mirror of
https://gitee.com/openharmony/third_party_ffmpeg
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7c9d2ad45f
This prevents potential ABI issues with GetBitContext. Reviewed-by: foo86 <foobaz86@gmail.com> Signed-off-by: James Almer <jamrial@gmail.com>
140 lines
4.4 KiB
C
140 lines
4.4 KiB
C
/*
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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 "libavutil/crc.h"
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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 exss_markers = 0, exss_nextpos = 0;
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int sum, max, pos, ret, i;
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int64_t diff = 0;
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uint8_t hdr[DCA_CORE_FRAME_HEADER_SIZE + AV_INPUT_BUFFER_PADDING_SIZE] = { 0 };
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for (pos = FFMIN(4096, p->buf_size); pos < p->buf_size - 2; pos += 2) {
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int marker, wide_hdr, hdr_size, framesize;
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DCACoreFrameHeader h;
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GetBitContext gb;
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bufp = buf = p->buf + pos;
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state = (state << 16) | bytestream_get_be16(&bufp);
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if (pos >= 4)
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diff += FFABS(((int16_t)AV_RL16(buf)) - (int16_t)AV_RL16(buf-4));
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/* extension substream (EXSS) */
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if (state == DCA_SYNCWORD_SUBSTREAM) {
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if (pos < exss_nextpos)
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continue;
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init_get_bits(&gb, buf - 2, 96);
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skip_bits_long(&gb, 42);
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wide_hdr = get_bits1(&gb);
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hdr_size = get_bits(&gb, 8 + 4 * wide_hdr) + 1;
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framesize = get_bits(&gb, 16 + 4 * wide_hdr) + 1;
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if (hdr_size & 3 || framesize & 3)
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continue;
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if (hdr_size < 16 || framesize < hdr_size)
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continue;
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if (pos - 2 + hdr_size > p->buf_size)
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continue;
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if (av_crc(av_crc_get_table(AV_CRC_16_CCITT), 0xffff, buf + 3, hdr_size - 5))
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continue;
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if (pos == exss_nextpos)
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exss_markers++;
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else
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exss_markers = FFMAX(1, exss_markers - 1);
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exss_nextpos = pos + framesize;
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continue;
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}
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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 ((ret = avpriv_dca_convert_bitstream(buf - 2, DCA_CORE_FRAME_HEADER_SIZE,
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hdr, DCA_CORE_FRAME_HEADER_SIZE)) < 0)
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continue;
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if (avpriv_dca_parse_core_frame_header(&h, hdr, ret) < 0)
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continue;
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marker += 4 * h.sr_code;
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markers[marker] ++;
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}
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if (exss_markers > 3)
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return AVPROBE_SCORE_EXTENSION + 1;
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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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