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 "avio_internal.h"
  24 #include "demux.h"
  25 #include "internal.h"
  26 #include "voc.h"
  27 #include "libavutil/intreadwrite.h"
  28
  29 typedef struct C93BlockRecord {
  30     uint16_t index;
  31     uint8_t length;
  32     uint8_t frames;
  33 } C93BlockRecord;
  34
  35 typedef struct C93DemuxContext {
  36     VocDecContext voc;
  37
  38     C93BlockRecord block_records[512];
  39     int current_block;
  40
  41     uint32_t frame_offsets[32];
  42     int current_frame;
  43     int next_pkt_is_audio;
  44
  45     AVStream *audio;
  46 } C93DemuxContext;
  47
  48 static int probe(const AVProbeData *p)
  49 {
  50     int i;
  51     int index = 1;
  52     if (p->buf_size < 16)
  53         return 0;
  54     for (i = 0; i < 16; i += 4) {
  55         if (AV_RL16(p->buf + i) != index || !p->buf[i + 2] || !p->buf[i + 3])
  56             return 0;
  57         index += p->buf[i + 2];
  58     }
  59     return AVPROBE_SCORE_MAX;
  60 }
  61
  62 static int read_header(AVFormatContext *s)
  63 {
  64     AVStream *video;
  65     AVIOContext *pb = s->pb;
  66     C93DemuxContext *c93 = s->priv_data;
  67     int i;
  68     int framecount = 0;
  69
  70     for (i = 0; i < 512; i++) {
  71         c93->block_records[i].index = avio_rl16(pb);
  72         c93->block_records[i].length = avio_r8(pb);
  73         c93->block_records[i].frames = avio_r8(pb);
  74         if (c93->block_records[i].frames > 32) {
  75             av_log(s, AV_LOG_ERROR, "too many frames in block\n");
  76             return AVERROR_INVALIDDATA;
  77         }
  78         framecount += c93->block_records[i].frames;
  79     }
  80
  81     /* Audio streams are added if audio packets are found */
  82     s->ctx_flags |= AVFMTCTX_NOHEADER;
  83
  84     video = avformat_new_stream(s, NULL);
  85     if (!video)
  86         return AVERROR(ENOMEM);
  87
  88     video->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
  89     video->codecpar->codec_id = AV_CODEC_ID_C93;
  90     video->codecpar->width = 320;
  91     video->codecpar->height = 192;
  92     /* 4:3 320x200 with 8 empty lines */
  93     video->sample_aspect_ratio = (AVRational) { 5, 6 };
  94     avpriv_set_pts_info(video, 64, 2, 25);
  95     video->nb_frames = framecount;
  96     video->duration = framecount;
  97     video->start_time = 0;
  98
  99     c93->current_block = 0;
 100     c93->current_frame = 0;
 101     c93->next_pkt_is_audio = 0;
 102     return 0;
 103 }
 104
 105 #define C93_HAS_PALETTE 0x01
 106 #define C93_FIRST_FRAME 0x02
 107
 108 static int read_packet(AVFormatContext *s, AVPacket *pkt)
 109 {
 110     AVIOContext *pb = s->pb;
 111     C93DemuxContext *c93 = s->priv_data;
 112     C93BlockRecord *br = &c93->block_records[c93->current_block];
 113     int datasize;
 114     int ret, i;
 115
 116     if (c93->next_pkt_is_audio) {
 117         c93->current_frame++;
 118         c93->next_pkt_is_audio = 0;
 119         datasize = avio_rl16(pb);
 120         if (datasize > 42) {
 121             if (!c93->audio) {
 122                 c93->audio = avformat_new_stream(s, NULL);
 123                 if (!c93->audio)
 124                     return AVERROR(ENOMEM);
 125                 c93->audio->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
 126             }
 127             avio_skip(pb, 26); /* VOC header */
 128             ret = ff_voc_get_packet(s, pkt, c93->audio, datasize - 26);
 129             if (ret > 0) {
 130                 pkt->stream_index = 1;
 131                 pkt->flags |= AV_PKT_FLAG_KEY;
 132                 return ret;
 133             }
 134         }
 135     }
 136     if (c93->current_frame >= br->frames) {
 137         if (c93->current_block >= 511 || !br[1].length)
 138             return AVERROR_EOF;
 139         br++;
 140         c93->current_block++;
 141         c93->current_frame = 0;
 142     }
 143
 144     if (c93->current_frame == 0) {
 145         avio_seek(pb, br->index * 2048, SEEK_SET);
 146         for (i = 0; i < 32; i++) {
 147             c93->frame_offsets[i] = avio_rl32(pb);
 148         }
 149     }
 150
 151     avio_seek(pb,br->index * 2048 +
 152             c93->frame_offsets[c93->current_frame], SEEK_SET);
 153     datasize = avio_rl16(pb); /* video frame size */
 154
 155     ret = av_new_packet(pkt, datasize + 768 + 1);
 156     if (ret < 0)
 157         return ret;
 158     pkt->data[0] = 0;
 159     pkt->size = datasize + 1;
 160
 161     ret = ffio_read_size(pb, pkt->data + 1, datasize);
 162     if (ret < 0) {
 163         return ret;
 164     }
 165
 166     datasize = avio_rl16(pb); /* palette size */
 167     if (datasize) {
 168         if (datasize != 768) {
 169             av_log(s, AV_LOG_ERROR, "invalid palette size %u\n", datasize);
 170             return AVERROR_INVALIDDATA;
 171         }
 172         pkt->data[0] |= C93_HAS_PALETTE;
 173         ret = ffio_read_size(pb, pkt->data + pkt->size, datasize);
 174         if (ret < 0) {
 175             return ret;
 176         }
 177         pkt->size += 768;
 178     }
 179     pkt->stream_index = 0;
 180     c93->next_pkt_is_audio = 1;
 181
 182     /* only the first frame is guaranteed to not reference previous frames */
 183     if (c93->current_block == 0 && c93->current_frame == 0) {
 184         pkt->flags |= AV_PKT_FLAG_KEY;
 185         pkt->data[0] |= C93_FIRST_FRAME;
 186     }
 187     return 0;
 188 }
 189
 190 const FFInputFormat ff_c93_demuxer = {
 191     .p.name         = "c93",
 192     .p.long_name    = NULL_IF_CONFIG_SMALL("Interplay C93"),
 193     .priv_data_size = sizeof(C93DemuxContext),
 194     .read_probe     = probe,
 195     .read_header    = read_header,
 196     .read_packet    = read_packet,
 197 };