| 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 | |
| 31 | typedef struct { |
| 32 | int continue_pes; |
| 33 | } PVAContext; |
| 34 | |
| 35 | static 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 | |
| 43 | static 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 | |
| 57 | static 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 | |
| 82 | static 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 | |
| 90 | recover: |
| 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 | |
| 182 | static 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 | |
| 197 | static 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 | |
| 226 | AVInputFormat 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 | }; |