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