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     /* keep reference to extradata but never free it */
  94     void *extradata;
  95 } IdcinDemuxContext;
  96
  97 static int idcin_probe(AVProbeData *p)
  98 {
  99     unsigned int number;
 100
 101     /*
 102      * This is what you could call a "probabilistic" file check: Id CIN
 103      * files don't have a definite file signature. In lieu of such a marker,
 104      * perform sanity checks on the 5 32-bit header fields:
 105      *  width, height: greater than 0, less than or equal to 1024
 106      * audio sample rate: greater than or equal to 8000, less than or
 107      *  equal to 48000, or 0 for no audio
 108      * audio sample width (bytes/sample): 0 for no audio, or 1 or 2
 109      * audio channels: 0 for no audio, or 1 or 2
 110      */
 111
 112     /* cannot proceed without 20 bytes */
 113     if (p->buf_size < 20)
 114         return 0;
 115
 116     /* check the video width */
 117     number = LE_32(&p->buf[0]);
 118     if ((number == 0) || (number > 1024))
 119        return 0;
 120
 121     /* check the video height */
 122     number = LE_32(&p->buf[4]);
 123     if ((number == 0) || (number > 1024))
 124        return 0;
 125
 126     /* check the audio sample rate */
 127     number = LE_32(&p->buf[8]);
 128     if ((number != 0) && ((number < 8000) | (number > 48000)))
 129         return 0;
 130
 131     /* check the audio bytes/sample */
 132     number = LE_32(&p->buf[12]);
 133     if (number > 2)
 134         return 0;
 135
 136     /* check the audio channels */
 137     number = LE_32(&p->buf[16]);
 138     if (number > 2)
 139         return 0;
 140
 141     /* return half certainly since this check is a bit sketchy */
 142     return AVPROBE_SCORE_MAX / 2;
 143 }
 144
 145 static int idcin_read_header(AVFormatContext *s,
 146                              AVFormatParameters *ap)
 147 {
 148     ByteIOContext *pb = &s->pb;
 149     IdcinDemuxContext *idcin = (IdcinDemuxContext *)s->priv_data;
 150     AVStream *st;
 151     unsigned int width, height;
 152     unsigned int sample_rate, bytes_per_sample, channels;
 153
 154     /* get the 5 header parameters */
 155     width = get_le32(pb);
 156     height = get_le32(pb);
 157     sample_rate = get_le32(pb);
 158     bytes_per_sample = get_le32(pb);
 159     channels = get_le32(pb);
 160
 161     st = av_new_stream(s, 0);
 162     if (!st)
 163         return AVERROR_NOMEM;
 164     idcin->video_stream_index = st->index;
 165     st->codec.codec_type = CODEC_TYPE_VIDEO;
 166     st->codec.codec_id = CODEC_ID_IDCIN;
 167     st->codec.codec_tag = 0;  /* no fourcc */
 168     st->codec.width = width;
 169     st->codec.height = height;
 170
 171     /* load up the Huffman tables into extradata */
 172     st->codec.extradata_size = HUFFMAN_TABLE_SIZE;
 173     st->codec.extradata = av_malloc(HUFFMAN_TABLE_SIZE);
 174     if (get_buffer(pb, st->codec.extradata, HUFFMAN_TABLE_SIZE) !=
 175         HUFFMAN_TABLE_SIZE)
 176         return -EIO;
 177     /* save a reference in order to transport the palette */
 178     idcin->extradata = st->codec.extradata;
 179
 180     /* if sample rate is 0, assume no audio */
 181     if (sample_rate) {
 182         idcin->audio_present = 1;
 183         st = av_new_stream(s, 0);
 184         if (!st)
 185             return AVERROR_NOMEM;
 186         idcin->audio_stream_index = st->index;
 187         st->codec.codec_type = CODEC_TYPE_AUDIO;
 188         st->codec.codec_tag = 1;
 189         st->codec.channels = channels;
 190         st->codec.sample_rate = sample_rate;
 191         st->codec.bits_per_sample = bytes_per_sample * 8;
