ref: 42b67917749de9e93b4d3fbfe585353e5d2e7a31
parent: 0092960d2746fa25a41235532df9c68fe2fe093a
author: Marco <marpan@chromium.org>
date: Mon Jul 6 11:55:57 EDT 2015
Allow for re-encoding frame if high overshoot. For 1 pass CBR mode under screen content mode: if pre-analysis (source temporal-sad) indicates significant change in content, then check the projected frame size after encode_frame(), and if size is above threshold, force re-encode of that frame at max QP. Change-Id: I91e66d9f3167aff2ffcc6f16f47f19f1c21dc688
--- a/vp9/encoder/vp9_encoder.c
+++ b/vp9/encoder/vp9_encoder.c
@@ -1623,6 +1623,8 @@
cpi->resize_buffer_underflow = 0;
cpi->common.buffer_pool = pool;
+ cpi->rc.high_source_sad = 0;
+
init_config(cpi, oxcf);
vp9_rc_init(&cpi->oxcf, oxcf->pass, &cpi->rc);
@@ -3180,7 +3182,9 @@
set_ref_ptrs(cm, xd, LAST_FRAME, LAST_FRAME);
}
-static void encode_without_recode_loop(VP9_COMP *cpi) {+static void encode_without_recode_loop(VP9_COMP *cpi,
+ size_t *size,
+ uint8_t *dest) {VP9_COMMON *const cm = &cpi->common;
int q = 0, bottom_index = 0, top_index = 0; // Dummy variables.
@@ -3210,6 +3214,13 @@
&cpi->scaled_last_source);
}
+ if (cpi->oxcf.pass == 0 &&
+ cpi->oxcf.rc_mode == VPX_CBR &&
+ cpi->resize_state == 0 &&
+ cm->frame_type != KEY_FRAME &&
+ cpi->oxcf.content == VP9E_CONTENT_SCREEN)
+ vp9_avg_source_sad(cpi);
+
if (frame_is_intra_only(cm) == 0) {vp9_scale_references(cpi);
}
@@ -3237,6 +3248,38 @@
// transform / motion compensation build reconstruction frame
vp9_encode_frame(cpi);
+ // Check if we should drop this frame because of high overshoot.
+ // Only for frames where high temporal-source sad is detected.
+ if (cpi->oxcf.pass == 0 &&
+ cpi->oxcf.rc_mode == VPX_CBR &&
+ cpi->resize_state == 0 &&
+ cm->frame_type != KEY_FRAME &&
+ cpi->oxcf.content == VP9E_CONTENT_SCREEN &&
+ cpi->rc.high_source_sad == 1) {+ int frame_size = 0;
+ // Get an estimate of the encoded frame size.
+ save_coding_context(cpi);
+ vp9_pack_bitstream(cpi, dest, size);
+ restore_coding_context(cpi);
+ frame_size = (int)(*size) << 3;
+ // Check if encoded frame will overshoot too much, and if so, set the q and
+ // adjust some rate control parameters, and return to re-encode the frame.
+ if (vp9_encodedframe_overshoot(cpi, frame_size, &q)) {+ vpx_clear_system_state();
+ vp9_set_quantizer(cm, q);
+ vp9_set_variance_partition_thresholds(cpi, q);
+ suppress_active_map(cpi);
+ // Turn-off cyclic refresh for re-encoded frame.
+ if (cpi->oxcf.aq_mode == CYCLIC_REFRESH_AQ) {+ unsigned char *const seg_map = cpi->segmentation_map;
+ memset(seg_map, 0, cm->mi_rows * cm->mi_cols);
+ vp9_disable_segmentation(&cm->seg);
+ }
+ apply_active_map(cpi);
+ vp9_encode_frame(cpi);
+ }
+ }
+
// Update some stats from cyclic refresh, and check if we should not update
// golden reference, for non-SVC 1 pass CBR.
if (cpi->oxcf.aq_mode == CYCLIC_REFRESH_AQ &&
@@ -3736,7 +3779,7 @@
#endif
if (cpi->sf.recode_loop == DISALLOW_RECODE) {- encode_without_recode_loop(cpi);
+ encode_without_recode_loop(cpi, size, dest);
} else {encode_with_recode_loop(cpi, size, dest);
}
--- a/vp9/encoder/vp9_ratectrl.c
+++ b/vp9/encoder/vp9_ratectrl.c
@@ -1900,3 +1900,86 @@
}
return resize_now;
}
+
+// Compute average source sad (temporal sad: between current source and
+// previous source) over a subset of superblocks. Use this is detect big changes
+// in content and allow rate control to react.
+// TODO(marpan): Superblock sad is computed again in variance partition for
+// non-rd mode (but based on last reconstructed frame). Should try to reuse
+// these computations.
