libavformat/idcin.c

   1 /*
   2  * id Quake II CIN File Demuxer
   3  * Copyright (c) 2003 The ffmpeg Project
   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 /**
  23  * @file idcin.c
  24  * id Quake II CIN file demuxer by Mike Melanson (melanson@pcisys.net)
  25  * For more information about the id CIN format, visit:
  26  *   http://www.csse.monash.edu.au/~timf/
  27  *
  28  * CIN is a somewhat quirky and ill-defined format. Here are some notes
  29  * for anyone trying to understand the technical details of this format:
  30  *
  31  * The format has no definite file signature. This is problematic for a
  32  * general-purpose media player that wants to automatically detect file
  33  * types. However, a CIN file does start with 5 32-bit numbers that
  34  * specify audio and video parameters. This demuxer gets around the lack
  35  * of file signature by performing sanity checks on those parameters.
  36  * Probabalistically, this is a reasonable solution since the number of
  37  * valid combinations of the 5 parameters is a very small subset of the
  38  * total 160-bit number space.
  39  *
  40  * Refer to the function idcin_probe() for the precise A/V parameters
  41  * that this demuxer allows.
  42  *
  43  * Next, each audio and video frame has a duration of 1/14 sec. If the
  44  * audio sample rate is a multiple of the common frequency 22050 Hz it will
  45  * divide evenly by 14. However, if the sample rate is 11025 Hz:
  46  *   11025 (samples/sec) / 14 (frames/sec) = 787.5 (samples/frame)
  47  * The way the CIN stores audio in this case is by storing 787 sample
  48  * frames in the first audio frame and 788 sample frames in the second
  49  * audio frame. Therefore, the total number of bytes in an audio frame
  50  * is given as:
  51  *   audio frame #0: 787 * (bytes/sample) * (# channels) bytes in frame
  52  *   audio frame #1: 788 * (bytes/sample) * (# channels) bytes in frame
  53  *   audio frame #2: 787 * (bytes/sample) * (# channels) bytes in frame
  54  *   audio frame #3: 788 * (bytes/sample) * (# channels) bytes in frame
  55  *
  56  * Finally, not all id CIN creation tools agree on the resolution of the
  57  * color palette, apparently. Some creation tools specify red, green, and
  58  * blue palette components in terms of 6-bit VGA color DAC values which
  59  * range from 0..63. Other tools specify the RGB components as full 8-bit
  60  * values that range from 0..255. Since there are no markers in the file to
  61  * differentiate between the two variants, this demuxer uses the following
  62  * heuristic:
  63  *   - load the 768 palette bytes from disk
  64  *   - assume that they will need to be shifted left by 2 bits to
  65  *     transform them from 6-bit values to 8-bit values
  66  *   - scan through all 768 palette bytes
  67  *     - if any bytes exceed 63, do not shift the bytes at all before
  68  *       transmitting them to the video decoder
  69  */
  70
  71 #include "avformat.h"
  72
  73 #define HUFFMAN_TABLE_SIZE (64 * 1024)
  74 #define IDCIN_FPS 14
  75
  76 typedef struct IdcinDemuxContext {
  77     int video_stream_index;
  78     int audio_stream_index;
  79     int audio_chunk_size1;
  80     int audio_chunk_size2;
  81
  82     /* demux state variables */
  83     int current_audio_chunk;
  84     int next_chunk_is_video;
  85     int audio_present;
  86
  87     int64_t pts;
  88
  89     AVPaletteControl palctrl;
  90 } IdcinDemuxContext;
  91
  92 static int idcin_probe(AVProbeData *p)
  93 {
  94     unsigned int number;
  95
  96     /*
