diff --git a/media/libmedia/include/media/PatchBuilder.h b/media/libmedia/include/media/PatchBuilder.h
new file mode 100644
index 0000000..f2722a6
--- /dev/null
+++ b/media/libmedia/include/media/PatchBuilder.h
@@ -0,0 +1,103 @@
+/*
+ * Copyright (C) 2018 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.
+ */
+
+#ifndef ANDROID_PATCH_BUILDER_H
+#define ANDROID_PATCH_BUILDER_H
+
+#include <functional>
+#include <utility>
+
+#include <system/audio.h>
+#include <utils/StrongPointer.h>
+
+// This is a header-only utility.
+
+namespace android {
+
+class PatchBuilder {
+  public:
+    using mix_usecase_t = decltype(audio_port_config_mix_ext::usecase);
+
+    PatchBuilder() = default;
+
+    // All existing methods operating on audio patches take a pointer to const.
+    // It's OK to construct a temporary PatchBuilder while preparing a parameter
+    // to such a function because the Builder will be kept alive until the code
+    // execution reaches the function call statement semicolon.
+    const struct audio_patch* patch() const { return &mPatch; }
+
+    template<typename T, typename... S>
+    PatchBuilder& addSink(T&& t, S&&... s) {
+        sinks().add(std::forward<T>(t), std::forward<S>(s)...);
+        return *this;
+    }
+    // Explicit type of the second parameter allows clients to provide the struct inline.
+    template<typename T>
+    PatchBuilder& addSink(T&& t, const mix_usecase_t& update) {
+        sinks().add(std::forward<T>(t), update);
+        return *this;
+    }
+    template<typename T, typename... S>
+    PatchBuilder& addSource(T&& t, S&&... s) {
+        sources().add(std::forward<T>(t), std::forward<S>(s)...);
+        return *this;
+    }
+    // Explicit type of the second parameter allows clients to provide the struct inline.
+    template<typename T>
+    PatchBuilder& addSource(T&& t, const mix_usecase_t& update) {
+        sources().add(std::forward<T>(t), update);
+        return *this;
+    }
+
+  private:
+    struct PortCfgs {
+        PortCfgs(unsigned int *countPtr, struct audio_port_config *portCfgs)
+                : mCountPtr(countPtr), mPortCfgs(portCfgs) {}
+        audio_port_config& add(const audio_port_config& portCfg) {
+            return *advance() = portCfg;
+        }
+        template<typename T>
+        audio_port_config& add(const sp<T>& entity) {
+            audio_port_config* added = advance();
+            entity->toAudioPortConfig(added);
+            return *added;
+        }
+        template<typename T>
+        void add(const sp<T>& entity, const mix_usecase_t& usecaseUpdate) {
+            add(entity).ext.mix.usecase = usecaseUpdate;
+        }
+        template<typename T>
+        void add(const sp<T>& entity,
+                std::function<mix_usecase_t(const mix_usecase_t&)> usecaseUpdater) {
+            mix_usecase_t* usecase = &add(entity).ext.mix.usecase;
+            *usecase = usecaseUpdater(*usecase);
+        }
+        struct audio_port_config* advance() {
+            return &mPortCfgs[(*mCountPtr)++];
+        }
+        unsigned int *mCountPtr;
+        struct audio_port_config *mPortCfgs;
+    };
+
+    PortCfgs sinks() { return PortCfgs(&mPatch.num_sinks, mPatch.sinks); }
+    PortCfgs sources() { return PortCfgs(&mPatch.num_sources, mPatch.sources); }
+
+    struct audio_patch mPatch = {};
+};
+
+}  // namespace android
+
+#endif  // ANDROID_PATCH_BUILDER_H
diff --git a/services/audioflinger/PatchPanel.cpp b/services/audioflinger/PatchPanel.cpp
index eaf1120..be3286f 100644
--- a/services/audioflinger/PatchPanel.cpp
+++ b/services/audioflinger/PatchPanel.cpp
@@ -26,6 +26,7 @@
 #include "AudioFlinger.h"
 #include "ServiceUtilities.h"
 #include <media/AudioParameter.h>
+#include <media/PatchBuilder.h>
 
