libavformat/ffmdec.c

   1 /*
   2  * FFM (avserver live feed) demuxer
   3  * Copyright (c) 2001 Fabrice Bellard
   4  *
   5  * This file is part of Libav.
   6  *
   7  * Libav 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  * Libav 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 Libav; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #include "libavutil/intreadwrite.h"
  23 #include "libavutil/intfloat.h"
  24 #include "avformat.h"
  25 #include "internal.h"
  26 #include "ffm.h"
  27
  28 static int ffm_is_avail_data(AVFormatContext *s, int size)
  29 {
  30     FFMContext *ffm = s->priv_data;
  31     int64_t pos, avail_size;
  32     int len;
  33
  34     len = ffm->packet_end - ffm->packet_ptr;
  35     if (size <= len)
  36         return 1;
  37     pos = avio_tell(s->pb);
  38     if (!ffm->write_index) {
  39         if (pos == ffm->file_size)
  40             return AVERROR_EOF;
  41         avail_size = ffm->file_size - pos;
  42     } else {
  43     if (pos == ffm->write_index) {
  44         /* exactly at the end of stream */
  45         return AVERROR(EAGAIN);
  46     } else if (pos < ffm->write_index) {
  47         avail_size = ffm->write_index - pos;
  48     } else {
  49         avail_size = (ffm->file_size - pos) + (ffm->write_index - FFM_PACKET_SIZE);
  50     }
  51     }
  52     avail_size = (avail_size / ffm->packet_size) * (ffm->packet_size - FFM_HEADER_SIZE) + len;
  53     if (size <= avail_size)
  54         return 1;
  55     else
  56         return AVERROR(EAGAIN);
  57 }
  58
  59 static int ffm_resync(AVFormatContext *s, int state)
  60 {
  61     av_log(s, AV_LOG_ERROR, "resyncing\n");
  62     while (state != PACKET_ID) {
  63         if (s->pb->eof_reached) {
  64             av_log(s, AV_LOG_ERROR, "cannot find FFM syncword\n");
  65             return -1;
  66         }
  67         state = (state << 8) | avio_r8(s->pb);
  68     }
  69     return 0;
  70 }
  71
  72 /* first is true if we read the frame header */
  73 static int ffm_read_data(AVFormatContext *s,
  74                          uint8_t *buf, int size, int header)
  75 {
  76     FFMContext *ffm = s->priv_data;
  77     AVIOContext *pb = s->pb;
  78     int len, fill_size, size1, frame_offset, id;
  79
  80     size1 = size;
  81     while (size > 0) {
  82     redo:
  83         len = ffm->packet_end - ffm->packet_ptr;
  84         if (len < 0)
  85             return -1;
  86         if (len > size)
  87             len = size;
  88         if (len == 0) {
  89             if (avio_tell(pb) == ffm->file_size)
  90                 avio_seek(pb, ffm->packet_size, SEEK_SET);
  91     retry_read:
  92             id = avio_rb16(pb); /* PACKET_ID */
  93             if (id != PACKET_ID)
  94                 if (ffm_resync(s, id) < 0)
  95                     return -1;
  96             fill_size = avio_rb16(pb);
  97             ffm->dts = avio_rb64(pb);
  98             frame_offset = avio_rb16(pb);
  99             avio_read(pb, ffm->packet, ffm->packet_size - FFM_HEADER_SIZE);
 100             ffm->packet_end = ffm->packet + (ffm->packet_size - FFM_HEADER_SIZE - fill_size);
 101             if (ffm->packet_end < ffm->packet || frame_offset < 0)
 102                 return -1;
 103             /* if first packet or resynchronization packet, we must
 104                handle it specifically */
