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https://git.ffmpeg.org/ffmpeg.git
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120 lines
3.8 KiB
C
120 lines
3.8 KiB
C
/*
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* RAW H.264 video demuxer
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* Copyright (c) 2008 Michael Niedermayer <michaelni@gmx.at>
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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 "libavcodec/get_bits.h"
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#include "libavcodec/golomb.h"
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#include "avformat.h"
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#include "rawdec.h"
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#define MAX_SPS_COUNT 32
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#define MAX_PPS_COUNT 256
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static int h264_probe(const AVProbeData *p)
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{
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uint32_t code = -1;
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int sps = 0, pps = 0, idr = 0, res = 0, sli = 0;
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int i, ret;
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int pps_ids[MAX_PPS_COUNT+1] = {0};
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int sps_ids[MAX_SPS_COUNT+1] = {0};
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unsigned pps_id, sps_id;
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GetBitContext gb;
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for (i = 0; i + 2 < p->buf_size; i++) {
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code = (code << 8) + p->buf[i];
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if ((code & 0xffffff00) == 0x100) {
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int ref_idc = (code >> 5) & 3;
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int type = code & 0x1F;
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static const int8_t ref_zero[] = {
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2, 0, 0, 0, 0, -1, 1, -1,
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-1, 1, 1, 1, 1, -1, 2, 2,
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2, 2, 2, 0, 2, 2, 2, 2,
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2, 2, 2, 2, 2, 2, 2, 2
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};
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if (code & 0x80) // forbidden_bit
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return 0;
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if (ref_zero[type] == 1 && ref_idc)
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return 0;
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if (ref_zero[type] == -1 && !ref_idc)
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return 0;
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if (ref_zero[type] == 2) {
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if (!(code == 0x100 && !p->buf[i + 1] && !p->buf[i + 2]))
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res++;
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}
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ret = init_get_bits8(&gb, p->buf + i + 1, p->buf_size - i - 1);
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if (ret < 0)
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return 0;
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switch (type) {
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case 1:
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case 5:
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get_ue_golomb_long(&gb);
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if (get_ue_golomb_long(&gb) > 9U)
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return 0;
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pps_id = get_ue_golomb_long(&gb);
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if (pps_id > MAX_PPS_COUNT)
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return 0;
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if (!pps_ids[pps_id])
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break;
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if (type == 1)
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sli++;
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else
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idr++;
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break;
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case 7:
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skip_bits(&gb, 14);
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if (get_bits(&gb, 2))
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return 0;
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skip_bits(&gb, 8);
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sps_id = get_ue_golomb_long(&gb);
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if (sps_id > MAX_SPS_COUNT)
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return 0;
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sps_ids[sps_id] = 1;
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sps++;
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break;
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case 8:
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pps_id = get_ue_golomb_long(&gb);
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if (pps_id > MAX_PPS_COUNT)
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return 0;
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sps_id = get_ue_golomb_long(&gb);
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if (sps_id > MAX_SPS_COUNT)
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return 0;
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if (!sps_ids[sps_id])
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break;
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pps_ids[pps_id] = 1;
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pps++;
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break;
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}
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}
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}
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ff_tlog(NULL, "sps:%d pps:%d idr:%d sli:%d res:%d\n", sps, pps, idr, sli, res);
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if (sps && pps && (idr || sli > 3) && res < (sps + pps + idr))
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return AVPROBE_SCORE_EXTENSION + 1; // 1 more than .mpg
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return 0;
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}
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FF_DEF_RAWVIDEO_DEMUXER(h264, "raw H.264 video", h264_probe, "h26l,h264,264,avc", AV_CODEC_ID_H264)
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