2 * FFM (ffserver live feed) encoder and decoder
3 * Copyright (c) 2001 Gerard Lantau.
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
22 /* The FFM file is made of blocks of fixed size */
23 #define FFM_HEADER_SIZE 14
24 #define PACKET_ID 0x666d
26 /* each packet contains frames (which can span several packets */
27 #define FRAME_HEADER_SIZE 5
28 #define FLAG_KEY_FRAME 0x01
30 typedef struct FFMStream {
39 typedef struct FFMContext {
40 /* only reading mode */
41 offset_t write_index, file_size;
43 UINT8 header[FRAME_HEADER_SIZE];
46 int first_packet; /* true if first packet, needed to set the discontinuity tag */
50 UINT8 *packet_ptr, *packet_end;
51 UINT8 packet[1]; /* must be last */
54 static void flush_packet(AVFormatContext *s)
56 FFMContext *ffm = s->priv_data;
58 ByteIOContext *pb = &s->pb;
60 fill_size = ffm->packet_end - ffm->packet_ptr;
61 memset(ffm->packet_ptr, 0, fill_size);
64 put_be16(pb, PACKET_ID);
65 put_be16(pb, fill_size);
66 put_be64(pb, ffm->pts);
67 h = ffm->frame_offset;
68 if (ffm->first_packet)
71 put_buffer(pb, ffm->packet, ffm->packet_end - ffm->packet);
73 /* prepare next packet */
74 ffm->frame_offset = 0; /* no key frame */
75 ffm->pts = 0; /* no pts */
76 ffm->packet_ptr = ffm->packet;
77 ffm->first_packet = 0;
80 /* 'first' is true if first data of a frame */
81 static void ffm_write_data(AVFormatContext *s,
85 FFMContext *ffm = s->priv_data;
88 if (first && ffm->frame_offset == 0)
89 ffm->frame_offset = ffm->packet_ptr - ffm->packet + FFM_HEADER_SIZE;
90 if (first && ffm->pts == 0)
93 /* write as many packets as needed */
95 len = ffm->packet_end - ffm->packet_ptr;
98 memcpy(ffm->packet_ptr, buf, len);
100 ffm->packet_ptr += len;
103 if (ffm->packet_ptr >= ffm->packet_end) {
104 /* special case : no pts in packet : we leave the current one */
113 static int ffm_write_header(AVFormatContext *s)
118 ByteIOContext *pb = &s->pb;
119 AVCodecContext *codec;
122 ffm = av_mallocz(sizeof(FFMContext) + FFM_PACKET_SIZE);
127 ffm->packet_size = FFM_PACKET_SIZE;
131 put_be32(pb, ffm->packet_size);
132 /* XXX: store write position in other file ? */
133 put_be64(pb, ffm->packet_size); /* current write position */
135 put_be32(pb, s->nb_streams);
137 for(i=0;i<s->nb_streams;i++) {
139 bit_rate += st->codec.bit_rate;
141 put_be32(pb, bit_rate);
143 /* list of streams */
144 for(i=0;i<s->nb_streams;i++) {
146 fst = av_mallocz(sizeof(FFMStream) + ffm->packet_size);
153 put_be32(pb, codec->codec_id);
154 put_byte(pb, codec->codec_type);
155 put_be32(pb, codec->bit_rate);
157 switch(codec->codec_type) {
158 case CODEC_TYPE_VIDEO:
159 put_be32(pb, (codec->frame_rate * 1000) / FRAME_RATE_BASE);
160 put_be16(pb, codec->width);
161 put_be16(pb, codec->height);
163 case CODEC_TYPE_AUDIO:
164 put_be32(pb, codec->sample_rate);
165 put_le16(pb, codec->channels);
168 /* hack to have real time */
169 fst->pts = gettime();
172 /* flush until end of block reached */
173 while ((url_ftell(pb) % ffm->packet_size) != 0)
176 put_flush_packet(pb);
178 /* init packet mux */
179 ffm->packet_ptr = ffm->packet;
180 ffm->packet_end = ffm->packet + ffm->packet_size - FFM_HEADER_SIZE;
181 ffm->frame_offset = 0;
183 ffm->first_packet = 1;
187 for(i=0;i<s->nb_streams;i++) {
197 static int ffm_write_packet(AVFormatContext *s, int stream_index,
198 UINT8 *buf, int size, int force_pts)
200 AVStream *st = s->streams[stream_index];
201 FFMStream *fst = st->priv_data;
203 UINT8 header[FRAME_HEADER_SIZE];
206 /* packet size & key_frame */