 // ----------------------------------------------------------------------------
 
@@ -373,15 +374,10 @@
 status_t AudioFlinger::PatchPanel::Patch::createConnections(PatchPanel *panel)
 {
     // create patch from source device to record thread input
-    struct audio_patch subPatch;
-    subPatch.num_sources = 1;
-    subPatch.sources[0] = mAudioPatch.sources[0];
-    subPatch.num_sinks = 1;
-
-    mRecord.thread()->getAudioPortConfig(&subPatch.sinks[0]);
-    subPatch.sinks[0].ext.mix.usecase.source = AUDIO_SOURCE_MIC;
-
-    status_t status = panel->createAudioPatch(&subPatch, mRecord.handlePtr());
+    status_t status = panel->createAudioPatch(
+            PatchBuilder().addSource(mAudioPatch.sources[0]).
+                addSink(mRecord.thread(), { .source = AUDIO_SOURCE_MIC }).patch(),
+            mRecord.handlePtr());
     if (status != NO_ERROR) {
         *mRecord.handlePtr() = AUDIO_PATCH_HANDLE_NONE;
         return status;
@@ -389,9 +385,9 @@
 
     // create patch from playback thread output to sink device
     if (mAudioPatch.num_sinks != 0) {
-        mPlayback.thread()->getAudioPortConfig(&subPatch.sources[0]);
-        subPatch.sinks[0] = mAudioPatch.sinks[0];
-        status = panel->createAudioPatch(&subPatch, mPlayback.handlePtr());
+        status = panel->createAudioPatch(
+                PatchBuilder().addSource(mPlayback.thread()).addSink(mAudioPatch.sinks[0]).patch(),
+                mPlayback.handlePtr());
         if (status != NO_ERROR) {
             *mPlayback.handlePtr() = AUDIO_PATCH_HANDLE_NONE;
             return status;
diff --git a/services/audioflinger/Threads.cpp b/services/audioflinger/Threads.cpp
index 5db3e44..4423033 100644
--- a/services/audioflinger/Threads.cpp
+++ b/services/audioflinger/Threads.cpp
@@ -1527,7 +1527,7 @@
     }
 }
 
-void AudioFlinger::ThreadBase::getAudioPortConfig(struct audio_port_config *config)
+void AudioFlinger::ThreadBase::toAudioPortConfig(struct audio_port_config *config)
 {
     config->type = AUDIO_PORT_TYPE_MIX;
     config->ext.mix.handle = mId;
@@ -3780,9 +3780,9 @@
     destroyTrack_l(track);
 }
 
-void AudioFlinger::PlaybackThread::getAudioPortConfig(struct audio_port_config *config)
+void AudioFlinger::PlaybackThread::toAudioPortConfig(struct audio_port_config *config)
 {
-    ThreadBase::getAudioPortConfig(config);
+    ThreadBase::toAudioPortConfig(config);
     config->role = AUDIO_PORT_ROLE_SOURCE;
     config->ext.mix.hw_module = mOutput->audioHwDev->handle();
     config->ext.mix.usecase.stream = AUDIO_STREAM_DEFAULT;
@@ -7875,9 +7875,9 @@
     destroyTrack_l(record);
 }
 
-void AudioFlinger::RecordThread::getAudioPortConfig(struct audio_port_config *config)
+void AudioFlinger::RecordThread::toAudioPortConfig(struct audio_port_config *config)
 {
-    ThreadBase::getAudioPortConfig(config);
+    ThreadBase::toAudioPortConfig(config);
     config->role = AUDIO_PORT_ROLE_SINK;
     config->ext.mix.hw_module = mInput->audioHwDev->handle();
     config->ext.mix.usecase.source = mAudioSource;
@@ -8462,9 +8462,9 @@
     return status;
 }
 
-void AudioFlinger::MmapThread::getAudioPortConfig(struct audio_port_config *config)
+void AudioFlinger::MmapThread::toAudioPortConfig(struct audio_port_config *config)
 {
-    ThreadBase::getAudioPortConfig(config);
+    ThreadBase::toAudioPortConfig(config);
     if (isOutput()) {
         config->role = AUDIO_PORT_ROLE_SOURCE;
         config->ext.mix.hw_module = mAudioHwDev->handle();
diff --git a/services/audioflinger/Threads.h b/services/audioflinger/Threads.h
index c490fb5..5e5e948 100644
--- a/services/audioflinger/Threads.h
+++ b/services/audioflinger/Threads.h
@@ -281,7 +281,7 @@
     virtual     status_t    createAudioPatch_l(const struct audio_patch *patch,
                                                audio_patch_handle_t *handle) = 0;
     virtual     status_t    releaseAudioPatch_l(const audio_patch_handle_t handle) = 0;
-    virtual     void        getAudioPortConfig(struct audio_port_config *config) = 0;
+    virtual     void        toAudioPortConfig(struct audio_port_config *config) = 0;
 
