libavformat/ffm.c

   1 /*
   2  * FFM (ffserver live feed) muxer and demuxer
   3  * Copyright (c) 2001 Fabrice Bellard.
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg 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  * FFmpeg 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 FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21 #include "avformat.h"
  22 #include <unistd.h>
  23
  24 /* The FFM file is made of blocks of fixed size */
  25 #define FFM_HEADER_SIZE 14
  26 #define PACKET_ID       0x666d
  27
  28 /* each packet contains frames (which can span several packets */
  29 #define FRAME_HEADER_SIZE    8
  30 #define FLAG_KEY_FRAME       0x01
  31
  32 typedef struct FFMStream {
  33     int64_t pts;
  34 } FFMStream;
  35
  36 enum {
  37     READ_HEADER,
  38     READ_DATA,
  39 };
  40
  41 typedef struct FFMContext {
  42     /* only reading mode */
  43     offset_t write_index, file_size;
  44     int read_state;
  45     uint8_t header[FRAME_HEADER_SIZE];
  46
  47     /* read and write */
  48     int first_packet; /* true if first packet, needed to set the discontinuity tag */
  49     int first_frame_in_packet; /* true if first frame in packet, needed to know if PTS information is valid */
  50     int packet_size;
  51     int frame_offset;
  52     int64_t pts;
  53     uint8_t *packet_ptr, *packet_end;
  54     uint8_t packet[FFM_PACKET_SIZE];
  55 } FFMContext;
  56
  57 static int64_t get_pts(AVFormatContext *s, offset_t pos);
  58
  59 /* disable pts hack for testing */
  60 int ffm_nopts = 0;
  61
  62 #ifdef CONFIG_MUXERS
  63 static void flush_packet(AVFormatContext *s)
  64 {
  65     FFMContext *ffm = s->priv_data;
  66     int fill_size, h;
  67     ByteIOContext *pb = s->pb;
  68
  69     fill_size = ffm->packet_end - ffm->packet_ptr;
  70     memset(ffm->packet_ptr, 0, fill_size);
  71
  72     if (url_ftell(pb) % ffm->packet_size)
  73         av_abort();
  74
  75     /* put header */
  76     put_be16(pb, PACKET_ID);
  77     put_be16(pb, fill_size);
  78     put_be64(pb, ffm->pts);
  79     h = ffm->frame_offset;
  80     if (ffm->first_packet)
  81         h |= 0x8000;
  82     put_be16(pb, h);
  83     put_buffer(pb, ffm->packet, ffm->packet_end - ffm->packet);
  84     put_flush_packet(pb);
  85
  86     /* prepare next packet */
  87     ffm->frame_offset = 0; /* no key frame */
  88     ffm->pts = 0; /* no pts */
  89     ffm->packet_ptr = ffm->packet;
  90     ffm->first_packet = 0;
  91 }
  92
  93 /* 'first' is true if first data of a frame */
  94 static void ffm_write_data(AVFormatContext *s,
  95                            const uint8_t *buf, int size,
  96                            int64_t pts, int first)
  97 {
  98     FFMContext *ffm = s->priv_data;
  99     int len;
 100
 101     if (first && ffm->frame_offset == 0)
 102         ffm->frame_offset = ffm->packet_ptr - ffm->packet + FFM_HEADER_SIZE;
 103     if (first && ffm->pts == 0)
 104         ffm->pts = pts;
 105
 106     /* write as many packets as needed */
 107     while (size > 0) {
 108         len = ffm->packet_end - ffm->packet_ptr;
 109         if (len > size)
 110             len = size;
 111         memcpy(ffm->packet_ptr, buf, len);
 112
 113         ffm->packet_ptr += len;
 114         buf += len;
 115         size -= len;
 116         if (ffm->packet_ptr >= ffm->packet_end) {
 117             /* special case : no pts in packet : we leave the current one */
 118             if (ffm->pts == 0)
 119                 ffm->pts = pts;
 120
 121             flush_packet(s);
 122         }
 123     }
 124 }
 125
 126 static int ffm_write_header(AVFormatContext *s)
 127 {
 128     FFMContext *ffm = s->priv_data;
 129     AVStream *st;
 130     FFMStream *fst;
