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#include <stdbool.h>
16
17#ifdef __cplusplus
18extern "C" {
19#endif
21struct AV1_COMP;
22struct AV1EncoderConfig;
23struct ThreadData;
24// TODO(wtc): These two variables are only used in avx2, sse2, neon
25// implementations, where the block size is still hard coded to TF_BLOCK_SIZE.
26// This should be fixed to align with the c implementation.
27#define BH 32
28#define BW 32
29
30// Block size used in temporal filtering.
31#define TF_BLOCK_SIZE BLOCK_32X32
32
33// Window size for temporal filtering.
34#define TF_WINDOW_LENGTH 5
35
36// A constant number, sqrt(pi / 2), used for noise estimation.
37static const double SQRT_PI_BY_2 = 1.25331413732;
38
39// Hyper-parameters used to compute filtering weight. These hyper-parameters can
40// be tuned for a better performance.
41// 0. A scale factor used in temporal filtering to raise the filter weight from
42// `double` with range [0, 1] to `int` with range [0, 1000].
43#define TF_WEIGHT_SCALE 1000
44// 1. Weight factor used to balance the weighted-average between window error
45// and block error. The weight is for window error while the weight for block
46// error is always set as 1.
47#define TF_WINDOW_BLOCK_BALANCE_WEIGHT 5
48// 2. Threshold for using q to adjust the filtering weight. Concretely, when
49// using a small q (high bitrate), we would like to reduce the filtering
50// strength such that more detailed information can be preserved. Hence, when
51// q is smaller than this threshold, we will adjust the filtering weight
52// based on the q-value.
53#define TF_Q_DECAY_THRESHOLD 20
54// 3. Normalization factor used to normalize the motion search error. Since the
55// motion search error can be large and uncontrollable, we will simply
56// normalize it before using it to compute the filtering weight.
57#define TF_SEARCH_ERROR_NORM_WEIGHT 20
58// 4. Threshold for using `arnr_strength` to adjust the filtering strength.
59// Concretely, users can use `arnr_strength` arguments to control the
60// strength of temporal filtering. When `arnr_strength` is small enough (
61// i.e., smaller than this threshold), we will adjust the filtering weight
62// based on the strength value.
63#define TF_STRENGTH_THRESHOLD 4
64// 5. Threshold for using motion search distance to adjust the filtering weight.
65// Concretely, larger motion search vector leads to a higher probability of
66// unreliable search. Hence, we would like to reduce the filtering strength
67// when the distance is large enough. Considering that the distance actually
68// relies on the frame size, this threshold is also a resolution-based
69// threshold. Taking 720p videos as an instance, if this field equals to 0.1,
70// then the actual threshold will be 720 * 0.1 = 72. Similarly, the threshold
71// for 360p videos will be 360 * 0.1 = 36.
72#define TF_SEARCH_DISTANCE_THRESHOLD 0.1
73// 6. Threshold to identify if the q is in a relative high range.
74// Above this cutoff q, a stronger filtering is applied.
75// For a high q, the quantization throws away more information, and thus a
76// stronger filtering is less likely to distort the encoded quality, while a
77// stronger filtering could reduce bit rates.
78// Ror a low q, more details are expected to be retained. Filtering is thus
79// more conservative.
80#define TF_QINDEX_CUTOFF 128
81
82#define NOISE_ESTIMATION_EDGE_THRESHOLD 50
83
84// Sum and SSE source vs filtered frame difference returned by
85// temporal filter.
