2 * Sega FILM Format (CPK) Muxer
3 * Copyright (C) 2003 The FFmpeg project
4 * Copyright (C) 2018 Misty De Meo
6 * This file is part of FFmpeg.
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
25 * Sega FILM (.cpk) file muxer
26 * @author Misty De Meo <misty@brew.sh>
28 * @see For more information regarding the Sega FILM file format, visit:
29 * http://wiki.multimedia.cx/index.php?title=Sega_FILM
32 #include "libavutil/intreadwrite.h"
35 #include "avio_internal.h"
37 typedef struct FILMPacket {
44 struct FILMPacket *next;
47 typedef struct FILMOutputContext {
57 static int film_write_packet_to_header(AVFormatContext *format_context, FILMPacket *pkt)
59 AVIOContext *pb = format_context->pb;
60 /* The bits in these two 32-bit integers contain info about the contents of this sample */
65 /* Always the same, carries no more information than "this is audio" */
70 info2 = pkt->duration;
71 /* The top bit being set indicates a key frame */
76 /* Write the 16-byte sample info packet to the STAB chunk in the header */
77 avio_wb32(pb, pkt->index);
78 avio_wb32(pb, pkt->size);
85 static int film_write_packet(AVFormatContext *format_context, AVPacket *pkt)
88 AVIOContext *pb = format_context->pb;
89 FILMOutputContext *film = format_context->priv_data;
90 int encoded_buf_size = 0;
91 enum AVCodecID codec_id;
93 /* Track the metadata used to write the header and add it to the linked list */
94 metadata = av_mallocz(sizeof(FILMPacket));
96 return AVERROR(ENOMEM);
97 metadata->audio = pkt->stream_index == film->audio_index;
98 metadata->keyframe = pkt->flags & AV_PKT_FLAG_KEY;
99 metadata->pts = pkt->pts;
100 metadata->duration = pkt->duration;
101 metadata->size = pkt->size;
102 if (film->last == NULL) {
105 metadata->index = film->last->index + film->last->size;
106 film->last->next = metadata;
108 metadata->next = NULL;
109 if (film->start == NULL)
110 film->start = metadata;
111 film->packet_count++;
112 film->last = metadata;
114 codec_id = format_context->streams[pkt->stream_index]->codecpar->codec_id;
116 /* Sega Cinepak has an extra two-byte header; write dummy data there,
117 * then adjust the cvid header to accommodate for the extra size */
118 if (codec_id == AV_CODEC_ID_CINEPAK) {
119 encoded_buf_size = AV_RB24(&pkt->data[1]);
120 /* Already Sega Cinepak, so no need to reformat the packets */
121 if (encoded_buf_size != pkt->size && (pkt->size % encoded_buf_size) != 0) {
122 avio_write(pb, pkt->data, pkt->size);
124 uint8_t padding[2] = {0, 0};
125 /* In Sega Cinepak, the reported size in the Cinepak header is
126 * 8 bytes too short. However, the size in the STAB section of the header
127 * is correct, taking into account the extra two bytes. */
128 AV_WB24(&pkt->data[1], pkt->size - 8 + 2);
131 avio_write(pb, pkt->data, 10);
132 avio_write(pb, padding, 2);
133 avio_write(pb, &pkt->data[10], pkt->size - 10);
136 /* Other formats can just be written as-is */
137 avio_write(pb, pkt->data, pkt->size);
143 static int get_audio_codec_id(enum AVCodecID codec_id)
145 /* 0 (PCM) and 2 (ADX) are the only known values */
147 case AV_CODEC_ID_PCM_S8_PLANAR:
148 case AV_CODEC_ID_PCM_S16BE_PLANAR:
151 case AV_CODEC_ID_ADPCM_ADX:
159 static int film_init(AVFormatContext *format_context)
161 AVStream *audio = NULL;
162 FILMOutputContext *film = format_context->priv_data;
163 film->audio_index = -1;
164 film->video_index = -1;
166 film->packet_count = 0;
170 for (int i = 0; i < format_context->nb_streams; i++) {
171 AVStream *st = format_context->streams[i];
172 if (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
173 if (film->audio_index > -1) {
174 av_log(format_context, AV_LOG_ERROR, "Sega FILM allows a maximum of one audio stream.\n");
175 return AVERROR(EINVAL);
177 film->audio_index = i;
181 if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
182 if (film->video_index > -1) {
183 av_log(format_context, AV_LOG_ERROR, "Sega FILM allows a maximum of one video stream.\n");
184 return AVERROR(EINVAL);
186 film->video_index = i;
189 if (film->video_index == -1) {
190 av_log(format_context, AV_LOG_ERROR, "No video stream present.\n");
191 return AVERROR(EINVAL);
195 if (audio != NULL && get_audio_codec_id(audio->codecpar->codec_id) < 0) {
196 av_log(format_context, AV_LOG_ERROR, "Incompatible audio stream format.\n");
197 return AVERROR(EINVAL);
203 static int shift_data(AVFormatContext *format_context, int64_t shift_size)
206 int64_t pos, pos_end = avio_tell(format_context->pb);
207 uint8_t *buf, *read_buf[2];
210 AVIOContext *read_pb;
212 buf = av_malloc(shift_size * 2);
214 return AVERROR(ENOMEM);
216 read_buf[1] = buf + shift_size;
218 /* Write the header at the beginning of the file, shifting all content as necessary;
219 * based on the approach used by MOV faststart. */
220 avio_flush(format_context->pb);
221 ret = format_context->io_open(format_context, &read_pb, format_context->url, AVIO_FLAG_READ, NULL);
223 av_log(format_context, AV_LOG_ERROR, "Unable to re-open %s output file to "
