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/**
*
* Copyright 2016-2020 Netflix, Inc.
*
* Licensed under the BSD+Patent License (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://opensource.org/licenses/BSDplusPatent
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
#ifndef VMAF_LUMINANCE_TOOLS_H_
#define VMAF_LUMINANCE_TOOLS_H_
typedef double (*VmafEOTF)(double V);
/*
* Limited pixel range means that only values between 16 and 235 will be used in 8 bits
* (rescale the bounds appropriately for other bitdepths).
* Full pixel range means that values from 0 to 2^bitdepth - 1 will be used.
*/
enum VmafPixelRange {
VMAF_PIXEL_RANGE_UNKNOWN,
VMAF_PIXEL_RANGE_LIMITED,
VMAF_PIXEL_RANGE_FULL,
};
/*
* Contains the necessary information to normalize a luma value down to [0, 1].
*/
typedef struct VmafLumaRange {
int foot;
int head;
} VmafLumaRange;
/*
* Constructor for the LumaRange struct.
*/
int vmaf_luminance_init_luma_range(VmafLumaRange *luma_range, int bitdepth, enum VmafPixelRange pix_range);
/*
* Returns the EOTF corresponding to the string given.
* eotf_str must be one of ['bt1886', 'pq']
*/
int vmaf_luminance_init_eotf(VmafEOTF *eotf, const char *eotf_str);
/*
* Takes a normalized luma value in the [0, 1] range and returns a luminance value.
*/
double vmaf_luminance_bt1886_eotf(double V);
/*
* Takes a normalized luma value in the [0, 1] range and returns a luminance value.
*/
double vmaf_luminance_pq_eotf(double V);
/*
* Takes a luma value, normalizes it and applies the given VmafEOTF
* to return a luminance value.
*/
double vmaf_luminance_get_luminance(int sample, VmafLumaRange luma_range, VmafEOTF eotf);
#endif