207 header[0] = stream_index;
209 if (st->codec.key_frame)
210 header[1] |= FLAG_KEY_FRAME;
211 header[2] = (size >> 16) & 0xff;
212 header[3] = (size >> 8) & 0xff;
213 header[4] = size & 0xff;
214 ffm_write_data(s, header, FRAME_HEADER_SIZE, pts, 1);
215 ffm_write_data(s, buf, size, pts, 0);
217 if (st->codec.codec_type == CODEC_TYPE_AUDIO) {
218 fst->pts += (INT64)((float)st->codec.frame_size / st->codec.sample_rate * 1000000.0);
220 fst->pts += (INT64)(1000000.0 * FRAME_RATE_BASE / (float)st->codec.frame_rate);
225 static int ffm_write_trailer(AVFormatContext *s)
227 ByteIOContext *pb = &s->pb;
228 FFMContext *ffm = s->priv_data;
232 if (ffm->packet_ptr > ffm->packet)
235 put_flush_packet(pb);
237 for(i=0;i<s->nb_streams;i++)
238 free(s->streams[i]->priv_data);
245 static int ffm_is_avail_data(AVFormatContext *s, int size)
247 FFMContext *ffm = s->priv_data;
248 offset_t pos, avail_size;
251 len = ffm->packet_end - ffm->packet_ptr;
254 pos = url_ftell(&s->pb);
255 if (pos == ffm->write_index) {
256 /* exactly at the end of stream */
258 } else if (pos < ffm->write_index) {
259 avail_size = ffm->write_index - pos;
261 avail_size = (ffm->file_size - pos) + (ffm->write_index - FFM_PACKET_SIZE);
263 avail_size = (avail_size / ffm->packet_size) * (ffm->packet_size - FFM_HEADER_SIZE) + len;
264 if (size <= avail_size)
270 /* first is true if we read the frame header */
271 static int ffm_read_data(AVFormatContext *s,
272 UINT8 *buf, int size, int first)
274 FFMContext *ffm = s->priv_data;
275 ByteIOContext *pb = &s->pb;
276 int len, fill_size, size1, frame_offset;
281 len = ffm->packet_end - ffm->packet_ptr;
285 if (url_ftell(pb) == ffm->file_size)
286 url_fseek(pb, ffm->packet_size, SEEK_SET);
287 get_be16(pb); /* PACKET_ID */
288 fill_size = get_be16(pb);
289 ffm->pts = get_be64(pb);
290 frame_offset = get_be16(pb);
291 get_buffer(pb, ffm->packet, ffm->packet_size - FFM_HEADER_SIZE);
292 ffm->packet_end = ffm->packet + (ffm->packet_size - FFM_HEADER_SIZE - fill_size);
293 /* if first packet or resynchronization packet, we must
294 handle it specifically */
295 if (ffm->first_packet || (frame_offset & 0x8000)) {
296 ffm->first_packet = 0;
297 ffm->packet_ptr = ffm->packet + (frame_offset & 0x7fff) - FFM_HEADER_SIZE;
301 ffm->packet_ptr = ffm->packet;
305 memcpy(buf, ffm->packet_ptr, len);
307 ffm->packet_ptr += len;
315 static int ffm_read_header(AVFormatContext *s, AVFormatParameters *ap)
320 ByteIOContext *pb = &s->pb;
321 AVCodecContext *codec;
325 ffm = av_mallocz(sizeof(FFMContext) + FFM_PACKET_SIZE);
333 if (tag != MKTAG('F', 'F', 'M', '1'))
335 ffm->packet_size = get_be32(pb);
336 if (ffm->packet_size != FFM_PACKET_SIZE)
338 ffm->write_index = get_be64(pb);
339 /* get also filesize */
340 if (!url_is_streamed(pb)) {
341 ffm->file_size = url_filesize(url_fileno(pb));
343 ffm->file_size = (UINT64_C(1) << 63) - 1;
346 s->nb_streams = get_be32(pb);
347 get_be32(pb); /* total bitrate */
348 /* read each stream */
349 for(i=0;i<s->nb_streams;i++) {
350 st = av_mallocz(sizeof(AVStream));
354 fst = av_mallocz(sizeof(FFMStream) + ffm->packet_size);
361 st->codec.codec_id = get_be32(pb);
362 st->codec.codec_type = get_byte(pb); /* codec_type */
363 codec->bit_rate = get_be32(pb);
365 switch(codec->codec_type) {
366 case CODEC_TYPE_VIDEO:
367 codec->frame_rate = ((INT64)get_be32(pb) * FRAME_RATE_BASE) / 1000;
368 codec->width = get_be16(pb);
369 codec->height = get_be16(pb);
371 case CODEC_TYPE_AUDIO:
372 codec->sample_rate = get_be32(pb);
