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Unstable BWE due to improper bit rate padding for VP9.

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Bug: webrtc:9345
Change-Id: I5b1e0b4ed7a8c1d0b942b09433017cac6d53c64b
Reviewed-on: https://webrtc-review.googlesource.com/79000
Commit-Queue: Michael Horowitz <mhoro@webrtc.org>
Reviewed-by: Erik Språng <sprang@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#23496}
This commit is contained in:
“Michael
2018-06-01 14:09:19 -05:00
committed by Commit Bot
parent a7087e37f1
commit 277a656263
6 changed files with 62 additions and 9 deletions
Download Patch File Download Diff File Expand all files Collapse all files

19
modules/video_coding/codecs/vp9/svc_config.cc
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@ -14,6 +14,7 @@
#include <cmath>
#include <vector>
#include "modules/video_coding/codecs/vp9/svc_rate_allocator.h"
#include "modules/video_coding/include/video_codec_interface.h"
namespace webrtc {
@ -63,6 +64,7 @@ std::vector<SpatialLayer> ConfigureSvcNormalVideo(size_t input_width,
num_spatial_layers =
std::min({num_spatial_layers, num_layers_fit_horz, num_layers_fit_vert});
float top_fraction = 0.;
for (size_t sl_idx = 0; sl_idx < num_spatial_layers; ++sl_idx) {
SpatialLayer spatial_layer = {0};
spatial_layer.width = input_width >> (num_spatial_layers - sl_idx - 1);
@ -77,17 +79,24 @@ std::vector<SpatialLayer> ConfigureSvcNormalVideo(size_t input_width,
// TODO(ssilkin): Add to the comment PSNR/SSIM we get at encoding certain
// video to min/max bitrate specified by those formulas.
const size_t num_pixels = spatial_layer.width * spatial_layer.height;
const size_t min_bitrate =
int min_bitrate =
static_cast<int>((600. * std::sqrt(num_pixels) - 95000.) / 1000.);
spatial_layer.minBitrate = std::max(min_bitrate, kMinVp9SvcBitrateKbps);
min_bitrate = std::max(min_bitrate, 0);
spatial_layer.minBitrate =
std::max(static_cast<size_t>(min_bitrate), kMinVp9SvcBitrateKbps);
spatial_layer.maxBitrate =
static_cast<int>((1.6 * num_pixels + 50 * 1000) / 1000);
spatial_layer.targetBitrate =
(spatial_layer.maxBitrate + spatial_layer.minBitrate) / 2;
(spatial_layer.minBitrate + spatial_layer.maxBitrate) / 2;
spatial_layers.push_back(spatial_layer);
top_fraction += std::pow(kSpatialLayeringRateScalingFactor, sl_idx);
}
// Compute spatial_layers[num_spatial_layers - 1].targetBitrate, which is
// used to set max_padding_bitrate_. Set max_padding_bitrate_ equal to the
// minimum total bit rate required to support all spatial layers.
spatial_layers[num_spatial_layers - 1].targetBitrate =
static_cast<unsigned int>(
spatial_layers[num_spatial_layers - 1].minBitrate * top_fraction);
return spatial_layers;
}

2
modules/video_coding/codecs/vp9/svc_rate_allocator.cc
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@ -18,10 +18,8 @@
namespace webrtc {
namespace {
const float kSpatialLayeringRateScalingFactor = 0.55f;
const float kTemporalLayeringRateScalingFactor = 0.55f;
} // namespace
SvcRateAllocator::SvcRateAllocator(const VideoCodec& codec) : codec_(codec) {
RTC_DCHECK_EQ(codec.codecType, kVideoCodecVP9);

3
modules/video_coding/codecs/vp9/svc_rate_allocator.h
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@ -20,6 +20,9 @@
namespace webrtc {
extern const float kSpatialLayeringRateScalingFactor;
extern const float kTemporalLayeringRateScalingFactor;
class SvcRateAllocator : public VideoBitrateAllocator {
public:
explicit SvcRateAllocator(const VideoCodec& codec);