 131     ByteIOContext *pb = s->pb;
 132     AVCodecContext *codec;
 133     int bit_rate, i;
 134
 135     ffm->packet_size = FFM_PACKET_SIZE;
 136
 137     /* header */
 138     put_le32(pb, MKTAG('F', 'F', 'M', '1'));
 139     put_be32(pb, ffm->packet_size);
 140     /* XXX: store write position in other file ? */
 141     put_be64(pb, ffm->packet_size); /* current write position */
 142
 143     put_be32(pb, s->nb_streams);
 144     bit_rate = 0;
 145     for(i=0;i<s->nb_streams;i++) {
 146         st = s->streams[i];
 147         bit_rate += st->codec->bit_rate;
 148     }
 149     put_be32(pb, bit_rate);
 150
 151     /* list of streams */
 152     for(i=0;i<s->nb_streams;i++) {
 153         st = s->streams[i];
 154         fst = av_mallocz(sizeof(FFMStream));
 155         if (!fst)
 156             goto fail;
 157         av_set_pts_info(st, 64, 1, 1000000);
 158         st->priv_data = fst;
 159
 160         codec = st->codec;
 161         /* generic info */
 162         put_be32(pb, codec->codec_id);
 163         put_byte(pb, codec->codec_type);
 164         put_be32(pb, codec->bit_rate);
 165         put_be32(pb, st->quality);
 166         put_be32(pb, codec->flags);
 167         put_be32(pb, codec->flags2);
 168         put_be32(pb, codec->debug);
 169         /* specific info */
 170         switch(codec->codec_type) {
 171         case CODEC_TYPE_VIDEO:
 172             put_be32(pb, codec->time_base.num);
 173             put_be32(pb, codec->time_base.den);
 174             put_be16(pb, codec->width);
 175             put_be16(pb, codec->height);
 176             put_be16(pb, codec->gop_size);
 177             put_be32(pb, codec->pix_fmt);
 178             put_byte(pb, codec->qmin);
 179             put_byte(pb, codec->qmax);
 180             put_byte(pb, codec->max_qdiff);
 181             put_be16(pb, (int) (codec->qcompress * 10000.0));
 182             put_be16(pb, (int) (codec->qblur * 10000.0));
 183             put_be32(pb, codec->bit_rate_tolerance);
 184             put_strz(pb, codec->rc_eq);
 185             put_be32(pb, codec->rc_max_rate);
 186             put_be32(pb, codec->rc_min_rate);
 187             put_be32(pb, codec->rc_buffer_size);
 188             put_be64(pb, av_dbl2int(codec->i_quant_factor));
 189             put_be64(pb, av_dbl2int(codec->b_quant_factor));
 190             put_be64(pb, av_dbl2int(codec->i_quant_offset));
 191             put_be64(pb, av_dbl2int(codec->b_quant_offset));
 192             put_be32(pb, codec->dct_algo);
 193             put_be32(pb, codec->strict_std_compliance);
 194             put_be32(pb, codec->max_b_frames);
 195             put_be32(pb, codec->luma_elim_threshold);
 196             put_be32(pb, codec->chroma_elim_threshold);
 197             put_be32(pb, codec->mpeg_quant);
 198             put_be32(pb, codec->intra_dc_precision);
 199             put_be32(pb, codec->me_method);
 200             put_be32(pb, codec->mb_decision);
 201             put_be32(pb, codec->nsse_weight);
 202             put_be32(pb, codec->frame_skip_cmp);
 203             put_be64(pb, av_dbl2int(codec->rc_buffer_aggressivity));
 204             put_be32(pb, codec->codec_tag);
 205             break;
 206         case CODEC_TYPE_AUDIO:
 207             put_be32(pb, codec->sample_rate);
 208             put_le16(pb, codec->channels);
 209             put_le16(pb, codec->frame_size);
 210             break;
 211         default:
 212             return -1;
 213         }
 214         /* hack to have real time */
 215         if (ffm_nopts)
 216             fst->pts = 0;
 217         else
 218             fst->pts = av_gettime();
 219     }
 220
 221     /* flush until end of block reached */
 222     while ((url_ftell(pb) % ffm->packet_size) != 0)
