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/*
* Copyright 2024 The WebRTC project authors. All rights reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "video/corruption_detection/generic_mapping_functions.h"
#include <cmath>
#include "api/video/video_codec_type.h"
#include "api/video_codecs/video_codec.h"
#include "rtc_base/checks.h"
namespace webrtc {
namespace {
constexpr int kLumaThreshold = 5;
constexpr int kChromaThresholdVp8 = 6;
constexpr int kChromaThresholdVp9 = 4;
constexpr int kChromaThresholdAv1 = 4;
constexpr int kChromaThresholdH264 = 2;
int LumaThreshold(VideoCodecType codec_type) {
return kLumaThreshold;
}
int ChromaThreshold(VideoCodecType codec_type) {
switch (codec_type) {
case VideoCodecType::kVideoCodecVP8:
return kChromaThresholdVp8;
case VideoCodecType::kVideoCodecVP9:
return kChromaThresholdVp9;
case VideoCodecType::kVideoCodecAV1:
return kChromaThresholdAv1;
case VideoCodecType::kVideoCodecH264:
return kChromaThresholdH264;
default:
RTC_FATAL() << "Codec type " << CodecTypeToPayloadString(codec_type)
<< " is not supported.";
}
}
double ExponentialFunction(double a, double b, double c, int qp) {
return a * std::exp(b * qp - c);
}
double RationalFunction(double a, double b, double c, int qp) {
return (-a * qp) / (qp + b) + c;
}
// Maps QP to the optimal standard deviation for the Gausian kernel.
// Observe that the values below can be changed unnoticed.
double MapQpToOptimalStdDev(int qp, VideoCodecType codec_type) {
switch (codec_type) {
case VideoCodecType::kVideoCodecVP8:
return ExponentialFunction(0.006, 0.01857465, -4.26470513, qp);
case VideoCodecType::kVideoCodecVP9:
return RationalFunction(1, -257, 0.3, qp);
case VideoCodecType::kVideoCodecAV1:
return RationalFunction(0.69, -256, 0.42, qp);
case VideoCodecType::kVideoCodecH264:
return ExponentialFunction(0.016, 0.13976962, -1.40179328, qp);
default:
RTC_FATAL() << "Codec type " << CodecTypeToPayloadString(codec_type)
<< " is not supported.";
}
}
} // namespace
FilterSettings GetCorruptionFilterSettings(int qp, VideoCodecType codec_type) {
return FilterSettings{.std_dev = MapQpToOptimalStdDev(qp, codec_type),
.luma_error_threshold = LumaThreshold(codec_type),
.chroma_error_threshold = ChromaThreshold(codec_type)};
}
} // namespace webrtc