 
                 // see note at declaration of mStandby, mOutDevice and mInDevice
@@ -782,7 +782,7 @@
                 void        addPatchTrack(const sp<PatchTrack>& track);
                 void        deletePatchTrack(const sp<PatchTrack>& track);
 
-    virtual     void        getAudioPortConfig(struct audio_port_config *config);
+    virtual     void        toAudioPortConfig(struct audio_port_config *config);
 
                 // Return the asynchronous signal wait time.
     virtual     int64_t     computeWaitTimeNs_l() const { return INT64_MAX; }
@@ -1459,7 +1459,7 @@
 
     virtual size_t      frameCount() const { return mFrameCount; }
             bool        hasFastCapture() const { return mFastCapture != 0; }
-    virtual void        getAudioPortConfig(struct audio_port_config *config);
+    virtual void        toAudioPortConfig(struct audio_port_config *config);
 
     virtual status_t    checkEffectCompatibility_l(const effect_descriptor_t *desc,
                                                    audio_session_t sessionId);
@@ -1602,7 +1602,7 @@
     virtual     status_t    createAudioPatch_l(const struct audio_patch *patch,
                                                audio_patch_handle_t *handle);
     virtual     status_t    releaseAudioPatch_l(const audio_patch_handle_t handle);
-    virtual     void        getAudioPortConfig(struct audio_port_config *config);
+    virtual     void        toAudioPortConfig(struct audio_port_config *config);
 
     virtual     sp<StreamHalInterface> stream() const { return mHalStream; }
     virtual     status_t    addEffectChain_l(const sp<EffectChain>& chain);
diff --git a/services/audiopolicy/common/managerdefinitions/include/AudioSessionInfoProvider.h b/services/audiopolicy/common/managerdefinitions/include/AudioIODescriptorInterface.h
similarity index 67%
rename from services/audiopolicy/common/managerdefinitions/include/AudioSessionInfoProvider.h
rename to services/audiopolicy/common/managerdefinitions/include/AudioIODescriptorInterface.h
index e0037fc..9f3fc0c 100644
--- a/services/audiopolicy/common/managerdefinitions/include/AudioSessionInfoProvider.h
+++ b/services/audiopolicy/common/managerdefinitions/include/AudioIODescriptorInterface.h
@@ -19,26 +19,27 @@
 namespace android {
 
 /**
- * Interface for input descriptors to implement so dependent audio sessions can query information
- * about their context
+ * Interface for I/O descriptors to implement so information about their context
+ * can be queried and updated.
  */
-class AudioSessionInfoProvider
+class AudioIODescriptorInterface
 {
 public:
-    virtual ~AudioSessionInfoProvider() {};
+    virtual ~AudioIODescriptorInterface() {};
 
     virtual audio_config_base_t getConfig() const = 0;
 
     virtual audio_patch_handle_t getPatchHandle() const = 0;
 
+    virtual void setPatchHandle(audio_patch_handle_t handle) = 0;
 };
 
-class AudioSessionInfoUpdateListener
+class AudioIODescriptorUpdateListener
 {
 public:
-    virtual ~AudioSessionInfoUpdateListener() {};
+    virtual ~AudioIODescriptorUpdateListener() {};
 
-    virtual void onSessionInfoUpdate() const = 0;;
+    virtual void onIODescriptorUpdate() const = 0;
 };
 
 } // namespace android
diff --git a/services/audiopolicy/common/managerdefinitions/include/AudioInputDescriptor.h b/services/audiopolicy/common/managerdefinitions/include/AudioInputDescriptor.h
index b25d6d4..85f3b86 100644
--- a/services/audiopolicy/common/managerdefinitions/include/AudioInputDescriptor.h
+++ b/services/audiopolicy/common/managerdefinitions/include/AudioInputDescriptor.h
@@ -16,9 +16,9 @@
 
 #pragma once
 
+#include "AudioIODescriptorInterface.h"
 #include "AudioPort.h"
 #include "AudioSession.h"
-#include "AudioSessionInfoProvider.h"
 #include <utils/Errors.h>
 #include <system/audio.h>
 #include <utils/SortedVector.h>
@@ -31,7 +31,7 @@
 
