1/*
2 * id Quake II CIN File Demuxer
3 * Copyright (c) 2003 The ffmpeg Project
4 *
5 * This file is part of Libav.
6 *
7 * Libav 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 * Libav 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 Libav; 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#include "internal.h"
74
75#define HUFFMAN_TABLE_SIZE (64 * 1024)
76#define IDCIN_FPS 14
77
78typedef struct IdcinDemuxContext {
79    int video_stream_index;
80    int audio_stream_index;
81    int audio_chunk_size1;
82    int audio_chunk_size2;
83
84    /* demux state variables */
85    int current_audio_chunk;
86    int next_chunk_is_video;
87    int audio_present;
88
89    int64_t pts;
90} IdcinDemuxContext;
91
92static int idcin_probe(AVProbeData *p)
93{
94    unsigned int number;
95
96    /*
97     * This is what you could call a "probabilistic" file check: id CIN
98     * files don't have a definite file signature. In lieu of such a marker,
99     * perform sanity checks on the 5 32-bit header fields:
100     *  width, height: greater than 0, less than or equal to 1024
101     * audio sample rate: greater than or equal to 8000, less than or
102     *  equal to 48000, or 0 for no audio
103     * audio sample width (bytes/sample): 0 for no audio, or 1 or 2
104     * audio channels: 0 for no audio, or 1 or 2
105     */
106
107    /* check we have enough data to do all checks, otherwise the
108       0-padding may cause a wrong recognition */
109    if (p->buf_size < 20)
110        return 0;
111
112    /* check the video width */
113    number = AV_RL32(&p->buf[0]);
114    if ((number == 0) || (number > 1024))
115       return 0;
116
117    /* check the video height */
118    number = AV_RL32(&p->buf[4]);
119    if ((number == 0) || (number > 1024))
120       return 0;
121
122    /* check the audio sample rate */
123    number = AV_RL32(&p->buf[8]);
124    if ((number != 0) && ((number < 8000) | (number > 48000)))
125        return 0;
126
127    /* check the audio bytes/sample */
128    number = AV_RL32(&p->buf[12]);
129    if (number > 2)
130        return 0;
131
132    /* check the audio channels */
133    number = AV_RL32(&p->buf[16]);
134    if (number > 2)
135        return 0;
136
137    /* return half certainly since this check is a bit sketchy */
138    return AVPROBE_SCORE_MAX / 2;
139}
140
141static int idcin_read_header(AVFormatContext *s,
142                             AVFormatParameters *ap)
143{
144    AVIOContext *pb = s->pb;
145    IdcinDemuxContext *idcin = s->priv_data;
146    AVStream *st;
147    unsigned int width, height;
148    unsigned int sample_rate, bytes_per_sample, channels;
149
150    /* get the 5 header parameters */
151    width = avio_rl32(pb);
152    height = avio_rl32(pb);
153    sample_rate = avio_rl32(pb);
154    bytes_per_sample = avio_rl32(pb);
155    channels = avio_rl32(pb);
156
157    st = avformat_new_stream(s, NULL);
158    if (!st)
159        return AVERROR(ENOMEM);
160    avpriv_set_pts_info(st, 33, 1, IDCIN_FPS);
161    idcin->video_stream_index = st->index;
162    st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
163    st->codec->codec_id = CODEC_ID_IDCIN;
164    st->codec->codec_tag = 0;  /* no fourcc */
165    st->codec->width = width;
166    st->codec->height = height;
167
168    /* load up the Huffman tables into extradata */
169    st->codec->extradata_size = HUFFMAN_TABLE_SIZE;
170    st->codec->extradata = av_malloc(HUFFMAN_TABLE_SIZE);
171    if (avio_read(pb, st->codec->extradata, HUFFMAN_TABLE_SIZE) !=
172        HUFFMAN_TABLE_SIZE)
173        return AVERROR(EIO);
174
175    /* if sample rate is 0, assume no audio */
176    if (sample_rate) {
177        idcin->audio_present = 1;
178        st = avformat_new_stream(s, NULL);
179        if (!st)
180            return AVERROR(ENOMEM);
181        avpriv_set_pts_info(st, 33, 1, IDCIN_FPS);
182        idcin->audio_stream_index = st->index;
183        st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
184        st->codec->codec_tag = 1;
185        st->codec->channels = channels;