+void vp9_avg_source_sad(VP9_COMP *cpi) {+ VP9_COMMON * const cm = &cpi->common;
+ RATE_CONTROL *const rc = &cpi->rc;
+ rc->high_source_sad = 0;
+ if (cpi->Last_Source != NULL) {+ const uint8_t *src_y = cpi->Source->y_buffer;
+ const int src_ystride = cpi->Source->y_stride;
+ const uint8_t *last_src_y = cpi->Last_Source->y_buffer;
+ const int last_src_ystride = cpi->Last_Source->y_stride;
+ int sbi_row, sbi_col;
+ const BLOCK_SIZE bsize = BLOCK_64X64;
+ // Loop over sub-sample of frame, and compute average sad over 64x64 blocks.
+ uint64_t avg_sad = 0;
+ int num_samples = 0;
+ int sb_cols = (cm->mi_cols + MI_BLOCK_SIZE - 1) / MI_BLOCK_SIZE;
+ int sb_rows = (cm->mi_rows + MI_BLOCK_SIZE - 1) / MI_BLOCK_SIZE;
+ for (sbi_row = 0; sbi_row < sb_rows; sbi_row ++) {+ for (sbi_col = 0; sbi_col < sb_cols; sbi_col ++) {+ // Checker-board pattern, ignore boundary.
+ if ((sbi_row > 0 && sbi_col > 0) &&
+ (sbi_row < sb_rows - 1 && sbi_col < sb_cols - 1) &&
+ ((sbi_row % 2 == 0 && sbi_col % 2 == 0) ||
+ (sbi_row % 2 != 0 && sbi_col % 2 != 0))) {+ num_samples++;
+ avg_sad += cpi->fn_ptr[bsize].sdf(src_y,
+ src_ystride,
+ last_src_y,
+ last_src_ystride);
+ }
+ src_y += 64;
+ last_src_y += 64;
+ }
+ src_y += (src_ystride << 6) - (sb_cols << 6);
+ last_src_y += (last_src_ystride << 6) - (sb_cols << 6);
+ }
+ if (num_samples > 0)
+ avg_sad = avg_sad / num_samples;
+ // Set high_source_sad flag if we detect very high increase in avg_sad
+ // between current and the previous frame value(s). Use a minimum threshold
+ // for cases where there is small change from content that is completely
+ // static.
+ if (avg_sad > MAX(4000, (rc->avg_source_sad << 3)) &&
+ rc->frames_since_key > 1)
+ rc->high_source_sad = 1;
+ else
+ rc->high_source_sad = 0;
+ rc->avg_source_sad = (rc->avg_source_sad + avg_sad) >> 1;
+ }
+}
+
+// Test if encoded frame will significantly overshoot the target bitrate, and
+// if so, set the QP, reset/adjust some rate control parameters, and return 1.
+int vp9_encodedframe_overshoot(VP9_COMP *cpi,
+ int frame_size,
+ int *q) {+ VP9_COMMON * const cm = &cpi->common;
+ RATE_CONTROL *const rc = &cpi->rc;
+ int thresh_qp = 3 * (rc->worst_quality >> 2);
+ int thresh_rate = rc->avg_frame_bandwidth * 10;
+ if (cm->base_qindex < thresh_qp &&
+ frame_size > thresh_rate) {+ // Force a re-encode, and for now use max-QP.
+ *q = cpi->rc.worst_quality;
+ // Adjust avg_frame_qindex and buffer_level, as these parameters will affect
+ // QP selection for subsequent frames. If they have settled down to a very
+ // different (low QP) state, then not re-adjusting them may cause next
+ // frame to select low QP and overshoot again.
+ // TODO(marpan): Check if rate correction factor should also be adjusted.
+ cpi->rc.avg_frame_qindex[INTER_FRAME] = *q;
+ rc->buffer_level = rc->optimal_buffer_level;
+ rc->bits_off_target = rc->optimal_buffer_level;
+ return 1;
+ } else {+ return 0;
+ }
+}
--- a/vp9/encoder/vp9_ratectrl.h
+++ b/vp9/encoder/vp9_ratectrl.h
@@ -142,6 +142,9 @@
int frame_width[FRAME_SCALE_STEPS];
int frame_height[FRAME_SCALE_STEPS];
int rf_level_maxq[RATE_FACTOR_LEVELS];
+
+ uint64_t avg_source_sad;
+ int high_source_sad;
} RATE_CONTROL;
struct VP9_COMP;
@@ -255,6 +258,10 @@
void vp9_set_target_rate(struct VP9_COMP *cpi);
int vp9_resize_one_pass_cbr(struct VP9_COMP *cpi);
+
+void vp9_avg_source_sad(struct VP9_COMP *cpi);
+
+int vp9_encodedframe_overshoot(struct VP9_COMP *cpi, int frame_size, int *q);
#ifdef __cplusplus
} // extern "C"
--
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