 // descriptor for audio inputs. Used to maintain current configuration of each opened audio input
 // and keep track of the usage of this input.
-class AudioInputDescriptor: public AudioPortConfig, public AudioSessionInfoProvider
+class AudioInputDescriptor: public AudioPortConfig, public AudioIODescriptorInterface
 {
 public:
     explicit AudioInputDescriptor(const sp<IOProfile>& profile,
@@ -67,11 +67,10 @@
     size_t getAudioSessionCount(bool activeOnly) const;
     audio_source_t getHighestPrioritySource(bool activeOnly) const;
 
-    // implementation of AudioSessionInfoProvider
-    virtual audio_config_base_t getConfig() const;
-    virtual audio_patch_handle_t getPatchHandle() const;
-
-    void setPatchHandle(audio_patch_handle_t handle);
+    // implementation of AudioIODescriptorInterface
+    audio_config_base_t getConfig() const override;
+    audio_patch_handle_t getPatchHandle() const override;
+    void setPatchHandle(audio_patch_handle_t handle) override;
 
     status_t open(const audio_config_t *config,
                   audio_devices_t device,
diff --git a/services/audiopolicy/common/managerdefinitions/include/AudioOutputDescriptor.h b/services/audiopolicy/common/managerdefinitions/include/AudioOutputDescriptor.h
index 5e5d38b..57d1cfa 100644
--- a/services/audiopolicy/common/managerdefinitions/include/AudioOutputDescriptor.h
+++ b/services/audiopolicy/common/managerdefinitions/include/AudioOutputDescriptor.h
@@ -24,6 +24,7 @@
 #include <utils/Timers.h>
 #include <utils/KeyedVector.h>
 #include <system/audio.h>
+#include "AudioIODescriptorInterface.h"
 #include "AudioSourceDescriptor.h"
 
 namespace android {
@@ -35,7 +36,7 @@
 
 // descriptor for audio outputs. Used to maintain current configuration of each opened audio output
 // and keep track of the usage of this output by each audio stream type.
-class AudioOutputDescriptor: public AudioPortConfig
+class AudioOutputDescriptor: public AudioPortConfig, public AudioIODescriptorInterface
 {
 public:
     AudioOutputDescriptor(const sp<AudioPort>& port,
@@ -73,8 +74,10 @@
 
     audio_module_handle_t getModuleHandle() const;
 
-    audio_patch_handle_t getPatchHandle() const { return mPatchHandle; };
-    void setPatchHandle(audio_patch_handle_t handle) { mPatchHandle = handle; };
+    // implementation of AudioIODescriptorInterface
+    audio_config_base_t getConfig() const override;
+    audio_patch_handle_t getPatchHandle() const override;
+    void setPatchHandle(audio_patch_handle_t handle) override;
 
     sp<AudioPort>       mPort;
     audio_devices_t mDevice;                   // current device this output is routed to
diff --git a/services/audiopolicy/common/managerdefinitions/include/AudioSession.h b/services/audiopolicy/common/managerdefinitions/include/AudioSession.h
index dd5247d..53e6ec9 100644
--- a/services/audiopolicy/common/managerdefinitions/include/AudioSession.h
+++ b/services/audiopolicy/common/managerdefinitions/include/AudioSession.h
@@ -23,13 +23,13 @@
 #include <utils/KeyedVector.h>
 #include <media/AudioPolicy.h>
 #include <media/IAudioPolicyServiceClient.h>
-#include "AudioSessionInfoProvider.h"
+#include "AudioIODescriptorInterface.h"
 
 namespace android {
 
 class AudioPolicyClientInterface;
 
-class AudioSession : public RefBase, public AudioSessionInfoUpdateListener
+class AudioSession : public RefBase, public AudioIODescriptorUpdateListener
 {
 public:
     AudioSession(audio_session_t session,
@@ -63,9 +63,9 @@
     uint32_t changeOpenCount(int delta);
     uint32_t changeActiveCount(int delta);
 