 223         put_byte(pb, 0);
 224
 225     put_flush_packet(pb);
 226
 227     /* init packet mux */
 228     ffm->packet_ptr = ffm->packet;
 229     ffm->packet_end = ffm->packet + ffm->packet_size - FFM_HEADER_SIZE;
 230     assert(ffm->packet_end >= ffm->packet);
 231     ffm->frame_offset = 0;
 232     ffm->pts = 0;
 233     ffm->first_packet = 1;
 234
 235     return 0;
 236  fail:
 237     for(i=0;i<s->nb_streams;i++) {
 238         st = s->streams[i];
 239         av_freep(&st->priv_data);
 240     }
 241     return -1;
 242 }
 243
 244 static int ffm_write_packet(AVFormatContext *s, AVPacket *pkt)
 245 {
 246     AVStream *st = s->streams[pkt->stream_index];
 247     FFMStream *fst = st->priv_data;
 248     int64_t pts;
 249     uint8_t header[FRAME_HEADER_SIZE];
 250     int duration;
 251     int size= pkt->size;
 252
 253     //XXX/FIXME use duration from pkt
 254     if (st->codec->codec_type == CODEC_TYPE_AUDIO) {
 255         duration = ((float)st->codec->frame_size / st->codec->sample_rate * 1000000.0);
 256     } else {
 257         duration = (1000000.0 * st->codec->time_base.num / (float)st->codec->time_base.den);
 258     }
 259
 260     pts = fst->pts;
 261     /* packet size & key_frame */
 262     header[0] = pkt->stream_index;
 263     header[1] = 0;
 264     if (pkt->flags & PKT_FLAG_KEY)
 265         header[1] |= FLAG_KEY_FRAME;
 266     header[2] = (size >> 16) & 0xff;
 267     header[3] = (size >> 8) & 0xff;
 268     header[4] = size & 0xff;
 269     header[5] = (duration >> 16) & 0xff;
 270     header[6] = (duration >> 8) & 0xff;
 271     header[7] = duration & 0xff;
 272     ffm_write_data(s, header, FRAME_HEADER_SIZE, pts, 1);
 273     ffm_write_data(s, pkt->data, size, pts, 0);
 274
 275     fst->pts += duration;
 276     return 0;
 277 }
 278
 279 static int ffm_write_trailer(AVFormatContext *s)
 280 {
 281     ByteIOContext *pb = s->pb;
 282     FFMContext *ffm = s->priv_data;
 283
 284     /* flush packets */
 285     if (ffm->packet_ptr > ffm->packet)
 286         flush_packet(s);
 287
 288     put_flush_packet(pb);
 289
 290     if (!url_is_streamed(pb)) {
 291         int64_t size;
 292         /* update the write offset */
 293         size = url_ftell(pb);
 294         url_fseek(pb, 8, SEEK_SET);
 295         put_be64(pb, size);
 296         put_flush_packet(pb);
 297     }
 298
 299     return 0;
 300 }
 301 #endif //CONFIG_MUXERS
 302
 303 /* ffm demux */
 304
 305 static int ffm_is_avail_data(AVFormatContext *s, int size)
 306 {
 307     FFMContext *ffm = s->priv_data;
 308     offset_t pos, avail_size;
 309     int len;
 310
 311     len = ffm->packet_end - ffm->packet_ptr;
 312     if (!ffm_nopts) {
 313         /* XXX: I don't understand this test, so I disabled it for testing */
 314         if (size <= len)
 315             return 1;
 316     }
 317     pos = url_ftell(s->pb);
 318     if (pos == ffm->write_index) {
 319         /* exactly at the end of stream */
 320         return 0;
 321     } else if (pos < ffm->write_index) {
 322         avail_size = ffm->write_index - pos;
 323     } else {
 324         avail_size = (ffm->file_size - pos) + (ffm->write_index - FFM_PACKET_SIZE);
 325     }
 326     avail_size = (avail_size / ffm->packet_size) * (ffm->packet_size - FFM_HEADER_SIZE) + len;
 327     if (size <= avail_size)
 328         return 1;
 329     else
 330         return 0;
 331 }
 332
 333 /* first is true if we read the frame header */
 334 static int ffm_read_data(AVFormatContext *s,
 335                          uint8_t *buf, int size, int first)
 336 {
 337     FFMContext *ffm = s->priv_data;
 338     ByteIOContext *pb = s->pb;
 339     int len, fill_size, size1, frame_offset;
 340
 341     size1 = size;
