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-rw-r--r-- | third_party/aom/aom_dsp/pyramid.h | 127 |
1 files changed, 127 insertions, 0 deletions
diff --git a/third_party/aom/aom_dsp/pyramid.h b/third_party/aom/aom_dsp/pyramid.h new file mode 100644 index 0000000000..9442a1ff08 --- /dev/null +++ b/third_party/aom/aom_dsp/pyramid.h @@ -0,0 +1,127 @@ +/* + * Copyright (c) 2022, Alliance for Open Media. All rights reserved + * + * This source code is subject to the terms of the BSD 2 Clause License and + * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License + * was not distributed with this source code in the LICENSE file, you can + * obtain it at www.aomedia.org/license/software. If the Alliance for Open + * Media Patent License 1.0 was not distributed with this source code in the + * PATENTS file, you can obtain it at www.aomedia.org/license/patent. + */ + +#ifndef AOM_AOM_DSP_PYRAMID_H_ +#define AOM_AOM_DSP_PYRAMID_H_ + +#include <stddef.h> +#include <stdint.h> +#include <stdbool.h> + +#include "config/aom_config.h" + +#include "aom_scale/yv12config.h" +#include "aom_util/aom_thread.h" + +#ifdef __cplusplus +extern "C" { +#endif + +// Minimum dimensions of a downsampled image +#define MIN_PYRAMID_SIZE_LOG2 3 +#define MIN_PYRAMID_SIZE (1 << MIN_PYRAMID_SIZE_LOG2) + +// Size of border around each pyramid image, in pixels +// Similarly to the border around regular image buffers, this border is filled +// with copies of the outermost pixels of the frame, to allow for more efficient +// convolution code +// TODO(rachelbarker): How many pixels do we actually need here? +// I think we only need 9 for disflow, but how many for corner matching? +#define PYRAMID_PADDING 16 + +// Byte alignment of each line within the image pyramids. +// That is, the first pixel inside the image (ie, not in the border region), +// on each row of each pyramid level, is aligned to this byte alignment. +// This value must be a power of 2. +#define PYRAMID_ALIGNMENT 32 + +typedef struct { + uint8_t *buffer; + int width; + int height; + int stride; +} PyramidLayer; + +// Struct for an image pyramid +typedef struct image_pyramid { +#if CONFIG_MULTITHREAD + // Mutex which is used to prevent the pyramid being computed twice at the + // same time + // + // Semantics: + // * This mutex must be held whenever reading or writing the `valid` flag + // + // * This mutex must also be held while computing the image pyramid, + // to ensure that only one thread may do so at a time. + // + // * However, once you have read the valid flag and seen a true value, + // it is safe to drop the mutex and read from the remaining fields. + // This is because, once the image pyramid is computed, its contents + // will not be changed until the parent frame buffer is recycled, + // which will not happen until there are no more outstanding references + // to the frame buffer. + pthread_mutex_t mutex; +#endif + // Flag indicating whether the pyramid contains valid data + bool valid; + // Number of allocated/filled levels in this pyramid + int n_levels; + // Pointer to allocated buffer + uint8_t *buffer_alloc; + // Data for each level + // The `buffer` pointers inside this array point into the region which + // is stored in the `buffer_alloc` field here + PyramidLayer *layers; +} ImagePyramid; + +size_t aom_get_pyramid_alloc_size(int width, int height, int n_levels, + bool image_is_16bit); + +ImagePyramid *aom_alloc_pyramid(int width, int height, int n_levels, + bool image_is_16bit); + +// Fill out a downsampling pyramid for a given frame. +// +// The top level (index 0) will always be an 8-bit copy of the input frame, +// regardless of the input bit depth. Additional levels are then downscaled +// by powers of 2. +// +// For small input frames, the number of levels actually constructed +// will be limited so that the smallest image is at least MIN_PYRAMID_SIZE +// pixels along each side. +// +// However, if the input frame has a side of length < MIN_PYRAMID_SIZE, +// we will still construct the top level. +bool aom_compute_pyramid(const YV12_BUFFER_CONFIG *frame, int bit_depth, + ImagePyramid *pyr); + +#ifndef NDEBUG +// Check if a pyramid has already been computed. +// This is mostly a debug helper - as it is necessary to hold pyr->mutex +// while reading the valid flag, we cannot just write: +// assert(pyr->valid); +// This function allows the check to be correctly written as: +// assert(aom_is_pyramid_valid(pyr)); +bool aom_is_pyramid_valid(ImagePyramid *pyr); +#endif + +// Mark a pyramid as no longer containing valid data. +// This must be done whenever the corresponding frame buffer is reused +void aom_invalidate_pyramid(ImagePyramid *pyr); + +// Release the memory associated with a pyramid +void aom_free_pyramid(ImagePyramid *pyr); + +#ifdef __cplusplus +} +#endif + +#endif // AOM_AOM_DSP_PYRAMID_H_ |