summaryrefslogtreecommitdiff
path: root/libavformat/segafilmenc.c
blob: f1048ff8082a264d3eabf8175392849c239e1405 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
/*
 * Sega FILM Format (CPK) Muxer
 * Copyright (C) 2003 The FFmpeg project
 * Copyright (C) 2018 Misty De Meo
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file
 * Sega FILM (.cpk) file muxer
 * @author Misty De Meo <misty@brew.sh>
 *
 * @see For more information regarding the Sega FILM file format, visit:
 *   http://wiki.multimedia.cx/index.php?title=Sega_FILM
 */

#include "libavutil/intreadwrite.h"
#include "avformat.h"
#include "internal.h"
#include "avio_internal.h"

typedef struct FILMPacket {
    int audio;
    int keyframe;
    int32_t pts;
    int32_t duration;
    int32_t size;
    int32_t index;
    struct FILMPacket *next;
} FILMPacket;

typedef struct FILMOutputContext {
    const AVClass *class;
    int audio_index;
    int video_index;
    int64_t stab_pos;
    FILMPacket *start;
    FILMPacket *last;
    int64_t packet_count;
} FILMOutputContext;

static int film_write_packet_to_header(AVFormatContext *format_context, FILMPacket *pkt)
{
    AVIOContext *pb = format_context->pb;
    /* The bits in these two 32-bit integers contain info about the contents of this sample */
    int32_t info1 = 0;
    int32_t info2 = 0;

    if (pkt->audio) {
        /* Always the same, carries no more information than "this is audio" */
        info1 = 0xFFFFFFFF;
        info2 = 1;
    } else {
        info1 = pkt->pts;
        info2 = pkt->duration;
        /* The top bit being set indicates a key frame */
        if (!pkt->keyframe)
            info1 |= (1 << 31);
    }

    /* Write the 16-byte sample info packet to the STAB chunk in the header */
    avio_wb32(pb, pkt->index);
    avio_wb32(pb, pkt->size);
    avio_wb32(pb, info1);
    avio_wb32(pb, info2);

    return 0;
}

static int film_write_packet(AVFormatContext *format_context, AVPacket *pkt)
{
    FILMPacket *metadata;
    AVIOContext *pb = format_context->pb;
    FILMOutputContext *film = format_context->priv_data;
    int encoded_buf_size = 0;
    enum AVCodecID codec_id;

    /* Track the metadata used to write the header and add it to the linked list */
    metadata = av_mallocz(sizeof(FILMPacket));
    if (!metadata)
        return AVERROR(ENOMEM);
    metadata->audio = pkt->stream_index == film->audio_index;
    metadata->keyframe = pkt->flags & AV_PKT_FLAG_KEY;
    metadata->pts = pkt->pts;
    metadata->duration = pkt->duration;
    metadata->size = pkt->size;
    if (film->last == NULL) {
        metadata->index = 0;
    } else {
        metadata->index = film->last->index + film->last->size;
        film->last->next = metadata;
    }
    metadata->next = NULL;
    if (film->start == NULL)
        film->start = metadata;
    film->packet_count++;
    film->last = metadata;

    codec_id = format_context->streams[pkt->stream_index]->codecpar->codec_id;

    /* Sega Cinepak has an extra two-byte header; write dummy data there,
     * then adjust the cvid header to accommodate for the extra size */
    if (codec_id == AV_CODEC_ID_CINEPAK) {
        encoded_buf_size = AV_RB24(&pkt->data[1]);
        /* Already Sega Cinepak, so no need to reformat the packets */
        if (encoded_buf_size != pkt->size && (pkt->size % encoded_buf_size) != 0) {
            avio_write(pb, pkt->data, pkt->size);
        } else {
            uint8_t padding[2] = {0, 0};
            /* In Sega Cinepak, the reported size in the Cinepak header is
             * 8 bytes too short. However, the size in the STAB section of the header
             * is correct, taking into account the extra two bytes. */
            AV_WB24(&pkt->data[1], pkt->size - 8 + 2);
            metadata->size += 2;

            avio_write(pb, pkt->data, 10);
            avio_write(pb, padding, 2);
            avio_write(pb, &pkt->data[10], pkt->size - 10);
        }
    } else {
        /* Other formats can just be written as-is */
        avio_write(pb, pkt->data, pkt->size);
    }

