Revision 625daac4 libavcodec/flacdec.c

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libavcodec/flacdec.c
67 67
    unsigned int allocated_bitstream_size;
68 68
} FLACContext;
69 69

  
70
static const int sample_size_table[] =
71
{ 0, 8, 12, 0, 16, 20, 24, 0 };
72

  
73
static int64_t get_utf8(GetBitContext *gb)
74
{
75
    int64_t val;
76
    GET_UTF8(val, get_bits(gb, 8), return -1;)
77
    return val;
78
}
79

  
80 70
static void allocate_buffers(FLACContext *s);
81 71

  
82 72
int ff_flac_is_extradata_valid(AVCodecContext *avctx,
......
480 470
    return 0;
481 471
}
482 472

  
483
/**
484
 * Validate and decode a frame header.
485
 * @param      avctx AVCodecContext to use as av_log() context
486
 * @param      gb    GetBitContext from which to read frame header
487
 * @param[out] fi    frame information
488
 * @return non-zero on error, 0 if ok
489
 */
490
static int decode_frame_header(AVCodecContext *avctx, GetBitContext *gb,
491
                               FLACFrameInfo *fi)
492
{
493
    int bs_code, sr_code, bps_code;
494

  
495
    /* frame sync code */
496
    skip_bits(gb, 16);
497

  
498
    /* block size and sample rate codes */
499
    bs_code = get_bits(gb, 4);
500
    sr_code = get_bits(gb, 4);
501

  
502
    /* channels and decorrelation */
503
    fi->ch_mode = get_bits(gb, 4);
504
    if (fi->ch_mode < FLAC_MAX_CHANNELS) {
505
        fi->channels = fi->ch_mode + 1;
506
        fi->ch_mode = FLAC_CHMODE_INDEPENDENT;
507
    } else if (fi->ch_mode <= FLAC_CHMODE_MID_SIDE) {
508
        fi->channels = 2;
509
    } else {
510
        av_log(avctx, AV_LOG_ERROR, "invalid channel mode: %d\n", fi->ch_mode);
511
        return -1;
512
    }
513

  
514
    /* bits per sample */
515
    bps_code = get_bits(gb, 3);
516
    if (bps_code == 3 || bps_code == 7) {
517
        av_log(avctx, AV_LOG_ERROR, "invalid sample size code (%d)\n",
518
               bps_code);
519
        return -1;
520
    }
521
    fi->bps = sample_size_table[bps_code];
522

  
523
    /* reserved bit */
524
    if (get_bits1(gb)) {
525
        av_log(avctx, AV_LOG_ERROR, "broken stream, invalid padding\n");
526
        return -1;
527
    }
528

  
529
    /* sample or frame count */
530
    if (get_utf8(gb) < 0) {
531
        av_log(avctx, AV_LOG_ERROR, "utf8 fscked\n");
532
        return -1;
533
    }
534

  
535
    /* blocksize */
536
    if (bs_code == 0) {
537
        av_log(avctx, AV_LOG_ERROR, "reserved blocksize code: 0\n");
538
        return -1;
539
    } else if (bs_code == 6) {
540
        fi->blocksize = get_bits(gb, 8) + 1;
541
    } else if (bs_code == 7) {
542
        fi->blocksize = get_bits(gb, 16) + 1;
543
    } else {
544
        fi->blocksize = ff_flac_blocksize_table[bs_code];
545
    }
546

  
547
    /* sample rate */
548
    if (sr_code < 12) {
549
        fi->samplerate = ff_flac_sample_rate_table[sr_code];
550
    } else if (sr_code == 12) {
551
        fi->samplerate = get_bits(gb, 8) * 1000;
552
    } else if (sr_code == 13) {
553
        fi->samplerate = get_bits(gb, 16);
554
    } else if (sr_code == 14) {
555
        fi->samplerate = get_bits(gb, 16) * 10;
556
    } else {
557
        av_log(avctx, AV_LOG_ERROR, "illegal sample rate code %d\n",
558
               sr_code);
559
        return -1;
560
    }
561

  
562
    /* header CRC-8 check */
563
    skip_bits(gb, 8);
564
    if (av_crc(av_crc_get_table(AV_CRC_8_ATM), 0, gb->buffer,
565
               get_bits_count(gb)/8)) {
566
        av_log(avctx, AV_LOG_ERROR, "header crc mismatch\n");
567
        return -1;
568
    }
569

  
570
    return 0;
571
}
572

  
573 473
static int decode_frame(FLACContext *s)
574 474
{
575 475
    int i;
576 476
    GetBitContext *gb = &s->gb;
577 477
    FLACFrameInfo fi;
578 478

  
579
    if (decode_frame_header(s->avctx, gb, &fi)) {
479
    if (ff_flac_decode_frame_header(s->avctx, gb, &fi)) {
580 480
        av_log(s->avctx, AV_LOG_ERROR, "invalid frame header\n");
581 481
        return -1;
582 482
    }

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