  97      * This is what you could call a "probabilistic" file check: id CIN
  98      * files don't have a definite file signature. In lieu of such a marker,
  99      * perform sanity checks on the 5 32-bit header fields:
 100      *  width, height: greater than 0, less than or equal to 1024
 101      * audio sample rate: greater than or equal to 8000, less than or
 102      *  equal to 48000, or 0 for no audio
 103      * audio sample width (bytes/sample): 0 for no audio, or 1 or 2
 104      * audio channels: 0 for no audio, or 1 or 2
 105      */
 106
 107     /* check the video width */
 108     number = AV_RL32(&p->buf[0]);
 109     if ((number == 0) || (number > 1024))
 110        return 0;
 111
 112     /* check the video height */
 113     number = AV_RL32(&p->buf[4]);
 114     if ((number == 0) || (number > 1024))
 115        return 0;
 116
 117     /* check the audio sample rate */
 118     number = AV_RL32(&p->buf[8]);
 119     if ((number != 0) && ((number < 8000) | (number > 48000)))
 120         return 0;
 121
 122     /* check the audio bytes/sample */
 123     number = AV_RL32(&p->buf[12]);
 124     if (number > 2)
 125         return 0;
 126
 127     /* check the audio channels */
 128     number = AV_RL32(&p->buf[16]);
 129     if (number > 2)
 130         return 0;
 131
 132     /* return half certainly since this check is a bit sketchy */
 133     return AVPROBE_SCORE_MAX / 2;
 134 }
 135
 136 static int idcin_read_header(AVFormatContext *s,
 137                              AVFormatParameters *ap)
 138 {
 139     ByteIOContext *pb = s->pb;
 140     IdcinDemuxContext *idcin = s->priv_data;
 141     AVStream *st;
 142     unsigned int width, height;
 143     unsigned int sample_rate, bytes_per_sample, channels;
 144
 145     /* get the 5 header parameters */
 146     width = get_le32(pb);
 147     height = get_le32(pb);
 148     sample_rate = get_le32(pb);
 149     bytes_per_sample = get_le32(pb);
 150     channels = get_le32(pb);
 151
 152     st = av_new_stream(s, 0);
 153     if (!st)
 154         return AVERROR(ENOMEM);
 155     av_set_pts_info(st, 33, 1, IDCIN_FPS);
 156     idcin->video_stream_index = st->index;
 157     st->codec->codec_type = CODEC_TYPE_VIDEO;
 158     st->codec->codec_id = CODEC_ID_IDCIN;
 159     st->codec->codec_tag = 0;  /* no fourcc */
 160     st->codec->width = width;
 161     st->codec->height = height;
 162
 163     /* load up the Huffman tables into extradata */
 164     st->codec->extradata_size = HUFFMAN_TABLE_SIZE;
 165     st->codec->extradata = av_malloc(HUFFMAN_TABLE_SIZE);
 166     if (get_buffer(pb, st->codec->extradata, HUFFMAN_TABLE_SIZE) !=
 167         HUFFMAN_TABLE_SIZE)
 168         return AVERROR(EIO);
 169     /* save a reference in order to transport the palette */
 170     st->codec->palctrl = &idcin->palctrl;
 171
 172     /* if sample rate is 0, assume no audio */
 173     if (sample_rate) {
 174         idcin->audio_present = 1;
 175         st = av_new_stream(s, 0);
 176         if (!st)
 177             return AVERROR(ENOMEM);
 178         av_set_pts_info(st, 33, 1, IDCIN_FPS);
 179         idcin->audio_stream_index = st->index;
 180         st->codec->codec_type = CODEC_TYPE_AUDIO;
 181         st->codec->codec_tag = 1;
 182         st->codec->channels = channels;
 183         st->codec->sample_rate = sample_rate;
 184         st->codec->bits_per_coded_sample = bytes_per_sample * 8;
 185         st->codec->bit_rate = sample_rate * bytes_per_sample * 8 * channels;
 186         st->codec->block_align = bytes_per_sample * channels;
 187         if (bytes_per_sample == 1)
 188             st->codec->codec_id = CODEC_ID_PCM_U8;
