AOMedia AV1 Codec: av1/encoder/temporal_filter.h Source File

| AOMedia AV1 Codec

temporal_filter.h
1/*
2 * Copyright (c) 2016, Alliance for Open Media. All rights reserved
3 *
4 * This source code is subject to the terms of the BSD 2 Clause License and
5 * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
6 * was not distributed with this source code in the LICENSE file, you can
7 * obtain it at www.aomedia.org/license/software. If the Alliance for Open
8 * Media Patent License 1.0 was not distributed with this source code in the
9 * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
10 */
11
12#ifndef AOM_AV1_ENCODER_TEMPORAL_FILTER_H_
13#define AOM_AV1_ENCODER_TEMPORAL_FILTER_H_
14
15#ifdef __cplusplus
16extern "C" {
17#endif
19struct AV1_COMP;
20struct AV1EncoderConfig;
21struct ThreadData;
22// TODO(any): These two variables are only used in avx2, sse2, sse4
23// implementations, where the block size is still hard coded. This should be
24// fixed to align with the c implementation.
25#define BH 32
26#define BW 32
27
28// Block size used in temporal filtering.
29#define TF_BLOCK_SIZE BLOCK_32X32
30
31// Window size for temporal filtering.
32#define TF_WINDOW_LENGTH 5
33
34// Hyper-parameters used to compute filtering weight. These hyper-parameters can
35// be tuned for a better performance.
36// 0. A scale factor used in temporal filtering to raise the filter weight from
37// `double` with range [0, 1] to `int` with range [0, 1000].
38#define TF_WEIGHT_SCALE 1000
39// 1. Weight factor used to balance the weighted-average between window error
40// and block error. The weight is for window error while the weight for block
41// error is always set as 1.
42#define TF_WINDOW_BLOCK_BALANCE_WEIGHT 5
43// 2. Threshold for using q to adjust the filtering weight. Concretely, when
44// using a small q (high bitrate), we would like to reduce the filtering
45// strength such that more detailed information can be preserved. Hence, when
46// q is smaller than this threshold, we will adjust the filtering weight
47// based on the q-value.
48#define TF_Q_DECAY_THRESHOLD 20
49// 3. Normalization factor used to normalize the motion search error. Since the
50// motion search error can be large and uncontrollable, we will simply
51// normalize it before using it to compute the filtering weight.
52#define TF_SEARCH_ERROR_NORM_WEIGHT 20
53// 4. Threshold for using `arnr_strength` to adjust the filtering strength.
54// Concretely, users can use `arnr_strength` arguments to control the
55// strength of temporal filtering. When `arnr_strength` is small enough (
56// i.e., smaller than this threshold), we will adjust the filtering weight
57// based on the strength value.
58#define TF_STRENGTH_THRESHOLD 4
59// 5. Threshold for using motion search distance to adjust the filtering weight.
60// Concretely, larger motion search vector leads to a higher probability of
61// unreliable search. Hence, we would like to reduce the filtering strength
62// when the distance is large enough. Considering that the distance actually
63// relies on the frame size, this threshold is also a resolution-based
64// threshold. Taking 720p videos as an instance, if this field equals to 0.1,
65// then the actual threshold will be 720 * 0.1 = 72. Similarly, the threshold
66// for 360p videos will be 360 * 0.1 = 36.
67#define TF_SEARCH_DISTANCE_THRESHOLD 0.1
68// 6. Threshold to identify if the q is in a relative high range.
69// Above this cutoff q, a stronger filtering is applied.
70// For a high q, the quantization throws away more information, and thus a
71// stronger filtering is less likely to distort the encoded quality, while a
72// stronger filtering could reduce bit rates.
73// Ror a low q, more details are expected to be retained. Filtering is thus
74// more conservative.
75#define TF_QINDEX_CUTOFF 128
76
77#define NOISE_ESTIMATION_EDGE_THRESHOLD 50
78
79// Sum and SSE source vs filtered frame difference returned by
80// temporal filter.
