1/* 2 * TechnoTrend PVA (.pva) demuxer 3 * Copyright (c) 2007, 2008 Ivo van Poorten 4 * 5 * This file is part of FFmpeg. 6 * 7 * FFmpeg 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 * FFmpeg 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 FFmpeg; 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_check(const uint8_t *p) { 36 int length = AV_RB16(p + 6); 37 if (AV_RB16(p) != PVA_MAGIC || !p[2] || p[2] > 2 || p[4] != 0x55 || 38 (p[5] & 0xe0) || length > PVA_MAX_PAYLOAD_LENGTH) 39 return -1; 40 return length + 8; 41} 42 43static int pva_probe(AVProbeData * pd) { 44 const unsigned char *buf = pd->buf; 45 int len = pva_check(buf); 46 47 if (len < 0) 48 return 0; 49 50 if (pd->buf_size >= len + 8 && 51 pva_check(buf + len) >= 0) 52 return AVPROBE_SCORE_EXTENSION; 53 54 return AVPROBE_SCORE_MAX / 4; 55} 56 57static int pva_read_header(AVFormatContext *s) { 58 AVStream *st; 59 60 if (!(st = avformat_new_stream(s, NULL))) 61 return AVERROR(ENOMEM); 62 st->codec->codec_type = AVMEDIA_TYPE_VIDEO; 63 st->codec->codec_id = AV_CODEC_ID_MPEG2VIDEO; 64 st->need_parsing = AVSTREAM_PARSE_FULL; 65 avpriv_set_pts_info(st, 32, 1, 90000); 66 av_add_index_entry(st, 0, 0, 0, 0, AVINDEX_KEYFRAME); 67 68 if (!(st = avformat_new_stream(s, NULL))) 69 return AVERROR(ENOMEM); 70 st->codec->codec_type = AVMEDIA_TYPE_AUDIO; 71 st->codec->codec_id = AV_CODEC_ID_MP2; 72 st->need_parsing = AVSTREAM_PARSE_FULL; 73 avpriv_set_pts_info(st, 33, 1, 90000); 74 av_add_index_entry(st, 0, 0, 0, 0, AVINDEX_KEYFRAME); 75 76 /* the parameters will be extracted from the compressed bitstream */ 77 return 0; 78} 79 80#define pva_log if (read_packet) av_log 81 82static int read_part_of_packet(AVFormatContext *s, int64_t *pts, 83 int *len, int *strid, int read_packet) { 84 AVIOContext *pb = s->pb; 85 PVAContext *pvactx = s->priv_data; 86 int syncword, streamid, reserved, flags, length, pts_flag; 87 int64_t pva_pts = AV_NOPTS_VALUE, startpos; 88 int ret; 89 90recover: 91 startpos = avio_tell(pb); 92 93 syncword = avio_rb16(pb); 94 streamid = avio_r8(pb); 95 avio_r8(pb); /* counter not used */ 96 reserved = avio_r8(pb); 97 flags = avio_r8(pb); 98 length = avio_rb16(pb); 99 100 pts_flag = flags & 0x10; 101 102 if (syncword != PVA_MAGIC) { 103 pva_log(s, AV_LOG_ERROR, "invalid syncword\n"); 104 return AVERROR(EIO); 105 } 106 if (streamid != PVA_VIDEO_PAYLOAD && streamid != PVA_AUDIO_PAYLOAD) { 107 pva_log(s, AV_LOG_ERROR, "invalid streamid\n"); 108 return AVERROR(EIO); 109 } 110 if (reserved != 0x55) { 111 pva_log(s, AV_LOG_WARNING, "expected reserved byte to be 0x55\n"); 112 } 113 if (length > PVA_MAX_PAYLOAD_LENGTH) { 114 pva_log(s, AV_LOG_ERROR, "invalid payload length %u\n", length); 115 return AVERROR(EIO); 116 } 117 118 if (streamid == PVA_VIDEO_PAYLOAD && pts_flag) { 119 pva_pts = avio_rb32(pb); 120 length -= 4; 121 } else if (streamid == PVA_AUDIO_PAYLOAD) { 122 /* PVA Audio Packets either start with a signaled PES packet or 123 * are a continuation of the previous PES packet. New PES packets 124 * always start at the beginning of a PVA Packet, never