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VP9 screenshare: drop base layer separately

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Because of a low bitrate target, base layer has drops much more frequently
than other layers. But it reduces overall framerate, especially then
input framerate is low (5 fps).

This CL allows pre-layer drops and disables droppoing on higher spatial
layers for screenshare, solving the issue.
Additional care have to be taken then new spatial layers are enabled
dynamically to not create non-compatible with RTP references.

Bug: webrtc:10257
Change-Id: Ie056484c99a3f35ff4405ef71337dc2d034db8bb
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/138262
Commit-Queue: Ilya Nikolaevskiy <ilnik@webrtc.org>
Reviewed-by: Sergey Silkin <ssilkin@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#28063}
This commit is contained in:
Ilya Nikolaevskiy
2019-05-24 16:50:00 +02:00
committed by Commit Bot
parent d9b4f3330f
commit 039a7146ab
3 changed files with 141 additions and 12 deletions
Download Patch File Download Diff File Expand all files Collapse all files

62
modules/video_coding/codecs/vp9/vp9_impl.cc
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@ -711,18 +711,35 @@ int VP9EncoderImpl::InitAndSetControlSettings(const VideoCodec* inst) {
RTC_NOTREACHED();
}
// Configure encoder to drop entire superframe whenever it needs to drop
// a layer. This mode is prefered over per-layer dropping which causes
// quality flickering and is not compatible with RTP non-flexible mode.
vpx_svc_frame_drop_t svc_drop_frame;
memset(&svc_drop_frame, 0, sizeof(svc_drop_frame));
svc_drop_frame.framedrop_mode =
full_superframe_drop_ ? FULL_SUPERFRAME_DROP : CONSTRAINED_LAYER_DROP;
svc_drop_frame.max_consec_drop = std::numeric_limits<int>::max();
for (size_t i = 0; i < num_spatial_layers_; ++i) {
svc_drop_frame.framedrop_thresh[i] = config_->rc_dropframe_thresh;
memset(&svc_drop_frame_, 0, sizeof(svc_drop_frame_));
dropping_only_base_layer_ = inter_layer_pred_ == InterLayerPredMode::kOn &&
codec_.mode == VideoCodecMode::kScreensharing &&
num_spatial_layers_ > 1;
if (dropping_only_base_layer_) {
// Screenshare dropping mode: only the base spatial layer
// can be dropped and it doesn't affect other spatial layers.
// This mode is preferable because base layer has low bitrate targets
// and more likely to drop frames. It shouldn't reduce framerate on other
// layers.
svc_drop_frame_.framedrop_mode = LAYER_DROP;
svc_drop_frame_.max_consec_drop = 5;
svc_drop_frame_.framedrop_thresh[0] = config_->rc_dropframe_thresh;
for (size_t i = 1; i < num_spatial_layers_; ++i) {
svc_drop_frame_.framedrop_thresh[i] = 0;
}
} else {
// Configure encoder to drop entire superframe whenever it needs to drop
// a layer. This mode is preferred over per-layer dropping which causes
// quality flickering and is not compatible with RTP non-flexible mode.
svc_drop_frame_.framedrop_mode =
full_superframe_drop_ ? FULL_SUPERFRAME_DROP : CONSTRAINED_LAYER_DROP;
svc_drop_frame_.max_consec_drop = std::numeric_limits<int>::max();
for (size_t i = 0; i < num_spatial_layers_; ++i) {
svc_drop_frame_.framedrop_thresh[i] = config_->rc_dropframe_thresh;
}
}
vpx_codec_control(encoder_, VP9E_SET_SVC_FRAME_DROP_LAYER, &svc_drop_frame);
vpx_codec_control(encoder_, VP9E_SET_SVC_FRAME_DROP_LAYER,
&svc_drop_frame_);
}
// Register callback for getting each spatial layer.
@ -888,9 +905,22 @@ int VP9EncoderImpl::Encode(const VideoFrame& input_image,
if (less_layers_requested || more_layers_requested) {
ss_info_needed_ = true;
}
if (more_layers_requested && !force_key_frame_) {
// Prohibit drop of all layers for the next frame, so newly enabled
// layer would have a valid spatial reference.
for (size_t i = 0; i < num_spatial_layers_; ++i) {
svc_drop_frame_.framedrop_thresh[i] = 0;
}
}
}
}
if (num_spatial_layers_ > 1) {
// Update frame dropping settings as they may change on per-frame basis.
vpx_codec_control(encoder_, VP9E_SET_SVC_FRAME_DROP_LAYER,
&svc_drop_frame_);
}
if (vpx_codec_enc_config_set(encoder_, config_)) {
return WEBRTC_VIDEO_CODEC_ERROR;
}
@ -1442,6 +1472,16 @@ int VP9EncoderImpl::GetEncodedLayerFrame(const vpx_codec_cx_pkt* pkt) {
void VP9EncoderImpl::DeliverBufferedFrame(bool end_of_picture) {
if (encoded_image_.size() > 0) {
if (num_spatial_layers_ > 1) {
// Restore frame dropping settings, as dropping may be temporary forbidden
// due to dynamically enabled layers.
svc_drop_frame_.framedrop_thresh[0] = config_->rc_dropframe_thresh;
for (size_t i = 1; i < num_spatial_layers_; ++i) {
svc_drop_frame_.framedrop_thresh[i] =
dropping_only_base_layer_ ? 0 : config_->rc_dropframe_thresh;
}
}
codec_specific_.codecSpecific.VP9.end_of_picture = end_of_picture;
// No data partitioning in VP9, so 1 partition only.