81typedef struct {
82 int64_t sum;
83 int64_t sse;
84} FRAME_DIFF;
85
91 typedef struct {
95 YV12_BUFFER_CONFIG *frames[MAX_LAG_BUFFERS];
99 int num_frames;
100
104 YV12_BUFFER_CONFIG *output_frame;
105
109 int filter_frame_idx;
113 int compute_frame_diff;
117 struct scale_factors sf;
121 double noise_levels[MAX_MB_PLANE];
125 int num_pels;
129 int mb_rows;
133 int mb_cols;
137 int is_highbitdepth;
141 int q_factor;
142} TemporalFilterCtx;
143
149#define TF_INFO_BUF_COUNT 2
150
154 typedef struct TEMPORAL_FILTER_INFO {
160 int is_temporal_filter_on;
165 YV12_BUFFER_CONFIG tf_buf[TF_INFO_BUF_COUNT];
166
173 YV12_BUFFER_CONFIG tf_buf_second_arf;
177 FRAME_DIFF frame_diff[TF_INFO_BUF_COUNT];
181 int tf_buf_gf_index[TF_INFO_BUF_COUNT];
185 int tf_buf_display_index_offset[TF_INFO_BUF_COUNT];
189 int tf_buf_valid[TF_INFO_BUF_COUNT];
190} TEMPORAL_FILTER_INFO;
191
197int av1_is_temporal_filter_on(const struct AV1EncoderConfig *oxcf);
198
203void av1_tf_info_alloc(TEMPORAL_FILTER_INFO *tf_info, struct AV1_COMP *cpi);
204
208void av1_tf_info_free(TEMPORAL_FILTER_INFO *tf_info);
209
213void av1_tf_info_reset(TEMPORAL_FILTER_INFO *tf_info);
214
220void av1_tf_info_filtering(TEMPORAL_FILTER_INFO *tf_info, struct AV1_COMP *cpi,
221 const GF_GROUP *gf_group);
222
229 YV12_BUFFER_CONFIG *av1_tf_info_get_filtered_buf(TEMPORAL_FILTER_INFO *tf_info,
230 int gf_index,
231 FRAME_DIFF *frame_diff);
232
235// Data related to temporal filtering.
236typedef struct {
237 // Source vs filtered frame error.
238 FRAME_DIFF diff;
239 // Pointer to temporary block info used to store state in temporal filtering
240 // process.
241 MB_MODE_INFO *tmp_mbmi;
242 // Pointer to accumulator buffer used in temporal filtering process.
243 uint32_t *accum;
244 // Pointer to count buffer used in temporal filtering process.
245 uint16_t *count;
246 // Pointer to predictor used in temporal filtering process.
247 uint8_t *pred;
248} TemporalFilterData;
249
250// Data related to temporal filter multi-thread synchronization.
251typedef struct {
252#if CONFIG_MULTITHREAD
253 // Mutex lock used for dispatching jobs.
254 pthread_mutex_t *mutex_;
255#endif // CONFIG_MULTITHREAD
256 // Next temporal filter block row to be filtered.
257 int next_tf_row;
258} AV1TemporalFilterSync;
259
260// Estimates noise level from a given frame using a single plane (Y, U, or V).
261// This is an adaptation of the mehtod in the following paper:
262// Shen-Chuan Tai, Shih-Ming Yang, "A fast method for image noise
263// estimation using Laplacian operator and adaptive edge detection",
264// Proc. 3rd International Symposium on Communications, Control and
265// Signal Processing, 2008, St Julians, Malta.
266// Inputs:
267// frame: Pointer to the frame to estimate noise level from.
268// plane: Index of the plane used for noise estimation. Commonly, 0 for
269// Y-plane, 1 for U-plane, and 2 for V-plane.
270// bit_depth: Actual bit-depth instead of the encoding bit-depth of the frame.
271// Returns:
272// The estimated noise, or -1.0 if there are too few smooth pixels.
273double av1_estimate_noise_from_single_plane(const YV12_BUFFER_CONFIG *frame,
274 const int plane,
275 const int bit_depth,
276 const int edge_thresh);
290void av1_tf_do_filtering_row(struct AV1_COMP *cpi, struct ThreadData *td,
291 int mb_row);
292
317 void av1_temporal_filter(struct AV1_COMP *cpi,
318 const int filter_frame_lookahead_idx,
319 int gf_frame_index, FRAME_DIFF *frame_diff,
320 YV12_BUFFER_CONFIG *output_frame);
321
336 int av1_check_show_filtered_frame(const YV12_BUFFER_CONFIG *frame,
337 const FRAME_DIFF *frame_diff, int q_index,
338 aom_bit_depth_t bit_depth);
339
341// Helper function to get `q` used for encoding.