 342     while (size > 0) {
 343     redo:
 344         len = ffm->packet_end - ffm->packet_ptr;
 345         if (len > size)
 346             len = size;
 347         if (len == 0) {
 348             if (url_ftell(pb) == ffm->file_size)
 349                 url_fseek(pb, ffm->packet_size, SEEK_SET);
 350     retry_read:
 351             get_be16(pb); /* PACKET_ID */
 352             fill_size = get_be16(pb);
 353             ffm->pts = get_be64(pb);
 354             ffm->first_frame_in_packet = 1;
 355             frame_offset = get_be16(pb);
 356             get_buffer(pb, ffm->packet, ffm->packet_size - FFM_HEADER_SIZE);
 357             ffm->packet_end = ffm->packet + (ffm->packet_size - FFM_HEADER_SIZE - fill_size);
 358             if (ffm->packet_end < ffm->packet)
 359                 return -1;
 360             /* if first packet or resynchronization packet, we must
 361                handle it specifically */
 362             if (ffm->first_packet || (frame_offset & 0x8000)) {
 363                 if (!frame_offset) {
 364                     /* This packet has no frame headers in it */
 365                     if (url_ftell(pb) >= ffm->packet_size * 3) {
 366                         url_fseek(pb, -ffm->packet_size * 2, SEEK_CUR);
 367                         goto retry_read;
 368                     }
 369                     /* This is bad, we cannot find a valid frame header */
 370                     return 0;
 371                 }
 372                 ffm->first_packet = 0;
 373                 if ((frame_offset & 0x7ffff) < FFM_HEADER_SIZE)
 374                     return -1;
 375                 ffm->packet_ptr = ffm->packet + (frame_offset & 0x7fff) - FFM_HEADER_SIZE;
 376                 if (!first)
 377                     break;
 378             } else {
 379                 ffm->packet_ptr = ffm->packet;
 380             }
 381             goto redo;
 382         }
 383         memcpy(buf, ffm->packet_ptr, len);
 384         buf += len;
 385         ffm->packet_ptr += len;
 386         size -= len;
 387         first = 0;
 388     }
 389     return size1 - size;
 390 }
 391
 392
 393 static void adjust_write_index(AVFormatContext *s)
 394 {
 395     FFMContext *ffm = s->priv_data;
 396     ByteIOContext *pb = s->pb;
 397     int64_t pts;
 398     //offset_t orig_write_index = ffm->write_index;
 399     offset_t pos_min, pos_max;
 400     int64_t pts_start;
 401     offset_t ptr = url_ftell(pb);
 402
 403
 404     pos_min = 0;
 405     pos_max = ffm->file_size - 2 * FFM_PACKET_SIZE;
 406
 407     pts_start = get_pts(s, pos_min);
 408
 409     pts = get_pts(s, pos_max);
 410
 411     if (pts - 100000 > pts_start)
 412         goto end;
 413
 414     ffm->write_index = FFM_PACKET_SIZE;
 415
 416     pts_start = get_pts(s, pos_min);
 417
 418     pts = get_pts(s, pos_max);
 419
 420     if (pts - 100000 <= pts_start) {
 421         while (1) {
 422             offset_t newpos;
 423             int64_t newpts;
 424
 425             newpos = ((pos_max + pos_min) / (2 * FFM_PACKET_SIZE)) * FFM_PACKET_SIZE;
 426
 427             if (newpos == pos_min)
 428                 break;
 429
 430             newpts = get_pts(s, newpos);
 431
 432             if (newpts - 100000 <= pts) {
 433                 pos_max = newpos;
 434                 pts = newpts;
 435             } else {
 436                 pos_min = newpos;
 437             }
 438         }
 439         ffm->write_index += pos_max;
 440     }
 441
 442     //printf("Adjusted write index from %"PRId64" to %"PRId64": pts=%0.6f\n", orig_write_index, ffm->write_index, pts / 1000000.);
 443     //printf("pts range %0.6f - %0.6f\n", get_pts(s, 0) / 1000000. , get_pts(s, ffm->file_size - 2 * FFM_PACKET_SIZE) / 1000000. );
