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/*
* Copyright 2020 The libgav1 Authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* 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 LIBGAV1_SRC_FRAME_BUFFER_UTILS_H_
#define LIBGAV1_SRC_FRAME_BUFFER_UTILS_H_
#include <cassert>
#include <cstdint>
#include "src/gav1/decoder_buffer.h"
namespace libgav1 {
// The following table is from Section 6.4.2 of the spec.
//
// subsampling_x subsampling_y mono_chrome Description
// -----------------------------------------------------------
// 0 0 0 YUV 4:4:4
// 1 0 0 YUV 4:2:2
// 1 1 0 YUV 4:2:0
// 1 1 1 Monochrome 4:0:0
inline Libgav1ImageFormat ComposeImageFormat(bool is_monochrome,
int8_t subsampling_x,
int8_t subsampling_y) {
Libgav1ImageFormat image_format;
if (subsampling_x == 0) {
assert(subsampling_y == 0 && !is_monochrome);
image_format = kLibgav1ImageFormatYuv444;
} else if (subsampling_y == 0) {
assert(!is_monochrome);
image_format = kLibgav1ImageFormatYuv422;
} else if (!is_monochrome) {
image_format = kLibgav1ImageFormatYuv420;
} else {
image_format = kLibgav1ImageFormatMonochrome400;
}
return image_format;
}
inline void DecomposeImageFormat(Libgav1ImageFormat image_format,
bool* is_monochrome, int8_t* subsampling_x,
int8_t* subsampling_y) {
*is_monochrome = false;
*subsampling_x = 1;
*subsampling_y = 1;
switch (image_format) {
case kLibgav1ImageFormatYuv420:
break;
case kLibgav1ImageFormatYuv422:
*subsampling_y = 0;
break;
case kLibgav1ImageFormatYuv444:
*subsampling_x = *subsampling_y = 0;
break;
default:
assert(image_format == kLibgav1ImageFormatMonochrome400);
*is_monochrome = true;
break;
}
}
} // namespace libgav1
#endif // LIBGAV1_SRC_FRAME_BUFFER_UTILS_H_
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