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  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 "internal.h"
  24. #include "voc.h"
  25. #include "libavutil/intreadwrite.h"
  26.  
  27. typedef struct {
  28.     uint16_t index;
  29.     uint8_t length;
  30.     uint8_t frames;
  31. } C93BlockRecord;
  32.  
  33. typedef struct {
  34.     VocDecContext voc;
  35.  
  36.     C93BlockRecord block_records[512];
  37.     int current_block;
  38.  
  39.     uint32_t frame_offsets[32];
  40.     int current_frame;
  41.     int next_pkt_is_audio;
  42.  
  43.     AVStream *audio;
  44. } C93DemuxContext;
  45.  
  46. static int probe(AVProbeData *p)
  47. {
  48.     int i;
  49.     int index = 1;
  50.     if (p->buf_size < 16)
  51.         return 0;
  52.     for (i = 0; i < 16; i += 4) {
  53.         if (AV_RL16(p->buf + i) != index || !p->buf[i + 2] || !p->buf[i + 3])
  54.             return 0;
  55.         index += p->buf[i + 2];
  56.     }
  57.     return AVPROBE_SCORE_MAX;
  58. }
  59.  
  60. static int read_header(AVFormatContext *s)
  61. {
  62.     AVStream *video;
  63.     AVIOContext *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 = avio_rl16(pb);
  70.         c93->block_records[i].length = avio_r8(pb);
  71.         c93->block_records[i].frames = avio_r8(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 = avformat_new_stream(s, NULL);
  83.     if (!video)
  84.         return AVERROR(ENOMEM);
  85.  
  86.     video->codec->codec_type = AVMEDIA_TYPE_VIDEO;
  87.     video->codec->codec_id = AV_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.     avpriv_set_pts_info(video, 64, 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.     AVIOContext *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 = avio_rl16(pb);
  118.         if (datasize > 42) {
  119.             if (!c93->audio) {
  120.                 c93->audio = avformat_new_stream(s, NULL);
  121.                 if (!c93->audio)
  122.                     return AVERROR(ENOMEM);
  123.                 c93->audio->codec->codec_type = AVMEDIA_TYPE_AUDIO;
  124.             }
  125.             avio_skip(pb, 26); /* VOC header */
  126.             ret = ff_voc_get_packet(s, pkt, c93->audio, datasize - 26);
  127.             if (ret > 0) {
  128.                 pkt->stream_index = 1;
  129.                 pkt->flags |= AV_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_EOF;
  137.         br++;
  138.         c93->current_block++;
  139.         c93->current_frame = 0;
  140.     }
  141.  
  142.     if (c93->current_frame == 0) {
  143.         avio_seek(pb, br->index * 2048, SEEK_SET);
  144.         for (i = 0; i < 32; i++) {
  145.             c93->frame_offsets[i] = avio_rl32(pb);
  146.         }
  147.     }
  148.  
  149.     avio_seek(pb,br->index * 2048 +
  150.             c93->frame_offsets[c93->current_frame], SEEK_SET);
  151.     datasize = avio_rl16(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 = avio_read(pb, pkt->data + 1, datasize);
  160.     if (ret < datasize) {
  161.         ret = AVERROR(EIO);
  162.         goto fail;
  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.             ret = AVERROR_INVALIDDATA;
  170.             goto fail;
  171.         }
  172.         pkt->data[0] |= C93_HAS_PALETTE;
  173.         ret = avio_read(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 |= AV_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 ff_c93_demuxer = {
  196.     .name           = "c93",
  197.     .long_name      = NULL_IF_CONFIG_SMALL("Interplay C93"),
  198.     .priv_data_size = sizeof(C93DemuxContext),
  199.     .read_probe     = probe,
  200.     .read_header    = read_header,
  201.     .read_packet    = read_packet,
  202. };
  203.