LCOV - code coverage report
Current view: top level - src/libavformat - dtsdec.c (source / functions) Hit Total Coverage
Test: coverage.info Lines: 63 81 77.8 %
Date: 2017-01-24 04:42:20 Functions: 1 1 100.0 %

          Line data    Source code
       1             : /*
       2             :  * RAW DTS demuxer
       3             :  * Copyright (c) 2008 Benjamin Larsson
       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             : 
      22             : #include "libavutil/crc.h"
      23             : 
      24             : #include "libavcodec/bytestream.h"
      25             : #include "libavcodec/dca.h"
      26             : #include "libavcodec/dca_syncwords.h"
      27             : #include "libavcodec/get_bits.h"
      28             : 
      29             : #include "avformat.h"
      30             : #include "rawdec.h"
      31             : 
      32        5563 : static int dts_probe(AVProbeData *p)
      33             : {
      34             :     const uint8_t *buf, *bufp;
      35        5563 :     uint32_t state = -1;
      36        5563 :     int markers[4*16] = {0};
      37        5563 :     int exss_markers = 0, exss_nextpos = 0;
      38             :     int sum, max, pos, i;
      39        5563 :     int64_t diff = 0;
      40        5563 :     uint8_t hdr[12 + AV_INPUT_BUFFER_PADDING_SIZE] = { 0 };
      41             : 
      42    48996412 :     for (pos = FFMIN(4096, p->buf_size); pos < p->buf_size - 2; pos += 2) {
      43             :         int marker, sample_blocks, sample_rate, sr_code, framesize;
      44             :         int lfe, wide_hdr, hdr_size;
      45             :         GetBitContext gb;
      46             : 
      47    48990849 :         bufp = buf = p->buf + pos;
      48    48990849 :         state = (state << 16) | bytestream_get_be16(&bufp);
      49             : 
      50    48990849 :         if (pos >= 4)
      51    48990849 :             diff += FFABS(((int16_t)AV_RL16(buf)) - (int16_t)AV_RL16(buf-4));
      52             : 
      53             :         /* extension substream (EXSS) */
      54    48990849 :         if (state == DCA_SYNCWORD_SUBSTREAM) {
      55           7 :             if (pos < exss_nextpos)
      56    48990820 :                 continue;
      57             : 
      58           7 :             init_get_bits(&gb, buf - 2, 96);
      59           7 :             skip_bits_long(&gb, 42);
      60             : 
      61           7 :             wide_hdr  = get_bits1(&gb);
      62           7 :             hdr_size  = get_bits(&gb,  8 + 4 * wide_hdr) + 1;
      63           7 :             framesize = get_bits(&gb, 16 + 4 * wide_hdr) + 1;
      64           7 :             if (hdr_size & 3 || framesize & 3)
      65           0 :                 continue;
      66           7 :             if (hdr_size < 16 || framesize < hdr_size)
      67           0 :                 continue;
      68           7 :             if (pos - 2 + hdr_size > p->buf_size)
      69           0 :                 continue;
      70           7 :             if (av_crc(av_crc_get_table(AV_CRC_16_CCITT), 0xffff, buf + 3, hdr_size - 5))
      71           0 :                 continue;
      72             : 
      73           7 :             if (pos == exss_nextpos)
      74           0 :                 exss_markers++;
      75             :             else
      76           7 :                 exss_markers = FFMAX(1, exss_markers - 1);
      77           7 :             exss_nextpos = pos + framesize;
      78           7 :             continue;
      79             :         }
      80             : 
      81             :         /* regular bitstream */
      82    48990871 :         if (state == DCA_SYNCWORD_CORE_BE &&
      83          29 :             (bytestream_get_be16(&bufp) & 0xFC00) == 0xFC00)
      84          29 :             marker = 0;
      85    48990813 :         else if (state == DCA_SYNCWORD_CORE_LE &&
      86           0 :                  (bytestream_get_be16(&bufp) & 0x00FC) == 0x00FC)
      87           0 :             marker = 1;
      88             : 
      89             :         /* 14 bits big-endian bitstream */
      90    48990813 :         else if (state == DCA_SYNCWORD_CORE_14B_BE &&
      91           0 :                  (bytestream_get_be16(&bufp) & 0xFFF0) == 0x07F0)
      92           0 :             marker = 2;
      93             : 
      94             :         /* 14 bits little-endian bitstream */
      95    48990813 :         else if (state == DCA_SYNCWORD_CORE_14B_LE &&
      96           0 :                  (bytestream_get_be16(&bufp) & 0xF0FF) == 0xF007)
      97           0 :             marker = 3;
      98             :         else
      99    48990813 :             continue;
     100             : 
     101          29 :         if (avpriv_dca_convert_bitstream(buf-2, 12, hdr, 12) < 0)
     102           0 :             continue;
     103             : 
     104          29 :         init_get_bits(&gb, hdr, 96);
     105          29 :         skip_bits_long(&gb, 39);
     106             : 
     107          29 :         sample_blocks = get_bits(&gb, 7) + 1;
     108          29 :         if (sample_blocks < 8)
     109           0 :             continue;
     110             : 
     111          29 :         framesize = get_bits(&gb, 14) + 1;
     112          29 :         if (framesize < 95)
     113           0 :             continue;
     114             : 
     115          29 :         skip_bits(&gb, 6);
     116          29 :         sr_code = get_bits(&gb, 4);
     117          29 :         sample_rate = avpriv_dca_sample_rates[sr_code];
     118          29 :         if (sample_rate == 0)
     119           0 :             continue;
     120             : 
     121          29 :         get_bits(&gb, 5);
     122          29 :         if (get_bits(&gb, 1))
     123           0 :             continue;
     124             : 
     125          29 :         skip_bits_long(&gb, 9);
     126          29 :         lfe = get_bits(&gb, 2);
     127          29 :         if (lfe > 2)
     128           0 :             continue;
     129             : 
     130          29 :         marker += 4* sr_code;
     131             : 
     132          29 :         markers[marker] ++;
     133             :     }
     134             : 
     135        5563 :     if (exss_markers > 3)
     136           0 :         return AVPROBE_SCORE_EXTENSION + 1;
     137             : 
     138        5563 :     sum = max = 0;
     139      361595 :     for (i=0; i<FF_ARRAY_ELEMS(markers); i++) {
     140      356032 :         sum += markers[i];
     141      356032 :         if (markers[max] < markers[i])
     142           8 :             max = i;
     143             :     }
     144             : 
     145        5567 :     if (markers[max] > 3 && p->buf_size / markers[max] < 32*1024 &&
     146           8 :         markers[max] * 4 > sum * 3 &&
     147           4 :         diff / p->buf_size > 200)
     148           4 :         return AVPROBE_SCORE_EXTENSION + 1;
     149             : 
     150        5559 :     return 0;
     151             : }
     152             : 
     153             : AVInputFormat ff_dts_demuxer = {
     154             :     .name           = "dts",
     155             :     .long_name      = NULL_IF_CONFIG_SMALL("raw DTS"),
     156             :     .read_probe     = dts_probe,
     157             :     .read_header    = ff_raw_audio_read_header,
     158             :     .read_packet    = ff_raw_read_partial_packet,
     159             :     .flags          = AVFMT_GENERIC_INDEX,
     160             :     .extensions     = "dts",
     161             :     .raw_codec_id   = AV_CODEC_ID_DTS,
     162             : };

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