mirror of
https://github.com/librempeg/librempeg
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78 lines
2.7 KiB
C
78 lines
2.7 KiB
C
/*
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* RAW MPEG-4 video demuxer
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* Copyright (c) 2006 Thijs Vermeir <thijs.vermeir@barco.com>
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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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#define VOS_STARTCODE 0x1B0
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#define USER_DATA_STARTCODE 0x1B2
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#define GOP_STARTCODE 0x1B3
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#define VISUAL_OBJ_STARTCODE 0x1B5
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#define VOP_STARTCODE 0x1B6
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#define SLICE_STARTCODE 0x1B7
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#define EXT_STARTCODE 0x1B8
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static int mpeg4video_probe(const AVProbeData *probe_packet)
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{
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uint32_t temp_buffer = -1;
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int VO = 0, VOL = 0, VOP = 0, VISO = 0, res = 0;
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int res_main = 0;
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int i;
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for (i = 0; i < probe_packet->buf_size; i++) {
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temp_buffer = (temp_buffer << 8) + probe_packet->buf[i];
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if (temp_buffer & 0xfffffe00)
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continue;
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if (temp_buffer < 2)
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continue;
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if (temp_buffer == VOP_STARTCODE)
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VOP++;
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else if (temp_buffer == VISUAL_OBJ_STARTCODE)
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VISO++;
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else if (temp_buffer >= 0x100 && temp_buffer < 0x120)
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VO++;
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else if (temp_buffer >= 0x120 && temp_buffer < 0x130)
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VOL++;
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else if (temp_buffer == SLICE_STARTCODE || temp_buffer == EXT_STARTCODE)
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res_main++;
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else if (!(0x1AF < temp_buffer && temp_buffer < 0x1B7) &&
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!(0x1B9 < temp_buffer && temp_buffer < 0x1C4))
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res++;
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}
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// res_main repesents the reserved codes within the "main" profile, they are
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// added to the reserved ones if it appears that this is a "main" profile
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// stream
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if (res_main && 2*res_main < VOP)
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res += res_main;
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if (VOP >= VISO && VOP >= VOL && VO >= VOL && VOL > 0 && res == 0)
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return VOP+VO > 4 ? AVPROBE_SCORE_EXTENSION : AVPROBE_SCORE_EXTENSION/2;
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if (VOP >= VISO && VOP >= VOL && VO >= VOL && VOL > 0 && VOP+VO > 4)
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return AVPROBE_SCORE_EXTENSION/10;
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return 0;
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}
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FF_DEF_RAWVIDEO_DEMUXER2(m4v, "raw MPEG-4 video", mpeg4video_probe, "m4v",
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AV_CODEC_ID_MPEG4, AVFMT_GENERIC_INDEX | AVFMT_TS_DISCONT)
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