/* * 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; } const 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 = &ff_raw_demuxer_class, };