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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 "webrtc/modules/audio_coding/audio_network_adaptor/bitrate_controller.h
" | |
12 | |
13 #include <algorithm> | |
14 | |
15 #include "webrtc/base/checks.h" | |
16 | |
17 namespace webrtc { | |
18 | |
19 namespace { | |
20 // TODO(minyue): consider passing this from a higher layer through | |
21 // SetConstraints(). | |
22 // L2(14B) + IPv4(20B) + UDP(8B) + RTP(12B) + SRTP_AUTH(10B) = 64B = 512 bits | |
23 constexpr int kPacketOverheadBits = 512; | |
24 } | |
25 | |
26 BitrateController::Config::Config(int initial_bitrate_bps, | |
27 int initial_frame_length_ms) | |
28 : initial_bitrate_bps(initial_bitrate_bps), | |
29 initial_frame_length_ms(initial_frame_length_ms) {} | |
30 | |
31 BitrateController::Config::~Config() = default; | |
32 | |
33 BitrateController::BitrateController(const Config& config) | |
34 : config_(config), | |
35 bitrate_bps_(config_.initial_bitrate_bps), | |
36 overhead_rate_bps_(kPacketOverheadBits * 1000 / | |
37 config_.initial_frame_length_ms) { | |
38 RTC_DCHECK_GT(bitrate_bps_, 0); | |
39 RTC_DCHECK_GT(overhead_rate_bps_, 0); | |
40 } | |
41 | |
42 void BitrateController::MakeDecision( | |
43 const NetworkMetrics& metrics, | |
44 AudioNetworkAdaptor::EncoderRuntimeConfig* config) { | |
45 // Decision on |bitrate_bps| should not have been made. | |
46 RTC_DCHECK(!config->bitrate_bps); | |
47 | |
48 if (metrics.target_audio_bitrate_bps) { | |
49 int overhead_rate = | |
50 config->frame_length_ms | |
51 ? kPacketOverheadBits * 1000 / *config->frame_length_ms | |
52 : overhead_rate_bps_; | |
53 // If |metrics.target_audio_bitrate_bps| had included overhead, we would | |
54 // simply do: | |
55 // bitrate_bps_ = metrics.target_audio_bitrate_bps - overhead_rate; | |
56 // Follow https://bugs.chromium.org/p/webrtc/issues/detail?id=6315 to track | |
57 // progress regarding this. | |
58 // Now we assume that |metrics.target_audio_bitrate_bps| can handle the | |
59 // overhead of most recent packets. | |
60 bitrate_bps_ = std::max(0, *metrics.target_audio_bitrate_bps + | |
61 overhead_rate_bps_ - overhead_rate); | |
62 // TODO(minyue): apply a smoothing on the |overhead_rate_bps_|. | |
63 overhead_rate_bps_ = overhead_rate; | |
64 } | |
65 config->bitrate_bps = rtc::Optional<int>(bitrate_bps_); | |
66 } | |
67 | |
68 } // namespace webrtc | |
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