libavformat/pva.c

   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 "mpeg.h"
  24
  25 #define PVA_MAX_PAYLOAD_LENGTH  0x17f8
  26 #define PVA_VIDEO_PAYLOAD       0x01
  27 #define PVA_AUDIO_PAYLOAD       0x02
  28 #define PVA_MAGIC               (('A' << 8) + 'V')
  29
  30 typedef struct {
  31     int continue_pes;
  32 } PVAContext;
  33
  34 static int pva_probe(AVProbeData * pd) {
  35     unsigned char *buf = pd->buf;
  36
  37     if (AV_RB16(buf) == PVA_MAGIC && buf[2] && buf[2] < 3 && buf[4] == 0x55)
  38         return AVPROBE_SCORE_MAX / 2;
  39
  40     return 0;
  41 }
  42
  43 static int pva_read_header(AVFormatContext *s, AVFormatParameters *ap) {
  44     AVStream *st;
  45
  46     if (!(st = av_new_stream(s, 0)))
  47         return AVERROR(ENOMEM);
  48     st->codec->codec_type = CODEC_TYPE_VIDEO;
  49     st->codec->codec_id   = CODEC_ID_MPEG2VIDEO;
  50     st->need_parsing      = AVSTREAM_PARSE_FULL;
  51     av_set_pts_info(st, 32, 1, 90000);
  52     av_add_index_entry(st, 0, 0, 0, 0, AVINDEX_KEYFRAME);
  53
  54     if (!(st = av_new_stream(s, 1)))
  55         return AVERROR(ENOMEM);
  56     st->codec->codec_type = CODEC_TYPE_AUDIO;
  57     st->codec->codec_id   = CODEC_ID_MP2;
  58     st->need_parsing      = AVSTREAM_PARSE_HEADERS;
  59     av_set_pts_info(st, 33, 1, 90000);
  60     av_add_index_entry(st, 0, 0, 0, 0, AVINDEX_KEYFRAME);
  61
  62     /* the parameters will be extracted from the compressed bitstream */
  63     return 0;
  64 }
  65
  66 #define pva_log if (read_packet) av_log
  67
  68 static int read_part_of_packet(AVFormatContext *s, int64_t *pts,
  69                                int *len, int *strid, int read_packet) {
  70     ByteIOContext *pb = s->pb;
  71     PVAContext *pvactx = s->priv_data;
  72     int syncword, streamid, reserved, flags, length, pts_flag;
  73     int64_t pva_pts = AV_NOPTS_VALUE, startpos;
  74
  75 recover:
  76     startpos = url_ftell(pb);
  77
  78     syncword = get_be16(pb);
  79     streamid = get_byte(pb);
  80     get_byte(pb);               /* counter not used */
  81     reserved = get_byte(pb);
  82     flags    = get_byte(pb);
  83     length   = get_be16(pb);
  84
  85     pts_flag = flags & 0x10;
  86
  87     if (syncword != PVA_MAGIC) {
  88         pva_log(s, AV_LOG_ERROR, "invalid syncword\n");
  89         return AVERROR(EIO);
  90     }
  91     if (streamid != PVA_VIDEO_PAYLOAD && streamid != PVA_AUDIO_PAYLOAD) {
  92         pva_log(s, AV_LOG_ERROR, "invalid streamid\n");
  93         return AVERROR(EIO);
  94     }
  95     if (reserved != 0x55) {
  96         pva_log(s, AV_LOG_WARNING, "expected reserved byte to be 0x55\n");
  97     }
  98     if (length > PVA_MAX_PAYLOAD_LENGTH) {
  99         pva_log(s, AV_LOG_ERROR, "invalid payload length %u\n", length);
 100         return AVERROR(EIO);
 101     }
 102
 103     if (streamid == PVA_VIDEO_PAYLOAD && pts_flag) {
 104         pva_pts = get_be32(pb);
 105         length -= 4;
 106     } else if (streamid == PVA_AUDIO_PAYLOAD) {
 107         /* PVA Audio Packets either start with a signaled PES packet or
 108          * are a continuation of the previous PES packet. New PES packets
 109          * always start at the beginning of a PVA Packet, never somewhere in
 110          * the middle. */
 111         if (!pvactx->continue_pes) {
 112             int pes_signal, pes_header_data_length, pes_packet_length,
