| /* |
| * RAW DTS demuxer |
| * Copyright (c) 2008 Benjamin Larsson |
| * |
| * This file is part of FFmpeg. |
| * |
| * FFmpeg is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Lesser General Public |
| * License as published by the Free Software Foundation; either |
| * version 2.1 of the License, or (at your option) any later version. |
| * |
| * FFmpeg is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * Lesser General Public License for more details. |
| * |
| * You should have received a copy of the GNU Lesser General Public |
| * License along with FFmpeg; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| */ |
| |
| #include "libavcodec/bytestream.h" |
| #include "libavcodec/dca.h" |
| #include "libavcodec/dca_syncwords.h" |
| #include "libavcodec/get_bits.h" |
| |
| #include "avformat.h" |
| #include "rawdec.h" |
| |
| static int dts_probe(AVProbeData *p) |
| { |
| const uint8_t *buf, *bufp; |
| uint32_t state = -1; |
| int markers[4*16] = {0}; |
| int sum, max, i; |
| int64_t diff = 0; |
| uint8_t hdr[12 + AV_INPUT_BUFFER_PADDING_SIZE] = { 0 }; |
| |
| buf = p->buf + FFMIN(4096, p->buf_size); |
| |
| for(; buf < (p->buf+p->buf_size)-2; buf+=2) { |
| int marker, sample_blocks, sample_rate, sr_code, framesize; |
| int lfe; |
| GetBitContext gb; |
| |
| bufp = buf; |
| state = (state << 16) | bytestream_get_be16(&bufp); |
| |
| if (buf - p->buf >= 4) |
| diff += FFABS(((int16_t)AV_RL16(buf)) - (int16_t)AV_RL16(buf-4)); |
| |
| /* regular bitstream */ |
| if (state == DCA_SYNCWORD_CORE_BE && |
| (bytestream_get_be16(&bufp) & 0xFC00) == 0xFC00) |
| marker = 0; |
| else if (state == DCA_SYNCWORD_CORE_LE && |
| (bytestream_get_be16(&bufp) & 0x00FC) == 0x00FC) |
| marker = 1; |
| |
| /* 14 bits big-endian bitstream */ |
| else if (state == DCA_SYNCWORD_CORE_14B_BE && |
| (bytestream_get_be16(&bufp) & 0xFFF0) == 0x07F0) |
| marker = 2; |
| |
| /* 14 bits little-endian bitstream */ |
| else if (state == DCA_SYNCWORD_CORE_14B_LE && |
| (bytestream_get_be16(&bufp) & 0xF0FF) == 0xF007) |
| marker = 3; |
| else |
| continue; |
| |
| if (avpriv_dca_convert_bitstream(buf-2, 12, hdr, 12) < 0) |
| continue; |
| |
| init_get_bits(&gb, hdr, 96); |
| skip_bits_long(&gb, 39); |
| |
| sample_blocks = get_bits(&gb, 7) + 1; |
| if (sample_blocks < 8) |
| continue; |
| |
| framesize = get_bits(&gb, 14) + 1; |
| if (framesize < 95) |
| continue; |
| |
| skip_bits(&gb, 6); |
| sr_code = get_bits(&gb, 4); |
| sample_rate = avpriv_dca_sample_rates[sr_code]; |
| if (sample_rate == 0) |
| continue; |
| |
| get_bits(&gb, 5); |
| if (get_bits(&gb, 1)) |
| continue; |
| |
| skip_bits_long(&gb, 9); |
| lfe = get_bits(&gb, 2); |
| if (lfe > 2) |
| continue; |
| |
| marker += 4* sr_code; |
| |
| markers[marker] ++; |
| } |
| |
| sum = max = 0; |
| for (i=0; i<FF_ARRAY_ELEMS(markers); i++) { |
| sum += markers[i]; |
| if (markers[max] < markers[i]) |
| max = i; |
| } |
| |
| if (markers[max] > 3 && p->buf_size / markers[max] < 32*1024 && |
| markers[max] * 4 > sum * 3 && |
| diff / p->buf_size > 200) |
| return AVPROBE_SCORE_EXTENSION + 1; |
| |
| return 0; |
| } |
| |
| AVInputFormat ff_dts_demuxer = { |
| .name = "dts", |
| .long_name = NULL_IF_CONFIG_SMALL("raw DTS"), |
| .read_probe = dts_probe, |
| .read_header = ff_raw_audio_read_header, |
| .read_packet = ff_raw_read_partial_packet, |
| .flags = AVFMT_GENERIC_INDEX, |
| .extensions = "dts", |
| .raw_codec_id = AV_CODEC_ID_DTS, |
| }; |