| 1 | /*
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| 2 | * Id Quake II CIN File Demuxer
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| 3 | * Copyright (c) 2003 The ffmpeg Project
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| 4 | *
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| 5 | * This library is free software; you can redistribute it and/or
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| 6 | * modify it under the terms of the GNU Lesser General Public
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| 7 | * License as published by the Free Software Foundation; either
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| 8 | * version 2 of the License, or (at your option) any later version.
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| 9 | *
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| 10 | * This library is distributed in the hope that it will be useful,
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| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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| 13 | * Lesser General Public License for more details.
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| 14 | *
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| 15 | * You should have received a copy of the GNU Lesser General Public
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| 16 | * License along with this library; if not, write to the Free Software
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| 17 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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| 18 | */
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| 19 |
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| 20 | /**
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| 21 | * @file idcin.c
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| 22 | * Id Quake II CIN file demuxer by Mike Melanson ([email protected])
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| 23 | * For more information about the Id CIN format, visit:
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| 24 | * http://www.csse.monash.edu.au/~timf/
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| 25 | *
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| 26 | * CIN is a somewhat quirky and ill-defined format. Here are some notes
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| 27 | * for anyone trying to understand the technical details of this format:
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| 28 | *
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| 29 | * The format has no definite file signature. This is problematic for a
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| 30 | * general-purpose media player that wants to automatically detect file
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| 31 | * types. However, a CIN file does start with 5 32-bit numbers that
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| 32 | * specify audio and video parameters. This demuxer gets around the lack
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| 33 | * of file signature by performing sanity checks on those parameters.
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| 34 | * Probabalistically, this is a reasonable solution since the number of
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| 35 | * valid combinations of the 5 parameters is a very small subset of the
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| 36 | * total 160-bit number space.
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| 37 | *
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| 38 | * Refer to the function idcin_probe() for the precise A/V parameters
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| 39 | * that this demuxer allows.
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| 40 | *
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| 41 | * Next, each audio and video frame has a duration of 1/14 sec. If the
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| 42 | * audio sample rate is a multiple of the common frequency 22050 Hz it will
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| 43 | * divide evenly by 14. However, if the sample rate is 11025 Hz:
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| 44 | * 11025 (samples/sec) / 14 (frames/sec) = 787.5 (samples/frame)
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| 45 | * The way the CIN stores audio in this case is by storing 787 sample
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| 46 | * frames in the first audio frame and 788 sample frames in the second
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| 47 | * audio frame. Therefore, the total number of bytes in an audio frame
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| 48 | * is given as:
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| 49 | * audio frame #0: 787 * (bytes/sample) * (# channels) bytes in frame
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| 50 | * audio frame #1: 788 * (bytes/sample) * (# channels) bytes in frame
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| 51 | * audio frame #2: 787 * (bytes/sample) * (# channels) bytes in frame
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| 52 | * audio frame #3: 788 * (bytes/sample) * (# channels) bytes in frame
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| 53 | *
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| 54 | * Finally, not all Id CIN creation tools agree on the resolution of the
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| 55 | * color palette, apparently. Some creation tools specify red, green, and
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| 56 | * blue palette components in terms of 6-bit VGA color DAC values which
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| 57 | * range from 0..63. Other tools specify the RGB components as full 8-bit
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| 58 | * values that range from 0..255. Since there are no markers in the file to
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| 59 | * differentiate between the two variants, this demuxer uses the following
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| 60 | * heuristic:
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| 61 | * - load the 768 palette bytes from disk
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| 62 | * - assume that they will need to be shifted left by 2 bits to
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| 63 | * transform them from 6-bit values to 8-bit values
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| 64 | * - scan through all 768 palette bytes
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| 65 | * - if any bytes exceed 63, do not shift the bytes at all before
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| 66 | * transmitting them to the video decoder
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| 67 | */
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| 68 |
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| 69 | #include "avformat.h"
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| 70 |
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| 71 | #define HUFFMAN_TABLE_SIZE (64 * 1024)
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| 72 | #define FRAME_PTS_INC (90000 / 14)
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| 73 |
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| 74 | typedef struct IdcinDemuxContext {
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| 75 | int video_stream_index;
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| 76 | int audio_stream_index;
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| 77 | int audio_chunk_size1;
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| 78 | int audio_chunk_size2;
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| 79 |
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| 80 | /* demux state variables */
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| 81 | int current_audio_chunk;
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| 82 | int next_chunk_is_video;
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| 83 | int audio_present;
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| 84 |
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| 85 | int64_t pts;
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| 86 |
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| 87 | AVPaletteControl palctrl;
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| 88 | } IdcinDemuxContext;
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| 89 |
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| 90 | static int idcin_probe(AVProbeData *p)
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| 91 | {
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| 92 | unsigned int number;
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| 93 |
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| 94 | /*
