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