somewhere in 125 * the middle. */ 126 if (!pvactx->continue_pes) { 127 int pes_signal, pes_header_data_length, pes_packet_length, 128 pes_flags; 129 unsigned char pes_header_data[256]; 130 131 pes_signal = avio_rb24(pb); 132 avio_r8(pb); 133 pes_packet_length = avio_rb16(pb); 134 pes_flags = avio_rb16(pb); 135 pes_header_data_length = avio_r8(pb); 136 137 if (pes_signal != 1 || pes_header_data_length == 0) { 138 pva_log(s, AV_LOG_WARNING, "expected non empty signaled PES packet, " 139 "trying to recover\n"); 140 avio_skip(pb, length - 9); 141 if (!read_packet) 142 return AVERROR(EIO); 143 goto recover; 144 } 145 146 ret = avio_read(pb, pes_header_data, pes_header_data_length); 147 if (ret != pes_header_data_length) 148 return ret < 0 ? ret : AVERROR_INVALIDDATA; 149 length -= 9 + pes_header_data_length; 150 151 pes_packet_length -= 3 + pes_header_data_length; 152 153 pvactx->continue_pes = pes_packet_length; 154 155 if (pes_flags & 0x80 && (pes_header_data[0] & 0xf0) == 0x20) { 156 if (pes_header_data_length < 5) { 157 pva_log(s, AV_LOG_ERROR, "header too short\n"); 158 avio_skip(pb, length); 159 return AVERROR_INVALIDDATA; 160 } 161 pva_pts = ff_parse_pes_pts(pes_header_data); 162 } 163 } 164 165 pvactx->continue_pes -= length; 166 167 if (pvactx->continue_pes < 0) { 168 pva_log(s, AV_LOG_WARNING, "audio data corruption\n"); 169 pvactx->continue_pes = 0; 170 } 171 } 172 173 if (pva_pts != AV_NOPTS_VALUE) 174 av_add_index_entry(s->streams[streamid-1], startpos, pva_pts, 0, 0, AVINDEX_KEYFRAME); 175 176 *pts = pva_pts; 177 *len = length; 178 *strid = streamid; 179 return 0; 180} 181 182static int pva_read_packet(AVFormatContext *s, AVPacket *pkt) { 183 AVIOContext *pb = s->pb; 184 int64_t pva_pts; 185 int ret, length, streamid; 186 187 if (read_part_of_packet(s, &pva_pts, &length, &streamid, 1) < 0 || 188 (ret = av_get_packet(pb, pkt, length)) <= 0) 189 return AVERROR(EIO); 190 191 pkt->stream_index = streamid - 1; 192 pkt->pts = pva_pts; 193 194 return ret; 195} 196 197static int64_t pva_read_timestamp(struct AVFormatContext *s, int stream_index, 198 int64_t *pos, int64_t pos_limit) { 199 AVIOContext *pb = s->pb; 200 PVAContext *pvactx = s->priv_data; 201 int length, streamid; 202 int64_t res = AV_NOPTS_VALUE; 203 204 pos_limit = FFMIN(*pos+PVA_MAX_PAYLOAD_LENGTH*8, (uint64_t)*pos+pos_limit); 205 206 while (*pos < pos_limit) { 207 res = AV_NOPTS_VALUE; 208 avio_seek(pb, *pos, SEEK_SET); 209 210 pvactx->continue_pes = 0; 211 if (read_part_of_packet(s, &res, &length, &streamid, 0)) { 212 (*pos)++; 213 continue; 214 } 215 if (streamid - 1 != stream_index || res == AV_NOPTS_VALUE) { 216 *pos = avio_tell(pb) + length; 217 continue; 218 } 219 break; 220 } 221 222 pvactx->continue_pes = 0; 223 return res; 224} 225 226AVInputFormat ff_pva_demuxer = { 227 .name = "pva", 228 .long_name = NULL_IF_CONFIG_SMALL("TechnoTrend PVA"), 229 .priv_data_size = sizeof(PVAContext), 230 .read_probe = pva_probe, 231 .read_header = pva_read_header, 232 .read_packet = pva_read_packet, 233 .read_timestamp = pva_read_timestamp, 234}; 235