Codec Extensibility A2DP HAL Reference Implementation

Test: m
Bug: 297037759
Change-Id: I84b32c2ef22da8c3e920e497501b9f16feaf803c
diff --git a/bluetooth/audio/aidl/default/A2dpOffloadCodecAac.cpp b/bluetooth/audio/aidl/default/A2dpOffloadCodecAac.cpp
new file mode 100644
index 0000000..0f5533a
--- /dev/null
+++ b/bluetooth/audio/aidl/default/A2dpOffloadCodecAac.cpp
@@ -0,0 +1,378 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "A2dpOffloadCodecAac.h"
+
+#include "A2dpBits.h"
+
+namespace aidl::android::hardware::bluetooth::audio {
+
+/**
+ * AAC Local Capabilities
+ */
+
+enum : bool {
+  kEnableObjectTypeMpeg2AacLc = true,
+  kEnableObjectTypeMpeg4AacLc = true,
+};
+
+enum : bool {
+  kEnableSamplingFrequency44100 = true,
+  kEnableSamplingFrequency48000 = true,
+  kEnableSamplingFrequency88200 = false,
+  kEnableSamplingFrequency96000 = false,
+};
+
+enum : bool {
+  kEnableChannels1 = true,
+  kEnableChannels2 = true,
+};
+
+enum : bool {
+  kEnableVbrSupported = true,
+};
+
+enum : int {
+  kBitdepth = 24,
+};
+
+/**
+ * AAC Signaling format [A2DP - 4.5]
+ */
+
+// clang-format off
+
+constexpr A2dpBits::Range kObjectType        (  0,  6 );
+constexpr A2dpBits::Range kDrcEnable         (  7     );
+constexpr A2dpBits::Range kSamplingFrequency (  8, 19 );
+constexpr A2dpBits::Range kChannels          ( 20, 23 );
+constexpr A2dpBits::Range kVbrSupported      ( 24     );
+constexpr A2dpBits::Range kBitrate           ( 25, 47 );
+constexpr size_t kCapabilitiesSize = 48/8;
+
+// clang-format on
+
+enum {
+  kObjectTypeMpeg2AacLc = kObjectType.first,
+  kObjectTypeMpeg4AacLc,
+  kObjectTypeMpeg4AacLtp,
+  kObjectTypeMpeg4AacScalable,
+  kObjectTypeMpeg4AacHeV1,
+  kObjectTypeMpeg4AacHeV2,
+  kObjectTypeMpeg4AacEldV2
+};
+
+enum {
+  kSamplingFrequency8000 = kSamplingFrequency.first,
+  kSamplingFrequency11025,
+  kSamplingFrequency12000,
+  kSamplingFrequency16000,
+  kSamplingFrequency22050,
+  kSamplingFrequency24000,
+  kSamplingFrequency32000,
+  kSamplingFrequency44100,
+  kSamplingFrequency48000,
+  kSamplingFrequency64000,
+  kSamplingFrequency88200,
+  kSamplingFrequency96000
+};
+
+enum { kChannels1 = kChannels.first, kChannels2, kChannels51, kChannels71 };
+
+/**
+ * AAC Conversion functions
+ */
+
+static AacParameters::ObjectType GetObjectTypeEnum(int object_type) {
+  switch (object_type) {
+    case kObjectTypeMpeg2AacLc:
+      return AacParameters::ObjectType::MPEG2_AAC_LC;
+    case kObjectTypeMpeg4AacLc:
+    default:
+      return AacParameters::ObjectType::MPEG4_AAC_LC;
+  }
+}
+
+static int GetSamplingFrequencyBit(int32_t sampling_frequency) {
+  switch (sampling_frequency) {
+    case 8000:
+      return kSamplingFrequency8000;
+    case 11025:
+      return kSamplingFrequency11025;
+    case 12000:
+      return kSamplingFrequency12000;
+    case 16000:
+      return kSamplingFrequency16000;
+    case 22050:
+      return kSamplingFrequency22050;
+    case 24000:
+      return kSamplingFrequency24000;
+    case 32000:
+      return kSamplingFrequency32000;
+    case 44100:
+      return kSamplingFrequency44100;
+    case 48000:
+      return kSamplingFrequency48000;
+    case 64000:
+      return kSamplingFrequency64000;
+    case 88200:
+      return kSamplingFrequency88200;
+    case 96000:
+      return kSamplingFrequency96000;
+    default:
+      return -1;
+  }
+}
+
+static int32_t GetSamplingFrequencyValue(int sampling_frequency) {
+  switch (sampling_frequency) {
+    case kSamplingFrequency8000:
+      return 8000;
+    case kSamplingFrequency11025:
+      return 11025;
+    case kSamplingFrequency12000:
+      return 12000;
+    case kSamplingFrequency16000:
+      return 16000;
+    case kSamplingFrequency22050:
+      return 22050;