224 "write the header\n", format_context->url);
229 /* mark the end of the shift to up to the last data we wrote, and get ready
231 pos_end = avio_tell(format_context->pb);
232 avio_seek(format_context->pb, shift_size, SEEK_SET);
234 /* start reading at where the new header will be placed */
235 avio_seek(read_pb, 0, SEEK_SET);
236 pos = avio_tell(read_pb);
238 #define READ_BLOCK do { \
239 read_size[read_buf_id] = avio_read(read_pb, read_buf[read_buf_id], shift_size); \
243 /* shift data by chunk of at most shift_size */
248 n = read_size[read_buf_id];
251 avio_write(format_context->pb, read_buf[read_buf_id], n);
253 } while (pos < pos_end);
254 ff_format_io_close(format_context, &read_pb);
260 static int film_write_header(AVFormatContext *format_context)
263 int64_t sample_table_size, stabsize, headersize;
265 AVIOContext *pb = format_context->pb;
266 FILMOutputContext *film = format_context->priv_data;
267 FILMPacket *prev, *packet;
268 AVStream *audio = NULL;
269 AVStream *video = NULL;
271 /* Calculate how much we need to reserve for the header;
272 * this is the amount the rest of the data will be shifted up by. */
273 sample_table_size = film->packet_count * 16;
274 stabsize = 16 + sample_table_size;
275 headersize = 16 + /* FILM header base */
276 32 + /* FDSC chunk */
279 ret = shift_data(format_context, headersize);
282 /* Seek back to the beginning to start writing the header now */
283 avio_seek(pb, 0, SEEK_SET);
285 if (film->audio_index > -1)
286 audio = format_context->streams[film->audio_index];
287 if (film->video_index > -1)
288 video = format_context->streams[film->video_index];
291 audio_codec = get_audio_codec_id(audio->codecpar->codec_id);
292 if (audio_codec < 0) {
293 av_log(format_context, AV_LOG_ERROR, "Incompatible audio stream format.\n");
294 return AVERROR(EINVAL);
298 if (video->codecpar->format != AV_PIX_FMT_RGB24) {
299 av_log(format_context, AV_LOG_ERROR, "Pixel format must be rgb24.\n");
300 return AVERROR(EINVAL);
303 /* First, write the FILM header; this is very simple */
305 ffio_wfourcc(pb, "FILM");
306 avio_wb32(pb, 48 + stabsize);
307 /* This seems to be okay to hardcode, since this muxer targets 1.09 features;
308 * videos produced by this muxer are readable by 1.08 and lower players. */
309 ffio_wfourcc(pb, "1.09");
310 /* I have no idea what this field does, might be reserved */
313 /* Next write the FDSC (file description) chunk */
314 ffio_wfourcc(pb, "FDSC");
315 avio_wb32(pb, 0x20); /* Size of FDSC chunk */
317 /* The only two supported codecs; raw video is rare */
318 switch (video->codecpar->codec_id) {
319 case AV_CODEC_ID_CINEPAK:
320 ffio_wfourcc(pb, "cvid");
322 case AV_CODEC_ID_RAWVIDEO:
323 ffio_wfourcc(pb, "raw ");
326 av_log(format_context, AV_LOG_ERROR, "Incompatible video stream format.\n");
327 return AVERROR(EINVAL);
330 avio_wb32(pb, video->codecpar->height);
331 avio_wb32(pb, video->codecpar->width);
332 avio_w8(pb, 24); /* Bits per pixel - observed to always be 24 */
335 avio_w8(pb, audio->codecpar->channels); /* Audio channels */
336 avio_w8(pb, audio->codecpar->bits_per_coded_sample); /* Audio bit depth */
337 avio_w8(pb, audio_codec); /* Compression - 0 is PCM, 2 is ADX */
338 avio_wb16(pb, audio->codecpar->sample_rate); /* Audio sampling rate */
340 /* Set all these fields to 0 if there's no audio */
347 /* I have no idea what this pair of fields does either, might be reserved */
351 /* Finally, write the STAB (sample table) chunk */
352 ffio_wfourcc(pb, "STAB");
353 avio_wb32(pb, 16 + (film->packet_count * 16));
354 /* Framerate base frequency. Here we're assuming that the frame rate is even.
355 * In real world Sega FILM files, there are usually a couple of approaches:
356 * a) framerate base frequency is the same as the framerate, and ticks
357 * increment by 1 every frame, or
358 * b) framerate base frequency is a much larger number, and ticks
359 * increment by larger steps every frame.
360 * The latter occurs even in cases where the frame rate is even; for example, in
361 * Lunar: Silver Star Story, the base frequency is 600 and each frame, the ticks
362 * are incremented by 25 for an evenly spaced framerate of 24fps. */
363 avio_wb32(pb, av_q2d(av_inv_q(video->time_base)));
365 avio_wb32(pb, film->packet_count);
369 /* Finally, write out each packet's data to the header */
370 packet = film->start;
371 while (packet != NULL) {
372 film_write_packet_to_header(format_context, packet);
374 packet = packet->next;
381 static const AVClass film_muxer_class = {
382 .class_name = "Sega FILM muxer",
383 .item_name = av_default_item_name,
384 .version = LIBAVUTIL_VERSION_INT,
387 AVOutputFormat ff_segafilm_muxer = {
389 .long_name = NULL_IF_CONFIG_SMALL("Sega FILM / CPK"),
391 .priv_data_size = sizeof(FILMOutputContext),
392 .audio_codec = AV_CODEC_ID_PCM_S16BE_PLANAR,
393 .video_codec = AV_CODEC_ID_CINEPAK,
395 .write_trailer = film_write_header,
396 .write_packet = film_write_packet,
397 .priv_class = &film_muxer_class,