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| 95 | * This is what you could call a "probabilistic" file check: Id CIN
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| 96 | * files don't have a definite file signature. In lieu of such a marker,
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| 97 | * perform sanity checks on the 5 32-bit header fields:
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| 98 | * width, height: greater than 0, less than or equal to 1024
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| 99 | * audio sample rate: greater than or equal to 8000, less than or
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| 100 | * equal to 48000, or 0 for no audio
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| 101 | * audio sample width (bytes/sample): 0 for no audio, or 1 or 2
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| 102 | * audio channels: 0 for no audio, or 1 or 2
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| 103 | */
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| 104 |
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| 105 | /* cannot proceed without 20 bytes */
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| 106 | if (p->buf_size < 20)
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| 107 | return 0;
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| 108 |
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| 109 | /* check the video width */
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| 110 | number = LE_32(&p->buf[0]);
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| 111 | if ((number == 0) || (number > 1024))
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| 112 | return 0;
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| 113 |
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| 114 | /* check the video height */
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| 115 | number = LE_32(&p->buf[4]);
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| 116 | if ((number == 0) || (number > 1024))
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| 117 | return 0;
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| 118 |
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| 119 | /* check the audio sample rate */
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| 120 | number = LE_32(&p->buf[8]);
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| 121 | if ((number != 0) && ((number < 8000) | (number > 48000)))
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| 122 | return 0;
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| 123 |
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| 124 | /* check the audio bytes/sample */
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| 125 | number = LE_32(&p->buf[12]);
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| 126 | if (number > 2)
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| 127 | return 0;
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| 128 |
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| 129 | /* check the audio channels */
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| 130 | number = LE_32(&p->buf[16]);
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| 131 | if (number > 2)
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| 132 | return 0;
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| 133 |
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| 134 | /* return half certainly since this check is a bit sketchy */
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| 135 | return AVPROBE_SCORE_MAX / 2;
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| 136 | }
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| 137 |
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| 138 | static int idcin_read_header(AVFormatContext *s,
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| 139 | AVFormatParameters *ap)
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| 140 | {
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| 141 | ByteIOContext *pb = &s->pb;
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| 142 | IdcinDemuxContext *idcin = (IdcinDemuxContext *)s->priv_data;
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| 143 | AVStream *st;
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| 144 | unsigned int width, height;
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| 145 | unsigned int sample_rate, bytes_per_sample, channels;
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| 146 |
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| 147 | /* get the 5 header parameters */
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| 148 | width = get_le32(pb);
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| 149 | height = get_le32(pb);
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| 150 | sample_rate = get_le32(pb);
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| 151 | bytes_per_sample = get_le32(pb);
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| 152 | channels = get_le32(pb);
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| 153 |
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| 154 | st = av_new_stream(s, 0);
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| 155 | if (!st)
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| 156 | return AVERROR_NOMEM;
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| 157 | av_set_pts_info(st, 33, 1, 90000);
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| 158 | idcin->video_stream_index = st->index;
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| 159 | st->codec->codec_type = CODEC_TYPE_VIDEO;
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| 160 | st->codec->codec_id = CODEC_ID_IDCIN;
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| 161 | st->codec->codec_tag = 0; /* no fourcc */
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| 162 | st->codec->width = width;
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| 163 | st->codec->height = height;
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| 164 |
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| 165 | /* load up the Huffman tables into extradata */
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| 166 | st->codec->extradata_size = HUFFMAN_TABLE_SIZE;
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| 167 | st->codec->extradata = av_malloc(HUFFMAN_TABLE_SIZE);
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| 168 | if (get_buffer(pb, st->codec->extradata, HUFFMAN_TABLE_SIZE) !=
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| 169 | HUFFMAN_TABLE_SIZE)
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| 170 | return AVERROR_IO;
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| 171 | /* save a reference in order to transport the palette */
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| 172 | st->codec->palctrl = &idcin->palctrl;
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| 173 |
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| 174 | /* if sample rate is 0, assume no audio */
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| 175 | if (sample_rate) {
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| 176 | idcin->audio_present = 1;
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| 177 | st = av_new_stream(s, 0);
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| 178 | if (!st)
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| 179 | return AVERROR_NOMEM;
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| 180 | av_set_pts_info(st, 33, 1, 90000);
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| 181 | idcin->audio_stream_index = st->index;
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| 182 | st->codec->codec_type = CODEC_TYPE_AUDIO;
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| 183 | st->codec->codec_tag = 1;
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| 184 | st->codec->channels = channels;
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| 185 | st->codec->sample_rate = sample_rate;
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| 186 | st->codec->bits_per_sample = bytes_per_sample * 8;
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| 187 | st->codec->bit_rate = sample_rate * bytes_per_sample * 8 * channels;
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| 188 | st->codec->block_align = bytes_per_sample * channels;
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| 189 | if (bytes_per_sample == 1)
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| 190 | st->codec->codec_id = CODEC_ID_PCM_U8;
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| 191 | else
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| 192 | st->codec->codec_id = CODEC_ID_PCM_S16LE;
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| 193 |
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| 194 | if (sample_rate % 14 != 0) {
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| 195 | idcin->audio_chunk_size1 = (sample_rate / 14) *
