Statistics
| Branch: | Revision:

ffmpeg / libavformat / idcin.c @ 649b918c

History | View | Annotate | Download (10.4 KB)

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 HUFFMAN_TABLE_SIZE (64 * 1024)
72
#define FRAME_PTS_INC (90000 / 14)
73

    
74
typedef struct IdcinDemuxContext {
75
    int video_stream_index;
76
    int audio_stream_index;
77
    int audio_chunk_size1;
78
    int audio_chunk_size2;
79

    
80
    /* demux state variables */
81
    int current_audio_chunk;
82
    int next_chunk_is_video;
83
    int audio_present;
84

    
85
    int64_t pts;
86

    
87
    AVPaletteControl palctrl;
88
} IdcinDemuxContext;
89

    
90
static int idcin_probe(AVProbeData *p)
91
{
92
    unsigned int number;
93

    
94
    /*
95
     * This is what you could call a "probabilistic" file check: Id CIN
96
     * files don't have a definite file signature. In lieu of such a marker,
97
     * perform sanity checks on the 5 32-bit header fields:
98
     *  width, height: greater than 0, less than or equal to 1024
99
     * audio sample rate: greater than or equal to 8000, less than or
100
     *  equal to 48000, or 0 for no audio
101
     * audio sample width (bytes/sample): 0 for no audio, or 1 or 2
102
     * audio channels: 0 for no audio, or 1 or 2
103
     */
104

    
105
    /* cannot proceed without 20 bytes */
106
    if (p->buf_size < 20)
107
        return 0;
108

    
109
    /* check the video width */
110
    number = LE_32(&p->buf[0]);
111
    if ((number == 0) || (number > 1024))
112
       return 0;
113

    
114
    /* check the video height */
115
    number = LE_32(&p->buf[4]);
116
    if ((number == 0) || (number > 1024))
117
       return 0;
118

    
119
    /* check the audio sample rate */
120
    number = LE_32(&p->buf[8]);
121
    if ((number != 0) && ((number < 8000) | (number > 48000)))
122
        return 0;
123

    
124
    /* check the audio bytes/sample */
125
    number = LE_32(&p->buf[12]);
126
    if (number > 2)
127
        return 0;
128

    
129
    /* check the audio channels */
130
    number = LE_32(&p->buf[16]);
131
    if (number > 2)
132
        return 0;
133

    
134
    /* return half certainly since this check is a bit sketchy */
135
    return AVPROBE_SCORE_MAX / 2;
136
}
137

    
138
static int idcin_read_header(AVFormatContext *s,
139
                             AVFormatParameters *ap)
140
{
141
    ByteIOContext *pb = &s->pb;
142
    IdcinDemuxContext *idcin = (IdcinDemuxContext *)s->priv_data;
143
    AVStream *st;
144
    unsigned int width, height;
145
    unsigned int sample_rate, bytes_per_sample, channels;
146

    
147
    /* get the 5 header parameters */
148
    width = get_le32(pb);
149
    height = get_le32(pb);
150
    sample_rate = get_le32(pb);
151
    bytes_per_sample = get_le32(pb);
152
    channels = get_le32(pb);
153

    
154
    st = av_new_stream(s, 0);
155
    if (!st)
156
        return AVERROR_NOMEM;
157
    av_set_pts_info(st, 33, 1, 90000);
158
    idcin->video_stream_index = st->index;
159
    st->codec.codec_type = CODEC_TYPE_VIDEO;
160
    st->codec.codec_id = CODEC_ID_IDCIN;
161
    st->codec.codec_tag = 0;  /* no fourcc */
162
    st->codec.width = width;
163
    st->codec.height = height;
164

    
165
    /* load up the Huffman tables into extradata */
166
    st->codec.extradata_size = HUFFMAN_TABLE_SIZE;
167
    st->codec.extradata = av_malloc(HUFFMAN_TABLE_SIZE);
168
    if (get_buffer(pb, st->codec.extradata, HUFFMAN_TABLE_SIZE) !=
169
        HUFFMAN_TABLE_SIZE)
170
        return AVERROR_IO;
171
    /* save a reference in order to transport the palette */
172
    st->codec.palctrl = &idcin->palctrl;
173

    
174
    /* if sample rate is 0, assume no audio */
175
    if (sample_rate) {
176
        idcin->audio_present = 1;
177
        st = av_new_stream(s, 0);
178
        if (!st)
179
            return AVERROR_NOMEM;
180
        av_set_pts_info(st, 33, 1, 90000);
181
        idcin->audio_stream_index = st->index;
182
        st->codec.codec_type = CODEC_TYPE_AUDIO;
183
        st->codec.codec_tag = 1;
184
        st->codec.channels = channels;
185
        st->codec.sample_rate = sample_rate;
186
        st->codec.bits_per_sample = bytes_per_sample * 8;
187
        st->codec.bit_rate = sample_rate * bytes_per_sample * 8 * channels;
188
        st->codec.block_align = bytes_per_sample * channels;
189
        if (bytes_per_sample == 1)
190
            st->codec.codec_id = CODEC_ID_PCM_U8;
191
        else
192
            st->codec.codec_id = CODEC_ID_PCM_S16LE;
193