 192         st->codec.bit_rate = sample_rate * bytes_per_sample * 8 * channels;
 193         st->codec.block_align = bytes_per_sample * channels;
 194         if (bytes_per_sample == 1)
 195             st->codec.codec_id = CODEC_ID_PCM_U8;
 196         else
 197             st->codec.codec_id = CODEC_ID_PCM_S16LE;
 198
 199         if (sample_rate % 14 != 0) {
 200             idcin->audio_chunk_size1 = (sample_rate / 14) *
 201             bytes_per_sample * channels;
 202             idcin->audio_chunk_size2 = (sample_rate / 14 + 1) *
 203                 bytes_per_sample * channels;
 204         } else {
 205             idcin->audio_chunk_size1 = idcin->audio_chunk_size2 =
 206                 (sample_rate / 14) * bytes_per_sample * channels;
 207         }
 208         idcin->current_audio_chunk = 0;
 209     } else
 210         idcin->audio_present = 1;
 211
 212     idcin->next_chunk_is_video = 1;
 213     idcin->pts = 0;
 214
 215     /* set the pts reference (1 pts = 1/90000) */
 216     s->pts_num = 1;
 217     s->pts_den = 90000;
 218
 219     return 0;
 220 }
 221
 222 static int idcin_read_packet(AVFormatContext *s,
 223                              AVPacket *pkt)
 224 {
 225     int ret;
 226     unsigned int command;
 227     unsigned int chunk_size;
 228     IdcinDemuxContext *idcin = (IdcinDemuxContext *)s->priv_data;
 229     ByteIOContext *pb = &s->pb;
 230     AVPaletteControl *palette_control = (AVPaletteControl *)idcin->extradata;
 231     int i;
 232     int palette_scale;
 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             palette_control->palette_changed = 1;
 244             if (get_buffer(pb, palette_control->palette, 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_control->palette[i] > 63) {
 250                     palette_scale = 0;
 251                     break;
 252                 }
 253
 254             if (palette_scale)
 255                 for (i = 0; i < 768; i++)
 256                     palette_control->palette[i] <<= palette_scale;
 257         }
 258
 259         chunk_size = get_le32(pb);
 260         /* skip the number of decoded bytes (always equal to width * height) */
 261         url_fseek(pb, 4, SEEK_CUR);
 262         chunk_size -= 4;
 263         if (av_new_packet(pkt, chunk_size))
 264             ret = -EIO;
 265         pkt->stream_index = idcin->video_stream_index;
 266         pkt->pts = idcin->pts;
 267         ret = get_buffer(pb, pkt->data, chunk_size);
 268         if (ret != chunk_size)
 269             ret = -EIO;
 270     } else {
 271         /* send out the audio chunk */
 272         if (idcin->current_audio_chunk)
 273             chunk_size = idcin->audio_chunk_size2;
 274         else
 275             chunk_size = idcin->audio_chunk_size1;
 276         if (av_new_packet(pkt, chunk_size))
 277             return -EIO;
 278         pkt->stream_index = idcin->audio_stream_index;
 279         pkt->pts = idcin->pts;
 280         ret = get_buffer(&s->pb, pkt->data, chunk_size);
 281         if (ret != chunk_size)
 282             ret = -EIO;
 283
 284         idcin->current_audio_chunk ^= 1;
 285         idcin->pts += FRAME_PTS_INC;
 286     }
 287
 288     if (idcin->audio_present)
 289         idcin->next_chunk_is_video ^= 1;
 290
 291     return ret;
 292 }
 293
 294 static int idcin_read_close(AVFormatContext *s)
 295 {
 296     return 0;
 297 }
 298
 299 static AVInputFormat idcin_iformat = {
 300     "idcin",
 301     "Id CIN format",
 302     sizeof(IdcinDemuxContext),
 303     idcin_probe,
 304     idcin_read_header,
 305     idcin_read_packet,
 306     idcin_read_close,
 307 };
 308
 309 int idcin_init(void)
 310 {
 311     av_register_input_format(&idcin_iformat);
 312     return 0;
 313 }