186        st->codec->sample_rate = sample_rate;
187        st->codec->bits_per_coded_sample = bytes_per_sample * 8;
188        st->codec->bit_rate = sample_rate * bytes_per_sample * 8 * channels;
189        st->codec->block_align = bytes_per_sample * channels;
190        if (bytes_per_sample == 1)
191            st->codec->codec_id = CODEC_ID_PCM_U8;
192        else
193            st->codec->codec_id = CODEC_ID_PCM_S16LE;
194
195        if (sample_rate % 14 != 0) {
196            idcin->audio_chunk_size1 = (sample_rate / 14) *
197            bytes_per_sample * channels;
198            idcin->audio_chunk_size2 = (sample_rate / 14 + 1) *
199                bytes_per_sample * channels;
200        } else {
201            idcin->audio_chunk_size1 = idcin->audio_chunk_size2 =
202                (sample_rate / 14) * bytes_per_sample * channels;
203        }
204        idcin->current_audio_chunk = 0;
205    } else
206        idcin->audio_present = 1;
207
208    idcin->next_chunk_is_video = 1;
209    idcin->pts = 0;
210
211    return 0;
212}
213
214static int idcin_read_packet(AVFormatContext *s,
215                             AVPacket *pkt)
216{
217    int ret;
218    unsigned int command;
219    unsigned int chunk_size;
220    IdcinDemuxContext *idcin = s->priv_data;
221    AVIOContext *pb = s->pb;
222    int i;
223    int palette_scale;
224    unsigned char r, g, b;
225    unsigned char palette_buffer[768];
226    uint32_t palette[256];
227
228    if (s->pb->eof_reached)
229        return AVERROR(EIO);
230
231    if (idcin->next_chunk_is_video) {
232        command = avio_rl32(pb);
233        if (command == 2) {
234            return AVERROR(EIO);
235        } else if (command == 1) {
236            /* trigger a palette change */
237            if (avio_read(pb, palette_buffer, 768) != 768)
238                return AVERROR(EIO);
239            /* scale the palette as necessary */
240            palette_scale = 2;
241            for (i = 0; i < 768; i++)
242                if (palette_buffer[i] > 63) {
243                    palette_scale = 0;
244                    break;
245                }
246
247            for (i = 0; i < 256; i++) {
248                r = palette_buffer[i * 3    ] << palette_scale;
249                g = palette_buffer[i * 3 + 1] << palette_scale;
250                b = palette_buffer[i * 3 + 2] << palette_scale;
251                palette[i] = (r << 16) | (g << 8) | (b);
252            }
253        }
254
255        chunk_size = avio_rl32(pb);
256        /* skip the number of decoded bytes (always equal to width * height) */
257        avio_skip(pb, 4);
258        chunk_size -= 4;
259        ret= av_get_packet(pb, pkt, chunk_size);
260        if (ret < 0)
261            return ret;
262        if (command == 1) {
263            uint8_t *pal;
264
265            pal = av_packet_new_side_data(pkt, AV_PKT_DATA_PALETTE,
266                                          AVPALETTE_SIZE);
267            if (ret < 0)
268                return ret;
269            memcpy(pal, palette, AVPALETTE_SIZE);
270        }
271        pkt->stream_index = idcin->video_stream_index;
272        pkt->pts = idcin->pts;
273    } else {
274        /* send out the audio chunk */
275        if (idcin->current_audio_chunk)
276            chunk_size = idcin->audio_chunk_size2;
277        else
278            chunk_size = idcin->audio_chunk_size1;
279        ret= av_get_packet(pb, pkt, chunk_size);
280        if (ret < 0)
281            return ret;
282        pkt->stream_index = idcin->audio_stream_index;
283        pkt->pts = idcin->pts;
284
285        idcin->current_audio_chunk ^= 1;
286        idcin->pts++;
287    }
288
289    if (idcin->audio_present)
290        idcin->next_chunk_is_video ^= 1;
291
292    return ret;
293}
294
295AVInputFormat ff_idcin_demuxer = {
296    .name           = "idcin",
297    .long_name      = NULL_IF_CONFIG_SMALL("id Cinematic format"),
298    .priv_data_size = sizeof(IdcinDemuxContext),
299    .read_probe     = idcin_probe,
300    .read_header    = idcin_read_header,
301    .read_packet    = idcin_read_packet,
302};
303