libav/ffm.c

   1 /*
   2  * FFM (ffserver live feed) encoder and decoder
   3  * Copyright (c) 2001 Gerard Lantau.
   4  *
   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.
   9  *
  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.
  14  *
  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.
  18  */
  19 #include <stdlib.h>
  20 #include <stdio.h>
  21 #include <errno.h>
  22 #include <string.h>
  23 #include <unistd.h>
  24
  25 #include "avformat.h"
  26
  27 /* The FFM file is made of blocks of fixed size */
  28 #define FFM_HEADER_SIZE 14
  29 #define PACKET_ID       0x666d
  30
  31 /* each packet contains frames (which can span several packets */
  32 #define FRAME_HEADER_SIZE    5
  33 #define FLAG_KEY_FRAME       0x01
  34
  35 typedef struct FFMStream {
  36     INT64 pts;
  37 } FFMStream;
  38
  39 enum {
  40     READ_HEADER,
  41     READ_DATA,
  42 };
  43
  44 typedef struct FFMContext {
  45     /* only reading mode */
  46     offset_t write_index, file_size;
  47     int read_state;
  48     UINT8 header[FRAME_HEADER_SIZE];
  49
  50     /* read and write */
  51     int first_packet; /* true if first packet, needed to set the discontinuity tag */
  52     int packet_size;
  53     int frame_offset;
  54     INT64 pts;
  55     UINT8 *packet_ptr, *packet_end;
  56     UINT8 packet[1]; /* must be last */
  57 } FFMContext;
  58
  59 static void flush_packet(AVFormatContext *s)
  60 {
  61     FFMContext *ffm = s->priv_data;
  62     int fill_size, h;
  63     ByteIOContext *pb = &s->pb;
  64
  65     fill_size = ffm->packet_end - ffm->packet_ptr;
  66     memset(ffm->packet_ptr, 0, fill_size);
  67
  68     /* put header */
  69     put_be16(pb, PACKET_ID);
  70     put_be16(pb, fill_size);
  71     put_be64(pb, ffm->pts);
  72     h = ffm->frame_offset;
  73     if (ffm->first_packet)
  74         h |= 0x8000;
  75     put_be16(pb, h);
  76     put_buffer(pb, ffm->packet, ffm->packet_end - ffm->packet);
  77
  78     /* prepare next packet */
  79     ffm->frame_offset = 0; /* no key frame */
  80     ffm->pts = 0; /* no pts */
  81     ffm->packet_ptr = ffm->packet;
  82     ffm->first_packet = 0;
  83 }
  84
  85 /* 'first' is true if first data of a frame */
  86 static void ffm_write_data(AVFormatContext *s,
  87                            UINT8 *buf, int size,
  88                            INT64 pts, int first)
  89 {
  90     FFMContext *ffm = s->priv_data;
  91     int len;
  92
  93     if (first && ffm->frame_offset == 0)
  94         ffm->frame_offset = ffm->packet_ptr - ffm->packet + FFM_HEADER_SIZE;
  95     if (first && ffm->pts == 0)
  96         ffm->pts = pts;
  97
  98     /* write as many packets as needed */
  99     while (size > 0) {
 100         len = ffm->packet_end - ffm->packet_ptr;
 101         if (len > size)
 102             len = size;
 103         memcpy(ffm->packet_ptr, buf, len);
 104
 105         ffm->packet_ptr += len;
 106         buf += len;
 107         size -= len;
 108         if (ffm->packet_ptr >= ffm->packet_end) {
 109             /* special case : no pts in packet : we leave the current one */
 110             if (ffm->pts == 0)
 111                 ffm->pts = pts;
 112
 113             flush_packet(s);
 114         }
 115     }
 116 }
 117
 118 static int ffm_write_header(AVFormatContext *s)
 119 {
 120     AVStream *st;
 121     FFMStream *fst;
 122     FFMContext *ffm;
 123     ByteIOContext *pb = &s->pb;
 124     AVCodecContext *codec;
 125     int bit_rate, i;
 126
 127     ffm = av_mallocz(sizeof(FFMContext) + FFM_PACKET_SIZE);
 128     if (!ffm)
 129         return -1;
 130
 131     s->priv_data = ffm;
 132     ffm->packet_size = FFM_PACKET_SIZE;