86typedef struct {
87 int64_t sum;
88 int64_t sse;
89} FRAME_DIFF;
90
96 typedef struct {
100 YV12_BUFFER_CONFIG *frames[MAX_LAG_BUFFERS];
104 int num_frames;
105
109 YV12_BUFFER_CONFIG *output_frame;
110
114 int filter_frame_idx;
118 int compute_frame_diff;
122 struct scale_factors sf;
126 double noise_levels[MAX_MB_PLANE];
130 int num_pels;
134 int mb_rows;
138 int mb_cols;
142 int is_highbitdepth;
146 int q_factor;
147} TemporalFilterCtx;
148
154#define TF_INFO_BUF_COUNT 2
155
159 typedef struct TEMPORAL_FILTER_INFO {
165 int is_temporal_filter_on;
170 YV12_BUFFER_CONFIG tf_buf[TF_INFO_BUF_COUNT];
171
178 YV12_BUFFER_CONFIG tf_buf_second_arf;
182 FRAME_DIFF frame_diff[TF_INFO_BUF_COUNT];
186 int tf_buf_gf_index[TF_INFO_BUF_COUNT];
190 int tf_buf_display_index_offset[TF_INFO_BUF_COUNT];
194 int tf_buf_valid[TF_INFO_BUF_COUNT];
195} TEMPORAL_FILTER_INFO;
196
202int av1_is_temporal_filter_on(const struct AV1EncoderConfig *oxcf);
203
208void av1_tf_info_alloc(TEMPORAL_FILTER_INFO *tf_info,
209 const struct AV1_COMP *cpi);
210
214void av1_tf_info_free(TEMPORAL_FILTER_INFO *tf_info);
215
219void av1_tf_info_reset(TEMPORAL_FILTER_INFO *tf_info);
220
226void av1_tf_info_filtering(TEMPORAL_FILTER_INFO *tf_info, struct AV1_COMP *cpi,
227 const GF_GROUP *gf_group);
228
235 YV12_BUFFER_CONFIG *av1_tf_info_get_filtered_buf(TEMPORAL_FILTER_INFO *tf_info,
236 int gf_index,
237 FRAME_DIFF *frame_diff);
238
241// Data related to temporal filtering.
242typedef struct {
243 // Source vs filtered frame error.
244 FRAME_DIFF diff;
245 // Pointer to temporary block info used to store state in temporal filtering
246 // process.
247 MB_MODE_INFO *tmp_mbmi;
248 // Pointer to accumulator buffer used in temporal filtering process.
249 uint32_t *accum;
250 // Pointer to count buffer used in temporal filtering process.
251 uint16_t *count;
252 // Pointer to predictor used in temporal filtering process.
253 uint8_t *pred;
254} TemporalFilterData;
255
256// Data related to temporal filter multi-thread synchronization.
257typedef struct {
258#if CONFIG_MULTITHREAD
259 // Mutex lock used for dispatching jobs.
260 pthread_mutex_t *mutex_;
261#endif // CONFIG_MULTITHREAD
262 // Next temporal filter block row to be filtered.
263 int next_tf_row;
264 // Initialized to false, set to true by the worker thread that encounters an
265 // error in order to abort the processing of other worker threads.
266 bool tf_mt_exit;
267} AV1TemporalFilterSync;
268
269// Estimates noise level from a given frame using a single plane (Y, U, or V).
270// This is an adaptation of the mehtod in the following paper:
271// Shen-Chuan Tai, Shih-Ming Yang, "A fast method for image noise
272// estimation using Laplacian operator and adaptive edge detection",
273// Proc. 3rd International Symposium on Communications, Control and
274// Signal Processing, 2008, St Julians, Malta.
275// Inputs:
276// frame: Pointer to the frame to estimate noise level from.
277// noise_level: Pointer to store the estimated noise.
278// plane_from: Index of the starting plane used for noise estimation.
279// Commonly, 0 for Y-plane, 1 for U-plane, and 2 for V-plane.
280// plane_to: Index of the end plane used for noise estimation.
281// bit_depth: Actual bit-depth instead of the encoding bit-depth of the frame.
282// edge_thresh: Edge threshold.
283void av1_estimate_noise_level(const YV12_BUFFER_CONFIG *frame,
284 double *noise_level, int plane_from, int plane_to,
285 int bit_depth, int edge_thresh);
299void av1_tf_do_filtering_row(struct AV1_COMP *cpi, struct ThreadData *td,
300 int mb_row);
301
326 void av1_temporal_filter(struct AV1_COMP *cpi,
327 const int filter_frame_lookahead_idx,
328 int gf_frame_index, FRAME_DIFF *frame_diff,
329 YV12_BUFFER_CONFIG *output_frame);
330
345 int av1_check_show_filtered_frame(const YV12_BUFFER_CONFIG *frame,
346 const FRAME_DIFF *frame_diff, int q_index,
347 aom_bit_depth_t bit_depth);
348
350// Helper function to get `q` used for encoding.