 105             if (ffm->first_packet || (frame_offset & 0x8000)) {
 106                 if (!frame_offset) {
 107                     /* This packet has no frame headers in it */
 108                     if (avio_tell(pb) >= ffm->packet_size * 3) {
 109                         avio_seek(pb, -ffm->packet_size * 2, SEEK_CUR);
 110                         goto retry_read;
 111                     }
 112                     /* This is bad, we cannot find a valid frame header */
 113                     return 0;
 114                 }
 115                 ffm->first_packet = 0;
 116                 if ((frame_offset & 0x7fff) < FFM_HEADER_SIZE)
 117                     return -1;
 118                 ffm->packet_ptr = ffm->packet + (frame_offset & 0x7fff) - FFM_HEADER_SIZE;
 119                 if (!header)
 120                     break;
 121             } else {
 122                 ffm->packet_ptr = ffm->packet;
 123             }
 124             goto redo;
 125         }
 126         memcpy(buf, ffm->packet_ptr, len);
 127         buf += len;
 128         ffm->packet_ptr += len;
 129         size -= len;
 130         header = 0;
 131     }
 132     return size1 - size;
 133 }
 134
 135 /* ensure that acutal seeking happens between FFM_PACKET_SIZE
 136    and file_size - FFM_PACKET_SIZE */
 137 static int64_t ffm_seek1(AVFormatContext *s, int64_t pos1)
 138 {
 139     FFMContext *ffm = s->priv_data;
 140     AVIOContext *pb = s->pb;
 141     int64_t pos;
 142
 143     pos = FFMIN(pos1, ffm->file_size - FFM_PACKET_SIZE);
 144     pos = FFMAX(pos, FFM_PACKET_SIZE);
 145     av_dlog(s, "seek to %"PRIx64" -> %"PRIx64"\n", pos1, pos);
 146     return avio_seek(pb, pos, SEEK_SET);
 147 }
 148
 149 static int64_t get_dts(AVFormatContext *s, int64_t pos)
 150 {
 151     AVIOContext *pb = s->pb;
 152     int64_t dts;
 153
 154     ffm_seek1(s, pos);
 155     avio_skip(pb, 4);
 156     dts = avio_rb64(pb);
 157     av_dlog(s, "dts=%0.6f\n", dts / 1000000.0);
 158     return dts;
 159 }
 160
 161 static void adjust_write_index(AVFormatContext *s)
 162 {
 163     FFMContext *ffm = s->priv_data;
 164     AVIOContext *pb = s->pb;
 165     int64_t pts;
 166     //int64_t orig_write_index = ffm->write_index;
 167     int64_t pos_min, pos_max;
 168     int64_t pts_start;
 169     int64_t ptr = avio_tell(pb);
 170
 171
 172     pos_min = 0;
 173     pos_max = ffm->file_size - 2 * FFM_PACKET_SIZE;
 174
 175     pts_start = get_dts(s, pos_min);
 176
 177     pts = get_dts(s, pos_max);
 178
 179     if (pts - 100000 > pts_start)
 180         goto end;
 181
 182     ffm->write_index = FFM_PACKET_SIZE;
 183
 184     pts_start = get_dts(s, pos_min);
 185
 186     pts = get_dts(s, pos_max);
 187
 188     if (pts - 100000 <= pts_start) {
 189         while (1) {
 190             int64_t newpos;
 191             int64_t newpts;
 192
 193             newpos = ((pos_max + pos_min) / (2 * FFM_PACKET_SIZE)) * FFM_PACKET_SIZE;
 194
 195             if (newpos == pos_min)
 196                 break;
 197
 198             newpts = get_dts(s, newpos);
 199
 200             if (newpts - 100000 <= pts) {
 201                 pos_max = newpos;
 202                 pts = newpts;
 203             } else {
 204                 pos_min = newpos;
 205             }
 206         }
 207         ffm->write_index += pos_max;
 208     }
 209
 210  end:
 211     avio_seek(pb, ptr, SEEK_SET);
 212 }
 213
