libavformat/idcin.c

   1 /*
   2  * Id Quake II CIN File Demuxer
   3  * Copyright (c) 2003 The ffmpeg Project
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General Public
  16  * License along with this library; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18  */
  19
  20 /**
  21  * @file idcin.c
  22  * Id Quake II CIN file demuxer by Mike Melanson (melanson@pcisys.net)
  23  * For more information about the Id CIN format, visit:
  24  *   http://www.csse.monash.edu.au/~timf/
  25  *
  26  * CIN is a somewhat quirky and ill-defined format. Here are some notes
  27  * for anyone trying to understand the technical details of this format:
  28  *
  29  * The format has no definite file signature. This is problematic for a
  30  * general-purpose media player that wants to automatically detect file
  31  * types. However, a CIN file does start with 5 32-bit numbers that
  32  * specify audio and video parameters. This demuxer gets around the lack
  33  * of file signature by performing sanity checks on those parameters.
  34  * Probabalistically, this is a reasonable solution since the number of
  35  * valid combinations of the 5 parameters is a very small subset of the
  36  * total 160-bit number space.
  37  *
  38  * Refer to the function idcin_probe() for the precise A/V parameters
  39  * that this demuxer allows.
  40  *
  41  * Next, each audio and video frame has a duration of 1/14 sec. If the
  42  * audio sample rate is a multiple of the common frequency 22050 Hz it will
  43  * divide evenly by 14. However, if the sample rate is 11025 Hz:
  44  *   11025 (samples/sec) / 14 (frames/sec) = 787.5 (samples/frame)
  45  * The way the CIN stores audio in this case is by storing 787 sample
  46  * frames in the first audio frame and 788 sample frames in the second
  47  * audio frame. Therefore, the total number of bytes in an audio frame
  48  * is given as:
  49  *   audio frame #0: 787 * (bytes/sample) * (# channels) bytes in frame
  50  *   audio frame #1: 788 * (bytes/sample) * (# channels) bytes in frame
  51  *   audio frame #2: 787 * (bytes/sample) * (# channels) bytes in frame
  52  *   audio frame #3: 788 * (bytes/sample) * (# channels) bytes in frame
  53  *
  54  * Finally, not all Id CIN creation tools agree on the resolution of the
  55  * color palette, apparently. Some creation tools specify red, green, and
  56  * blue palette components in terms of 6-bit VGA color DAC values which
  57  * range from 0..63. Other tools specify the RGB components as full 8-bit
  58  * values that range from 0..255. Since there are no markers in the file to
  59  * differentiate between the two variants, this demuxer uses the following
  60  * heuristic:
  61  *   - load the 768 palette bytes from disk
  62  *   - assume that they will need to be shifted left by 2 bits to
  63  *     transform them from 6-bit values to 8-bit values
  64  *   - scan through all 768 palette bytes
  65  *     - if any bytes exceed 63, do not shift the bytes at all before
  66  *       transmitting them to the video decoder
  67  */
  68
  69 #include "avformat.h"
  70
  71 #define LE_16(x)  ((((uint8_t*)(x))[1] << 8) | ((uint8_t*)(x))[0])
  72 #define LE_32(x)  ((((uint8_t*)(x))[3] << 24) | \
  73                    (((uint8_t*)(x))[2] << 16) | \
  74                    (((uint8_t*)(x))[1] << 8) | \
  75                     ((uint8_t*)(x))[0])
  76
  77 #define HUFFMAN_TABLE_SIZE (64 * 1024)
  78 #define FRAME_PTS_INC (90000 / 14)
  79
  80 typedef struct IdcinDemuxContext {
  81     int video_stream_index;
  82     int audio_stream_index;
  83     int audio_chunk_size1;
  84     int audio_chunk_size2;
  85
  86     /* demux state variables */
  87     int current_audio_chunk;
  88     int next_chunk_is_video;
  89     int audio_present;
  90
  91     int64_t pts;
  92
  93     AVPaletteControl palctrl;
  94 } IdcinDemuxContext;
  95