+    case kSamplingFrequency24000:
+      return 24000;
+    case kSamplingFrequency32000:
+      return 32000;
+    case kSamplingFrequency44100:
+      return 44100;
+    case kSamplingFrequency48000:
+      return 48000;
+    case kSamplingFrequency64000:
+      return 64000;
+    case kSamplingFrequency88200:
+      return 88200;
+    case kSamplingFrequency96000:
+      return 96000;
+    default:
+      return 0;
+  }
+}
+
+static int GetChannelsBit(ChannelMode channel_mode) {
+  switch (channel_mode) {
+    case ChannelMode::MONO:
+      return kChannels1;
+    case ChannelMode::STEREO:
+      return kChannels2;
+    default:
+      return -1;
+  }
+}
+
+static ChannelMode GetChannelModeEnum(int channel_mode) {
+  switch (channel_mode) {
+    case kChannels1:
+      return ChannelMode::MONO;
+    case kChannels2:
+      return ChannelMode::STEREO;
+    default:
+      return ChannelMode::UNKNOWN;
+  }
+}
+
+/**
+ * AAC Class implementation
+ */
+
+const A2dpOffloadCodecAac* A2dpOffloadCodecAac::GetInstance() {
+  static A2dpOffloadCodecAac instance;
+  return &instance;
+}
+
+A2dpOffloadCodecAac::A2dpOffloadCodecAac()
+    : A2dpOffloadCodec(info_),
+      info_({.id = CodecId(CodecId::A2dp::AAC), .name = "AAC"}) {
+  info_.transport.set<CodecInfo::Transport::Tag::a2dp>();
+  auto& a2dp_info = info_.transport.get<CodecInfo::Transport::Tag::a2dp>();
+
+  /* --- Setup Capabilities --- */
+
+  a2dp_info.capabilities.resize(kCapabilitiesSize);
+  std::fill(begin(a2dp_info.capabilities), end(a2dp_info.capabilities), 0);
+
+  auto capabilities = A2dpBits(a2dp_info.capabilities);
+
+  capabilities.set(kObjectTypeMpeg2AacLc, kEnableObjectTypeMpeg2AacLc);
+  capabilities.set(kObjectTypeMpeg4AacLc, kEnableObjectTypeMpeg4AacLc);
+
+  capabilities.set(kSamplingFrequency44100, kEnableSamplingFrequency44100);
+  capabilities.set(kSamplingFrequency48000, kEnableSamplingFrequency48000);
+  capabilities.set(kSamplingFrequency88200, kEnableSamplingFrequency88200);
+  capabilities.set(kSamplingFrequency96000, kEnableSamplingFrequency96000);
+
+  capabilities.set(kChannels1, kEnableChannels1);
+  capabilities.set(kChannels2, kEnableChannels2);
+
+  capabilities.set(kVbrSupported, kEnableVbrSupported);
+
+  /* --- Setup Sampling Frequencies --- */
+
+  auto& sampling_frequency = a2dp_info.samplingFrequencyHz;
+
+  for (auto v : {8000, 11025, 12000, 16000, 22050, 24000, 32000, 44100, 48000,
+                 64000, 88200, 96000})
+    if (capabilities.get(GetSamplingFrequencyBit(int32_t(v))))
+      sampling_frequency.push_back(v);
+
+  /* --- Setup Channel Modes --- */
+
+  auto& channel_modes = a2dp_info.channelMode;
+
+  for (auto v : {ChannelMode::MONO, ChannelMode::STEREO})
+    if (capabilities.get(GetChannelsBit(v))) channel_modes.push_back(v);
+
+  /* --- Setup Bitdepth --- */
+
+  a2dp_info.bitdepth.push_back(kBitdepth);
+}
+
+A2dpStatus A2dpOffloadCodecAac::ParseConfiguration(
+    const std::vector<uint8_t>& configuration,
+    CodecParameters* codec_parameters, AacParameters* aac_parameters) const {
+  auto& a2dp_info = info.transport.get<CodecInfo::Transport::Tag::a2dp>();
+
+  if (configuration.size() != a2dp_info.capabilities.size())
+    return A2dpStatus::BAD_LENGTH;
+
+  auto config = A2dpBits(configuration);
+  auto lcaps = A2dpBits(a2dp_info.capabilities);
+
+  /* --- Check Object Type --- */
+
+  int object_type = config.find_active_bit(kObjectType);
+  if (object_type < 0) return A2dpStatus::INVALID_OBJECT_TYPE;
+  if (!lcaps.get(object_type)) return A2dpStatus::NOT_SUPPORTED_OBJECT_TYPE;
+
+  /* --- Check Sampling Frequency --- */
+
+  int sampling_frequency = config.find_active_bit(kSamplingFrequency);
+  if (sampling_frequency < 0) return A2dpStatus::INVALID_SAMPLING_FREQUENCY;
