зеркало из https://github.com/mozilla/gecko-dev.git
136 строки
4.3 KiB
C++
136 строки
4.3 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 "call/rtp_bitrate_configurator.h"
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#include <algorithm>
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#include "rtc_base/checks.h"
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namespace {
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// Returns its smallest positive argument. If neither argument is positive,
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// returns an arbitrary nonpositive value.
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int MinPositive(int a, int b) {
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if (a <= 0) {
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return b;
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}
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if (b <= 0) {
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return a;
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}
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return std::min(a, b);
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}
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} // namespace
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namespace webrtc {
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RtpBitrateConfigurator::RtpBitrateConfigurator(
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const BitrateConstraints& bitrate_config)
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: bitrate_config_(bitrate_config), base_bitrate_config_(bitrate_config) {
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RTC_DCHECK_GE(bitrate_config.min_bitrate_bps, 0);
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RTC_DCHECK_GE(bitrate_config.start_bitrate_bps,
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bitrate_config.min_bitrate_bps);
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if (bitrate_config.max_bitrate_bps != -1) {
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RTC_DCHECK_GE(bitrate_config.max_bitrate_bps,
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bitrate_config.start_bitrate_bps);
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}
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}
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RtpBitrateConfigurator::~RtpBitrateConfigurator() = default;
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BitrateConstraints RtpBitrateConfigurator::GetConfig() const {
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return bitrate_config_;
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}
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absl::optional<BitrateConstraints>
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RtpBitrateConfigurator::UpdateWithSdpParameters(
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const BitrateConstraints& bitrate_config) {
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RTC_DCHECK_GE(bitrate_config.min_bitrate_bps, 0);
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RTC_DCHECK_NE(bitrate_config.start_bitrate_bps, 0);
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if (bitrate_config.max_bitrate_bps != -1) {
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RTC_DCHECK_GT(bitrate_config.max_bitrate_bps, 0);
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}
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absl::optional<int> new_start;
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// Only update the "start" bitrate if it's set, and different from the old
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// value. In practice, this value comes from the x-google-start-bitrate codec
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// parameter in SDP, and setting the same remote description twice shouldn't
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// restart bandwidth estimation.
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if (bitrate_config.start_bitrate_bps != -1 &&
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bitrate_config.start_bitrate_bps !=
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base_bitrate_config_.start_bitrate_bps) {
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new_start.emplace(bitrate_config.start_bitrate_bps);
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}
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base_bitrate_config_ = bitrate_config;
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return UpdateConstraints(new_start);
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}
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absl::optional<BitrateConstraints>
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RtpBitrateConfigurator::UpdateWithClientPreferences(
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const BitrateSettings& bitrate_mask) {
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bitrate_config_mask_ = bitrate_mask;
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return UpdateConstraints(bitrate_mask.start_bitrate_bps);
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}
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// Relay cap can change only max bitrate.
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absl::optional<BitrateConstraints> RtpBitrateConfigurator::UpdateWithRelayCap(
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DataRate cap) {
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if (cap.IsFinite()) {
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RTC_DCHECK(!cap.IsZero());
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}
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max_bitrate_over_relay_ = cap;
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return UpdateConstraints(absl::nullopt);
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}
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absl::optional<BitrateConstraints> RtpBitrateConfigurator::UpdateConstraints(
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const absl::optional<int>& new_start) {
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BitrateConstraints updated;
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updated.min_bitrate_bps =
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std::max(bitrate_config_mask_.min_bitrate_bps.value_or(0),
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base_bitrate_config_.min_bitrate_bps);
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updated.max_bitrate_bps =
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MinPositive(bitrate_config_mask_.max_bitrate_bps.value_or(-1),
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base_bitrate_config_.max_bitrate_bps);
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updated.max_bitrate_bps =
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MinPositive(updated.max_bitrate_bps, max_bitrate_over_relay_.bps_or(-1));
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// If the combined min ends up greater than the combined max, the max takes
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// priority.
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if (updated.max_bitrate_bps != -1 &&
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updated.min_bitrate_bps > updated.max_bitrate_bps) {
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updated.min_bitrate_bps = updated.max_bitrate_bps;
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}
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// If there is nothing to update (min/max unchanged, no new bandwidth
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// estimation start value), return early.
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if (updated.min_bitrate_bps == bitrate_config_.min_bitrate_bps &&
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updated.max_bitrate_bps == bitrate_config_.max_bitrate_bps &&
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!new_start) {
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return absl::nullopt;
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}
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if (new_start) {
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// Clamp start by min and max.
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updated.start_bitrate_bps = MinPositive(
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std::max(*new_start, updated.min_bitrate_bps), updated.max_bitrate_bps);
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} else {
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updated.start_bitrate_bps = -1;
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}
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BitrateConstraints config_to_return = updated;
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if (!new_start) {
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updated.start_bitrate_bps = bitrate_config_.start_bitrate_bps;
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}
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bitrate_config_ = updated;
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return config_to_return;
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}
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} // namespace webrtc
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