 444
 445  end:
 446     url_fseek(pb, ptr, SEEK_SET);
 447 }
 448
 449
 450 static int ffm_read_header(AVFormatContext *s, AVFormatParameters *ap)
 451 {
 452     FFMContext *ffm = s->priv_data;
 453     AVStream *st;
 454     FFMStream *fst;
 455     ByteIOContext *pb = s->pb;
 456     AVCodecContext *codec;
 457     int i, nb_streams;
 458     uint32_t tag;
 459
 460     /* header */
 461     tag = get_le32(pb);
 462     if (tag != MKTAG('F', 'F', 'M', '1'))
 463         goto fail;
 464     ffm->packet_size = get_be32(pb);
 465     if (ffm->packet_size != FFM_PACKET_SIZE)
 466         goto fail;
 467     ffm->write_index = get_be64(pb);
 468     /* get also filesize */
 469     if (!url_is_streamed(pb)) {
 470         ffm->file_size = url_fsize(pb);
 471         adjust_write_index(s);
 472     } else {
 473         ffm->file_size = (UINT64_C(1) << 63) - 1;
 474     }
 475
 476     nb_streams = get_be32(pb);
 477     get_be32(pb); /* total bitrate */
 478     /* read each stream */
 479     for(i=0;i<nb_streams;i++) {
 480         char rc_eq_buf[128];
 481
 482         st = av_new_stream(s, 0);
 483         if (!st)
 484             goto fail;
 485         fst = av_mallocz(sizeof(FFMStream));
 486         if (!fst)
 487             goto fail;
 488         s->streams[i] = st;
 489
 490         av_set_pts_info(st, 64, 1, 1000000);
 491
 492         st->priv_data = fst;
 493
 494         codec = st->codec;
 495         /* generic info */
 496         codec->codec_id = get_be32(pb);
 497         codec->codec_type = get_byte(pb); /* codec_type */
 498         codec->bit_rate = get_be32(pb);
 499         st->quality = get_be32(pb);
 500         codec->flags = get_be32(pb);
 501         codec->flags2 = get_be32(pb);
 502         codec->debug = get_be32(pb);
 503         /* specific info */
 504         switch(codec->codec_type) {
 505         case CODEC_TYPE_VIDEO:
 506             codec->time_base.num = get_be32(pb);
 507             codec->time_base.den = get_be32(pb);
 508             codec->width = get_be16(pb);
 509             codec->height = get_be16(pb);
 510             codec->gop_size = get_be16(pb);
 511             codec->pix_fmt = get_be32(pb);
 512             codec->qmin = get_byte(pb);
 513             codec->qmax = get_byte(pb);
 514             codec->max_qdiff = get_byte(pb);
 515             codec->qcompress = get_be16(pb) / 10000.0;
 516             codec->qblur = get_be16(pb) / 10000.0;
 517             codec->bit_rate_tolerance = get_be32(pb);
 518             codec->rc_eq = av_strdup(get_strz(pb, rc_eq_buf, sizeof(rc_eq_buf)));
 519             codec->rc_max_rate = get_be32(pb);
 520             codec->rc_min_rate = get_be32(pb);
 521             codec->rc_buffer_size = get_be32(pb);
 522             codec->i_quant_factor = av_int2dbl(get_be64(pb));
 523             codec->b_quant_factor = av_int2dbl(get_be64(pb));
 524             codec->i_quant_offset = av_int2dbl(get_be64(pb));
 525             codec->b_quant_offset = av_int2dbl(get_be64(pb));
 526             codec->dct_algo = get_be32(pb);
 527             codec->strict_std_compliance = get_be32(pb);
 528             codec->max_b_frames = get_be32(pb);
 529             codec->luma_elim_threshold = get_be32(pb);
 530             codec->chroma_elim_threshold = get_be32(pb);
 531             codec->mpeg_quant = get_be32(pb);
 532             codec->intra_dc_precision = get_be32(pb);
 533             codec->me_method = get_be32(pb);
 534             codec->mb_decision = get_be32(pb);
 535             codec->nsse_weight = get_be32(pb);
 536             codec->frame_skip_cmp = get_be32(pb);
 537             codec->rc_buffer_aggressivity = av_int2dbl(get_be64(pb));
 538             codec->codec_tag = get_be32(pb);