+  if (!lcaps.get(sampling_frequency))
+    return A2dpStatus::NOT_SUPPORTED_SAMPLING_FREQUENCY;
+
+  /* --- Check Channels --- */
+
+  int channels = config.find_active_bit(kChannels);
+  if (channels < 0) return A2dpStatus::INVALID_CHANNELS;
+  if (!lcaps.get(channels)) return A2dpStatus::NOT_SUPPORTED_CHANNELS;
+
+  /* --- Check Bitrate --- */
+
+  bool vbr = config.get(kVbrSupported);
+  if (vbr && !lcaps.get(kVbrSupported)) return A2dpStatus::NOT_SUPPORTED_VBR;
+
+  int bitrate = config.get(kBitrate);
+  if (vbr && lcaps.get(kBitrate) && bitrate > lcaps.get(kBitrate))
+    return A2dpStatus::NOT_SUPPORTED_BIT_RATE;
+
+  /* --- Return --- */
+
+  codec_parameters->channelMode = GetChannelModeEnum(channels);
+  codec_parameters->samplingFrequencyHz =
+      GetSamplingFrequencyValue(sampling_frequency);
+  codec_parameters->bitdepth = kBitdepth;
+
+  codec_parameters->minBitrate = vbr ? 0 : bitrate;
+  codec_parameters->maxBitrate = bitrate;
+
+  if (aac_parameters)
+    aac_parameters->object_type = GetObjectTypeEnum(object_type);
+
+  return A2dpStatus::OK;
+}
+
+bool A2dpOffloadCodecAac::BuildConfiguration(
+    const std::vector<uint8_t>& remote_capabilities,
+    const std::optional<CodecParameters>& hint,
+    std::vector<uint8_t>* configuration) const {
+  auto& a2dp_info = info_.transport.get<CodecInfo::Transport::Tag::a2dp>();
+
+  if (remote_capabilities.size() != a2dp_info.capabilities.size()) return false;
+
+  auto lcaps = A2dpBits(a2dp_info.capabilities);
+  auto rcaps = A2dpBits(remote_capabilities);
+
+  configuration->resize(a2dp_info.capabilities.size());
+  std::fill(begin(*configuration), end(*configuration), 0);
+  auto config = A2dpBits(*configuration);
+
+  /* --- Select Object Type --- */
+
+  if (lcaps.get(kObjectTypeMpeg2AacLc) && rcaps.get(kObjectTypeMpeg2AacLc))
+    config.set(kObjectTypeMpeg2AacLc);
+  else if (lcaps.get(kObjectTypeMpeg4AacLc) && rcaps.get(kObjectTypeMpeg4AacLc))
+    config.set(kObjectTypeMpeg4AacLc);
+  else
+    return false;
+
+  /* --- Select Sampling Frequency --- */
+
+  auto sf_hint = hint ? GetSamplingFrequencyBit(hint->samplingFrequencyHz) : -1;
+
+  if (sf_hint >= 0 && lcaps.get(sf_hint) && rcaps.get(sf_hint))
+    config.set(sf_hint);
+  else if (lcaps.get(kSamplingFrequency96000) &&
+           rcaps.get(kSamplingFrequency96000))
+    config.set(kSamplingFrequency96000);
+  else if (lcaps.get(kSamplingFrequency88200) &&
+           rcaps.get(kSamplingFrequency88200))
+    config.set(kSamplingFrequency88200);
+  else if (lcaps.get(kSamplingFrequency48000) &&
+           rcaps.get(kSamplingFrequency48000))
+    config.set(kSamplingFrequency48000);
+  else if (lcaps.get(kSamplingFrequency44100) &&
+           rcaps.get(kSamplingFrequency44100))
+    config.set(kSamplingFrequency44100);
+  else
+    return false;
+
+  /* --- Select Channels --- */
+
+  auto ch_hint = hint ? GetChannelsBit(hint->channelMode) : -1;
+
+  if (ch_hint >= 0 && lcaps.get(ch_hint) && rcaps.get(ch_hint))
+    config.set(ch_hint);
+  else if (lcaps.get(kChannels2) && rcaps.get(kChannels2))
+    config.set(kChannels2);
+  else if (lcaps.get(kChannels1) && rcaps.get(kChannels1))
+    config.set(kChannels1);
+  else
+    return false;
+
+  /* --- Select Bitrate --- */
+
+  if (!hint || hint->minBitrate == 0)
+    config.set(kVbrSupported,
+               lcaps.get(kVbrSupported) && rcaps.get(kVbrSupported));
+
+  int32_t bitrate = lcaps.get(kBitrate);
+  if (hint && hint->maxBitrate > 0 && bitrate)
+    bitrate = std::min(hint->maxBitrate, bitrate);
+  else if (hint && hint->maxBitrate > 0)
+    bitrate = hint->maxBitrate;
+  config.set(kBitrate, bitrate);
+
+  return true;
+}
+
+}  // namespace aidl::android::hardware::bluetooth::audio