    return 0;
}

static int get_audio_codec_id(enum AVCodecID codec_id)
{
    /* 0 (PCM) and 2 (ADX) are the only known values */
    switch (codec_id) {
    case AV_CODEC_ID_PCM_S8_PLANAR:
    case AV_CODEC_ID_PCM_S16BE_PLANAR:
        return 0;
    case AV_CODEC_ID_ADPCM_ADX:
        return 2;
    default:
        return -1;
    }
}

static int film_init(AVFormatContext *format_context)
{
    AVStream *audio = NULL;
    FILMOutputContext *film = format_context->priv_data;
    film->audio_index = -1;
    film->video_index = -1;
    film->stab_pos = 0;
    film->packet_count = 0;
    film->start = NULL;
    film->last = NULL;

    for (int i = 0; i < format_context->nb_streams; i++) {
        AVStream *st = format_context->streams[i];
        if (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
            if (film->audio_index > -1) {
                av_log(format_context, AV_LOG_ERROR, "Sega FILM allows a maximum of one audio stream.\n");
                return AVERROR(EINVAL);
            }
            film->audio_index = i;
            audio = st;
        }

        if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
            if (film->video_index > -1) {
                av_log(format_context, AV_LOG_ERROR, "Sega FILM allows a maximum of one video stream.\n");
                return AVERROR(EINVAL);
            }
            film->video_index = i;
        }

        if (film->video_index == -1) {
            av_log(format_context, AV_LOG_ERROR, "No video stream present.\n");
            return AVERROR(EINVAL);
        }
    }

    if (audio != NULL && get_audio_codec_id(audio->codecpar->codec_id) < 0) {
        av_log(format_context, AV_LOG_ERROR, "Incompatible audio stream format.\n");
        return AVERROR(EINVAL);
    }

    return 0;
}

static int shift_data(AVFormatContext *format_context, int64_t shift_size)
{
    int ret = 0;
    int64_t pos, pos_end = avio_tell(format_context->pb);
    uint8_t *buf, *read_buf[2];
    int read_buf_id = 0;
    int read_size[2];
    AVIOContext *read_pb;

    buf = av_malloc(shift_size * 2);
    if (!buf)
        return AVERROR(ENOMEM);
    read_buf[0] = buf;
    read_buf[1] = buf + shift_size;

    /* Write the header at the beginning of the file, shifting all content as necessary;
     * based on the approach used by MOV faststart. */
    avio_flush(format_context->pb);
    ret = format_context->io_open(format_context, &read_pb, format_context->url, AVIO_FLAG_READ, NULL);
    if (ret < 0) {
        av_log(format_context, AV_LOG_ERROR, "Unable to re-open %s output file to "
               "write the header\n", format_context->url);
        av_free(buf);
        return ret;
    }

    /* mark the end of the shift to up to the last data we wrote, and get ready
     * for writing */
    pos_end = avio_tell(format_context->pb);
    avio_seek(format_context->pb, shift_size, SEEK_SET);

    /* start reading at where the new header will be placed */
    avio_seek(read_pb, 0, SEEK_SET);
    pos = avio_tell(read_pb);

#define READ_BLOCK do {                                                             \
    read_size[read_buf_id] = avio_read(read_pb, read_buf[read_buf_id], shift_size);  \
    read_buf_id ^= 1;                                                               \
} while (0)

    /* shift data by chunk of at most shift_size */
    READ_BLOCK;
    do {
        int n;
        READ_BLOCK;
        n = read_size[read_buf_id];
        if (n <= 0)
            break;
        avio_write(format_context->pb, read_buf[read_buf_id], n);
        pos += n;
    } while (pos < pos_end);
    ff_format_io_close(format_context, &read_pb);

    av_free(buf);
    return 0;
}

static int film_write_header(AVFormatContext *format_context)
{
    int ret = 0;
    int64_t sample_table_size, stabsize, headersize;
    int8_t audio_codec;
    AVIOContext *pb = format_context->pb;
    FILMOutputContext *film = format_context->priv_data;
    FILMPacket *prev, *packet;
    AVStream *audio = NULL;
    AVStream *video = NULL;

    /* Calculate how much we need to reserve for the header;
     * this is the amount the rest of the data will be shifted up by. */
    sample_table_size = film->packet_count * 16;
    stabsize = 16 + sample_table_size;
    headersize = 16 + /* FILM header base */
                 32 + /* FDSC chunk */
                 stabsize;

    ret = shift_data(format_context, headersize);
    if (ret < 0)
        return ret;
    /* Seek back to the beginning to start writing the header now */
    avio_seek(pb, 0, SEEK_SET);

    if (film->audio_index > -1)
        audio = format_context->streams[film->audio_index];
    if (film->video_index > -1)
        video = format_context->streams[film->video_index];

    if (audio != NULL) {
        audio_codec = get_audio_codec_id(audio->codecpar->codec_id);
        if (audio_codec < 0) {
            av_log(format_context, AV_LOG_ERROR, "Incompatible audio stream format.\n");
            return AVERROR(EINVAL);
        }
    }

    if (video->codecpar->format != AV_PIX_FMT_RGB24) {
        av_log(format_context, AV_LOG_ERROR, "Pixel format must be rgb24.\n");
        return AVERROR(EINVAL);
    }