 214
 215 static int ffm_close(AVFormatContext *s)
 216 {
 217     int i;
 218
 219     for (i = 0; i < s->nb_streams; i++)
 220         av_freep(&s->streams[i]->codec->rc_eq);
 221
 222     return 0;
 223 }
 224
 225
 226 static int ffm_read_header(AVFormatContext *s)
 227 {
 228     FFMContext *ffm = s->priv_data;
 229     AVStream *st;
 230     AVIOContext *pb = s->pb;
 231     AVCodecContext *codec;
 232     int i, nb_streams;
 233     uint32_t tag;
 234
 235     /* header */
 236     tag = avio_rl32(pb);
 237     if (tag != MKTAG('F', 'F', 'M', '1'))
 238         goto fail;
 239     ffm->packet_size = avio_rb32(pb);
 240     if (ffm->packet_size != FFM_PACKET_SIZE)
 241         goto fail;
 242     ffm->write_index = avio_rb64(pb);
 243     /* get also filesize */
 244     if (pb->seekable) {
 245         ffm->file_size = avio_size(pb);
 246         if (ffm->write_index)
 247             adjust_write_index(s);
 248     } else {
 249         ffm->file_size = (UINT64_C(1) << 63) - 1;
 250     }
 251
 252     nb_streams = avio_rb32(pb);
 253     avio_rb32(pb); /* total bitrate */
 254     /* read each stream */
 255     for(i=0;i<nb_streams;i++) {
 256         char rc_eq_buf[128];
 257
 258         st = avformat_new_stream(s, NULL);
 259         if (!st)
 260             goto fail;
 261
 262         avpriv_set_pts_info(st, 64, 1, 1000000);
 263
 264         codec = st->codec;
 265         /* generic info */
 266         codec->codec_id = avio_rb32(pb);
 267         codec->codec_type = avio_r8(pb); /* codec_type */
 268         codec->bit_rate = avio_rb32(pb);
 269         codec->flags = avio_rb32(pb);
 270         codec->flags2 = avio_rb32(pb);
 271         codec->debug = avio_rb32(pb);
 272         /* specific info */
 273         switch(codec->codec_type) {
 274         case AVMEDIA_TYPE_VIDEO:
 275             codec->time_base.num = avio_rb32(pb);
 276             codec->time_base.den = avio_rb32(pb);
 277             codec->width = avio_rb16(pb);
 278             codec->height = avio_rb16(pb);
 279             codec->gop_size = avio_rb16(pb);
 280             codec->pix_fmt = avio_rb32(pb);
 281             codec->qmin = avio_r8(pb);
 282             codec->qmax = avio_r8(pb);
 283             codec->max_qdiff = avio_r8(pb);
 284             codec->qcompress = avio_rb16(pb) / 10000.0;
 285             codec->qblur = avio_rb16(pb) / 10000.0;
 286             codec->bit_rate_tolerance = avio_rb32(pb);
 287             avio_get_str(pb, INT_MAX, rc_eq_buf, sizeof(rc_eq_buf));
 288             codec->rc_eq = av_strdup(rc_eq_buf);
 289             codec->rc_max_rate = avio_rb32(pb);
 290             codec->rc_min_rate = avio_rb32(pb);
 291             codec->rc_buffer_size = avio_rb32(pb);
 292             codec->i_quant_factor = av_int2double(avio_rb64(pb));
 293             codec->b_quant_factor = av_int2double(avio_rb64(pb));
 294             codec->i_quant_offset = av_int2double(avio_rb64(pb));
 295             codec->b_quant_offset = av_int2double(avio_rb64(pb));
 296             codec->dct_algo = avio_rb32(pb);
 297             codec->strict_std_compliance = avio_rb32(pb);
 298             codec->max_b_frames = avio_rb32(pb);
 299             codec->mpeg_quant = avio_rb32(pb);
 300             codec->intra_dc_precision = avio_rb32(pb);
 301             codec->me_method = avio_rb32(pb);
 302             codec->mb_decision = avio_rb32(pb);
