1 /*
2 * Copyright (c) 2019 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 "api/audio_codecs/opus/audio_encoder_multi_channel_opus_config.h"
12
13 namespace webrtc {
14
15 namespace {
16 constexpr int kDefaultComplexity = 9;
17 } // namespace
18
AudioEncoderMultiChannelOpusConfig()19 AudioEncoderMultiChannelOpusConfig::AudioEncoderMultiChannelOpusConfig()
20 : frame_size_ms(kDefaultFrameSizeMs),
21 num_channels(1),
22 application(ApplicationMode::kVoip),
23 bitrate_bps(32000),
24 fec_enabled(false),
25 cbr_enabled(false),
26 dtx_enabled(false),
27 max_playback_rate_hz(48000),
28 complexity(kDefaultComplexity),
29 num_streams(-1),
30 coupled_streams(-1) {}
31 AudioEncoderMultiChannelOpusConfig::AudioEncoderMultiChannelOpusConfig(
32 const AudioEncoderMultiChannelOpusConfig&) = default;
33 AudioEncoderMultiChannelOpusConfig::~AudioEncoderMultiChannelOpusConfig() =
34 default;
35 AudioEncoderMultiChannelOpusConfig& AudioEncoderMultiChannelOpusConfig::
36 operator=(const AudioEncoderMultiChannelOpusConfig&) = default;
37
IsOk() const38 bool AudioEncoderMultiChannelOpusConfig::IsOk() const {
39 if (frame_size_ms <= 0 || frame_size_ms % 10 != 0)
40 return false;
41 if (num_channels >= 255) {
42 return false;
43 }
44 if (bitrate_bps < kMinBitrateBps || bitrate_bps > kMaxBitrateBps)
45 return false;
46 if (complexity < 0 || complexity > 10)
47 return false;
48
49 // Check the lengths:
50 if (num_streams < 0 || coupled_streams < 0) {
51 return false;
52 }
53 if (num_streams < coupled_streams) {
54 return false;
55 }
56 if (channel_mapping.size() != static_cast<size_t>(num_channels)) {
57 return false;
58 }
59
60 // Every mono stream codes one channel, every coupled stream codes two. This
61 // is the total coded channel count:
62 const int max_coded_channel = num_streams + coupled_streams;
63 for (const auto& x : channel_mapping) {
64 // Coded channels >= max_coded_channel don't exist. Except for 255, which
65 // tells Opus to ignore input channel x.
66 if (x >= max_coded_channel && x != 255) {
67 return false;
68 }
69 }
70
71 // Inverse mapping.
72 constexpr int kNotSet = -1;
73 std::vector<int> coded_channels_to_input_channels(max_coded_channel, kNotSet);
74 for (size_t i = 0; i < num_channels; ++i) {
75 if (channel_mapping[i] == 255) {
76 continue;
77 }
78
79 // If it's not ignored, put it in the inverted mapping. But first check if
80 // we've told Opus to use another input channel for this coded channel:
81 const int coded_channel = channel_mapping[i];
82 if (coded_channels_to_input_channels[coded_channel] != kNotSet) {
83 // Coded channel `coded_channel` comes from both input channels
84 // `coded_channels_to_input_channels[coded_channel]` and `i`.
85 return false;
86 }
87
88 coded_channels_to_input_channels[coded_channel] = i;
89 }
90
91 // Check that we specified what input the encoder should use to produce
92 // every coded channel.
93 for (int i = 0; i < max_coded_channel; ++i) {
94 if (coded_channels_to_input_channels[i] == kNotSet) {
95 // Coded channel `i` has unspecified input channel.
96 return false;
97 }
98 }
99
100 if (num_channels > 255 || max_coded_channel >= 255) {
101 return false;
102 }
103 return true;
104 }
105
106 } // namespace webrtc
107