 189         else
 190             st->codec->codec_id = CODEC_ID_PCM_S16LE;
 191
 192         if (sample_rate % 14 != 0) {
 193             idcin->audio_chunk_size1 = (sample_rate / 14) *
 194             bytes_per_sample * channels;
 195             idcin->audio_chunk_size2 = (sample_rate / 14 + 1) *
 196                 bytes_per_sample * channels;
 197         } else {
 198             idcin->audio_chunk_size1 = idcin->audio_chunk_size2 =
 199                 (sample_rate / 14) * bytes_per_sample * channels;
 200         }
 201         idcin->current_audio_chunk = 0;
 202     } else
 203         idcin->audio_present = 1;
 204
 205     idcin->next_chunk_is_video = 1;
 206     idcin->pts = 0;
 207
 208     return 0;
 209 }
 210
 211 static int idcin_read_packet(AVFormatContext *s,
 212                              AVPacket *pkt)
 213 {
 214     int ret;
 215     unsigned int command;
 216     unsigned int chunk_size;
 217     IdcinDemuxContext *idcin = s->priv_data;
 218     ByteIOContext *pb = s->pb;
 219     int i;
 220     int palette_scale;
 221     unsigned char r, g, b;
 222     unsigned char palette_buffer[768];
 223
 224     if (url_feof(s->pb))
 225         return AVERROR(EIO);
 226
 227     if (idcin->next_chunk_is_video) {
 228         command = get_le32(pb);
 229         if (command == 2) {
 230             return AVERROR(EIO);
 231         } else if (command == 1) {
 232             /* trigger a palette change */
 233             idcin->palctrl.palette_changed = 1;
 234             if (get_buffer(pb, palette_buffer, 768) != 768)
 235                 return AVERROR(EIO);
 236             /* scale the palette as necessary */
 237             palette_scale = 2;
 238             for (i = 0; i < 768; i++)
 239                 if (palette_buffer[i] > 63) {
 240                     palette_scale = 0;
 241                     break;
 242                 }
 243
 244             for (i = 0; i < 256; i++) {
 245                 r = palette_buffer[i * 3    ] << palette_scale;
 246                 g = palette_buffer[i * 3 + 1] << palette_scale;
 247                 b = palette_buffer[i * 3 + 2] << palette_scale;
 248                 idcin->palctrl.palette[i] = (r << 16) | (g << 8) | (b);
 249             }
 250         }
 251
 252         chunk_size = get_le32(pb);
 253         /* skip the number of decoded bytes (always equal to width * height) */
 254         url_fseek(pb, 4, SEEK_CUR);
 255         chunk_size -= 4;
 256         ret= av_get_packet(pb, pkt, chunk_size);
 257         if (ret != chunk_size)
 258             return AVERROR(EIO);
 259         pkt->stream_index = idcin->video_stream_index;
 260         pkt->pts = idcin->pts;
 261     } else {
 262         /* send out the audio chunk */
 263         if (idcin->current_audio_chunk)
 264             chunk_size = idcin->audio_chunk_size2;
 265         else
 266             chunk_size = idcin->audio_chunk_size1;
 267         ret= av_get_packet(pb, pkt, chunk_size);
 268         if (ret != chunk_size)
 269             return AVERROR(EIO);
 270         pkt->stream_index = idcin->audio_stream_index;
 271         pkt->pts = idcin->pts;
 272
 273         idcin->current_audio_chunk ^= 1;
 274         idcin->pts++;
 275     }
 276
 277     if (idcin->audio_present)
 278         idcin->next_chunk_is_video ^= 1;
 279
 280     return ret;
 281 }
 282
 283 AVInputFormat idcin_demuxer = {
 284     "idcin",
 285     NULL_IF_CONFIG_SMALL("id CIN format"),
 286     sizeof(IdcinDemuxContext),
 287     idcin_probe,
 288     idcin_read_header,
 289     idcin_read_packet,
 290 };