    
194
        if (sample_rate % 14 != 0) {
195
            idcin->audio_chunk_size1 = (sample_rate / 14) *
196
            bytes_per_sample * channels;
197
            idcin->audio_chunk_size2 = (sample_rate / 14 + 1) *
198
                bytes_per_sample * channels;
199
        } else {
200
            idcin->audio_chunk_size1 = idcin->audio_chunk_size2 =
201
                (sample_rate / 14) * bytes_per_sample * channels;
202
        }
203
        idcin->current_audio_chunk = 0;
204
    } else
205
        idcin->audio_present = 1;
206

    
207
    idcin->next_chunk_is_video = 1;
208
    idcin->pts = 0;
209

    
210
    return 0;
211
}
212

    
213
static int idcin_read_packet(AVFormatContext *s,
214
                             AVPacket *pkt)
215
{
216
    int ret;
217
    unsigned int command;
218
    unsigned int chunk_size;
219
    IdcinDemuxContext *idcin = (IdcinDemuxContext *)s->priv_data;
220
    ByteIOContext *pb = &s->pb;
221
    int i;
222
    int palette_scale;
223
    unsigned char r, g, b;
224
    unsigned char palette_buffer[768];
225

    
226
    if (url_feof(&s->pb))
227
        return AVERROR_IO;
228

    
229
    if (idcin->next_chunk_is_video) {
230
        command = get_le32(pb);
231
        if (command == 2) {
232
            return AVERROR_IO;
233
        } else if (command == 1) {
234
            /* trigger a palette change */
235
            idcin->palctrl.palette_changed = 1;
236
            if (get_buffer(pb, palette_buffer, 768) != 768)
237
                return AVERROR_IO;
238
            /* scale the palette as necessary */
239
            palette_scale = 2;
240
            for (i = 0; i < 768; i++)
241
                if (palette_buffer[i] > 63) {
242
                    palette_scale = 0;
243
                    break;
244
                }
245

    
246
            for (i = 0; i < 256; i++) {
247
                r = palette_buffer[i * 3    ] << palette_scale;
248
                g = palette_buffer[i * 3 + 1] << palette_scale;
249
                b = palette_buffer[i * 3 + 2] << palette_scale;
250
                idcin->palctrl.palette[i] = (r << 16) | (g << 8) | (b);
251
            }
252
        }
253

    
254
        chunk_size = get_le32(pb);
255
        /* skip the number of decoded bytes (always equal to width * height) */
256
        url_fseek(pb, 4, SEEK_CUR);
257
        chunk_size -= 4;
258
        if (av_new_packet(pkt, chunk_size))
259
            ret = AVERROR_IO;
260
        pkt->stream_index = idcin->video_stream_index;
261
        pkt->pts = idcin->pts;
262
        ret = get_buffer(pb, pkt->data, chunk_size);
263
        if (ret != chunk_size)
264
            ret = AVERROR_IO;
265
    } else {
266
        /* send out the audio chunk */
267
        if (idcin->current_audio_chunk)
268
            chunk_size = idcin->audio_chunk_size2;
269
        else
270
            chunk_size = idcin->audio_chunk_size1;
271
        if (av_new_packet(pkt, chunk_size))
272
            return AVERROR_IO;
273
        pkt->stream_index = idcin->audio_stream_index;
274
        pkt->pts = idcin->pts;
275
        ret = get_buffer(&s->pb, pkt->data, chunk_size);
276
        if (ret != chunk_size)
277
            ret = AVERROR_IO;
278

    
279
        idcin->current_audio_chunk ^= 1;
280
        idcin->pts += FRAME_PTS_INC;
281
    }
282

    
283
    if (idcin->audio_present)
284
        idcin->next_chunk_is_video ^= 1;
285

    
286
    return ret;
287
}
288

    
289
static int idcin_read_close(AVFormatContext *s)
290
{
291

    
292
    return 0;
293
}
294

    
295
static AVInputFormat idcin_iformat = {
296
    "idcin",
297
    "Id CIN format",
298
    sizeof(IdcinDemuxContext),
299
    idcin_probe,
300
    idcin_read_header,
301
    idcin_read_packet,
302
    idcin_read_close,
303
};
304

    
305
int idcin_init(void)
306
{
307
    av_register_input_format(&idcin_iformat);
308
    return 0;
309
}