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 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 "libavutil/intreadwrite.h" 72#include "avformat.h" 73 74#define HUFFMAN_TABLE_SIZE (64 * 1024) 75#define IDCIN_FPS 14 76 77typedef struct IdcinDemuxContext { 78 int video_stream_index; 79 int audio_stream_index; 80 int audio_chunk_size1; 81 int audio_chunk_size2; 82 83 /* demux state variables */ 84 int current_audio_chunk; 85 int next_chunk_is_video; 86 int audio_present; 87 88 int64_t pts; 89 90 AVPaletteControl palctrl; 91} IdcinDemuxContext; 92 93static int idcin_probe(AVProbeData *p) 94{ 95 unsigned int number; 96 97 /* 98 * This is what you could call a "probabilistic" file check: id CIN 99 * files don't have a definite file signature. In lieu of such a marker, 100 * perform sanity checks on the 5 32-bit header fields: 101 * width, height: greater than 0, less than or equal to 1024 102 * audio sample rate: greater than or equal to 8000, less than or 103 * equal to 48000, or 0 for no audio 104 * audio sample width (bytes/sample): 0 for no audio, or 1 or 2 105 * audio channels: 0 for no audio, or 1 or 2 106 */ 107 108 /* check we have enough data to do all checks, otherwise the 109 0-padding may cause a wrong recognition */ 110 if (p->buf_size < 20) 111 return 0; 112 113 /* check the video width */ 114 number = AV_RL32(&p->buf[0]); 115 if ((number == 0) || (number > 1024)) 116 return 0; 117 118 /* check the video height */ 119 number = AV_RL32(&p->buf[4]); 120 if ((number == 0) || (number > 1024)) 121 return 0; 122 123 /* check the audio sample rate */ 124 number = AV_RL32(&p->buf[8]); 125 if ((number != 0) && ((number < 8000) | (number > 48000))) 126 return 0; 127 128 /* check the audio bytes/sample */ 129 number = AV_RL32(&p->buf[12]); 130 if (number > 2) 131 return 0; 132 133 /* check the audio channels */ 134 number = AV_RL32(&p->buf[16]); 135 if (number > 2) 136 return 0; 137 138 /* return half certainly since this check is a bit sketchy */ 139 return AVPROBE_SCORE_MAX / 2; 140} 141 142static int idcin_read_header(AVFormatContext *s, 143 AVFormatParameters *ap) 144{ 145 ByteIOContext *pb = s->pb; 146 IdcinDemuxContext *idcin = s->priv_data; 147 AVStream *st; 148 unsigned int width, height; 149 unsigned int sample_rate, bytes_per_sample, channels; 150 151 /* get the 5 header parameters */ 152 width = get_le32(pb); 153 height = get_le32(pb); 154 sample_rate = get_le32(pb); 155 bytes_per_sample = get_le32(pb); 156 channels = get_le32(pb); 157 158 st = av_new_stream(s, 0); 159 if (!st) 160 return AVERROR(ENOMEM); 161 av_set_pts_info(st, 33, 1, IDCIN_FPS); 162 idcin->video_stream_index = st->index; 163 st->codec->codec_type = AVMEDIA_TYPE_VIDEO; 164 st->codec->codec_id = CODEC_ID_IDCIN; 165 st->codec->codec_tag = 0; /* no fourcc */ 166 st->codec->width = width; 167 st->codec->height = height; 168 169 /* load up the Huffman tables into extradata */ 170 st->codec->extradata_size = HUFFMAN_TABLE_SIZE; 171 st->codec->extradata = av_malloc(HUFFMAN_TABLE_SIZE); 172 if (get_buffer(pb, st->codec->extradata, HUFFMAN_TABLE_SIZE) != 173 HUFFMAN_TABLE_SIZE) 174 return AVERROR(EIO); 175 /* save a reference in order to transport the palette */ 176 st->codec->palctrl = &idcin->palctrl; 177 178 /* if sample rate is 0, assume no audio */ 179 if (sample_rate) { 180 idcin->audio_present = 1; 181 st = av_new_stream(s, 0); 182 if (!st) 183 return AVERROR(ENOMEM); 184 av_set_pts_info(st, 33, 1, IDCIN_FPS); 185 idcin->audio_stream_index = st->index; 186 st->codec->codec_type = AVMEDIA_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_coded_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 return 0; 215} 216 217static int idcin_read_packet(AVFormatContext *s, 218 AVPacket *pkt) 219{ 220 int ret; 221 unsigned int command; 222 unsigned int chunk_size; 223 IdcinDemuxContext *idcin = s->priv_data; 224 ByteIOContext *pb = s->pb; 225 int i; 226 int palette_scale; 227 unsigned char r, g, b; 228 unsigned char palette_buffer[768]; 229 230 if (url_feof(s->pb)) 231 return AVERROR(EIO); 232 233 if (idcin->next_chunk_is_video) { 234 command = get_le32(pb); 235 if (command == 2) { 236 return AVERROR(EIO); 237 } else if (command == 1) { 238 /* trigger a palette change */ 239 idcin->palctrl.palette_changed = 1; 240 if (get_buffer(pb, palette_buffer, 768) != 768) 241 return AVERROR(EIO); 242 /* scale the palette as necessary */ 243 palette_scale = 2; 244 for (i = 0; i < 768; i++) 245 if (palette_buffer[i] > 63) { 246 palette_scale = 0; 247 break; 248 } 249 250 for (i = 0; i < 256; i++) { 251 r = palette_buffer[i * 3 ] << palette_scale; 252 g = palette_buffer[i * 3 + 1] << palette_scale; 253 b = palette_buffer[i * 3 + 2] << palette_scale; 254 idcin->palctrl.palette[i] = (r << 16) | (g << 8) | (b); 255 } 256 } 257 258 chunk_size = get_le32(pb); 259 /* skip the number of decoded bytes (always equal to width * height) */ 260 url_fseek(pb, 4, SEEK_CUR); 261 chunk_size -= 4; 262 ret= av_get_packet(pb, pkt, chunk_size); 263 if (ret < 0) 264 return ret; 265 pkt->stream_index = idcin->video_stream_index; 266 pkt->pts = idcin->pts; 267 } else { 268 /* send out the audio chunk */ 269 if (idcin->current_audio_chunk) 270 chunk_size = idcin->audio_chunk_size2; 271 else 272 chunk_size = idcin->audio_chunk_size1; 273 ret= av_get_packet(pb, pkt, chunk_size); 274 if (ret < 0) 275 return ret; 276 pkt->stream_index = idcin->audio_stream_index; 277 pkt->pts = idcin->pts; 278 279 idcin->current_audio_chunk ^= 1; 280 idcin->pts++; 281 } 282 283 if (idcin->audio_present) 284 idcin->next_chunk_is_video ^= 1; 285 286 return ret; 287} 288 289AVInputFormat idcin_demuxer = { 290 "idcin", 291 NULL_IF_CONFIG_SMALL("id Cinematic format"), 292 sizeof(IdcinDemuxContext), 293 idcin_probe, 294 idcin_read_header, 295 idcin_read_packet, 296}; 297