-    void setInfoProvider(AudioSessionInfoProvider *provider);
-    // implementation of AudioSessionInfoUpdateListener
-    virtual void onSessionInfoUpdate() const;
+    void setInfoProvider(AudioIODescriptorInterface *provider);
+    // implementation of AudioIODescriptorUpdateListener
+    virtual void onIODescriptorUpdate() const;
 
 private:
     record_client_info_t mRecordClientInfo;
@@ -77,17 +77,17 @@
     uint32_t  mActiveCount;
     AudioMix* mPolicyMix; // non NULL when used by a dynamic policy
     AudioPolicyClientInterface* mClientInterface;
-    const AudioSessionInfoProvider* mInfoProvider;
+    const AudioIODescriptorInterface* mInfoProvider;
 };
 
 class AudioSessionCollection :
     public DefaultKeyedVector<audio_session_t, sp<AudioSession> >,
-    public AudioSessionInfoUpdateListener
+    public AudioIODescriptorUpdateListener
 {
 public:
     status_t addSession(audio_session_t session,
                              const sp<AudioSession>& audioSession,
-                             AudioSessionInfoProvider *provider);
+                             AudioIODescriptorInterface *provider);
 
     status_t removeSession(audio_session_t session);
 
@@ -99,8 +99,8 @@
     bool isSourceActive(audio_source_t source) const;
     audio_source_t getHighestPrioritySource(bool activeOnly) const;
 
-    // implementation of AudioSessionInfoUpdateListener
-    virtual void onSessionInfoUpdate() const;
+    // implementation of AudioIODescriptorUpdateListener
+    virtual void onIODescriptorUpdate() const;
 
     status_t dump(int fd, int spaces) const;
 };
diff --git a/services/audiopolicy/common/managerdefinitions/src/AudioInputDescriptor.cpp b/services/audiopolicy/common/managerdefinitions/src/AudioInputDescriptor.cpp
index 92332fb..f0144db 100644
--- a/services/audiopolicy/common/managerdefinitions/src/AudioInputDescriptor.cpp
+++ b/services/audiopolicy/common/managerdefinitions/src/AudioInputDescriptor.cpp
@@ -164,7 +164,7 @@
 
 status_t AudioInputDescriptor::addAudioSession(audio_session_t session,
                          const sp<AudioSession>& audioSession) {
-    return mSessions.addSession(session, audioSession, /*AudioSessionInfoProvider*/this);
+    return mSessions.addSession(session, audioSession, /*AudioIODescriptorInterface*/this);
 }
 
 status_t AudioInputDescriptor::removeAudioSession(audio_session_t session) {
@@ -179,7 +179,7 @@
 void AudioInputDescriptor::setPatchHandle(audio_patch_handle_t handle)
 {
     mPatchHandle = handle;
-    mSessions.onSessionInfoUpdate();
+    mSessions.onIODescriptorUpdate();
 }
 
 audio_config_base_t AudioInputDescriptor::getConfig() const
diff --git a/services/audiopolicy/common/managerdefinitions/src/AudioOutputDescriptor.cpp b/services/audiopolicy/common/managerdefinitions/src/AudioOutputDescriptor.cpp
index 294a2a6..3c69de5 100644
--- a/services/audiopolicy/common/managerdefinitions/src/AudioOutputDescriptor.cpp
+++ b/services/audiopolicy/common/managerdefinitions/src/AudioOutputDescriptor.cpp
@@ -55,11 +55,28 @@
     }
 }
 
+audio_config_base_t AudioOutputDescriptor::getConfig() const
+{
+    const audio_config_base_t config = { .sample_rate = mSamplingRate, .channel_mask = mChannelMask,
+            .format = mFormat };
+    return config;
+}
+
 audio_module_handle_t AudioOutputDescriptor::getModuleHandle() const
 {
     return mPort.get() != nullptr ? mPort->getModuleHandle() : AUDIO_MODULE_HANDLE_NONE;
 }
 
+audio_patch_handle_t AudioOutputDescriptor::getPatchHandle() const
+{
+    return mPatchHandle;
+}
+
+void AudioOutputDescriptor::setPatchHandle(audio_patch_handle_t handle)
+{
+    mPatchHandle = handle;
+}
+
 audio_port_handle_t AudioOutputDescriptor::getId() const
 {
     return mId;
diff --git a/services/audiopolicy/common/managerdefinitions/src/AudioSession.cpp b/services/audiopolicy/common/managerdefinitions/src/AudioSession.cpp
index 7cda46b..91dee35 100644
--- a/services/audiopolicy/common/managerdefinitions/src/AudioSession.cpp
+++ b/services/audiopolicy/common/managerdefinitions/src/AudioSession.cpp
@@ -86,7 +86,7 @@
         }
 