 133
 134     /* header */
 135     put_tag(pb, "FFM1");
 136     put_be32(pb, ffm->packet_size);
 137     /* XXX: store write position in other file ? */
 138     put_be64(pb, ffm->packet_size); /* current write position */
 139
 140     put_be32(pb, s->nb_streams);
 141     bit_rate = 0;
 142     for(i=0;i<s->nb_streams;i++) {
 143         st = s->streams[i];
 144         bit_rate += st->codec.bit_rate;
 145     }
 146     put_be32(pb, bit_rate);
 147
 148     /* list of streams */
 149     for(i=0;i<s->nb_streams;i++) {
 150         st = s->streams[i];
 151         fst = av_mallocz(sizeof(FFMStream) + ffm->packet_size);
 152         if (!fst)
 153             goto fail;
 154         st->priv_data = fst;
 155
 156         codec = &st->codec;
 157         /* generic info */
 158         put_be32(pb, codec->codec_id);
 159         put_byte(pb, codec->codec_type);
 160         put_be32(pb, codec->bit_rate);
 161         /* specific info */
 162         switch(codec->codec_type) {
 163         case CODEC_TYPE_VIDEO:
 164             put_be32(pb, (codec->frame_rate * 1000) / FRAME_RATE_BASE);
 165             put_be16(pb, codec->width);
 166             put_be16(pb, codec->height);
 167             break;
 168         case CODEC_TYPE_AUDIO:
 169             put_be32(pb, codec->sample_rate);
 170             put_le16(pb, codec->channels);
 171             break;
 172         }
 173         /* hack to have real time */
 174         fst->pts = gettime();
 175     }
 176
 177     /* flush until end of block reached */
 178     while ((url_ftell(pb) % ffm->packet_size) != 0)
 179         put_byte(pb, 0);
 180
 181     put_flush_packet(pb);
 182
 183     /* init packet mux */
 184     ffm->packet_ptr = ffm->packet;
 185     ffm->packet_end = ffm->packet + ffm->packet_size - FFM_HEADER_SIZE;
 186     ffm->frame_offset = 0;
 187     ffm->pts = 0;
 188     ffm->first_packet = 1;
 189
 190     return 0;
 191  fail:
 192     for(i=0;i<s->nb_streams;i++) {
 193         st = s->streams[i];
 194         fst = st->priv_data;
 195         if (fst)
 196             free(fst);
 197     }
 198     free(ffm);
 199     return -1;
 200 }
 201
 202 static int ffm_write_packet(AVFormatContext *s, int stream_index,
 203                             UINT8 *buf, int size)
 204 {
 205     AVStream *st = s->streams[stream_index];
 206     FFMStream *fst = st->priv_data;
 207     INT64 pts;
 208     UINT8 header[FRAME_HEADER_SIZE];
 209
 210     pts = fst->pts;
 211     /* packet size & key_frame */
 212     header[0] = stream_index;
 213     header[1] = 0;
 214     if (st->codec.key_frame)
 215         header[1] |= FLAG_KEY_FRAME;
 216     header[2] = (size >> 16) & 0xff;
 217     header[3] = (size >> 8) & 0xff;
 218     header[4] = size & 0xff;
 219     ffm_write_data(s, header, FRAME_HEADER_SIZE, pts, 1);
 220     ffm_write_data(s, buf, size, pts, 0);
 221
 222     if (st->codec.codec_type == CODEC_TYPE_AUDIO) {
 223         fst->pts += (INT64)((float)st->codec.frame_size / st->codec.sample_rate * 1000000.0);
 224     } else {
 225         fst->pts += (INT64)(1000000.0 * FRAME_RATE_BASE / (float)st->codec.frame_rate);
 226     }
 227     return 0;
 228 }
 229
 230 static int ffm_write_trailer(AVFormatContext *s)
 231 {
 232     ByteIOContext *pb = &s->pb;
 233     FFMContext *ffm = s->priv_data;
 234     int i;
 235
 236     /* flush packets */
 237     if (ffm->packet_ptr > ffm->packet)
 238         flush_packet(s);
 239
 240     put_flush_packet(pb);
 241
 242     for(i=0;i<s->nb_streams;i++)
 243         free(s->streams[i]->priv_data);
 244     free(ffm);
 245     return 0;
 246 }
 247
 248 /* ffm demux */
 249
