2 * id Quake II CIN File Demuxer
3 * Copyright (c) 2003 The ffmpeg Project
5 * This file is part of FFmpeg.
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.
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.
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
23 * @file libavformat/idcin.c
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/
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:
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.
40 * Refer to the function idcin_probe() for the precise A/V parameters
41 * that this demuxer allows.
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
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
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
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
71 #include "libavutil/intreadwrite.h"
74 #define HUFFMAN_TABLE_SIZE (64 * 1024)
77 typedef struct IdcinDemuxContext
{
78 int video_stream_index
;
79 int audio_stream_index
;
80 int audio_chunk_size1
;
81 int audio_chunk_size2
;
83 /* demux state variables */
84 int current_audio_chunk
;
85 int next_chunk_is_video
;
90 AVPaletteControl palctrl
;
93 static int idcin_probe(AVProbeData
*p
)
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
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)
113 /* check the video width */
114 number
= AV_RL32(&p
->buf
[0]);
115 if ((number
== 0) || (number
> 1024))
118 /* check the video height */
119 number
= AV_RL32(&p
->buf
[4]);
120 if ((number
== 0) || (number
> 1024))
123 /* check the audio sample rate */
124 number
= AV_RL32(&p
->buf
[8]);
125 if ((number
!= 0) && ((number
< 8000) | (number
> 48000)))
128 /* check the audio bytes/sample */
129 number
= AV_RL32(&p
->buf
[12]);
133 /* check the audio channels */
134 number
= AV_RL32(&p
->buf
[16]);
138 /* return half certainly since this check is a bit sketchy */
139 return AVPROBE_SCORE_MAX
/ 2;
142 static int idcin_read_header(AVFormatContext
*s
,
143 AVFormatParameters
*ap
)
145 ByteIOContext
*pb
= s
->pb
;
146 IdcinDemuxContext
*idcin
= s
->priv_data
;
148 unsigned int width
, height
;
149 unsigned int sample_rate
, bytes_per_sample
, channels
;
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
);
158 st
= av_new_stream(s
, 0);
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
= CODEC_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
;
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
) !=
175 /* save a reference in order to transport the palette */
176 st
->codec
->palctrl
= &idcin
->palctrl
;
178 /* if sample rate is 0, assume no audio */
180 idcin
->audio_present
= 1;
181 st
= av_new_stream(s
, 0);
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
= 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_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
;
196 st
->codec
->codec_id
= CODEC_ID_PCM_S16LE
;
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
;
204 idcin
->audio_chunk_size1
= idcin
->audio_chunk_size2
=
205 (sample_rate
/ 14) * bytes_per_sample
* channels
;
207 idcin
->current_audio_chunk
= 0;
209 idcin
->audio_present
= 1;
211 idcin
->next_chunk_is_video
= 1;
217 static int idcin_read_packet(AVFormatContext
*s
,
221 unsigned int command
;
222 unsigned int chunk_size
;
223 IdcinDemuxContext
*idcin
= s
->priv_data
;
224 ByteIOContext
*pb
= s
->pb
;
227 unsigned char r
, g
, b
;
228 unsigned char palette_buffer
[768];
233 if (idcin
->next_chunk_is_video
) {
234 command
= get_le32(pb
);
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)
242 /* scale the palette as necessary */
244 for (i
= 0; i
< 768; i
++)
245 if (palette_buffer
[i
] > 63) {
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
);
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
);
262 ret
= av_get_packet(pb
, pkt
, chunk_size
);
263 if (ret
!= chunk_size
)
265 pkt
->stream_index
= idcin
->video_stream_index
;
266 pkt
->pts
= idcin
->pts
;
268 /* send out the audio chunk */
269 if (idcin
->current_audio_chunk
)
270 chunk_size
= idcin
->audio_chunk_size2
;
272 chunk_size
= idcin
->audio_chunk_size1
;
273 ret
= av_get_packet(pb
, pkt
, chunk_size
);
274 if (ret
!= chunk_size
)
276 pkt
->stream_index
= idcin
->audio_stream_index
;
277 pkt
->pts
= idcin
->pts
;
279 idcin
->current_audio_chunk
^= 1;
283 if (idcin
->audio_present
)
284 idcin
->next_chunk_is_video
^= 1;
289 AVInputFormat idcin_demuxer
= {
291 NULL_IF_CONFIG_SMALL("id Cinematic format"),
292 sizeof(IdcinDemuxContext
),