         // Recording configuration callback:
-        const AudioSessionInfoProvider* provider = mInfoProvider;
+        const AudioIODescriptorInterface* provider = mInfoProvider;
         const audio_config_base_t deviceConfig = (provider != NULL) ? provider->getConfig() :
                 AUDIO_CONFIG_BASE_INITIALIZER;
         const audio_patch_handle_t patchHandle = (provider != NULL) ? provider->getPatchHandle() :
@@ -114,16 +114,16 @@
     return false;
 }
 
-void AudioSession::setInfoProvider(AudioSessionInfoProvider *provider)
+void AudioSession::setInfoProvider(AudioIODescriptorInterface *provider)
 {
     mInfoProvider = provider;
 }
 
-void AudioSession::onSessionInfoUpdate() const
+void AudioSession::onIODescriptorUpdate() const
 {
     if (mActiveCount > 0) {
         // resend the callback after requerying the informations from the info provider
-        const AudioSessionInfoProvider* provider = mInfoProvider;
+        const AudioIODescriptorInterface* provider = mInfoProvider;
         const audio_config_base_t deviceConfig = (provider != NULL) ? provider->getConfig() :
                 AUDIO_CONFIG_BASE_INITIALIZER;
         const audio_patch_handle_t patchHandle = (provider != NULL) ? provider->getPatchHandle() :
@@ -170,7 +170,7 @@
 
 status_t AudioSessionCollection::addSession(audio_session_t session,
                                          const sp<AudioSession>& audioSession,
-                                         AudioSessionInfoProvider *provider)
+                                         AudioIODescriptorInterface *provider)
 {
     ssize_t index = indexOfKey(session);
 
@@ -271,10 +271,10 @@
     return source;
 }
 
-void AudioSessionCollection::onSessionInfoUpdate() const
+void AudioSessionCollection::onIODescriptorUpdate() const
 {
     for (size_t i = 0; i < size(); i++) {
-        valueAt(i)->onSessionInfoUpdate();
+        valueAt(i)->onIODescriptorUpdate();
     }
 }
 
diff --git a/services/audiopolicy/managerdefault/AudioPolicyManager.cpp b/services/audiopolicy/managerdefault/AudioPolicyManager.cpp
index 992cf74..0770134 100644
--- a/services/audiopolicy/managerdefault/AudioPolicyManager.cpp
+++ b/services/audiopolicy/managerdefault/AudioPolicyManager.cpp
@@ -38,6 +38,7 @@
 #include <utils/Log.h>
 #include <media/AudioParameter.h>
 #include <media/AudioPolicyHelper.h>
+#include <media/PatchBuilder.h>
 #include <soundtrigger/SoundTrigger.h>
 #include <system/audio.h>
 #include <audio_policy_conf.h>
@@ -433,20 +434,15 @@
 
 sp<AudioPatch> AudioPolicyManager::createTelephonyPatch(
         bool isRx, audio_devices_t device, uint32_t delayMs) {
-    struct audio_patch patch;
-    patch.num_sources = 1;
-    patch.num_sinks = 1;
+    PatchBuilder patchBuilder;
 
     sp<DeviceDescriptor> txSourceDeviceDesc;
     if (isRx) {
-        fillAudioPortConfigForDevice(mAvailableOutputDevices, device, &patch.sinks[0]);
-        fillAudioPortConfigForDevice(
-                mAvailableInputDevices, AUDIO_DEVICE_IN_TELEPHONY_RX, &patch.sources[0]);
+        patchBuilder.addSink(findDevice(mAvailableOutputDevices, device)).
+                addSource(findDevice(mAvailableInputDevices, AUDIO_DEVICE_IN_TELEPHONY_RX));
     } else {
-        txSourceDeviceDesc = fillAudioPortConfigForDevice(
-                mAvailableInputDevices, device, &patch.sources[0]);
-        fillAudioPortConfigForDevice(
-                mAvailableOutputDevices, AUDIO_DEVICE_OUT_TELEPHONY_TX, &patch.sinks[0]);
+        patchBuilder.addSource(txSourceDeviceDesc = findDevice(mAvailableInputDevices, device)).
+                addSink(findDevice(mAvailableOutputDevices, AUDIO_DEVICE_OUT_TELEPHONY_TX));
     }
 