 250 static int ffm_is_avail_data(AVFormatContext *s, int size)
 251 {
 252     FFMContext *ffm = s->priv_data;
 253     offset_t pos, avail_size;
 254     int len;
 255
 256     len = ffm->packet_end - ffm->packet_ptr;
 257     if (size <= len)
 258         return 1;
 259     pos = url_ftell(&s->pb);
 260     if (pos == ffm->write_index) {
 261         /* exactly at the end of stream */
 262         return 0;
 263     } else if (pos < ffm->write_index) {
 264         avail_size = ffm->write_index - pos;
 265     } else {
 266         avail_size = (ffm->file_size - pos) + (ffm->write_index - FFM_PACKET_SIZE);
 267     }
 268     avail_size = (avail_size / ffm->packet_size) * (ffm->packet_size - FFM_HEADER_SIZE) + len;
 269     if (size <= avail_size)
 270         return 1;
 271     else
 272         return 0;
 273 }
 274
 275 /* first is true if we read the frame header */
 276 static int ffm_read_data(AVFormatContext *s,
 277                           UINT8 *buf, int size, int first)
 278 {
 279     FFMContext *ffm = s->priv_data;
 280     ByteIOContext *pb = &s->pb;
 281     int len, fill_size, size1, frame_offset;
 282
 283     size1 = size;
 284     while (size > 0) {
 285     redo:
 286         len = ffm->packet_end - ffm->packet_ptr;
 287         if (len > size)
 288             len = size;
 289         if (len == 0) {
 290             if (url_ftell(pb) == ffm->file_size)
 291                 url_fseek(pb, ffm->packet_size, SEEK_SET);
 292             get_be16(pb); /* PACKET_ID */
 293             fill_size = get_be16(pb);
 294             ffm->pts = get_be64(pb);
 295             frame_offset = get_be16(pb);
 296             get_buffer(pb, ffm->packet, ffm->packet_size - FFM_HEADER_SIZE);
 297             ffm->packet_end = ffm->packet + (ffm->packet_size - FFM_HEADER_SIZE - fill_size);
 298             /* if first packet or resynchronization packet, we must
 299                handle it specifically */
 300             if (ffm->first_packet || (frame_offset & 0x8000)) {
 301                 ffm->first_packet = 0;
 302                 ffm->packet_ptr = ffm->packet + (frame_offset & 0x7fff) - FFM_HEADER_SIZE;
 303                 if (!first)
 304                     break;
 305             } else {
 306                 ffm->packet_ptr = ffm->packet;
 307             }
 308             goto redo;
 309         }
 310         memcpy(buf, ffm->packet_ptr, len);
 311         buf += len;
 312         ffm->packet_ptr += len;
 313         size -= len;
 314         first = 0;
 315     }
 316     return size1 - size;
 317 }
 318
 319
 320 static int ffm_read_header(AVFormatContext *s, AVFormatParameters *ap)
 321 {
 322     AVStream *st;
 323     FFMStream *fst;
 324     FFMContext *ffm;
 325     ByteIOContext *pb = &s->pb;
 326     AVCodecContext *codec;
 327     int i;
 328     UINT32 tag;
 329
 330     ffm = av_mallocz(sizeof(FFMContext) + FFM_PACKET_SIZE);
 331     if (!ffm)
 332         return -1;
 333
 334     s->priv_data = ffm;
 335
 336     /* header */
 337     tag = get_le32(pb);
 338     if (tag != MKTAG('F', 'F', 'M', '1'))
 339         goto fail;
 340     ffm->packet_size = get_be32(pb);
 341     if (ffm->packet_size != FFM_PACKET_SIZE)
 342         goto fail;
 343     ffm->write_index = get_be64(pb);
 344     /* get also filesize */
 345     if (!url_is_streamed(pb)) {
 346         ffm->file_size = url_filesize(url_fileno(pb));
 347     } else {
 348         ffm->file_size = (1ULL << 63) - 1;
 349     }
 350
 351     s->nb_streams = get_be32(pb);
 352     get_be32(pb); /* total bitrate */
 353     /* read each stream */
 354     for(i=0;i<s->nb_streams;i++) {
 355         st = av_mallocz(sizeof(AVStream));
