87 lines
2.7 KiB
C
87 lines
2.7 KiB
C
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/*
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* VC-1 demuxer
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* Copyright (c) 2015 Carl Eugen Hoyos
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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 "avformat.h"
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#include "rawdec.h"
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#include "libavutil/intreadwrite.h"
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#include "libavcodec/vc1_common.h"
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static int vc1_probe(const AVProbeData *p)
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{
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int seq = 0, entry = 0, invalid = 0, frame = 0, i;
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for (i = 0; i < p->buf_size + 5; i++) {
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uint32_t code = AV_RB32(p->buf + i);
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if ((code & 0xffffffe0) == 0x100) {
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int type = code & 0x11f;
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i += 4;
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switch (type) {
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case VC1_CODE_SEQHDR: {
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int profile, level, chromaformat;
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profile = (p->buf[i] & 0xc0) >> 6;
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if (profile != PROFILE_ADVANCED) {
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seq = 0;
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invalid++;
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continue;
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}
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level = (p->buf[i] & 0x38) >> 3;
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if (level >= 5) {
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seq = 0;
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invalid++;
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continue;
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}
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chromaformat = (p->buf[i] & 0x6) >> 1;
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if (chromaformat != 1) {
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seq = 0;
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invalid++;
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continue;
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}
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seq++;
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i += 6;
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break;
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}
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case VC1_CODE_ENTRYPOINT:
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if (!seq) {
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invalid++;
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continue;
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}
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entry++;
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i += 2;
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break;
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case VC1_CODE_FRAME:
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case VC1_CODE_FIELD:
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case VC1_CODE_SLICE:
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if (seq && entry)
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frame++;
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break;
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}
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}
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}
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if (frame > 1 && frame >> 1 > invalid)
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return AVPROBE_SCORE_EXTENSION / 2 + 1;
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if (frame >= 1)
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return AVPROBE_SCORE_EXTENSION / 4;
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return 0;
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}
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FF_DEF_RAWVIDEO_DEMUXER2(vc1, "raw VC-1", vc1_probe, "vc1", AV_CODEC_ID_VC1, AVFMT_GENERIC_INDEX|AVFMT_NOTIMESTAMPS)
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