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media / gpu / h264_rate_control_util.cc [blame]
// Copyright 2023 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "media/gpu/h264_rate_control_util.h"
#include <algorithm>
#include "base/logging.h"
namespace media::h264_rate_control_util {
float QP2QStepSize(uint32_t qp) {
// 0.625 is Q-step value for QP=0 for H.26x codecs.
return 0.625f * std::pow(2, qp / 6.0f);
}
uint32_t QStepSize2QP(float q_step) {
const float q_step_min = QP2QStepSize(kQPMin);
const float q_step_max = QP2QStepSize(kQPMax);
q_step = std::clamp(q_step, q_step_min, q_step_max);
// 0.625 is Q-step value for QP=0 for H.26x codecs.
return static_cast<uint32_t>(std::round(6 * std::log2(q_step / 0.625f)));
}
base::TimeDelta ClampedTimestampDiff(base::TimeDelta ts_new,
base::TimeDelta ts_old) {
base::TimeDelta elapsed_time = ts_new - ts_old;
base::TimeDelta clamped_elapsed_time =
std::clamp(elapsed_time, base::Seconds(0), base::Minutes(5));
if (clamped_elapsed_time != elapsed_time) {
DLOG(WARNING) << "Unexpected elapsed time " << elapsed_time;
}
return clamped_elapsed_time;
}
float ClampedLinearInterpolation(float x,
float x0,
float x1,
float y0,
float y1) {
return std::clamp(y0 + (x - x0) * (y1 - y0) / (x1 - x0), std::min(y0, y1),
std::max(y0, y1));
}
} // namespace media::h264_rate_control_util