libavformat/pva.c

   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
  31 typedef struct {
  32     int continue_pes;
  33 } PVAContext;
  34
  35 static 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
  44 static int pva_read_header(AVFormatContext *s) {
  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   = AV_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   = AV_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
  69 static 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
  76 recover:
  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
 160 static 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
 175 static 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
 204 AVInputFormat ff_pva_demuxer = {
 205     .name           = "pva",
 206     .long_name      = NULL_IF_CONFIG_SMALL("TechnoTrend PVA"),
 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 };