351int av1_get_q(const struct AV1_COMP *cpi);
352
353// Allocates memory for members of TemporalFilterData.
354// Inputs:
355// tf_data: Pointer to the structure containing temporal filter related data.
356// num_pels: Number of pixels in the block across all planes.
357// is_high_bitdepth: Whether the frame is high-bitdepth or not.
358// Returns:
359// True if allocation is successful and false otherwise.
360static AOM_INLINE bool tf_alloc_and_reset_data(TemporalFilterData *tf_data,
361 int num_pels,
362 int is_high_bitdepth) {
363 tf_data->tmp_mbmi = (MB_MODE_INFO *)aom_calloc(1, sizeof(*tf_data->tmp_mbmi));
364 tf_data->accum =
365 (uint32_t *)aom_memalign(16, num_pels * sizeof(*tf_data->accum));
366 tf_data->count =
367 (uint16_t *)aom_memalign(16, num_pels * sizeof(*tf_data->count));
368 if (is_high_bitdepth)
369 tf_data->pred = CONVERT_TO_BYTEPTR(
370 aom_memalign(32, num_pels * 2 * sizeof(*tf_data->pred)));
371 else
372 tf_data->pred =
373 (uint8_t *)aom_memalign(32, num_pels * sizeof(*tf_data->pred));
374 // In case of an allocation failure, other successfully allocated buffers will
375 // be freed by the tf_dealloc_data() call in encoder_destroy().
376 if (!(tf_data->tmp_mbmi && tf_data->accum && tf_data->count && tf_data->pred))
377 return false;
378 memset(&tf_data->diff, 0, sizeof(tf_data->diff));
379 return true;
380}
381
382// Setup macroblockd params for temporal filtering process.
383// Inputs:
384// mbd: Pointer to the block for filtering.
385// tf_data: Pointer to the structure containing temporal filter related data.
386// scale: Scaling factor.
387// Returns:
388// Nothing will be returned. Contents of mbd will be modified.
389static AOM_INLINE void tf_setup_macroblockd(MACROBLOCKD *mbd,
390 TemporalFilterData *tf_data,
391 const struct scale_factors *scale) {
392 mbd->block_ref_scale_factors[0] = scale;
393 mbd->block_ref_scale_factors[1] = scale;
394 mbd->mi = &tf_data->tmp_mbmi;
395 mbd->mi[0]->motion_mode = SIMPLE_TRANSLATION;
396}
397
398// Deallocates the memory allocated for members of TemporalFilterData.
399// Inputs:
400// tf_data: Pointer to the structure containing temporal filter related data.
401// is_high_bitdepth: Whether the frame is high-bitdepth or not.
402// Returns:
403// Nothing will be returned.
404static AOM_INLINE void tf_dealloc_data(TemporalFilterData *tf_data,
405 int is_high_bitdepth) {
406 if (is_high_bitdepth)
407 tf_data->pred = (uint8_t *)CONVERT_TO_SHORTPTR(tf_data->pred);
408 aom_free(tf_data->tmp_mbmi);
409 tf_data->tmp_mbmi = NULL;
410 aom_free(tf_data->accum);
411 tf_data->accum = NULL;
412 aom_free(tf_data->count);
413 tf_data->count = NULL;
414 aom_free(tf_data->pred);
415 tf_data->pred = NULL;
416}
417
418// Saves the state prior to temporal filter process.
419// Inputs:
420// mbd: Pointer to the block for filtering.
421// input_mbmi: Backup block info to save input state.
422// input_buffer: Backup buffer pointer to save input state.
423// num_planes: Number of planes.
424// Returns:
425// Nothing will be returned. Contents of input_mbmi and input_buffer will be
426// modified.