     audio_devices_t outputDevice = isRx ? device : AUDIO_DEVICE_OUT_TELEPHONY_TX;
@@ -457,9 +453,7 @@
         sp<AudioOutputDescriptor> outputDesc = mOutputs.valueFor(output);
         ALOG_ASSERT(!outputDesc->isDuplicated(),
                 "%s() %#x device output %d is duplicated", __func__, outputDevice, output);
-        outputDesc->toAudioPortConfig(&patch.sources[1]);
-        patch.sources[1].ext.mix.usecase.stream = AUDIO_STREAM_PATCH;
-        patch.num_sources = 2;
+        patchBuilder.addSource(outputDesc, { .stream = AUDIO_STREAM_PATCH });
     }
 
     if (!isRx) {
@@ -481,26 +475,25 @@
     }
 
     audio_patch_handle_t afPatchHandle = AUDIO_PATCH_HANDLE_NONE;
-    status_t status = mpClientInterface->createAudioPatch(&patch, &afPatchHandle, delayMs);
+    status_t status = mpClientInterface->createAudioPatch(
+            patchBuilder.patch(), &afPatchHandle, delayMs);
     ALOGW_IF(status != NO_ERROR,
             "%s() error %d creating %s audio patch", __func__, status, isRx ? "RX" : "TX");
     sp<AudioPatch> audioPatch;
     if (status == NO_ERROR) {
-        audioPatch = new AudioPatch(&patch, mUidCached);
+        audioPatch = new AudioPatch(patchBuilder.patch(), mUidCached);
         audioPatch->mAfPatchHandle = afPatchHandle;
         audioPatch->mUid = mUidCached;
     }
     return audioPatch;
 }
 
-sp<DeviceDescriptor> AudioPolicyManager::fillAudioPortConfigForDevice(
-        const DeviceVector& devices, audio_devices_t device, audio_port_config *config) {
+sp<DeviceDescriptor> AudioPolicyManager::findDevice(
+        const DeviceVector& devices, audio_devices_t device) {
     DeviceVector deviceList = devices.getDevicesFromType(device);
     ALOG_ASSERT(!deviceList.isEmpty(),
             "%s() selected device type %#x is not in devices list", __func__, device);
-    sp<DeviceDescriptor> deviceDesc = deviceList.itemAt(0);
-    deviceDesc->toAudioPortConfig(config);
-    return deviceDesc;
+    return deviceList.itemAt(0);
 }
 
 void AudioPolicyManager::setPhoneState(audio_mode_t state)
@@ -2991,28 +2984,8 @@
             }
             // TODO: check from routing capabilities in config file and other conflicting patches
 
-            audio_patch_handle_t afPatchHandle = AUDIO_PATCH_HANDLE_NONE;
-            if (index >= 0) {
-                afPatchHandle = patchDesc->mAfPatchHandle;
-            }
-
-            status_t status = mpClientInterface->createAudioPatch(&newPatch,
-                                                                  &afPatchHandle,
-                                                                  0);
-            ALOGV("createAudioPatch() patch panel returned %d patchHandle %d",
-                                                                  status, afPatchHandle);
-            if (status == NO_ERROR) {
-                if (index < 0) {
-                    patchDesc = new AudioPatch(&newPatch, uid);
-                    addAudioPatch(patchDesc->mHandle, patchDesc);
-                } else {
-                    patchDesc->mPatch = newPatch;
-                }
-                patchDesc->mAfPatchHandle = afPatchHandle;
-                *handle = patchDesc->mHandle;
-                nextAudioPortGeneration();
-                mpClientInterface->onAudioPatchListUpdate();
-            } else {
+            status_t status = installPatch(__func__, index, handle, &newPatch, 0, uid, &patchDesc);
+            if (status != NO_ERROR) {
                 ALOGW("createAudioPatch() patch panel could not connect device patch, error %d",
                 status);
                 return INVALID_OPERATION;
@@ -3324,7 +3297,6 @@
             mAvailableOutputDevices.getDevice(sinkDevice, String8(""));
 
     audio_patch_handle_t afPatchHandle = AUDIO_PATCH_HANDLE_NONE;
-    struct audio_patch *patch = &sourceDesc->mPatchDesc->mPatch;
 