 303             codec->nsse_weight = avio_rb32(pb);
 304             codec->frame_skip_cmp = avio_rb32(pb);
 305             codec->rc_buffer_aggressivity = av_int2double(avio_rb64(pb));
 306             codec->codec_tag = avio_rb32(pb);
 307             codec->thread_count = avio_r8(pb);
 308             codec->coder_type = avio_rb32(pb);
 309             codec->me_cmp = avio_rb32(pb);
 310             codec->me_subpel_quality = avio_rb32(pb);
 311             codec->me_range = avio_rb32(pb);
 312             codec->keyint_min = avio_rb32(pb);
 313             codec->scenechange_threshold = avio_rb32(pb);
 314             codec->b_frame_strategy = avio_rb32(pb);
 315             codec->qcompress = av_int2double(avio_rb64(pb));
 316             codec->qblur = av_int2double(avio_rb64(pb));
 317             codec->max_qdiff = avio_rb32(pb);
 318             codec->refs = avio_rb32(pb);
 319             break;
 320         case AVMEDIA_TYPE_AUDIO:
 321             codec->sample_rate = avio_rb32(pb);
 322             codec->channels = avio_rl16(pb);
 323             codec->frame_size = avio_rl16(pb);
 324             break;
 325         default:
 326             goto fail;
 327         }
 328         if (codec->flags & CODEC_FLAG_GLOBAL_HEADER) {
 329             codec->extradata_size = avio_rb32(pb);
 330             codec->extradata = av_malloc(codec->extradata_size);
 331             if (!codec->extradata)
 332                 return AVERROR(ENOMEM);
 333             avio_read(pb, codec->extradata, codec->extradata_size);
 334         }
 335     }
 336
 337     /* get until end of block reached */
 338     while ((avio_tell(pb) % ffm->packet_size) != 0)
 339         avio_r8(pb);
 340
 341     /* init packet demux */
 342     ffm->packet_ptr = ffm->packet;
 343     ffm->packet_end = ffm->packet;
 344     ffm->frame_offset = 0;
 345     ffm->dts = 0;
 346     ffm->read_state = READ_HEADER;
 347     ffm->first_packet = 1;
 348     return 0;
 349  fail:
 350     ffm_close(s);
 351     return -1;
 352 }
 353
 354 /* return < 0 if eof */
 355 static int ffm_read_packet(AVFormatContext *s, AVPacket *pkt)
 356 {
 357     int size;
 358     FFMContext *ffm = s->priv_data;
 359     int duration, ret;
 360
 361     switch(ffm->read_state) {
 362     case READ_HEADER:
 363         if ((ret = ffm_is_avail_data(s, FRAME_HEADER_SIZE+4)) < 0)
 364             return ret;
 365
 366         av_dlog(s, "pos=%08"PRIx64" spos=%"PRIx64", write_index=%"PRIx64" size=%"PRIx64"\n",
 367                avio_tell(s->pb), s->pb->pos, ffm->write_index, ffm->file_size);
 368         if (ffm_read_data(s, ffm->header, FRAME_HEADER_SIZE, 1) !=
 369             FRAME_HEADER_SIZE)
 370             return -1;
 371         if (ffm->header[1] & FLAG_DTS)
 372             if (ffm_read_data(s, ffm->header+16, 4, 1) != 4)
 373                 return -1;
 374         ffm->read_state = READ_DATA;
 375         /* fall thru */
 376     case READ_DATA:
 377         size = AV_RB24(ffm->header + 2);
 378         if ((ret = ffm_is_avail_data(s, size)) < 0)
 379             return ret;
 380
 381         duration = AV_RB24(ffm->header + 5);
 382
 383         av_new_packet(pkt, size);
 384         pkt->stream_index = ffm->header[0];
 385         if ((unsigned)pkt->stream_index >= s->nb_streams) {
 386             av_log(s, AV_LOG_ERROR, "invalid stream index %d\n", pkt->stream_index);
