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Diffstat (limited to '')
| -rw-r--r-- | third_party/aom/aom_dsp/flow_estimation/disflow.h | 106 |
1 files changed, 106 insertions, 0 deletions
diff --git a/third_party/aom/aom_dsp/flow_estimation/disflow.h b/third_party/aom/aom_dsp/flow_estimation/disflow.h new file mode 100644 index 0000000000..ef877b638c --- /dev/null +++ b/third_party/aom/aom_dsp/flow_estimation/disflow.h @@ -0,0 +1,106 @@ +/* + * 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 { + // Start of allocation for u and v buffers + double *buf0; + + // 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_ |