  96 static int idcin_probe(AVProbeData *p)
  97 {
  98     unsigned int number;
  99
 100     /*
 101      * This is what you could call a "probabilistic" file check: Id CIN
 102      * files don't have a definite file signature. In lieu of such a marker,
 103      * perform sanity checks on the 5 32-bit header fields:
 104      *  width, height: greater than 0, less than or equal to 1024
 105      * audio sample rate: greater than or equal to 8000, less than or
 106      *  equal to 48000, or 0 for no audio
 107      * audio sample width (bytes/sample): 0 for no audio, or 1 or 2
 108      * audio channels: 0 for no audio, or 1 or 2
 109      */
 110
 111     /* cannot proceed without 20 bytes */
 112     if (p->buf_size < 20)
 113         return 0;
 114
 115     /* check the video width */
 116     number = LE_32(&p->buf[0]);
 117     if ((number == 0) || (number > 1024))
 118        return 0;
 119
 120     /* check the video height */
 121     number = LE_32(&p->buf[4]);
 122     if ((number == 0) || (number > 1024))
 123        return 0;
 124
 125     /* check the audio sample rate */
 126     number = LE_32(&p->buf[8]);
 127     if ((number != 0) && ((number < 8000) | (number > 48000)))
 128         return 0;
 129
 130     /* check the audio bytes/sample */
 131     number = LE_32(&p->buf[12]);
 132     if (number > 2)
 133         return 0;
 134
 135     /* check the audio channels */
 136     number = LE_32(&p->buf[16]);
 137     if (number > 2)
 138         return 0;
 139
 140     /* return half certainly since this check is a bit sketchy */
 141     return AVPROBE_SCORE_MAX / 2;
 142 }
 143
 144 static int idcin_read_header(AVFormatContext *s,
 145                              AVFormatParameters *ap)
 146 {
 147     ByteIOContext *pb = &s->pb;
 148     IdcinDemuxContext *idcin = (IdcinDemuxContext *)s->priv_data;
 149     AVStream *st;
 150     unsigned int width, height;
 151     unsigned int sample_rate, bytes_per_sample, channels;
 152
 153     /* get the 5 header parameters */
 154     width = get_le32(pb);
 155     height = get_le32(pb);
 156     sample_rate = get_le32(pb);
 157     bytes_per_sample = get_le32(pb);
 158     channels = get_le32(pb);
 159
 160     st = av_new_stream(s, 0);
 161     if (!st)
 162         return AVERROR_NOMEM;
 163     idcin->video_stream_index = st->index;
 164     st->codec.codec_type = CODEC_TYPE_VIDEO;
 165     st->codec.codec_id = CODEC_ID_IDCIN;
 166     st->codec.codec_tag = 0;  /* no fourcc */
 167     st->codec.width = width;
 168     st->codec.height = height;
 169
 170     /* load up the Huffman tables into extradata */
 171     st->codec.extradata_size = HUFFMAN_TABLE_SIZE;
 172     st->codec.extradata = av_malloc(HUFFMAN_TABLE_SIZE);
 173     if (get_buffer(pb, st->codec.extradata, HUFFMAN_TABLE_SIZE) !=
 174         HUFFMAN_TABLE_SIZE)
 175         return -EIO;
 176     /* save a reference in order to transport the palette */
 177     st->codec.palctrl = &idcin->palctrl;
 178
 179     /* if sample rate is 0, assume no audio */
 180     if (sample_rate) {
 181         idcin->audio_present = 1;
 182         st = av_new_stream(s, 0);
 183         if (!st)
 184             return AVERROR_NOMEM;
 185         idcin->audio_stream_index = st->index;
 186         st->codec.codec_type = CODEC_TYPE_AUDIO;
 187         st->codec.codec_tag = 1;
 188         st->codec.channels = channels;
 189         st->codec.sample_rate = sample_rate;
 190         st->codec.bits_per_sample = bytes_per_sample * 8;
 191         st->codec.bit_rate = sample_rate * bytes_per_sample * 8 * channels;
 192         st->codec.block_align = bytes_per_sample * channels;
 193         if (bytes_per_sample == 1)
 194             st->codec.codec_id = CODEC_ID_PCM_U8;
 195         else
 196             st->codec.codec_id = CODEC_ID_PCM_S16LE;
 197
 198         if (sample_rate % 14 != 0) {
 199             idcin->audio_chunk_size1 = (sample_rate / 14) *
