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https://gitee.com/openharmony/third_party_ffmpeg
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b6c207f535
The problem is that with particularly complex images and especially at high bit depths and 5-level transforms the coefficients would overflow, causing huge artifacts to appear. This was discovered thanks to the fate tests, which will have to be redone as this fixes a multitude of problems and increases PSNR. There is a slight performance drop associated with this change, making the encoder slower by 1.15 times, however this is necessary in order to avoid undefined behavior and overflows. It would be worth to template the transforms to keep the performance for 8 bit images as 32 bit coefficients are unnecessary for that case, but the primary use of the encoder is to encode video at 10 bits. Reviewed-by: Christophe Gisquet <christophe.gisquet@gmail.com> Reviewed-by: Michael Niedermayer <michael@niedermayer.cc> Signed-off-by: Rostislav Pehlivanov <atomnuker@gmail.com>
53 lines
1.9 KiB
C
53 lines
1.9 KiB
C
/*
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* Copyright (C) 2016 Open Broadcast Systems Ltd.
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* Author 2016 Rostislav Pehlivanov <atomnuker@gmail.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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#ifndef AVCODEC_VC2ENC_DWT_H
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#define AVCODEC_VC2ENC_DWT_H
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#include <stddef.h>
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#include <stdint.h>
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typedef int32_t dwtcoef;
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enum VC2TransformType {
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VC2_TRANSFORM_9_7 = 0, /* Deslauriers-Dubuc (9,7) */
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VC2_TRANSFORM_5_3 = 1, /* LeGall (5,3) */
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VC2_TRANSFORM_13_7 = 2, /* Deslauriers-Dubuc (13,7) */
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VC2_TRANSFORM_HAAR = 3, /* Haar without shift */
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VC2_TRANSFORM_HAAR_S = 4, /* Haar with 1 shift/lvl */
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VC2_TRANSFORM_FIDEL = 5, /* Fidelity filter */
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VC2_TRANSFORM_9_7_I = 6, /* Daubechies (9,7) */
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VC2_TRANSFORMS_NB
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};
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typedef struct VC2TransformContext {
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dwtcoef *buffer;
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void (*vc2_subband_dwt[VC2_TRANSFORMS_NB])(struct VC2TransformContext *t,
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dwtcoef *data, ptrdiff_t stride,
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int width, int height);
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} VC2TransformContext;
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int ff_vc2enc_init_transforms(VC2TransformContext *t, int p_width, int p_height);
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void ff_vc2enc_free_transforms(VC2TransformContext *t);
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#endif /* AVCODEC_VC2ENC_DWT_H */
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