ref: 84b19ab5acb9f7104441c2c3c5a8157a95e417e1
parent: 460f66aa9985e2546588806f66e0a59d264e76d1
author: Marco Paniconi <marpan@google.com>
date: Sun Nov 11 17:09:31 EST 2018
vp9: Reorganize the buffer level for cbr mode Refactor the code with some changes. Split update into two parts: move the fillup (with per-frame-bandwidth) before the encoding, and keep the leaking part (with encoded_frame_size) after the encoding (postencode). For SVC with ref_frame_config usage: allow usage of timestamp delta for the fillup part of buffer, instead of the (average) framerate passed in via the duration. Moving the buffer fillup (+per-frame-bandwidth) part to the pre-encode causes some difference in performance (since buffer level affects active_worst/QPand frame-dropping), but the change is observed to be small. Made small adjustment to active_worst_quality to compensate. Adjust some thresholds in datarate tests. Change-Id: I81a5562367034f318cffd451304bc4a34bf02a1d
--- a/test/svc_datarate_test.cc
+++ b/test/svc_datarate_test.cc
@@ -863,7 +863,7 @@
layer_framedrop_ = GET_PARAM(2);
AssignLayerBitrates();
ASSERT_NO_FATAL_FAILURE(RunLoop(&video));
- CheckLayerRateTargeting(number_spatial_layers_, number_temporal_layers_, 0.71,
+ CheckLayerRateTargeting(number_spatial_layers_, number_temporal_layers_, 0.65,
1.45);
#if CONFIG_VP9_DECODER
// The non-reference frames are expected to be mismatched frames as the
--- a/vp9/encoder/vp9_encoder.c
+++ b/vp9/encoder/vp9_encoder.c
@@ -3716,6 +3716,9 @@
return 1;
}
+ cpi->svc.time_stamp_prev[cpi->svc.spatial_layer_id] =
+ cpi->svc.time_stamp_superframe;
+
// Flag to check if its valid to compute the source sad (used for
// scene detection and for superblock content state in CBR mode).
// The flag may get reset below based on SVC or resizing state.
--- a/vp9/encoder/vp9_ratectrl.c
+++ b/vp9/encoder/vp9_ratectrl.c
@@ -247,20 +247,65 @@
return target;
}
+// Update the buffer level before encoding with the per-frame-bandwidth,
+static void update_buffer_level_preencode(VP9_COMP *cpi) {+ RATE_CONTROL *const rc = &cpi->rc;
+ rc->bits_off_target += rc->avg_frame_bandwidth;
+ // Clip the buffer level to the maximum specified buffer size.
+ rc->bits_off_target = VPXMIN(rc->bits_off_target, rc->maximum_buffer_size);
+ rc->buffer_level = rc->bits_off_target;
+}
+
+// Update the buffer level before encoding with the per-frame-bandwidth
+// for SVC. The current and all upper temporal layers are updated, needed
+// for the layered rate control which involves cumulative buffer levels for
+// the temporal layers. Allow for using the timestamp(pts) delta for the
+// framerate when the set_ref_frame_config is used.
+static void update_buffer_level_svc_preencode(VP9_COMP *cpi) {+ SVC *const svc = &cpi->svc;
+ int i;
+ // Set this to 1 to use timestamp delta for "framerate" under
+ // ref_frame_config usage.
+ int use_timestamp = 1;
+ const int64_t ts_delta =
+ svc->time_stamp_superframe - svc->time_stamp_prev[svc->spatial_layer_id];
+ for (i = svc->temporal_layer_id; i < svc->number_temporal_layers; ++i) {+ const int layer =
+ LAYER_IDS_TO_IDX(svc->spatial_layer_id, i, svc->number_temporal_layers);
+ LAYER_CONTEXT *const lc = &svc->layer_context[layer];
+ RATE_CONTROL *const lrc = &lc->rc;
+ if (use_timestamp && cpi->svc.use_set_ref_frame_config && ts_delta > 0 &&
+ svc->current_superframe > 0) {+ const double framerate_pts = 10000000.0 / ts_delta;
+ const double lc_framerate_pts =
+ framerate_pts / cpi->oxcf.ts_rate_decimator[i];
+ lrc->bits_off_target += (int)(lc->target_bandwidth / lc_framerate_pts);
+ } else {+ lrc->bits_off_target += (int)(lc->target_bandwidth / lc->framerate);
+ }
+ // Clip buffer level to maximum buffer size for the layer.
