1 /*
2 * Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
3 *
4 * Use of this source code is governed by a BSD-style license
5 * that can be found in the LICENSE file in the root of the source
6 * tree. An additional intellectual property rights grant can be found
7 * in the file PATENTS. All contributing project authors may
8 * be found in the AUTHORS file in the root of the source tree.
9 */
10
11 #include "modules/audio_coding/audio_network_adaptor/bitrate_controller.h"
12
13 #include <algorithm>
14
15 #include "rtc_base/checks.h"
16 #include "system_wrappers/include/field_trial.h"
17
18 namespace webrtc {
19 namespace audio_network_adaptor {
20
Config(int initial_bitrate_bps,int initial_frame_length_ms,int fl_increase_overhead_offset,int fl_decrease_overhead_offset)21 BitrateController::Config::Config(int initial_bitrate_bps,
22 int initial_frame_length_ms,
23 int fl_increase_overhead_offset,
24 int fl_decrease_overhead_offset)
25 : initial_bitrate_bps(initial_bitrate_bps),
26 initial_frame_length_ms(initial_frame_length_ms),
27 fl_increase_overhead_offset(fl_increase_overhead_offset),
28 fl_decrease_overhead_offset(fl_decrease_overhead_offset) {}
29
30 BitrateController::Config::~Config() = default;
31
BitrateController(const Config & config)32 BitrateController::BitrateController(const Config& config)
33 : config_(config),
34 bitrate_bps_(config_.initial_bitrate_bps),
35 frame_length_ms_(config_.initial_frame_length_ms) {
36 RTC_DCHECK_GT(bitrate_bps_, 0);
37 RTC_DCHECK_GT(frame_length_ms_, 0);
38 }
39
40 BitrateController::~BitrateController() = default;
41
UpdateNetworkMetrics(const NetworkMetrics & network_metrics)42 void BitrateController::UpdateNetworkMetrics(
43 const NetworkMetrics& network_metrics) {
44 if (network_metrics.target_audio_bitrate_bps)
45 target_audio_bitrate_bps_ = network_metrics.target_audio_bitrate_bps;
46 if (network_metrics.overhead_bytes_per_packet) {
47 RTC_DCHECK_GT(*network_metrics.overhead_bytes_per_packet, 0);
48 overhead_bytes_per_packet_ = network_metrics.overhead_bytes_per_packet;
49 }
50 }
51
MakeDecision(AudioEncoderRuntimeConfig * config)52 void BitrateController::MakeDecision(AudioEncoderRuntimeConfig* config) {
53 // Decision on |bitrate_bps| should not have been made.
54 RTC_DCHECK(!config->bitrate_bps);
55 if (target_audio_bitrate_bps_ && overhead_bytes_per_packet_) {
56 // Current implementation of BitrateController can only work when
57 // |metrics.target_audio_bitrate_bps| includes overhead is enabled. This is
58 // currently governed by the following field trial.
59 RTC_DCHECK(
60 webrtc::field_trial::IsEnabled("WebRTC-SendSideBwe-WithOverhead"));
61 if (config->frame_length_ms)
62 frame_length_ms_ = *config->frame_length_ms;
63 int offset = config->last_fl_change_increase
64 ? config_.fl_increase_overhead_offset
65 : config_.fl_decrease_overhead_offset;
66 // Check that
67 // -(*overhead_bytes_per_packet_) <= offset <= (*overhead_bytes_per_packet_)
68 RTC_DCHECK_GE(*overhead_bytes_per_packet_, -offset);
69 RTC_DCHECK_LE(offset, *overhead_bytes_per_packet_);
70 int overhead_rate_bps = static_cast<int>(
71 (*overhead_bytes_per_packet_ + offset) * 8 * 1000 / frame_length_ms_);
72 bitrate_bps_ = std::max(0, *target_audio_bitrate_bps_ - overhead_rate_bps);
73 }
74 config->bitrate_bps = bitrate_bps_;
75 }
76
77 } // namespace audio_network_adaptor
78 } // namespace webrtc
79