/* * 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 "demux.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;} const FFInputFormat ff_dts_demuxer = {    .p.name         = "dts",    .p.long_name    = NULL_IF_CONFIG_SMALL("raw DTS"),    .p.flags        = AVFMT_GENERIC_INDEX,    .p.extensions   = "dts",    .p.priv_class   = &ff_raw_demuxer_class,    .read_probe     = dts_probe,    .read_header    = ff_raw_audio_read_header,    .read_packet    = ff_raw_read_partial_packet,    .raw_codec_id   = AV_CODEC_ID_DTS,    .priv_data_size = sizeof(FFRawDemuxerContext),};