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 #include "libavutil/intreadwrite.h"
  25
  26 typedef struct {
  27     uint16_t index;
  28     uint8_t length;
  29     uint8_t frames;
  30 } C93BlockRecord;
  31
  32 typedef struct {
  33     VocDecContext voc;
  34
  35     C93BlockRecord block_records[512];
  36     int current_block;
  37
  38     uint32_t frame_offsets[32];
  39     int current_frame;
  40     int next_pkt_is_audio;
  41
  42     AVStream *audio;
  43 } C93DemuxContext;
  44
  45 static int probe(AVProbeData *p)
  46 {
  47     int i;
  48     int index = 1;
  49     if (p->buf_size < 16)
  50         return 0;
  51     for (i = 0; i < 16; i += 4) {
  52         if (AV_RL16(p->buf + i) != index || !p->buf[i + 2] || !p->buf[i + 3])
  53             return 0;
  54         index += p->buf[i + 2];
  55     }
  56     return AVPROBE_SCORE_MAX;
  57 }
  58
  59 static int read_header(AVFormatContext *s,
  60                            AVFormatParameters *ap)
  61 {
  62     AVStream *video;
  63     ByteIOContext *pb = s->pb;
  64     C93DemuxContext *c93 = s->priv_data;
  65     int i;
  66     int framecount = 0;
  67
  68     for (i = 0; i < 512; i++) {
  69         c93->block_records[i].index = get_le16(pb);
  70         c93->block_records[i].length = get_byte(pb);
  71         c93->block_records[i].frames = get_byte(pb);
  72         if (c93->block_records[i].frames > 32) {
  73             av_log(s, AV_LOG_ERROR, "too many frames in block\n");
  74             return AVERROR_INVALIDDATA;
  75         }
  76         framecount += c93->block_records[i].frames;
  77     }
  78
  79     /* Audio streams are added if audio packets are found */
  80     s->ctx_flags |= AVFMTCTX_NOHEADER;
  81
  82     video = av_new_stream(s, 0);
  83     if (!video)
  84         return AVERROR(ENOMEM);
  85
  86     video->codec->codec_type = CODEC_TYPE_VIDEO;
  87     video->codec->codec_id = CODEC_ID_C93;
  88     video->codec->width = 320;
  89     video->codec->height = 192;
  90     /* 4:3 320x200 with 8 empty lines */
  91     video->sample_aspect_ratio = (AVRational) { 5, 6 };
  92     video->time_base = (AVRational) { 2, 25 };
  93     video->nb_frames = framecount;
  94     video->duration = framecount;
  95     video->start_time = 0;
  96
  97     c93->current_block = 0;
  98     c93->current_frame = 0;
  99     c93->next_pkt_is_audio = 0;
 100     return 0;
 101 }
 102
 103 #define C93_HAS_PALETTE 0x01
 104 #define C93_FIRST_FRAME 0x02
 105
 106 static int read_packet(AVFormatContext *s, AVPacket *pkt)
 107 {
 108     ByteIOContext *pb = s->pb;
 109     C93DemuxContext *c93 = s->priv_data;
 110     C93BlockRecord *br = &c93->block_records[c93->current_block];
 111     int datasize;
 112     int ret, i;
 113
 114     if (c93->next_pkt_is_audio) {
 115         c93->current_frame++;
 116         c93->next_pkt_is_audio = 0;
 117         datasize = get_le16(pb);
 118         if (datasize > 42) {
 119             if (!c93->audio) {
 120                 c93->audio = av_new_stream(s, 1);
 121                 if (!c93->audio)
 122                     return AVERROR(ENOMEM);
 123                 c93->audio->codec->codec_type = CODEC_TYPE_AUDIO;
 124             }
 125             url_fskip(pb, 26); /* VOC header */
 126             ret = voc_get_packet(s, pkt, c93->audio, datasize - 26);
 127             if (ret > 0) {
 128                 pkt->stream_index = 1;
 129                 pkt->flags |= PKT_FLAG_KEY;
 130                 return ret;
 131             }
 132         }
 133     }
 134     if (c93->current_frame >= br->frames) {
 135         if (c93->current_block >= 511 || !br[1].length)
 136             return AVERROR(EIO);
 137         br++;
 138         c93->current_block++;
 139         c93->current_frame = 0;
 140     }
 141
 142     if (c93->current_frame == 0) {
 143         url_fseek(pb, br->index * 2048, SEEK_SET);
 144         for (i = 0; i < 32; i++) {
 145             c93->frame_offsets[i] = get_le32(pb);
 146         }
 147     }
 148
 149     url_fseek(pb,br->index * 2048 +
 150             c93->frame_offsets[c93->current_frame], SEEK_SET);
 151     datasize = get_le16(pb); /* video frame size */
 152
 153     ret = av_new_packet(pkt, datasize + 768 + 1);
 154     if (ret < 0)
 155         return ret;
 156     pkt->data[0] = 0;
 157     pkt->size = datasize + 1;
 158
 159     ret = get_buffer(pb, pkt->data + 1, datasize);
 160     if (ret < datasize) {
 161         ret = AVERROR(EIO);
 162         goto fail;
 163     }
 164
 165     datasize = get_le16(pb); /* palette size */
 166     if (datasize) {
 167         if (datasize != 768) {
 168             av_log(s, AV_LOG_ERROR, "invalid palette size %u\n", datasize);
 169             ret = AVERROR_INVALIDDATA;
 170             goto fail;
 171         }
 172         pkt->data[0] |= C93_HAS_PALETTE;
 173         ret = get_buffer(pb, pkt->data + pkt->size, datasize);
 174         if (ret < datasize) {
 175             ret = AVERROR(EIO);
 176             goto fail;
 177         }
 178         pkt->size += 768;
 179     }
 180     pkt->stream_index = 0;
 181     c93->next_pkt_is_audio = 1;
 182
 183     /* only the first frame is guaranteed to not reference previous frames */
 184     if (c93->current_block == 0 && c93->current_frame == 0) {
 185         pkt->flags |= PKT_FLAG_KEY;
 186         pkt->data[0] |= C93_FIRST_FRAME;
 187     }
 188     return 0;
 189
 190     fail:
 191     av_free_packet(pkt);
 192     return ret;
 193 }
 194
 195 AVInputFormat c93_demuxer = {
 196     "c93",
 197     NULL_IF_CONFIG_SMALL("Interplay C93"),
 198     sizeof(C93DemuxContext),
 199     probe,
 200     read_header,
 201     read_packet,
 202 };