| /* |
| * 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_DISFLOW_H_ |
| #define AOM_AOM_DSP_FLOW_ESTIMATION_DISFLOW_H_ |
| |
| #include <stdbool.h> |
| |
| #include "aom_dsp/flow_estimation/flow_estimation.h" |
| #include "aom_dsp/rect.h" |
| #include "aom_scale/yv12config.h" |
| |
| #ifdef __cplusplus |
| extern "C" { |
| #endif |
| |
| // Number of pyramid levels in disflow computation |
| #define DISFLOW_PYRAMID_LEVELS 12 |
| |
| // Size of square patches in the disflow dense grid |
| // Must be a power of 2 |
| #define DISFLOW_PATCH_SIZE_LOG2 3 |
| #define DISFLOW_PATCH_SIZE (1 << DISFLOW_PATCH_SIZE_LOG2) |
| // Center point of square patch |
| #define DISFLOW_PATCH_CENTER ((DISFLOW_PATCH_SIZE / 2) - 1) |
| |
| // Overall scale of the `dx`, `dy` and `dt` arrays in the disflow code |
| // In other words, the various derivatives are calculated with an internal |
| // precision of (8 + DISFLOW_DERIV_SCALE_LOG2) bits, from an 8-bit input. |
| // |
| // This must be carefully synchronized with the code in sobel_filter() |
| // (which fills the dx and dy arrays) and compute_flow_error() (which |
| // fills dt); see the comments in those functions for more details |
| #define DISFLOW_DERIV_SCALE_LOG2 3 |
| #define DISFLOW_DERIV_SCALE (1 << DISFLOW_DERIV_SCALE_LOG2) |
| |
| // Scale factor applied to each step in the main refinement loop |
| // |
| // This should be <= 1.0 to avoid overshoot. Values below 1.0 |
| // may help in some cases, but slow convergence overall, so |
| // will require careful tuning. |
| // TODO(rachelbarker): Tune this value |
| #define DISFLOW_STEP_SIZE 1.0 |
| |
| // Step size at which we should terminate iteration |
| // The idea here is that, if we take a step which is much smaller than 1px in |
| // size, then the values won't change much from iteration to iteration, so |
| // many future steps will also be small, and that won't have much effect |
| // on the ultimate result. So we can terminate early. |
| // |
| // To look at it another way, when we take a small step, that means that |
| // either we're near to convergence (so can stop), or we're stuck in a |
| // shallow valley and will take many iterations to get unstuck. |
| // |
| // Solving the latter properly requires fancier methods, such as "gradient |
| // descent with momentum". For now, we terminate to avoid wasting a ton of |
| // time on points which are either nearly-converged or stuck. |
| // |
| // Terminating at 1/8 px seems to give good results for global motion estimation |
| #define DISFLOW_STEP_SIZE_THRESOLD (1. / 8.) |
| |
| // Max number of iterations if warp convergence is not found |
| #define DISFLOW_MAX_ITR 4 |
| |
| // Internal precision of cubic interpolation filters |
| // The limiting factor here is that: |
| // * Before integerizing, the maximum value of any kernel tap is 1.0 |
| // * After integerizing, each tap must fit into an int16_t. |
| // Thus the largest multiplier we can get away with is 2^14 = 16384, |
| // as 2^15 = 32768 is too large to fit in an int16_t. |
| #define DISFLOW_INTERP_BITS 14 |
| |
| typedef struct { |
| // x and y directions of flow, per patch |
| double *u; |
| double *v; |
| |
| // Sizes of the above arrays |
| int width; |
| int height; |
| int stride; |
| } FlowField; |
| |
| bool av1_compute_global_motion_disflow(TransformationType type, |
| YV12_BUFFER_CONFIG *src, |
| YV12_BUFFER_CONFIG *ref, int bit_depth, |
| MotionModel *motion_models, |
| int num_motion_models, |
| bool *mem_alloc_failed); |
| |
| #ifdef __cplusplus |
| } |
| #endif |
| |
| #endif // AOM_AOM_DSP_FLOW_ESTIMATION_DISFLOW_H_ |