 200             bytes_per_sample * channels;
 201             idcin->audio_chunk_size2 = (sample_rate / 14 + 1) *
 202                 bytes_per_sample * channels;
 203         } else {
 204             idcin->audio_chunk_size1 = idcin->audio_chunk_size2 =
 205                 (sample_rate / 14) * bytes_per_sample * channels;
 206         }
 207         idcin->current_audio_chunk = 0;
 208     } else
 209         idcin->audio_present = 1;
 210
 211     idcin->next_chunk_is_video = 1;
 212     idcin->pts = 0;
 213
 214     /* set the pts reference (1 pts = 1/90000) */
 215     s->pts_num = 1;
 216     s->pts_den = 90000;
 217
 218     return 0;
 219 }
 220
 221 static int idcin_read_packet(AVFormatContext *s,
 222                              AVPacket *pkt)
 223 {
 224     int ret;
 225     unsigned int command;
 226     unsigned int chunk_size;
 227     IdcinDemuxContext *idcin = (IdcinDemuxContext *)s->priv_data;
 228     ByteIOContext *pb = &s->pb;
 229     int i;
 230     int palette_scale;
 231     unsigned char r, g, b;
 232     unsigned char palette_buffer[768];
 233
 234     if (url_feof(&s->pb))
 235         return -EIO;
 236
 237     if (idcin->next_chunk_is_video) {
 238         command = get_le32(pb);
 239         if (command == 2) {
 240             return -EIO;
 241         } else if (command == 1) {
 242             /* trigger a palette change */
 243             idcin->palctrl.palette_changed = 1;
 244             if (get_buffer(pb, palette_buffer, 768) != 768)
 245                 return -EIO;
 246             /* scale the palette as necessary */
 247             palette_scale = 2;
 248             for (i = 0; i < 768; i++)
 249                 if (palette_buffer[i] > 63) {
 250                     palette_scale = 0;
 251                     break;
 252                 }
 253
 254             for (i = 0; i < 256; i++) {
 255                 r = palette_buffer[i * 3    ] << palette_scale;
 256                 g = palette_buffer[i * 3 + 1] << palette_scale;
 257                 b = palette_buffer[i * 3 + 2] << palette_scale;
 258                 idcin->palctrl.palette[i] = (r << 16) | (g << 8) | (b);
 259             }
 260         }
 261
 262         chunk_size = get_le32(pb);
 263         /* skip the number of decoded bytes (always equal to width * height) */
 264         url_fseek(pb, 4, SEEK_CUR);
 265         chunk_size -= 4;
 266         if (av_new_packet(pkt, chunk_size))
 267             ret = -EIO;
 268         pkt->stream_index = idcin->video_stream_index;
 269         pkt->pts = idcin->pts;
 270         ret = get_buffer(pb, pkt->data, chunk_size);
 271         if (ret != chunk_size)
 272             ret = -EIO;
 273     } else {
 274         /* send out the audio chunk */
 275         if (idcin->current_audio_chunk)
 276             chunk_size = idcin->audio_chunk_size2;
 277         else
 278             chunk_size = idcin->audio_chunk_size1;
 279         if (av_new_packet(pkt, chunk_size))
 280             return -EIO;
 281         pkt->stream_index = idcin->audio_stream_index;
 282         pkt->pts = idcin->pts;
 283         ret = get_buffer(&s->pb, pkt->data, chunk_size);
 284         if (ret != chunk_size)
 285             ret = -EIO;
 286
 287         idcin->current_audio_chunk ^= 1;
 288         idcin->pts += FRAME_PTS_INC;
 289     }
 290
 291     if (idcin->audio_present)
 292         idcin->next_chunk_is_video ^= 1;
 293
 294     return ret;
 295 }
 296
 297 static int idcin_read_close(AVFormatContext *s)
 298 {
 299
 300     return 0;
 301 }
 302
 303 static AVInputFormat idcin_iformat = {
 304     "idcin",
 305     "Id CIN format",
 306     sizeof(IdcinDemuxContext),
 307     idcin_probe,
 308     idcin_read_header,
 309     idcin_read_packet,
 310     idcin_read_close,
 311 };
 312
 313 int idcin_init(void)
 314 {
 315     av_register_input_format(&idcin_iformat);
 316     return 0;
 317 }