+ lrc->bits_off_target =
+ VPXMIN(lrc->bits_off_target, lrc->maximum_buffer_size);
+ lrc->buffer_level = lrc->bits_off_target;
+ if (i == svc->temporal_layer_id) {+ cpi->rc.bits_off_target = lrc->bits_off_target;
+ cpi->rc.buffer_level = lrc->buffer_level;
+ }
+ }
+}
+
// Update the buffer level for higher temporal layers, given the encoded current
// temporal layer.
-static void update_layer_buffer_level(SVC *svc, int encoded_frame_size) {+static void update_layer_buffer_level_postencode(SVC *svc,
+ int encoded_frame_size) {int i = 0;
- int current_temporal_layer = svc->temporal_layer_id;
+ const int current_temporal_layer = svc->temporal_layer_id;
for (i = current_temporal_layer + 1; i < svc->number_temporal_layers; ++i) {const int layer =
LAYER_IDS_TO_IDX(svc->spatial_layer_id, i, svc->number_temporal_layers);
LAYER_CONTEXT *lc = &svc->layer_context[layer];
RATE_CONTROL *lrc = &lc->rc;
- int bits_off_for_this_layer =
- (int)(lc->target_bandwidth / lc->framerate - encoded_frame_size);
- lrc->bits_off_target += bits_off_for_this_layer;
-
+ lrc->bits_off_target -= encoded_frame_size;
// Clip buffer level to maximum buffer size for the layer.
lrc->bits_off_target =
VPXMIN(lrc->bits_off_target, lrc->maximum_buffer_size);
@@ -268,29 +313,13 @@
}
}
-// Update the buffer level: leaky bucket model.
-static void update_buffer_level(VP9_COMP *cpi, int encoded_frame_size) {- const VP9_COMMON *const cm = &cpi->common;
+// Update the buffer level after encoding with encoded frame size.
+static void update_buffer_level_postencode(VP9_COMP *cpi,
+ int encoded_frame_size) {RATE_CONTROL *const rc = &cpi->rc;
-
- // On dropped frame, don't update buffer if its currently stable
- // (above optimal level). This can cause issues when full superframe
- // can drop (!= LAYER_DROP), since QP is adjusted downwards with buffer
- // overflow, which can cause more frame drops.
- if (cpi->svc.framedrop_mode != LAYER_DROP && encoded_frame_size == 0 &&
- rc->buffer_level > rc->optimal_buffer_level)
- return;
-
- // Non-viewable frames are a special case and are treated as pure overhead.
- if (!cm->show_frame) {- rc->bits_off_target -= encoded_frame_size;
- } else {- rc->bits_off_target += rc->avg_frame_bandwidth - encoded_frame_size;
- }
-
+ rc->bits_off_target -= encoded_frame_size;
// Clip the buffer level to the maximum specified buffer size.
rc->bits_off_target = VPXMIN(rc->bits_off_target, rc->maximum_buffer_size);
-
// For screen-content mode, and if frame-dropper is off, don't let buffer
// level go below threshold, given here as -rc->maximum_ buffer_size.
if (cpi->oxcf.content == VP9E_CONTENT_SCREEN &&
@@ -300,7 +329,7 @@
rc->buffer_level = rc->bits_off_target;
if (is_one_pass_cbr_svc(cpi)) {- update_layer_buffer_level(&cpi->svc, encoded_frame_size);
+ update_layer_buffer_level_postencode(&cpi->svc, encoded_frame_size);
}
}
@@ -884,6 +913,7 @@
? VPXMIN(rc->avg_frame_qindex[INTER_FRAME],
rc->avg_frame_qindex[KEY_FRAME])
: rc->avg_frame_qindex[INTER_FRAME];
+ active_worst_quality = VPXMIN(rc->worst_quality, (ambient_qp * 5) >> 2);
// For SVC if the current base spatial layer was key frame, use the QP from
// that base layer for ambient_qp.