373 codec->channels = get_le16(pb);
379 /* get until end of block reached */
380 while ((url_ftell(pb) % ffm->packet_size) != 0)
383 /* init packet demux */
384 ffm->packet_ptr = ffm->packet;
385 ffm->packet_end = ffm->packet;
386 ffm->frame_offset = 0;
388 ffm->read_state = READ_HEADER;
389 ffm->first_packet = 1;
392 for(i=0;i<s->nb_streams;i++) {
406 /* return < 0 if eof */
407 static int ffm_read_packet(AVFormatContext *s, AVPacket *pkt)
410 FFMContext *ffm = s->priv_data;
412 switch(ffm->read_state) {
414 if (!ffm_is_avail_data(s, FRAME_HEADER_SIZE))
417 printf("pos=%08Lx spos=%Lx, write_index=%Lx size=%Lx\n",
418 url_ftell(&s->pb), s->pb.pos, ffm->write_index, ffm->file_size);
420 if (ffm_read_data(s, ffm->header, FRAME_HEADER_SIZE, 1) != FRAME_HEADER_SIZE)
426 for(i=0;i<FRAME_HEADER_SIZE;i++)
427 printf("%02x ", ffm->header[i]);
431 ffm->read_state = READ_DATA;
434 size = (ffm->header[2] << 16) | (ffm->header[3] << 8) | ffm->header[4];
435 if (!ffm_is_avail_data(s, size)) {
439 av_new_packet(pkt, size);
440 pkt->stream_index = ffm->header[0];
441 if (ffm->header[1] & FLAG_KEY_FRAME)
442 pkt->flags |= PKT_FLAG_KEY;
444 ffm->read_state = READ_HEADER;
445 if (ffm_read_data(s, pkt->data, size, 0) != size) {
446 /* bad case: desynchronized packet. we cancel all the packet loading */
457 /* pos is between 0 and file_size - FFM_PACKET_SIZE. It is translated
458 by the write position inside this function */
459 static void ffm_seek1(AVFormatContext *s, offset_t pos1)
461 FFMContext *ffm = s->priv_data;
462 ByteIOContext *pb = &s->pb;
465 pos = pos1 + ffm->write_index;
466 if (pos >= ffm->file_size)
467 pos -= (ffm->file_size - FFM_PACKET_SIZE);
469 printf("seek to %Lx -> %Lx\n", pos1, pos);
471 url_fseek(pb, pos, SEEK_SET);
474 static INT64 get_pts(AVFormatContext *s, offset_t pos)
476 ByteIOContext *pb = &s->pb;
483 printf("pts=%0.6f\n", pts / 1000000.0);
488 /* seek to a given time in the file. The file read pointer is
489 positionned at or before pts. XXX: the following code is quite
491 static int ffm_seek(AVFormatContext *s, INT64 wanted_pts)
493 FFMContext *ffm = s->priv_data;
494 offset_t pos_min, pos_max, pos;
495 INT64 pts_min, pts_max, pts;
499 printf("wanted_pts=%0.6f\n", wanted_pts / 1000000.0);
501 /* find the position using linear interpolation (better than
502 dichotomy in typical cases) */
504 pos_max = ffm->file_size - 2 * FFM_PACKET_SIZE;
505 while (pos_min <= pos_max) {
506 pts_min = get_pts(s, pos_min);
507 pts_max = get_pts(s, pos_max);
508 /* linear interpolation */
509 pos1 = (double)(pos_max - pos_min) * (double)(wanted_pts - pts_min) /
510 (double)(pts_max - pts_min);
511 pos = (((INT64)pos1) / FFM_PACKET_SIZE) * FFM_PACKET_SIZE;
514 else if (pos >= pos_max)
516 pts = get_pts(s, pos);
517 /* check if we are lucky */
518 if (pts == wanted_pts) {
520 } else if (pts > wanted_pts) {
521 pos_max = pos - FFM_PACKET_SIZE;
523 pos_min = pos + FFM_PACKET_SIZE;
528 pos -= FFM_PACKET_SIZE;
534 offset_t ffm_read_write_index(int fd)
540 lseek(fd, 8, SEEK_SET);
544 pos |= buf[i] << (56 - i * 8);
548 void ffm_write_write_index(int fd, offset_t pos)
554 buf[i] = (pos >> (56 - i * 8)) & 0xff;
555 lseek(fd, 8, SEEK_SET);
559 void ffm_set_write_index(AVFormatContext *s, offset_t pos, offset_t file_size)
561 FFMContext *ffm = s->priv_data;
562 ffm->write_index = pos;
563 ffm->file_size = file_size;
566 static int ffm_read_close(AVFormatContext *s)
571 for(i=0;i<s->nb_streams;i++) {
579 AVFormat ffm_format = {
584 /* not really used */