 356         if (!st)
 357             goto fail;
 358         s->streams[i] = st;
 359         fst = av_mallocz(sizeof(FFMStream) + ffm->packet_size);
 360         if (!fst)
 361             goto fail;
 362         st->priv_data = fst;
 363
 364         codec = &st->codec;
 365         /* generic info */
 366         st->codec.codec_id = get_be32(pb);
 367         st->codec.codec_type = get_byte(pb); /* codec_type */
 368         codec->bit_rate = get_be32(pb);
 369         /* specific info */
 370         switch(codec->codec_type) {
 371         case CODEC_TYPE_VIDEO:
 372             codec->frame_rate = ((INT64)get_be32(pb) * FRAME_RATE_BASE) / 1000;
 373             codec->width = get_be16(pb);
 374             codec->height = get_be16(pb);
 375             break;
 376         case CODEC_TYPE_AUDIO:
 377             codec->sample_rate = get_be32(pb);
 378             codec->channels = get_le16(pb);
 379             break;
 380         }
 381
 382     }
 383
 384     /* get until end of block reached */
 385     while ((url_ftell(pb) % ffm->packet_size) != 0)
 386         get_byte(pb);
 387
 388     /* init packet demux */
 389     ffm->packet_ptr = ffm->packet;
 390     ffm->packet_end = ffm->packet;
 391     ffm->frame_offset = 0;
 392     ffm->pts = 0;
 393     ffm->read_state = READ_HEADER;
 394     ffm->first_packet = 1;
 395     return 0;
 396  fail:
 397     for(i=0;i<s->nb_streams;i++) {
 398         st = s->streams[i];
 399         if (st) {
 400             fst = st->priv_data;
 401             if (fst)
 402                 free(fst);
 403             free(st);
 404         }
 405     }
 406     if (ffm)
 407         free(ffm);
 408     return -1;
 409 }
 410
 411 /* return < 0 if eof */
 412 static int ffm_read_packet(AVFormatContext *s, AVPacket *pkt)
 413 {
 414     int size;
 415     FFMContext *ffm = s->priv_data;
 416
 417     switch(ffm->read_state) {
 418     case READ_HEADER:
 419         if (!ffm_is_avail_data(s, FRAME_HEADER_SIZE))
 420             return -EAGAIN;
 421 #if 0
 422         printf("pos=%08Lx spos=%Lx, write_index=%Lx size=%Lx\n",
 423                url_ftell(&s->pb), s->pb.pos, ffm->write_index, ffm->file_size);
 424 #endif
 425         if (ffm_read_data(s, ffm->header, FRAME_HEADER_SIZE, 1) != FRAME_HEADER_SIZE)
 426             return -EAGAIN;
 427
 428 #if 0
 429         {
 430             int i;
 431             for(i=0;i<FRAME_HEADER_SIZE;i++)
 432                 printf("%02x ", ffm->header[i]);
 433             printf("\n");
 434         }
 435 #endif
 436         ffm->read_state = READ_DATA;
 437         /* fall thru */
 438     case READ_DATA:
 439         size = (ffm->header[2] << 16) | (ffm->header[3] << 8) | ffm->header[4];
 440         if (!ffm_is_avail_data(s, size)) {
 441             return -EAGAIN;
 442         }
 443
 444         av_new_packet(pkt, size);
 445         pkt->stream_index = ffm->header[0];
 446         if (ffm->header[1] & FLAG_KEY_FRAME)
 447             pkt->flags |= PKT_FLAG_KEY;
 448
 449         ffm->read_state = READ_HEADER;
 450         if (ffm_read_data(s, pkt->data, size, 0) != size) {
 451             /* bad case: desynchronized packet. we cancel all the packet loading */
 452             av_free_packet(pkt);
 453             return -EAGAIN;
 454         }
 455         break;
 456     }
 457     return 0;
 458 }
 459
 460 //#define DEBUG_SEEK
 461
 462 /* pos is between 0 and file_size - FFM_PACKET_SIZE. It is translated
 463    by the write position inside this function */
 464 static void ffm_seek1(AVFormatContext *s, offset_t pos1)
 465 {
 466     FFMContext *ffm = s->priv_data;
 467     ByteIOContext *pb = &s->pb;
 468     offset_t pos;