342int av1_get_q(const struct AV1_COMP *cpi);
343
344// Allocates memory for members of TemporalFilterData.
345// Inputs:
346// tf_data: Pointer to the structure containing temporal filter related data.
347// num_pels: Number of pixels in the block across all planes.
348// is_high_bitdepth: Whether the frame is high-bitdepth or not.
349// Returns:
350// Nothing will be returned. But the contents of tf_data will be modified.
351static AOM_INLINE void tf_alloc_and_reset_data(TemporalFilterData *tf_data,
352 int num_pels,
353 int is_high_bitdepth) {
354 tf_data->tmp_mbmi = (MB_MODE_INFO *)malloc(sizeof(*tf_data->tmp_mbmi));
355 memset(tf_data->tmp_mbmi, 0, sizeof(*tf_data->tmp_mbmi));
356 tf_data->accum =
357 (uint32_t *)aom_memalign(16, num_pels * sizeof(*tf_data->accum));
358 tf_data->count =
359 (uint16_t *)aom_memalign(16, num_pels * sizeof(*tf_data->count));
360 memset(&tf_data->diff, 0, sizeof(tf_data->diff));
361 if (is_high_bitdepth)
362 tf_data->pred = CONVERT_TO_BYTEPTR(
363 aom_memalign(32, num_pels * 2 * sizeof(*tf_data->pred)));
364 else
365 tf_data->pred =
366 (uint8_t *)aom_memalign(32, num_pels * sizeof(*tf_data->pred));
367}
368
369// Setup macroblockd params for temporal filtering process.
370// Inputs:
371// mbd: Pointer to the block for filtering.
372// tf_data: Pointer to the structure containing temporal filter related data.
373// scale: Scaling factor.
374// Returns:
375// Nothing will be returned. Contents of mbd will be modified.
376static AOM_INLINE void tf_setup_macroblockd(MACROBLOCKD *mbd,
377 TemporalFilterData *tf_data,
378 const struct scale_factors *scale) {
379 mbd->block_ref_scale_factors[0] = scale;
380 mbd->block_ref_scale_factors[1] = scale;
381 mbd->mi = &tf_data->tmp_mbmi;
382 mbd->mi[0]->motion_mode = SIMPLE_TRANSLATION;
383}
384
385// Deallocates the memory allocated for members of TemporalFilterData.
386// Inputs:
387// tf_data: Pointer to the structure containing temporal filter related data.
388// is_high_bitdepth: Whether the frame is high-bitdepth or not.
389// Returns:
390// Nothing will be returned.
391static AOM_INLINE void tf_dealloc_data(TemporalFilterData *tf_data,
392 int is_high_bitdepth) {
393 if (is_high_bitdepth)
394 tf_data->pred = (uint8_t *)CONVERT_TO_SHORTPTR(tf_data->pred);
395 free(tf_data->tmp_mbmi);
396 aom_free(tf_data->accum);
397 aom_free(tf_data->count);
398 aom_free(tf_data->pred);
399}
400
401// Saves the state prior to temporal filter process.
402// Inputs:
403// mbd: Pointer to the block for filtering.
404// input_mbmi: Backup block info to save input state.
405// input_buffer: Backup buffer pointer to save input state.
406// num_planes: Number of planes.
407// Returns:
408// Nothing will be returned. Contents of input_mbmi and input_buffer will be
409// modified.
410static INLINE void tf_save_state(MACROBLOCKD *mbd, MB_MODE_INFO ***input_mbmi,
411 uint8_t **input_buffer, int num_planes) {
412 for (int i = 0; i < num_planes; i++) {
413 input_buffer[i] = mbd->plane[i].pre[0].buf;
414 }
415 *input_mbmi = mbd->mi;
416}
417
418// Restores the initial state after temporal filter process.
419// Inputs:
420// mbd: Pointer to the block for filtering.
421// input_mbmi: Backup block info from where input state is restored.
422// input_buffer: Backup buffer pointer from where input state is restored.
423// num_planes: Number of planes.
424// Returns:
425// Nothing will be returned. Contents of mbd will be modified.