 539             break;
 540         case CODEC_TYPE_AUDIO:
 541             codec->sample_rate = get_be32(pb);
 542             codec->channels = get_le16(pb);
 543             codec->frame_size = get_le16(pb);
 544             break;
 545         default:
 546             goto fail;
 547         }
 548
 549     }
 550
 551     /* get until end of block reached */
 552     while ((url_ftell(pb) % ffm->packet_size) != 0)
 553         get_byte(pb);
 554
 555     /* init packet demux */
 556     ffm->packet_ptr = ffm->packet;
 557     ffm->packet_end = ffm->packet;
 558     ffm->frame_offset = 0;
 559     ffm->pts = 0;
 560     ffm->read_state = READ_HEADER;
 561     ffm->first_packet = 1;
 562     return 0;
 563  fail:
 564     for(i=0;i<s->nb_streams;i++) {
 565         st = s->streams[i];
 566         if (st) {
 567             av_freep(&st->priv_data);
 568             av_free(st);
 569         }
 570     }
 571     return -1;
 572 }
 573
 574 /* return < 0 if eof */
 575 static int ffm_read_packet(AVFormatContext *s, AVPacket *pkt)
 576 {
 577     int size;
 578     FFMContext *ffm = s->priv_data;
 579     int duration;
 580
 581     switch(ffm->read_state) {
 582     case READ_HEADER:
 583         if (!ffm_is_avail_data(s, FRAME_HEADER_SIZE)) {
 584             return AVERROR(EAGAIN);
 585         }
 586 #if 0
 587         printf("pos=%08"PRIx64" spos=%"PRIx64", write_index=%"PRIx64" size=%"PRIx64"\n",
 588                url_ftell(s->pb), s->pb.pos, ffm->write_index, ffm->file_size);
 589 #endif
 590         if (ffm_read_data(s, ffm->header, FRAME_HEADER_SIZE, 1) !=
 591             FRAME_HEADER_SIZE)
 592             return AVERROR(EAGAIN);
 593 #if 0
 594         {
 595             int i;
 596             for(i=0;i<FRAME_HEADER_SIZE;i++)
 597                 printf("%02x ", ffm->header[i]);
 598             printf("\n");
 599         }
 600 #endif
 601         ffm->read_state = READ_DATA;
 602         /* fall thru */
 603     case READ_DATA:
 604         size = AV_RB24(ffm->header + 2);
 605         if (!ffm_is_avail_data(s, size)) {
 606             return AVERROR(EAGAIN);
 607         }
 608
 609         duration = AV_RB24(ffm->header + 5);
 610
 611         av_new_packet(pkt, size);
 612         pkt->stream_index = ffm->header[0];
 613         pkt->pos = url_ftell(s->pb);
 614         if (ffm->header[1] & FLAG_KEY_FRAME)
 615             pkt->flags |= PKT_FLAG_KEY;
 616
 617         ffm->read_state = READ_HEADER;
 618         if (ffm_read_data(s, pkt->data, size, 0) != size) {
 619             /* bad case: desynchronized packet. we cancel all the packet loading */
 620             av_free_packet(pkt);
 621             return AVERROR(EAGAIN);
 622         }
 623         if (ffm->first_frame_in_packet)
 624         {
 625             pkt->pts = ffm->pts;
 626             ffm->first_frame_in_packet = 0;
 627         }
 628         pkt->duration = duration;
 629         break;
 630     }
 631     return 0;
 632 }
 633
 634 //#define DEBUG_SEEK
 635
 636 /* pos is between 0 and file_size - FFM_PACKET_SIZE. It is translated
 637    by the write position inside this function */
 638 static void ffm_seek1(AVFormatContext *s, offset_t pos1)
 639 {
 640     FFMContext *ffm = s->priv_data;
 641     ByteIOContext *pb = s->pb;
 642     offset_t pos;
 643
 644     pos = pos1 + ffm->write_index;
 645     if (pos >= ffm->file_size)
 646         pos -= (ffm->file_size - FFM_PACKET_SIZE);
 647 #ifdef DEBUG_SEEK
 648     printf("seek to %"PRIx64" -> %"PRIx64"\n", pos1, pos);
 649 #endif
 650     url_fseek(pb, pos, SEEK_SET);
 651 }
 652
 653 static int64_t get_pts(AVFormatContext *s, offset_t pos)
 654 {
 655     ByteIOContext *pb = s->pb;
 656     int64_t pts;
 657
 658     ffm_seek1(s, pos);
