| /* |
| * 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 "libavutil/crc.h" |
| |
| #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(const AVProbeData *p) |
| { |
| const uint8_t *buf, *bufp; |
| uint32_t state = -1; |
| int markers[4*16] = {0}; |
| int exss_markers = 0, exss_nextpos = 0; |
| int sum, max, pos, ret, i; |
| int64_t diff = 0; |
| int diffcount = 1; |
| uint8_t hdr[DCA_CORE_FRAME_HEADER_SIZE + AV_INPUT_BUFFER_PADDING_SIZE] = { 0 }; |
| |
| for (pos = FFMIN(4096, p->buf_size); pos < p->buf_size - 2; pos += 2) { |
| int marker, wide_hdr, hdr_size, framesize; |
| DCACoreFrameHeader h; |
| GetBitContext gb; |
| |
| bufp = buf = p->buf + pos; |
| state = (state << 16) | bytestream_get_be16(&bufp); |
| |
| if (pos >= 4) { |
| if (AV_RL16(buf) || AV_RL16(buf-4)) { |
| diff += FFABS(((int16_t)AV_RL16(buf)) - (int16_t)AV_RL16(buf-4)); |
| diffcount ++; |
| } |
| } |
| |
| /* extension substream (EXSS) */ |
| if (state == DCA_SYNCWORD_SUBSTREAM) { |
| if (pos < exss_nextpos) |
| continue; |
| |
| init_get_bits(&gb, buf - 2, 96); |
| skip_bits_long(&gb, 42); |
| |
| wide_hdr = get_bits1(&gb); |
| hdr_size = get_bits(&gb, 8 + 4 * wide_hdr) + 1; |
| framesize = get_bits(&gb, 16 + 4 * wide_hdr) + 1; |
| if (hdr_size & 3 || framesize & 3) |
| continue; |
| if (hdr_size < 16 || framesize < hdr_size) |
| continue; |
| if (pos - 2 + hdr_size > p->buf_size) |
| continue; |
| if (av_crc(av_crc_get_table(AV_CRC_16_CCITT), 0xffff, buf + 3, hdr_size - 5)) |
| continue; |
| |
| if (pos == exss_nextpos) |
| exss_markers++; |
| else |
| exss_markers = FFMAX(1, exss_markers - 1); |
| exss_nextpos = pos + framesize; |
| continue; |
| } |
| |
| /* 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 ((ret = avpriv_dca_convert_bitstream(buf - 2, DCA_CORE_FRAME_HEADER_SIZE, |
| hdr, DCA_CORE_FRAME_HEADER_SIZE)) < 0) |
| continue; |
| if (avpriv_dca_parse_core_frame_header(&h, hdr, ret) < 0) |
| continue; |
| |
| marker += 4 * h.sr_code; |
| |
| markers[marker] ++; |
| } |
| |
| if (exss_markers > 3) |
| return AVPROBE_SCORE_EXTENSION + 1; |
| |
| 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 / diffcount > 600) |
| return AVPROBE_SCORE_EXTENSION + 1; |
| |
| return 0; |
| } |
| |
| FF_RAW_DEMUXER_CLASS(dts) |
| 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, |
| .priv_data_size = sizeof(FFRawDemuxerContext), |
| .priv_class = &dts_demuxer_class,}; |