427static INLINE void tf_save_state(MACROBLOCKD *mbd, MB_MODE_INFO ***input_mbmi,
428 uint8_t **input_buffer, int num_planes) {
429 for (int i = 0; i < num_planes; i++) {
430 input_buffer[i] = mbd->plane[i].pre[0].buf;
431 }
432 *input_mbmi = mbd->mi;
433}
434
435// Restores the initial state after temporal filter process.
436// Inputs:
437// mbd: Pointer to the block for filtering.
438// input_mbmi: Backup block info from where input state is restored.
439// input_buffer: Backup buffer pointer from where input state is restored.
440// num_planes: Number of planes.
441// Returns:
442// Nothing will be returned. Contents of mbd will be modified.
443static INLINE void tf_restore_state(MACROBLOCKD *mbd, MB_MODE_INFO **input_mbmi,
444 uint8_t **input_buffer, int num_planes) {
445 for (int i = 0; i < num_planes; i++) {
446 mbd->plane[i].pre[0].buf = input_buffer[i];
447 }
448 mbd->mi = input_mbmi;
449}
450
452#ifdef __cplusplus
453} // extern "C"
454#endif
455
456#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:859
AV1EncoderConfig
Main encoder configuration data structure.
Definition encoder.h:915
AV1_COMP
Top level encoder structure.
Definition encoder.h:2872
GF_GROUP
Data related to the current GF/ARF group and the individual frames within the group.
Definition firstpass.h:354
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:159
TEMPORAL_FILTER_INFO::tf_buf_display_index_offset
int tf_buf_display_index_offset[2]
Definition temporal_filter.h:190
TEMPORAL_FILTER_INFO::tf_buf
YV12_BUFFER_CONFIG tf_buf[2]
Definition temporal_filter.h:170
TEMPORAL_FILTER_INFO::tf_buf_gf_index
int tf_buf_gf_index[2]
Definition temporal_filter.h:186
TEMPORAL_FILTER_INFO::frame_diff
FRAME_DIFF frame_diff[2]
Definition temporal_filter.h:182
TEMPORAL_FILTER_INFO::is_temporal_filter_on
int is_temporal_filter_on
Definition temporal_filter.h:165
TEMPORAL_FILTER_INFO::tf_buf_valid
int tf_buf_valid[2]
Definition temporal_filter.h:194
TEMPORAL_FILTER_INFO::tf_buf_second_arf
YV12_BUFFER_CONFIG tf_buf_second_arf
Definition temporal_filter.h:178
TemporalFilterCtx
Parameters related to temporal filtering.
Definition temporal_filter.h:96
TemporalFilterCtx::output_frame
YV12_BUFFER_CONFIG * output_frame
Definition temporal_filter.h:109
TemporalFilterCtx::q_factor
int q_factor
Definition temporal_filter.h:146
TemporalFilterCtx::num_pels
int num_pels
Definition temporal_filter.h:130
TemporalFilterCtx::num_frames
int num_frames
Definition temporal_filter.h:104
TemporalFilterCtx::compute_frame_diff
int compute_frame_diff
Definition temporal_filter.h:118
TemporalFilterCtx::mb_rows
int mb_rows
Definition temporal_filter.h:134
TemporalFilterCtx::mb_cols
int mb_cols
Definition temporal_filter.h:138
TemporalFilterCtx::is_highbitdepth
int is_highbitdepth
Definition temporal_filter.h:142
TemporalFilterCtx::filter_frame_idx
int filter_frame_idx
Definition temporal_filter.h:114
macroblockd
Variables related to current coding block.
Definition blockd.h:570
macroblockd::plane
struct macroblockd_plane plane[3]
Definition blockd.h:606
macroblockd::block_ref_scale_factors
const struct scale_factors * block_ref_scale_factors[2]
Definition blockd.h:687
macroblockd::mi
MB_MODE_INFO ** mi
Definition blockd.h:617
yv12_buffer_config
YV12 frame buffer data structure.
Definition yv12config.h:44