mirror of https://git.ffmpeg.org/ffmpeg.git
69 lines
1.9 KiB
C
69 lines
1.9 KiB
C
/*
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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 <stdint.h>
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#include "vaapi_encode_h26x.h"
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int ff_vaapi_encode_h26x_nal_unit_to_byte_stream(uint8_t *dst, size_t *dst_bit_len,
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uint8_t *src, size_t src_bit_len)
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{
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size_t dp, sp;
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int zero_run = 0;
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size_t dst_len = *dst_bit_len / 8;
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size_t src_len = (src_bit_len + 7) / 8;
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int trailing_zeroes = src_len * 8 - src_bit_len;
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if (dst_len < src_len + 4) {
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// Definitely doesn't fit.
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goto fail;
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}
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// Start code.
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dst[0] = dst[1] = dst[2] = 0;
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dst[3] = 1;
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dp = 4;
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for (sp = 0; sp < src_len; sp++) {
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if (dp >= dst_len)
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goto fail;
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if (zero_run < 2) {
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if (src[sp] == 0)
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++zero_run;
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else
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zero_run = 0;
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} else {
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if ((src[sp] & ~3) == 0) {
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// emulation_prevention_three_byte
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dst[dp++] = 3;
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if (dp >= dst_len)
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goto fail;
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}
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zero_run = src[sp] == 0;
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}
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dst[dp++] = src[sp];
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}
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*dst_bit_len = 8 * dp - trailing_zeroes;
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return 0;
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fail:
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*dst_bit_len = 0;
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return AVERROR(ENOSPC);
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}
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