426static INLINE void tf_restore_state(MACROBLOCKD *mbd, MB_MODE_INFO **input_mbmi,
427 uint8_t **input_buffer, int num_planes) {
428 for (int i = 0; i < num_planes; i++) {
429 mbd->plane[i].pre[0].buf = input_buffer[i];
430 }
431 mbd->mi = input_mbmi;
432}
433
435#ifdef __cplusplus
436} // extern "C"
437#endif
438
439#endif // AOM_AV1_ENCODER_TEMPORAL_FILTER_H_
aom_bit_depth_t
enum aom_bit_depth aom_bit_depth_t
Bit depth for codecThis enumeration determines the bit depth of the codec.
av1_check_show_filtered_frame
int av1_check_show_filtered_frame(const YV12_BUFFER_CONFIG *frame, const FRAME_DIFF *frame_diff, int q_index, aom_bit_depth_t bit_depth)
Check whether a filtered frame can be show directly.
av1_temporal_filter
void av1_temporal_filter(struct AV1_COMP *cpi, const int filter_frame_lookahead_idx, int gf_frame_index, FRAME_DIFF *frame_diff, YV12_BUFFER_CONFIG *output_frame)
Performs temporal filtering if needed on a source frame. For example to create a filtered alternate r...
av1_tf_do_filtering_row
void av1_tf_do_filtering_row(struct AV1_COMP *cpi, struct ThreadData *td, int mb_row)
Does temporal filter for a given macroblock row.
Definition: temporal_filter.c:764
GF_GROUP
Data related to the current GF/ARF group and the individual frames within the group.
Definition: firstpass.h:344
MB_MODE_INFO
Stores the prediction/txfm mode of the current coding block.
Definition: blockd.h:222
MB_MODE_INFO::motion_mode
MOTION_MODE motion_mode
The motion mode used by the inter prediction.
Definition: blockd.h:250
TEMPORAL_FILTER_INFO
Temporal filter info for a gop.
Definition: temporal_filter.h:154
TEMPORAL_FILTER_INFO::tf_buf_display_index_offset
int tf_buf_display_index_offset[2]
Definition: temporal_filter.h:185
TEMPORAL_FILTER_INFO::tf_buf
YV12_BUFFER_CONFIG tf_buf[2]
Definition: temporal_filter.h:165
TEMPORAL_FILTER_INFO::tf_buf_gf_index
int tf_buf_gf_index[2]
Definition: temporal_filter.h:181
TEMPORAL_FILTER_INFO::frame_diff
FRAME_DIFF frame_diff[2]
Definition: temporal_filter.h:177
TEMPORAL_FILTER_INFO::is_temporal_filter_on
int is_temporal_filter_on
Definition: temporal_filter.h:160
TEMPORAL_FILTER_INFO::tf_buf_valid
int tf_buf_valid[2]
Definition: temporal_filter.h:189
TEMPORAL_FILTER_INFO::tf_buf_second_arf
YV12_BUFFER_CONFIG tf_buf_second_arf
Definition: temporal_filter.h:173
TemporalFilterCtx
Parameters related to temporal filtering.
Definition: temporal_filter.h:91
TemporalFilterCtx::output_frame
YV12_BUFFER_CONFIG * output_frame
Definition: temporal_filter.h:104
TemporalFilterCtx::q_factor
int q_factor
Definition: temporal_filter.h:141
TemporalFilterCtx::num_pels
int num_pels
Definition: temporal_filter.h:125
TemporalFilterCtx::num_frames
int num_frames
Definition: temporal_filter.h:99
TemporalFilterCtx::compute_frame_diff
int compute_frame_diff
Definition: temporal_filter.h:113
TemporalFilterCtx::mb_rows
int mb_rows
Definition: temporal_filter.h:129
TemporalFilterCtx::mb_cols
int mb_cols
Definition: temporal_filter.h:133
TemporalFilterCtx::is_highbitdepth
int is_highbitdepth
Definition: temporal_filter.h:137
TemporalFilterCtx::filter_frame_idx
int filter_frame_idx
Definition: temporal_filter.h:109
macroblockd
Variables related to current coding block.
Definition: blockd.h:577
macroblockd::plane
struct macroblockd_plane plane[3]
Definition: blockd.h:613
macroblockd::block_ref_scale_factors
const struct scale_factors * block_ref_scale_factors[2]
Definition: blockd.h:694
macroblockd::mi
MB_MODE_INFO ** mi
Definition: blockd.h:624
yv12_buffer_config
YV12 frame buffer data structure.
Definition: yv12config.h:39