Libav 0.7.1
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00001 /* 00002 * RAW DTS demuxer 00003 * Copyright (c) 2008 Benjamin Larsson 00004 * 00005 * This file is part of Libav. 00006 * 00007 * Libav is free software; you can redistribute it and/or 00008 * modify it under the terms of the GNU Lesser General Public 00009 * License as published by the Free Software Foundation; either 00010 * version 2.1 of the License, or (at your option) any later version. 00011 * 00012 * Libav is distributed in the hope that it will be useful, 00013 * but WITHOUT ANY WARRANTY; without even the implied warranty of 00014 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 00015 * Lesser General Public License for more details. 00016 * 00017 * You should have received a copy of the GNU Lesser General Public 00018 * License along with Libav; if not, write to the Free Software 00019 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 00020 */ 00021 00022 #include "libavcodec/bytestream.h" 00023 #include "avformat.h" 00024 #include "rawdec.h" 00025 00026 #define DCA_MARKER_14B_BE 0x1FFFE800 00027 #define DCA_MARKER_14B_LE 0xFF1F00E8 00028 #define DCA_MARKER_RAW_BE 0x7FFE8001 00029 #define DCA_MARKER_RAW_LE 0xFE7F0180 00030 00031 static int dts_probe(AVProbeData *p) 00032 { 00033 const uint8_t *buf, *bufp; 00034 uint32_t state = -1; 00035 int markers[3] = {0}; 00036 int sum, max; 00037 00038 buf = p->buf; 00039 00040 for(; buf < (p->buf+p->buf_size)-2; buf+=2) { 00041 bufp = buf; 00042 state = (state << 16) | bytestream_get_be16(&bufp); 00043 00044 /* regular bitstream */ 00045 if (state == DCA_MARKER_RAW_BE || state == DCA_MARKER_RAW_LE) 00046 markers[0]++; 00047 00048 /* 14 bits big-endian bitstream */ 00049 if (state == DCA_MARKER_14B_BE) 00050 if ((bytestream_get_be16(&bufp) & 0xFFF0) == 0x07F0) 00051 markers[1]++; 00052 00053 /* 14 bits little-endian bitstream */ 00054 if (state == DCA_MARKER_14B_LE) 00055 if ((bytestream_get_be16(&bufp) & 0xF0FF) == 0xF007) 00056 markers[2]++; 00057 } 00058 sum = markers[0] + markers[1] + markers[2]; 00059 max = markers[1] > markers[0]; 00060 max = markers[2] > markers[max] ? 2 : max; 00061 if (markers[max] > 3 && p->buf_size / markers[max] < 32*1024 && 00062 markers[max] * 4 > sum * 3) 00063 return AVPROBE_SCORE_MAX/2+1; 00064 00065 return 0; 00066 } 00067 00068 AVInputFormat ff_dts_demuxer = { 00069 "dts", 00070 NULL_IF_CONFIG_SMALL("raw DTS"), 00071 0, 00072 dts_probe, 00073 ff_raw_audio_read_header, 00074 ff_raw_read_partial_packet, 00075 .flags= AVFMT_GENERIC_INDEX, 00076 .extensions = "dts", 00077 .value = CODEC_ID_DTS, 00078 };