1 files changed, 106 insertions, 0 deletions
diff --git a/third_party/libwebrtc/api/audio_codecs/opus/audio_encoder_multi_channel_opus_config.cc b/third_party/libwebrtc/api/audio_codecs/opus/audio_encoder_multi_channel_opus_config.cc
new file mode 100644
index 0000000000..0052c429b2
--- /dev/null
+++ b/third_party/libwebrtc/api/audio_codecs/opus/audio_encoder_multi_channel_opus_config.cc
@@ -0,0 +1,106 @@
+/*
+ *  Copyright (c) 2019 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "api/audio_codecs/opus/audio_encoder_multi_channel_opus_config.h"
+
+namespace webrtc {
+
+namespace {
+constexpr int kDefaultComplexity = 9;
+}  // namespace
+
+AudioEncoderMultiChannelOpusConfig::AudioEncoderMultiChannelOpusConfig()
+    : frame_size_ms(kDefaultFrameSizeMs),
+      num_channels(1),
+      application(ApplicationMode::kVoip),
+      bitrate_bps(32000),
+      fec_enabled(false),
+      cbr_enabled(false),
+      dtx_enabled(false),
+      max_playback_rate_hz(48000),
+      complexity(kDefaultComplexity),
+      num_streams(-1),
+      coupled_streams(-1) {}
+AudioEncoderMultiChannelOpusConfig::AudioEncoderMultiChannelOpusConfig(
+    const AudioEncoderMultiChannelOpusConfig&) = default;
+AudioEncoderMultiChannelOpusConfig::~AudioEncoderMultiChannelOpusConfig() =
+    default;
+AudioEncoderMultiChannelOpusConfig& AudioEncoderMultiChannelOpusConfig::
+operator=(const AudioEncoderMultiChannelOpusConfig&) = default;
+
+bool AudioEncoderMultiChannelOpusConfig::IsOk() const {
+  if (frame_size_ms <= 0 || frame_size_ms % 10 != 0)
+    return false;
+  if (num_channels >= 255) {
+    return false;
+  }
+  if (bitrate_bps < kMinBitrateBps || bitrate_bps > kMaxBitrateBps)
+    return false;
+  if (complexity < 0 || complexity > 10)
+    return false;
+
+  // Check the lengths:
+  if (num_streams < 0 || coupled_streams < 0) {
+    return false;
+  }
+  if (num_streams < coupled_streams) {
+    return false;
+  }
+  if (channel_mapping.size() != static_cast<size_t>(num_channels)) {
+    return false;
+  }
+
+  // Every mono stream codes one channel, every coupled stream codes two. This
+  // is the total coded channel count:
+  const int max_coded_channel = num_streams + coupled_streams;
+  for (const auto& x : channel_mapping) {
+    // Coded channels >= max_coded_channel don't exist. Except for 255, which
+    // tells Opus to ignore input channel x.
+    if (x >= max_coded_channel && x != 255) {
+      return false;
+    }
+  }
+
+  // Inverse mapping.
+  constexpr int kNotSet = -1;
+  std::vector<int> coded_channels_to_input_channels(max_coded_channel, kNotSet);
+  for (size_t i = 0; i < num_channels; ++i) {
+    if (channel_mapping[i] == 255) {
+      continue;
+    }
+
+    // If it's not ignored, put it in the inverted mapping. But first check if
+    // we've told Opus to use another input channel for this coded channel:
+    const int coded_channel = channel_mapping[i];
+    if (coded_channels_to_input_channels[coded_channel] != kNotSet) {
+      // Coded channel `coded_channel` comes from both input channels
+      // `coded_channels_to_input_channels[coded_channel]` and `i`.
+      return false;
+    }
+
+    coded_channels_to_input_channels[coded_channel] = i;
+  }
+
+  // Check that we specified what input the encoder should use to produce
+  // every coded channel.
+  for (int i = 0; i < max_coded_channel; ++i) {
+    if (coded_channels_to_input_channels[i] == kNotSet) {
+      // Coded channel `i` has unspecified input channel.
+      return false;
+    }
+  }
+
+  if (num_channels > 255 || max_coded_channel >= 255) {
+    return false;
+  }
+  return true;
+}
+
+}  // namespace webrtc