libavformat/c93.c

   1 /*
   2  * Interplay C93 demuxer
   3  * Copyright (c) 2007 Anssi Hannula <anssi.hannula@gmail.com>
   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 "demux.h"
  24 #include "internal.h"
  25 #include "voc.h"
  26 #include "libavutil/intreadwrite.h"
  27
  28 typedef struct C93BlockRecord {
  29     uint16_t index;
  30     uint8_t length;
  31     uint8_t frames;
  32 } C93BlockRecord;
  33
  34 typedef struct C93DemuxContext {
  35     VocDecContext voc;
  36
  37     C93BlockRecord block_records[512];
  38     int current_block;
  39
  40     uint32_t frame_offsets[32];
  41     int current_frame;
  42     int next_pkt_is_audio;
  43
  44     AVStream *audio;
  45 } C93DemuxContext;
  46
  47 static int probe(const AVProbeData *p)
  48 {
  49     int i;
  50     int index = 1;
  51     if (p->buf_size < 16)
  52         return 0;
  53     for (i = 0; i < 16; i += 4) {
  54         if (AV_RL16(p->buf + i) != index || !p->buf[i + 2] || !p->buf[i + 3])
  55             return 0;
  56         index += p->buf[i + 2];
  57     }
  58     return AVPROBE_SCORE_MAX;
  59 }
  60
  61 static int read_header(AVFormatContext *s)
  62 {
  63     AVStream *video;
  64     AVIOContext *pb = s->pb;
  65     C93DemuxContext *c93 = s->priv_data;
  66     int i;
  67     int framecount = 0;
  68
  69     for (i = 0; i < 512; i++) {
  70         c93->block_records[i].index = avio_rl16(pb);
  71         c93->block_records[i].length = avio_r8(pb);
  72         c93->block_records[i].frames = avio_r8(pb);
  73         if (c93->block_records[i].frames > 32) {
  74             av_log(s, AV_LOG_ERROR, "too many frames in block\n");
  75             return AVERROR_INVALIDDATA;
  76         }
  77         framecount += c93->block_records[i].frames;
  78     }
  79
  80     /* Audio streams are added if audio packets are found */
  81     s->ctx_flags |= AVFMTCTX_NOHEADER;
  82
  83     video = avformat_new_stream(s, NULL);
  84     if (!video)
  85         return AVERROR(ENOMEM);
  86
  87     video->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
  88     video->codecpar->codec_id = AV_CODEC_ID_C93;
  89     video->codecpar->width = 320;
  90     video->codecpar->height = 192;
  91     /* 4:3 320x200 with 8 empty lines */
  92     video->sample_aspect_ratio = (AVRational) { 5, 6 };
  93     avpriv_set_pts_info(video, 64, 2, 25);
  94     video->nb_frames = framecount;
  95     video->duration = framecount;
  96     video->start_time = 0;
  97
  98     c93->current_block = 0;
  99     c93->current_frame = 0;
 100     c93->next_pkt_is_audio = 0;
 101     return 0;
 102 }
 103
 104 #define C93_HAS_PALETTE 0x01
 105 #define C93_FIRST_FRAME 0x02
 106
 107 static int read_packet(AVFormatContext *s, AVPacket *pkt)
 108 {
 109     AVIOContext *pb = s->pb;
 110     C93DemuxContext *c93 = s->priv_data;
 111     C93BlockRecord *br = &c93->block_records[c93->current_block];
 112     int datasize;
 113     int ret, i;
 114
 115     if (c93->next_pkt_is_audio) {
 116         c93->current_frame++;
 117         c93->next_pkt_is_audio = 0;
 118         datasize = avio_rl16(pb);
 119         if (datasize > 42) {
 120             if (!c93->audio) {
 121                 c93->audio = avformat_new_stream(s, NULL);
 122                 if (!c93->audio)
 123                     return AVERROR(ENOMEM);
 124                 c93->audio->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
 125             }
 126             avio_skip(pb, 26); /* VOC header */
 127             ret = ff_voc_get_packet(s, pkt, c93->audio, datasize - 26);
 128             if (ret > 0) {
 129                 pkt->stream_index = 1;
 130                 pkt->flags |= AV_PKT_FLAG_KEY;
 131                 return ret;
 132             }
 133         }
 134     }
 135     if (c93->current_frame >= br->frames) {
 136         if (c93->current_block >= 511 || !br[1].length)
 137             return AVERROR_EOF;
 138         br++;
 139         c93->current_block++;
 140         c93->current_frame = 0;
 141     }
 142
 143     if (c93->current_frame == 0) {
 144         avio_seek(pb, br->index * 2048, SEEK_SET);
 145         for (i = 0; i < 32; i++) {
 146             c93->frame_offsets[i] = avio_rl32(pb);
 147         }
 148     }
 149
 150     avio_seek(pb,br->index * 2048 +
 151             c93->frame_offsets[c93->current_frame], SEEK_SET);
 152     datasize = avio_rl16(pb); /* video frame size */
 153
 154     ret = av_new_packet(pkt, datasize + 768 + 1);
 155     if (ret < 0)
 156         return ret;
 157     pkt->data[0] = 0;
 158     pkt->size = datasize + 1;
 159
 160     ret = avio_read(pb, pkt->data + 1, datasize);
 161     if (ret < datasize) {
 162         return AVERROR(EIO);
 163     }
 164
 165     datasize = avio_rl16(pb); /* palette size */
 166     if (datasize) {
 167         if (datasize != 768) {
 168             av_log(s, AV_LOG_ERROR, "invalid palette size %u\n", datasize);
 169             return AVERROR_INVALIDDATA;
 170         }
 171         pkt->data[0] |= C93_HAS_PALETTE;
 172         ret = avio_read(pb, pkt->data + pkt->size, datasize);
 173         if (ret < datasize) {
 174             return AVERROR(EIO);
 175         }
 176         pkt->size += 768;
 177     }
 178     pkt->stream_index = 0;
 179     c93->next_pkt_is_audio = 1;
 180
 181     /* only the first frame is guaranteed to not reference previous frames */
 182     if (c93->current_block == 0 && c93->current_frame == 0) {
 183         pkt->flags |= AV_PKT_FLAG_KEY;
 184         pkt->data[0] |= C93_FIRST_FRAME;
 185     }
 186     return 0;
 187 }
 188
 189 const FFInputFormat ff_c93_demuxer = {
 190     .p.name         = "c93",
 191     .p.long_name    = NULL_IF_CONFIG_SMALL("Interplay C93"),
 192     .priv_data_size = sizeof(C93DemuxContext),
 193     .read_probe     = probe,
 194     .read_header    = read_header,
 195     .read_packet    = read_packet,
 196 };