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 "voc.h"
  24
  25 typedef struct {
  26     uint16_t index;
  27     uint8_t length;
  28     uint8_t frames;
  29 } C93BlockRecord;
  30
  31 typedef struct {
  32     VocDecContext voc;
  33
  34     C93BlockRecord block_records[512];
  35     int current_block;
  36
  37     uint32_t frame_offsets[32];
  38     int current_frame;
  39     int next_pkt_is_audio;
  40
  41     AVStream *audio;
  42 } C93DemuxContext;
  43
  44 static int probe(AVProbeData *p)
  45 {
  46     if (p->buf[0] == 0x01 && p->buf[1] == 0x00 &&
  47         p->buf[4] == 0x01 + p->buf[2] &&
  48         p->buf[8] == p->buf[4] + p->buf[6] &&
  49         p->buf[12] == p->buf[8] + p->buf[10])
  50         return AVPROBE_SCORE_MAX;
  51
  52     return 0;
  53 }
  54
  55 static int read_header(AVFormatContext *s,
  56                            AVFormatParameters *ap)
  57 {
  58     AVStream *video;
  59     ByteIOContext *pb = s->pb;
  60     C93DemuxContext *c93 = s->priv_data;
  61     int i;
  62     int framecount = 0;
  63
  64     for (i = 0; i < 512; i++) {
  65         c93->block_records[i].index = get_le16(pb);
  66         c93->block_records[i].length = get_byte(pb);
  67         c93->block_records[i].frames = get_byte(pb);
  68         if (c93->block_records[i].frames > 32) {
  69             av_log(s, AV_LOG_ERROR, "too many frames in block\n");
  70             return AVERROR_INVALIDDATA;
  71         }
  72         framecount += c93->block_records[i].frames;
  73     }
  74
  75     /* Audio streams are added if audio packets are found */
  76     s->ctx_flags |= AVFMTCTX_NOHEADER;
  77
  78     video = av_new_stream(s, 0);
  79     if (!video)
  80         return AVERROR(ENOMEM);
  81
  82     video->codec->codec_type = CODEC_TYPE_VIDEO;
  83     video->codec->codec_id = CODEC_ID_C93;
  84     video->codec->width = 320;
  85     video->codec->height = 192;
  86     /* 4:3 320x200 with 8 empty lines */
  87     video->sample_aspect_ratio = (AVRational) { 5, 6 };
  88     video->time_base = (AVRational) { 2, 25 };
  89     video->nb_frames = framecount;
  90     video->duration = framecount;
  91     video->start_time = 0;
  92
  93     c93->current_block = 0;
  94     c93->current_frame = 0;
  95     c93->next_pkt_is_audio = 0;
  96     return 0;
  97 }
  98
  99 #define C93_HAS_PALETTE 0x01
 100 #define C93_FIRST_FRAME 0x02
 101
 102 static int read_packet(AVFormatContext *s, AVPacket *pkt)
 103 {
 104     ByteIOContext *pb = s->pb;
 105     C93DemuxContext *c93 = s->priv_data;
 106     C93BlockRecord *br = &c93->block_records[c93->current_block];
 107     int datasize;
 108     int ret, i;
 109
 110     if (c93->next_pkt_is_audio) {
 111         c93->current_frame++;
 112         c93->next_pkt_is_audio = 0;
 113         datasize = get_le16(pb);
 114         if (datasize > 42) {
 115             if (!c93->audio) {
 116                 c93->audio = av_new_stream(s, 1);
 117                 if (!c93->audio)
 118                     return AVERROR(ENOMEM);
 119                 c93->audio->codec->codec_type = CODEC_TYPE_AUDIO;
 120             }
 121             url_fskip(pb, 26); /* VOC header */
 122             ret = voc_get_packet(s, pkt, c93->audio, datasize - 26);
 123             if (ret > 0) {
 124                 pkt->stream_index = 1;
 125                 pkt->flags |= PKT_FLAG_KEY;
 126                 return ret;
 127             }
 128         }
 129     }
 130     if (c93->current_frame >= br->frames) {
 131         if (c93->current_block >= 511 || !br[1].length)
 132             return AVERROR(EIO);
 133         br++;
 134         c93->current_block++;
 135         c93->current_frame = 0;
 136     }
 137
 138     if (c93->current_frame == 0) {
 139         url_fseek(pb, br->index * 2048, SEEK_SET);
 140         for (i = 0; i < 32; i++) {
 141             c93->frame_offsets[i] = get_le32(pb);
 142         }
 143     }
 144
 145     url_fseek(pb,br->index * 2048 +
 146             c93->frame_offsets[c93->current_frame], SEEK_SET);
 147     datasize = get_le16(pb); /* video frame size */
 148
 149     ret = av_new_packet(pkt, datasize + 768 + 1);
 150     if (ret < 0)
 151         return ret;
 152     pkt->data[0] = 0;
 153     pkt->size = datasize + 1;
 154
 155     ret = get_buffer(pb, pkt->data + 1, datasize);
 156     if (ret < datasize) {
 157         ret = AVERROR(EIO);
 158         goto fail;
 159     }
 160
 161     datasize = get_le16(pb); /* palette size */
 162     if (datasize) {
 163         if (datasize != 768) {
 164             av_log(s, AV_LOG_ERROR, "invalid palette size %u\n", datasize);
 165             ret = AVERROR_INVALIDDATA;
 166             goto fail;
 167         }
 168         pkt->data[0] |= C93_HAS_PALETTE;
 169         ret = get_buffer(pb, pkt->data + pkt->size, datasize);
 170         if (ret < datasize) {
 171             ret = AVERROR(EIO);
 172             goto fail;
 173         }
 174         pkt->size += 768;
 175     }
 176     pkt->stream_index = 0;
 177     c93->next_pkt_is_audio = 1;
 178
 179     /* only the first frame is guaranteed to not reference previous frames */
 180     if (c93->current_block == 0 && c93->current_frame == 0) {
 181         pkt->flags |= PKT_FLAG_KEY;
 182         pkt->data[0] |= C93_FIRST_FRAME;
 183     }
 184     return 0;
 185
 186     fail:
 187     av_free_packet(pkt);
 188     return ret;
 189 }
 190
 191 AVInputFormat c93_demuxer = {
 192     "c93",
 193     NULL_IF_CONFIG_SMALL("Interplay C93"),
 194     sizeof(C93DemuxContext),
 195     probe,
 196     read_header,
 197     read_packet,
 198 };