| /* |
| * Copyright (c) 2016, 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_FLOW_ESTIMATION_CORNER_DETECT_H_ |
| #define AOM_AOM_DSP_FLOW_ESTIMATION_CORNER_DETECT_H_ |
| |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <stdbool.h> |
| #include <memory.h> |
| |
| #include "aom_dsp/pyramid.h" |
| #include "aom_util/aom_pthread.h" |
| |
| #ifdef __cplusplus |
| extern "C" { |
| #endif |
| |
| #define MAX_CORNERS 4096 |
| |
| typedef struct corner_list { |
| #if CONFIG_MULTITHREAD |
| // Mutex which is used to prevent the corner list from 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 // CONFIG_MULTITHREAD |
| // Flag indicating whether the corner list contains valid data |
| bool valid; |
| // Number of corners found |
| int num_corners; |
| // (x, y) coordinates of each corner |
| int corners[2 * MAX_CORNERS]; |
| } CornerList; |
| |
| size_t av1_get_corner_list_size(void); |
| |
| CornerList *av1_alloc_corner_list(void); |
| |
| bool av1_compute_corner_list(const YV12_BUFFER_CONFIG *frame, int bit_depth, |
| int downsample_level, CornerList *corners); |
| |
| #ifndef NDEBUG |
| // Check if a corner list has already been computed. |
| // This is mostly a debug helper - as it is necessary to hold corners->mutex |
| // while reading the valid flag, we cannot just write: |
| // assert(corners->valid); |
| // This function allows the check to be correctly written as: |
| // assert(aom_is_corner_list_valid(corners)); |
| bool aom_is_corner_list_valid(CornerList *corners); |
| #endif |
| |
| void av1_invalidate_corner_list(CornerList *corners); |
| |
| void av1_free_corner_list(CornerList *corners); |
| |
| #ifdef __cplusplus |
| } |
| #endif |
| |
| #endif // AOM_AOM_DSP_FLOW_ESTIMATION_CORNER_DETECT_H_ |