 387             av_free_packet(pkt);
 388             ffm->read_state = READ_HEADER;
 389             return -1;
 390         }
 391         pkt->pos = avio_tell(s->pb);
 392         if (ffm->header[1] & FLAG_KEY_FRAME)
 393             pkt->flags |= AV_PKT_FLAG_KEY;
 394
 395         ffm->read_state = READ_HEADER;
 396         if (ffm_read_data(s, pkt->data, size, 0) != size) {
 397             /* bad case: desynchronized packet. we cancel all the packet loading */
 398             av_free_packet(pkt);
 399             return -1;
 400         }
 401         pkt->pts = AV_RB64(ffm->header+8);
 402         if (ffm->header[1] & FLAG_DTS)
 403             pkt->dts = pkt->pts - AV_RB32(ffm->header+16);
 404         else
 405             pkt->dts = pkt->pts;
 406         pkt->duration = duration;
 407         break;
 408     }
 409     return 0;
 410 }
 411
 412 /* seek to a given time in the file. The file read pointer is
 413    positioned at or before pts. XXX: the following code is quite
 414    approximative */
 415 static int ffm_seek(AVFormatContext *s, int stream_index, int64_t wanted_pts, int flags)
 416 {
 417     FFMContext *ffm = s->priv_data;
 418     int64_t pos_min, pos_max, pos;
 419     int64_t pts_min, pts_max, pts;
 420     double pos1;
 421
 422     av_dlog(s, "wanted_pts=%0.6f\n", wanted_pts / 1000000.0);
 423     /* find the position using linear interpolation (better than
 424        dichotomy in typical cases) */
 425     pos_min = FFM_PACKET_SIZE;
 426     pos_max = ffm->file_size - FFM_PACKET_SIZE;
 427     while (pos_min <= pos_max) {
 428         pts_min = get_dts(s, pos_min);
 429         pts_max = get_dts(s, pos_max);
 430         /* linear interpolation */
 431         pos1 = (double)(pos_max - pos_min) * (double)(wanted_pts - pts_min) /
 432             (double)(pts_max - pts_min);
 433         pos = (((int64_t)pos1) / FFM_PACKET_SIZE) * FFM_PACKET_SIZE;
 434         if (pos <= pos_min)
 435             pos = pos_min;
 436         else if (pos >= pos_max)
 437             pos = pos_max;
 438         pts = get_dts(s, pos);
 439         /* check if we are lucky */
 440         if (pts == wanted_pts) {
 441             goto found;
 442         } else if (pts > wanted_pts) {
 443             pos_max = pos - FFM_PACKET_SIZE;
 444         } else {
 445             pos_min = pos + FFM_PACKET_SIZE;
 446         }
 447     }
 448     pos = (flags & AVSEEK_FLAG_BACKWARD) ? pos_min : pos_max;
 449
 450  found:
 451     if (ffm_seek1(s, pos) < 0)
 452         return -1;
 453
 454     /* reset read state */
 455     ffm->read_state = READ_HEADER;
 456     ffm->packet_ptr = ffm->packet;
 457     ffm->packet_end = ffm->packet;
 458     ffm->first_packet = 1;
 459
 460     return 0;
 461 }
 462
 463 static int ffm_probe(AVProbeData *p)
 464 {
 465     if (
 466         p->buf[0] == 'F' && p->buf[1] == 'F' && p->buf[2] == 'M' &&
 467         p->buf[3] == '1')
 468         return AVPROBE_SCORE_MAX + 1;
 469     return 0;
 470 }
 471
 472 AVInputFormat ff_ffm_demuxer = {
 473     .name           = "ffm",
 474     .long_name      = NULL_IF_CONFIG_SMALL("FFM (AVserver live feed)"),
 475     .priv_data_size = sizeof(FFMContext),
 476     .read_probe     = ffm_probe,
 477     .read_header    = ffm_read_header,
 478     .read_packet    = ffm_read_packet,
 479     .read_close     = ffm_close,
 480     .read_seek      = ffm_seek,
 481 };