 113                 pes_flags;
 114             unsigned char pes_header_data[256];
 115
 116             pes_signal             = get_be24(pb);
 117             get_byte(pb);
 118             pes_packet_length      = get_be16(pb);
 119             pes_flags              = get_be16(pb);
 120             pes_header_data_length = get_byte(pb);
 121
 122             if (pes_signal != 1) {
 123                 pva_log(s, AV_LOG_WARNING, "expected signaled PES packet, "
 124                                           "trying to recover\n");
 125                 url_fskip(pb, length - 9);
 126                 if (!read_packet)
 127                     return AVERROR(EIO);
 128                 goto recover;
 129             }
 130
 131             get_buffer(pb, pes_header_data, pes_header_data_length);
 132             length -= 9 + pes_header_data_length;
 133
 134             pes_packet_length -= 3 + pes_header_data_length;
 135
 136             pvactx->continue_pes = pes_packet_length;
 137
 138             if (pes_flags & 0x80 && (pes_header_data[0] & 0xf0) == 0x20)
 139                 pva_pts = ff_parse_pes_pts(pes_header_data);
 140         }
 141
 142         pvactx->continue_pes -= length;
 143
 144         if (pvactx->continue_pes < 0) {
 145             pva_log(s, AV_LOG_WARNING, "audio data corruption\n");
 146             pvactx->continue_pes = 0;
 147         }
 148     }
 149
 150     if (pva_pts != AV_NOPTS_VALUE)
 151         av_add_index_entry(s->streams[streamid-1], startpos, pva_pts, 0, 0, AVINDEX_KEYFRAME);
 152
 153     *pts   = pva_pts;
 154     *len   = length;
 155     *strid = streamid;
 156     return 0;
 157 }
 158
 159 static int pva_read_packet(AVFormatContext *s, AVPacket *pkt) {
 160     ByteIOContext *pb = s->pb;
 161     int64_t pva_pts;
 162     int ret, length, streamid;
 163
 164     if (read_part_of_packet(s, &pva_pts, &length, &streamid, 1) < 0 ||
 165        (ret = av_get_packet(pb, pkt, length)) <= 0)
 166         return AVERROR(EIO);
 167
 168     pkt->stream_index = streamid - 1;
 169     pkt->pts = pva_pts;
 170
 171     return ret;
 172 }
 173
 174 static int64_t pva_read_timestamp(struct AVFormatContext *s, int stream_index,
 175                                           int64_t *pos, int64_t pos_limit) {
 176     ByteIOContext *pb = s->pb;
 177     PVAContext *pvactx = s->priv_data;
 178     int length, streamid;
 179     int64_t res = AV_NOPTS_VALUE;
 180
 181     pos_limit = FFMIN(*pos+PVA_MAX_PAYLOAD_LENGTH*8, (uint64_t)*pos+pos_limit);
 182
 183     while (*pos < pos_limit) {
 184         res = AV_NOPTS_VALUE;
 185         url_fseek(pb, *pos, SEEK_SET);
 186
 187         pvactx->continue_pes = 0;
 188         if (read_part_of_packet(s, &res, &length, &streamid, 0)) {
 189             (*pos)++;
 190             continue;
 191         }
 192         if (streamid - 1 != stream_index || res == AV_NOPTS_VALUE) {
 193             *pos = url_ftell(pb) + length;
 194             continue;
 195         }
 196         break;
 197     }
 198
 199     pvactx->continue_pes = 0;
 200     return res;
 201 }
 202
 203 AVInputFormat pva_demuxer = {
 204     "pva",
 205     NULL_IF_CONFIG_SMALL("TechnoTrend PVA file and stream format"),
 206     sizeof(PVAContext),
 207     pva_probe,
 208     pva_read_header,
 209     pva_read_packet,
 210     .read_timestamp = pva_read_timestamp
 211 };