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| 196 | bytes_per_sample * channels;
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| 197 | idcin->audio_chunk_size2 = (sample_rate / 14 + 1) *
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| 198 | bytes_per_sample * channels;
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| 199 | } else {
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| 200 | idcin->audio_chunk_size1 = idcin->audio_chunk_size2 =
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| 201 | (sample_rate / 14) * bytes_per_sample * channels;
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| 202 | }
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| 203 | idcin->current_audio_chunk = 0;
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| 204 | } else
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| 205 | idcin->audio_present = 1;
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| 206 |
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| 207 | idcin->next_chunk_is_video = 1;
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| 208 | idcin->pts = 0;
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| 209 |
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| 210 | return 0;
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| 211 | }
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| 212 |
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| 213 | static int idcin_read_packet(AVFormatContext *s,
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| 214 | AVPacket *pkt)
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| 215 | {
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| 216 | int ret;
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| 217 | unsigned int command;
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| 218 | unsigned int chunk_size;
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| 219 | IdcinDemuxContext *idcin = (IdcinDemuxContext *)s->priv_data;
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| 220 | ByteIOContext *pb = &s->pb;
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| 221 | int i;
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| 222 | int palette_scale;
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| 223 | unsigned char r, g, b;
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| 224 | unsigned char palette_buffer[768];
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| 225 |
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| 226 | if (url_feof(&s->pb))
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| 227 | return AVERROR_IO;
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| 228 |
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| 229 | if (idcin->next_chunk_is_video) {
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| 230 | command = get_le32(pb);
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| 231 | if (command == 2) {
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| 232 | return AVERROR_IO;
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| 233 | } else if (command == 1) {
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| 234 | /* trigger a palette change */
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| 235 | idcin->palctrl.palette_changed = 1;
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| 236 | if (get_buffer(pb, palette_buffer, 768) != 768)
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| 237 | return AVERROR_IO;
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| 238 | /* scale the palette as necessary */
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| 239 | palette_scale = 2;
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| 240 | for (i = 0; i < 768; i++)
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| 241 | if (palette_buffer[i] > 63) {
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| 242 | palette_scale = 0;
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| 243 | break;
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| 244 | }
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| 245 |
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| 246 | for (i = 0; i < 256; i++) {
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| 247 | r = palette_buffer[i * 3 ] << palette_scale;
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| 248 | g = palette_buffer[i * 3 + 1] << palette_scale;
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| 249 | b = palette_buffer[i * 3 + 2] << palette_scale;
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| 250 | idcin->palctrl.palette[i] = (r << 16) | (g << 8) | (b);
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| 251 | }
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| 252 | }
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| 253 |
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| 254 | chunk_size = get_le32(pb);
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| 255 | /* skip the number of decoded bytes (always equal to width * height) */
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| 256 | url_fseek(pb, 4, SEEK_CUR);
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| 257 | chunk_size -= 4;
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| 258 | ret= av_get_packet(pb, pkt, chunk_size);
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| 259 | if (ret != chunk_size)
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| 260 | return AVERROR_IO;
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| 261 | pkt->stream_index = idcin->video_stream_index;
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| 262 | pkt->pts = idcin->pts;
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| 263 | } else {
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| 264 | /* send out the audio chunk */
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| 265 | if (idcin->current_audio_chunk)
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| 266 | chunk_size = idcin->audio_chunk_size2;
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| 267 | else
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| 268 | chunk_size = idcin->audio_chunk_size1;
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| 269 | ret= av_get_packet(pb, pkt, chunk_size);
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| 270 | if (ret != chunk_size)
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| 271 | return AVERROR_IO;
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| 272 | pkt->stream_index = idcin->audio_stream_index;
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| 273 | pkt->pts = idcin->pts;
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| 274 |
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| 275 | idcin->current_audio_chunk ^= 1;
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| 276 | idcin->pts += FRAME_PTS_INC;
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| 277 | }
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| 278 |
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| 279 | if (idcin->audio_present)
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| 280 | idcin->next_chunk_is_video ^= 1;
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| 281 |
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| 282 | return ret;
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| 283 | }
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| 284 |
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| 285 | static int idcin_read_close(AVFormatContext *s)
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| 286 | {
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| 287 |
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| 288 | return 0;
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| 289 | }
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| 290 |
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| 291 | static AVInputFormat idcin_demuxer = {
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| 292 | "idcin",
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| 293 | "Id CIN format",
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| 294 | sizeof(IdcinDemuxContext),
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| 295 | idcin_probe,
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| 296 | idcin_read_header,
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| 297 | idcin_read_packet,
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| 298 | idcin_read_close,
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| 299 | };
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| 300 |
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| 301 | int idcin_init(void)
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| 302 | {
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| 303 | av_register_input_format(&idcin_demuxer);
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| 304 | return 0;
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| 305 | }
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