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1322dbc81a
This fixes misprint in the code which calculates target bitrate of a VP9 spatial layer where "-" was used instead of "+". Bug: none Change-Id: I17d76a84d00e453c055c068968d7b276e9c23f51 Reviewed-on: https://webrtc-review.googlesource.com/71663 Commit-Queue: Sergey Silkin <ssilkin@webrtc.org> Reviewed-by: Rasmus Brandt <brandtr@webrtc.org> Cr-Commit-Position: refs/heads/master@{#22974}
67 lines
2.7 KiB
C++
67 lines
2.7 KiB
C++
/*
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* Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include "modules/video_coding/codecs/vp9/svc_config.h"
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#include <algorithm>
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#include <cmath>
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#include <vector>
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#include "modules/video_coding/include/video_codec_interface.h"
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namespace webrtc {
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std::vector<SpatialLayer> GetSvcConfig(size_t input_width,
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size_t input_height,
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size_t num_spatial_layers,
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size_t num_temporal_layers) {
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RTC_DCHECK_GT(input_width, 0);
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RTC_DCHECK_GT(input_height, 0);
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RTC_DCHECK_GT(num_spatial_layers, 0);
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RTC_DCHECK_GT(num_temporal_layers, 0);
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std::vector<SpatialLayer> spatial_layers;
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// Limit number of layers for given resolution.
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const size_t num_layers_fit_horz = static_cast<size_t>(std::floor(
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1 + std::max(0.0f,
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std::log2(1.0f * input_width / kMinVp9SpatialLayerWidth))));
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const size_t num_layers_fit_vert = static_cast<size_t>(
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std::floor(1 + std::max(0.0f, std::log2(1.0f * input_height /
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kMinVp9SpatialLayerHeight))));
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num_spatial_layers =
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std::min({num_spatial_layers, num_layers_fit_horz, num_layers_fit_vert});
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for (size_t sl_idx = 0; sl_idx < num_spatial_layers; ++sl_idx) {
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SpatialLayer spatial_layer = {0};
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spatial_layer.width = input_width >> (num_spatial_layers - sl_idx - 1);
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spatial_layer.height = input_height >> (num_spatial_layers - sl_idx - 1);
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spatial_layer.numberOfTemporalLayers = num_temporal_layers;
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// minBitrate and maxBitrate formulas were derived to fit VP9
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// subjective-quality data for bit rate below which video quality is
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// unacceptable and above which additional bits do not provide benefit.
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// TODO(ssilkin): Add to the comment PSNR/SSIM we get at encoding certain
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// video to min/max bitrate specified by those formulas.
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const size_t num_pixels = spatial_layer.width * spatial_layer.height;
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spatial_layer.minBitrate =
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static_cast<int>(360 * std::sqrt(num_pixels) / 1000);
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spatial_layer.maxBitrate =
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static_cast<int>((1.5 * num_pixels + 75 * 1000) / 1000);
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spatial_layer.targetBitrate =
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(spatial_layer.maxBitrate + spatial_layer.minBitrate) / 2;
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spatial_layers.push_back(spatial_layer);
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}
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return spatial_layers;
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}
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} // namespace webrtc
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