if (cpi->use_svc && cpi->svc.spatial_layer_id > 0) {@@ -893,9 +923,9 @@
if (lc->is_key_frame) {const RATE_CONTROL *lrc = &lc->rc;
ambient_qp = VPXMIN(ambient_qp, lrc->last_q[KEY_FRAME]);
+ active_worst_quality = VPXMIN(rc->worst_quality, (ambient_qp * 9) >> 3);
}
}
- active_worst_quality = VPXMIN(rc->worst_quality, ambient_qp * 5 >> 2);
if (rc->buffer_level > rc->optimal_buffer_level) {// Adjust down.
// Maximum limit for down adjustment ~30%; make it lower for screen content.
@@ -1727,7 +1757,7 @@
}
if (frame_is_intra_only(cm)) rc->last_kf_qindex = qindex;
- update_buffer_level(cpi, rc->projected_frame_size);
+ update_buffer_level_postencode(cpi, rc->projected_frame_size);
// Rolling monitors of whether we are over or underspending used to help
// regulate min and Max Q in two pass.
@@ -1824,8 +1854,6 @@
}
void vp9_rc_postencode_update_drop_frame(VP9_COMP *cpi) {- // Update buffer level with zero size, update frame counters, and return.
- update_buffer_level(cpi, 0);
cpi->common.current_video_frame++;
cpi->rc.frames_since_key++;
cpi->rc.frames_to_key--;
@@ -1832,6 +1860,14 @@
cpi->rc.rc_2_frame = 0;
cpi->rc.rc_1_frame = 0;
cpi->rc.last_avg_frame_bandwidth = cpi->rc.avg_frame_bandwidth;
+ // For SVC on dropped frame when framedrop_mode != LAYER_DROP:
+ // in this mode the whole superframe may be dropped if only a single layer
+ // has buffer underflow (below threshold). Since this can then lead to
+ // increasing buffer levels/overflow for certain layers even though whole
+ // superframe is dropped, we cap buffer level if its already stable.
+ if (cpi->use_svc && cpi->svc.framedrop_mode != LAYER_DROP &&
+ cpi->rc.buffer_level > cpi->rc.optimal_buffer_level)
+ cpi->rc.buffer_level = cpi->rc.optimal_buffer_level;
}
static int calc_pframe_target_size_one_pass_vbr(const VP9_COMP *const cpi) {@@ -2165,6 +2201,7 @@
vp9_cyclic_refresh_update_parameters(cpi);
vp9_rc_set_frame_target(cpi, target);
+ if (cm->show_frame) update_buffer_level_svc_preencode(cpi);
}
void vp9_rc_get_one_pass_cbr_params(VP9_COMP *cpi) {@@ -2206,6 +2243,9 @@
target = calc_pframe_target_size_one_pass_cbr(cpi);
vp9_rc_set_frame_target(cpi, target);
+
+ if (cm->show_frame) update_buffer_level_preencode(cpi);
+
if (cpi->oxcf.resize_mode == RESIZE_DYNAMIC)
cpi->resize_pending = vp9_resize_one_pass_cbr(cpi);
else
--- a/vp9/encoder/vp9_svc_layercontext.h
+++ b/vp9/encoder/vp9_svc_layercontext.h
@@ -178,9 +178,12 @@
int first_spatial_layer_to_encode;
+ // Parameters for allowing framerate per spatial layer, and buffer
+ // update based on timestamps.
int64_t duration[VPX_SS_MAX_LAYERS];
-
int64_t timebase_fac;
+ int64_t time_stamp_superframe;
+ int64_t time_stamp_prev[VPX_SS_MAX_LAYERS];
} SVC;
struct VP9_COMP;
--- a/vp9/vp9_cx_iface.c
+++ b/vp9/vp9_cx_iface.c
@@ -1151,6 +1151,7 @@
unsigned char *cx_data;
cpi->svc.timebase_fac = timebase_units_to_ticks(timebase, 1);
+ cpi->svc.time_stamp_superframe = dst_time_stamp;
// Set up internal flags
if (ctx->base.init_flags & VPX_CODEC_USE_PSNR) cpi->b_calculate_psnr = 1;