pb = s->pb; 72 PVAContext *pvactx = s->priv_data; 73 int syncword, streamid, reserved, flags, length, pts_flag; 74 int64_t pva_pts = AV_NOPTS_VALUE, startpos; 75 76recover: 77 startpos = avio_tell(pb); 78 79 syncword = avio_rb16(pb); 80 streamid = avio_r8(pb); 81 avio_r8(pb); /* counter not used */ 82 reserved = avio_r8(pb); 83 flags = avio_r8(pb); 84 length = avio_rb16(pb); 85 86 pts_flag = flags & 0x10; 87 88 if (syncword != PVA_MAGIC) { 89 pva_log(s, AV_LOG_ERROR, "invalid syncword\n"); 90 return AVERROR(EIO); 91 } 92 if (streamid != PVA_VIDEO_PAYLOAD && streamid != PVA_AUDIO_PAYLOAD) { 93 pva_log(s, AV_LOG_ERROR, "invalid streamid\n"); 94 return AVERROR(EIO); 95 } 96 if (reserved != 0x55) { 97 pva_log(s, AV_LOG_WARNING, "expected reserved byte to be 0x55\n"); 98 } 99 if (length > PVA_MAX_PAYLOAD_LENGTH) { 100 pva_log(s, AV_LOG_ERROR, "invalid payload length %u\n", length); 101 return AVERROR(EIO); 102 } 103 104 if (streamid == PVA_VIDEO_PAYLOAD && pts_flag) { 105 pva_pts = avio_rb32(pb); 106 length -= 4; 107 } else if (streamid == PVA_AUDIO_PAYLOAD) { 108 /* PVA Audio Packets either start with a signaled PES packet or 109 * are a continuation of the previous PES packet. New PES packets 110 * always start at the beginning of a PVA Packet, never somewhere in 111 * the middle. */ 112 if (!pvactx->continue_pes) { 113 int pes_signal, pes_header_data_length, pes_packet_length, 114 pes_flags; 115 unsigned char pes_header_data[256]; 116 117 pes_signal = avio_rb24(pb); 118 avio_r8(pb); 119 pes_packet_length = avio_rb16(pb); 120 pes_flags = avio_rb16(pb); 121 pes_header_data_length = avio_r8(pb); 122 123 if (pes_signal != 1) { 124 pva_log(s, AV_LOG_WARNING, "expected signaled PES packet, " 125 "trying to recover\n"); 126 avio_skip(pb, length - 9); 127 if (!read_packet) 128 return AVERROR(EIO); 129 goto recover; 130 } 131 132 avio_read(pb, pes_header_data, pes_header_data_length); 133 length -= 9 + pes_header_data_length; 134 135 pes_packet_length -= 3 + pes_header_data_length; 136 137 pvactx->continue_pes = pes_packet_length; 138 139 if (pes_flags & 0x80 && (pes_header_data[0] & 0xf0) == 0x20) 140 pva_pts = ff_parse_pes_pts(pes_header_data); 141 } 142 143 pvactx->continue_pes -= length; 144 145 if (pvactx->continue_pes < 0) { 146 pva_log(s, AV_LOG_WARNING, "audio data corruption\n"); 147 pvactx->continue_pes = 0; 148 } 149 } 150 151 if (pva_pts != AV_NOPTS_VALUE) 152 av_add_index_entry(s->streams[streamid-1], startpos, pva_pts, 0, 0, AVINDEX_KEYFRAME); 153 154 *pts = pva_pts; 155 *len = length; 156 *strid = streamid; 157 return 0; 158} 159 160static int pva_read_packet(AVFormatContext *s, AVPacket *pkt) { 161 AVIOContext *pb = s->pb; 162 int64_t pva_pts; 163 int ret, length, streamid; 164 165 if (read_part_of_packet(s, &pva_pts, &length, &streamid, 1) < 0 || 166 (ret = av_get_packet(pb, pkt, length)) <= 0) 167 return AVERROR(EIO); 168 169 pkt->stream_index = streamid - 1; 170 pkt->pts = pva_pts; 171 172 return ret; 173} 174 175static int64_t pva_read_timestamp(struct AVFormatContext *s, int stream_index, 176 int64_t *pos, int64_t pos_limit) { 177 AVIOContext *pb = s->pb; 178 PVAContext *pvactx = s->priv_data; 179 int length, streamid; 180 int64_t res = AV_NOPTS_VALUE; 181 182 pos_limit = FFMIN(*pos+PVA_MAX_PAYLOAD_LENGTH*8, (uint64_t)*pos+pos_limit); 183 184 while (*pos < pos_limit) { 185 res = AV_NOPTS_VALUE; 186 avio_seek(pb, *pos, SEEK_SET); 187 188 pvactx->continue_pes = 0; 189 if (read_part_of_packet(s, &res, &length, &streamid, 0)) { 190 (*pos)++; 191 continue; 192 } 193 if (streamid - 1 != stream_index || res == AV_NOPTS_VALUE) { 194 *pos = avio_tell(pb) + length; 195 continue; 196 } 197 break; 198 } 199 200 pvactx->continue_pes = 0; 201 return res; 202} 203 204AVInputFormat ff_pva_demuxer = { 205 .name = "pva", 206 .long_name = NULL_IF_CONFIG_SMALL("TechnoTrend PVA file and stream format"), 207 .priv_data_size = sizeof(PVAContext), 208 .read_probe = pva_probe, 209 .read_header = pva_read_header, 210 .read_packet = pva_read_packet, 211 .read_timestamp = pva_read_timestamp 212}; 213