 659     url_fskip(pb, 4);
 660     pts = get_be64(pb);
 661 #ifdef DEBUG_SEEK
 662     printf("pts=%0.6f\n", pts / 1000000.0);
 663 #endif
 664     return pts;
 665 }
 666
 667 /* seek to a given time in the file. The file read pointer is
 668    positioned at or before pts. XXX: the following code is quite
 669    approximative */
 670 static int ffm_seek(AVFormatContext *s, int stream_index, int64_t wanted_pts, int flags)
 671 {
 672     FFMContext *ffm = s->priv_data;
 673     offset_t pos_min, pos_max, pos;
 674     int64_t pts_min, pts_max, pts;
 675     double pos1;
 676
 677 #ifdef DEBUG_SEEK
 678     printf("wanted_pts=%0.6f\n", wanted_pts / 1000000.0);
 679 #endif
 680     /* find the position using linear interpolation (better than
 681        dichotomy in typical cases) */
 682     pos_min = 0;
 683     pos_max = ffm->file_size - 2 * FFM_PACKET_SIZE;
 684     while (pos_min <= pos_max) {
 685         pts_min = get_pts(s, pos_min);
 686         pts_max = get_pts(s, pos_max);
 687         /* linear interpolation */
 688         pos1 = (double)(pos_max - pos_min) * (double)(wanted_pts - pts_min) /
 689             (double)(pts_max - pts_min);
 690         pos = (((int64_t)pos1) / FFM_PACKET_SIZE) * FFM_PACKET_SIZE;
 691         if (pos <= pos_min)
 692             pos = pos_min;
 693         else if (pos >= pos_max)
 694             pos = pos_max;
 695         pts = get_pts(s, pos);
 696         /* check if we are lucky */
 697         if (pts == wanted_pts) {
 698             goto found;
 699         } else if (pts > wanted_pts) {
 700             pos_max = pos - FFM_PACKET_SIZE;
 701         } else {
 702             pos_min = pos + FFM_PACKET_SIZE;
 703         }
 704     }
 705     pos = (flags & AVSEEK_FLAG_BACKWARD) ? pos_min : pos_max;
 706     if (pos > 0)
 707         pos -= FFM_PACKET_SIZE;
 708  found:
 709     ffm_seek1(s, pos);
 710     return 0;
 711 }
 712
 713 #ifdef CONFIG_FFSERVER
 714 offset_t ffm_read_write_index(int fd)
 715 {
 716     uint8_t buf[8];
 717
 718     lseek(fd, 8, SEEK_SET);
 719     read(fd, buf, 8);
 720     return AV_RB64(buf);
 721 }
 722
 723 void ffm_write_write_index(int fd, offset_t pos)
 724 {
 725     uint8_t buf[8];
 726     int i;
 727
 728     for(i=0;i<8;i++)
 729         buf[i] = (pos >> (56 - i * 8)) & 0xff;
 730     lseek(fd, 8, SEEK_SET);
 731     write(fd, buf, 8);
 732 }
 733
 734 void ffm_set_write_index(AVFormatContext *s, offset_t pos, offset_t file_size)
 735 {
 736     FFMContext *ffm = s->priv_data;
 737     ffm->write_index = pos;
 738     ffm->file_size = file_size;
 739 }
 740 #endif // CONFIG_FFSERVER
 741
 742 static int ffm_read_close(AVFormatContext *s)
 743 {
 744     AVStream *st;
 745     int i;
 746
 747     for(i=0;i<s->nb_streams;i++) {
 748         st = s->streams[i];
 749         av_freep(&st->priv_data);
 750     }
 751     return 0;
 752 }
 753
 754 static int ffm_probe(AVProbeData *p)
 755 {
 756     if (
 757         p->buf[0] == 'F' && p->buf[1] == 'F' && p->buf[2] == 'M' &&
 758         p->buf[3] == '1')
 759         return AVPROBE_SCORE_MAX + 1;
 760     return 0;
 761 }
 762
 763 #ifdef CONFIG_FFM_DEMUXER
 764 AVInputFormat ffm_demuxer = {
 765     "ffm",
 766     "ffm format",
 767     sizeof(FFMContext),
 768     ffm_probe,
 769     ffm_read_header,
 770     ffm_read_packet,
 771     ffm_read_close,
 772     ffm_seek,
 773 };
 774 #endif
 775 #ifdef CONFIG_FFM_MUXER
 776 AVOutputFormat ffm_muxer = {
 777     "ffm",
 778     "ffm format",
 779     "",
 780     "ffm",
 781     sizeof(FFMContext),
 782     /* not really used */
 783     CODEC_ID_MP2,
 784     CODEC_ID_MPEG1VIDEO,
 785     ffm_write_header,
 786     ffm_write_packet,
 787     ffm_write_trailer,
 788 };
 789 #endif //CONFIG_FFM_MUXER