    /* First, write the FILM header; this is very simple */

    ffio_wfourcc(pb, "FILM");
    avio_wb32(pb, 48 + stabsize);
    /* This seems to be okay to hardcode, since this muxer targets 1.09 features;
     * videos produced by this muxer are readable by 1.08 and lower players. */
    ffio_wfourcc(pb, "1.09");
    /* I have no idea what this field does, might be reserved */
    avio_wb32(pb, 0);

    /* Next write the FDSC (file description) chunk */
    ffio_wfourcc(pb, "FDSC");
    avio_wb32(pb, 0x20); /* Size of FDSC chunk */

    /* The only two supported codecs; raw video is rare */
    switch (video->codecpar->codec_id) {
    case AV_CODEC_ID_CINEPAK:
        ffio_wfourcc(pb, "cvid");
        break;
    case AV_CODEC_ID_RAWVIDEO:
        ffio_wfourcc(pb, "raw ");
        break;
    default:
        av_log(format_context, AV_LOG_ERROR, "Incompatible video stream format.\n");
        return AVERROR(EINVAL);
    }

    avio_wb32(pb, video->codecpar->height);
    avio_wb32(pb, video->codecpar->width);
    avio_w8(pb, 24); /* Bits per pixel - observed to always be 24 */

    if (audio != NULL) {
        avio_w8(pb, audio->codecpar->channels); /* Audio channels */
        avio_w8(pb, audio->codecpar->bits_per_coded_sample); /* Audio bit depth */
        avio_w8(pb, audio_codec); /* Compression - 0 is PCM, 2 is ADX */
        avio_wb16(pb, audio->codecpar->sample_rate); /* Audio sampling rate */
    } else {
        /* Set all these fields to 0 if there's no audio */
        avio_w8(pb, 0);
        avio_w8(pb, 0);
        avio_w8(pb, 0);
        avio_wb16(pb, 0);
    }

    /* I have no idea what this pair of fields does either, might be reserved */
    avio_wb32(pb, 0);
    avio_wb16(pb, 0);

    /* Finally, write the STAB (sample table) chunk */
    ffio_wfourcc(pb, "STAB");
    avio_wb32(pb, 16 + (film->packet_count * 16));
    /* Framerate base frequency. Here we're assuming that the frame rate is even.
     * In real world Sega FILM files, there are usually a couple of approaches:
     * a) framerate base frequency is the same as the framerate, and ticks
     *    increment by 1 every frame, or
     * b) framerate base frequency is a much larger number, and ticks
     *    increment by larger steps every frame.
     * The latter occurs even in cases where the frame rate is even; for example, in
     * Lunar: Silver Star Story, the base frequency is 600 and each frame, the ticks
     * are incremented by 25 for an evenly spaced framerate of 24fps. */
    avio_wb32(pb, av_q2d(av_inv_q(video->time_base)));

    avio_wb32(pb, film->packet_count);

    avio_flush(pb);

    /* Finally, write out each packet's data to the header */
    packet = film->start;
    while (packet != NULL) {
        film_write_packet_to_header(format_context, packet);
        prev = packet;
        packet = packet->next;
        av_freep(&prev);
    }

    return 0;
}

static const AVClass film_muxer_class = {
    .class_name     = "Sega FILM muxer",
    .item_name      = av_default_item_name,
    .version        = LIBAVUTIL_VERSION_INT,
};

AVOutputFormat ff_segafilm_muxer = {
    .name           = "film_cpk",
    .long_name      = NULL_IF_CONFIG_SMALL("Sega FILM / CPK"),
    .extensions     = "cpk",
    .priv_data_size = sizeof(FILMOutputContext),
    .audio_codec    = AV_CODEC_ID_PCM_S16BE_PLANAR,
    .video_codec    = AV_CODEC_ID_CINEPAK,
    .init           = film_init,
    .write_trailer  = film_write_header,
    .write_packet   = film_write_packet,
    .priv_class     = &film_muxer_class,
};