 469
 470     pos = pos1 + ffm->write_index;
 471     if (pos >= ffm->file_size)
 472         pos -= (ffm->file_size - FFM_PACKET_SIZE);
 473 #ifdef DEBUG_SEEK
 474     printf("seek to %Lx -> %Lx\n", pos1, pos);
 475 #endif
 476     url_fseek(pb, pos, SEEK_SET);
 477 }
 478
 479 static INT64 get_pts(AVFormatContext *s, offset_t pos)
 480 {
 481     ByteIOContext *pb = &s->pb;
 482     INT64 pts;
 483
 484     ffm_seek1(s, pos);
 485     url_fskip(pb, 4);
 486     pts = get_be64(pb);
 487 #ifdef DEBUG_SEEK
 488     printf("pts=%0.6f\n", pts / 1000000.0);
 489 #endif
 490     return pts;
 491 }
 492
 493 /* seek to a given time in the file. The file read pointer is
 494    positionned at or before pts. XXX: the following code is quite
 495    approximative */
 496 static int ffm_seek(AVFormatContext *s, INT64 wanted_pts)
 497 {
 498     FFMContext *ffm = s->priv_data;
 499     offset_t pos_min, pos_max, pos;
 500     INT64 pts_min, pts_max, pts;
 501     double pos1;
 502
 503 #ifdef DEBUG_SEEK
 504     printf("wanted_pts=%0.6f\n", wanted_pts / 1000000.0);
 505 #endif
 506     /* find the position using linear interpolation (better than
 507        dichotomy in typical cases) */
 508     pos_min = 0;
 509     pos_max = ffm->file_size - 2 * FFM_PACKET_SIZE;
 510     while (pos_min <= pos_max) {
 511         pts_min = get_pts(s, pos_min);
 512         pts_max = get_pts(s, pos_max);
 513         /* linear interpolation */
 514         pos1 = (double)(pos_max - pos_min) * (double)(wanted_pts - pts_min) /
 515             (double)(pts_max - pts_min);
 516         pos = (((INT64)pos1) / FFM_PACKET_SIZE) * FFM_PACKET_SIZE;
 517         if (pos <= pos_min)
 518             pos = pos_min;
 519         else if (pos >= pos_max)
 520             pos = pos_max;
 521         pts = get_pts(s, pos);
 522         /* check if we are lucky */
 523         if (pts == wanted_pts) {
 524             goto found;
 525         } else if (pts > wanted_pts) {
 526             pos_max = pos - FFM_PACKET_SIZE;
 527         } else {
 528             pos_min = pos + FFM_PACKET_SIZE;
 529         }
 530     }
 531     pos = pos_min;
 532     if (pos > 0)
 533         pos -= FFM_PACKET_SIZE;
 534  found:
 535     ffm_seek1(s, pos);
 536     return 0;
 537 }
 538
 539 offset_t ffm_read_write_index(int fd)
 540 {
 541     UINT8 buf[8];
 542     offset_t pos;
 543     int i;
 544
 545     lseek(fd, 8, SEEK_SET);
 546     read(fd, buf, 8);
 547     pos = 0;
 548     for(i=0;i<8;i++)
 549         pos |= buf[i] << (56 - i * 8);
 550     return pos;
 551 }
 552
 553 void ffm_write_write_index(int fd, offset_t pos)
 554 {
 555     UINT8 buf[8];
 556     int i;
 557
 558     for(i=0;i<8;i++)
 559         buf[i] = (pos >> (56 - i * 8)) & 0xff;
 560     lseek(fd, 8, SEEK_SET);
 561     write(fd, buf, 8);
 562 }
 563
 564 void ffm_set_write_index(AVFormatContext *s, offset_t pos, offset_t file_size)
 565 {
 566     FFMContext *ffm = s->priv_data;
 567     ffm->write_index = pos;
 568     ffm->file_size = file_size;
 569 }
 570
 571 static int ffm_read_close(AVFormatContext *s)
 572 {
 573     AVStream *st;
 574     int i;
 575
 576     for(i=0;i<s->nb_streams;i++) {
 577         st = s->streams[i];
 578         free(st->priv_data);
 579     }
 580     free(s->priv_data);
 581     return 0;
 582 }
 583
 584 AVFormat ffm_format = {
 585     "ffm",
 586     "ffm format",
 587     "",
 588     "ffm",
 589     /* not really used */
 590     CODEC_ID_MP2,
 591     CODEC_ID_MPEG1VIDEO,
 592     ffm_write_header,
 593     ffm_write_packet,
 594     ffm_write_trailer,
 595     ffm_read_header,
 596     ffm_read_packet,
 597     ffm_read_close,
 598     ffm_seek,
 599 };