     if (srcDeviceDesc->getAudioPort()->mModule->getHandle() ==
             sinkDeviceDesc->getAudioPort()->mModule->getHandle() &&
@@ -3356,16 +3328,14 @@
         // be connected as well as the stream type for volume control
         // - the sink is defined by whatever output device is currently selected for the output
         // though which this patch is routed.
-        patch->num_sinks = 0;
-        patch->num_sources = 2;
-        srcDeviceDesc->toAudioPortConfig(&patch->sources[0], NULL);
-        outputDesc->toAudioPortConfig(&patch->sources[1], NULL);
-        patch->sources[1].ext.mix.usecase.stream = stream;
-        status = mpClientInterface->createAudioPatch(patch,
+        PatchBuilder patchBuilder;
+        patchBuilder.addSource(srcDeviceDesc).addSource(outputDesc, { .stream = stream });
+        status = mpClientInterface->createAudioPatch(patchBuilder.patch(),
                                                               &afPatchHandle,
                                                               0);
         ALOGV("%s patch panel returned %d patchHandle %d", __FUNCTION__,
                                                               status, afPatchHandle);
+        sourceDesc->mPatchDesc->mPatch = *patchBuilder.patch();
         if (status != NO_ERROR) {
             ALOGW("%s patch panel could not connect device patch, error %d",
                   __FUNCTION__, status);
@@ -4875,48 +4845,12 @@
         }
 
         if (!deviceList.isEmpty()) {
-            struct audio_patch patch;
-            outputDesc->toAudioPortConfig(&patch.sources[0]);
-            patch.num_sources = 1;
-            patch.num_sinks = 0;
+            PatchBuilder patchBuilder;
+            patchBuilder.addSource(outputDesc);
             for (size_t i = 0; i < deviceList.size() && i < AUDIO_PATCH_PORTS_MAX; i++) {
-                deviceList.itemAt(i)->toAudioPortConfig(&patch.sinks[i]);
-                patch.num_sinks++;
+                patchBuilder.addSink(deviceList.itemAt(i));
             }
-            ssize_t index;
-            if (patchHandle && *patchHandle != AUDIO_PATCH_HANDLE_NONE) {
-                index = mAudioPatches.indexOfKey(*patchHandle);
-            } else {
-                index = mAudioPatches.indexOfKey(outputDesc->getPatchHandle());
-            }
-            sp< AudioPatch> patchDesc;
-            audio_patch_handle_t afPatchHandle = AUDIO_PATCH_HANDLE_NONE;
-            if (index >= 0) {
-                patchDesc = mAudioPatches.valueAt(index);
-                afPatchHandle = patchDesc->mAfPatchHandle;
-            }
-
-            status_t status = mpClientInterface->createAudioPatch(&patch,
-                                                                   &afPatchHandle,
-                                                                   delayMs);
-            ALOGV("setOutputDevice() createAudioPatch returned %d patchHandle %d"
-                    "num_sources %d num_sinks %d",
-                                       status, afPatchHandle, patch.num_sources, patch.num_sinks);
-            if (status == NO_ERROR) {
-                if (index < 0) {
-                    patchDesc = new AudioPatch(&patch, mUidCached);
-                    addAudioPatch(patchDesc->mHandle, patchDesc);
-                } else {
-                    patchDesc->mPatch = patch;
-                }
-                patchDesc->mAfPatchHandle = afPatchHandle;
-                if (patchHandle) {
-                    *patchHandle = patchDesc->mHandle;
-                }
-                outputDesc->setPatchHandle(patchDesc->mHandle);
-                nextAudioPortGeneration();
-                mpClientInterface->onAudioPatchListUpdate();
-            }
+            installPatch(__func__, patchHandle, outputDesc.get(), patchBuilder.patch(), delayMs);
         }
 
         // inform all input as well
@@ -4976,51 +4910,19 @@
 
         DeviceVector deviceList = mAvailableInputDevices.getDevicesFromType(device);
         if (!deviceList.isEmpty()) {
-            struct audio_patch patch;
-            inputDesc->toAudioPortConfig(&patch.sinks[0]);
+            PatchBuilder patchBuilder;
+            patchBuilder.addSink(inputDesc,
             // AUDIO_SOURCE_HOTWORD is for internal use only:
             // handled as AUDIO_SOURCE_VOICE_RECOGNITION by the audio HAL
-            if (patch.sinks[0].ext.mix.usecase.source == AUDIO_SOURCE_HOTWORD &&
-                    !inputDesc->isSoundTrigger()) {
-                patch.sinks[0].ext.mix.usecase.source = AUDIO_SOURCE_VOICE_RECOGNITION;
-            }
-            patch.num_sinks = 1;
+                    [inputDesc](const PatchBuilder::mix_usecase_t& usecase) {
+                        auto result = usecase;
+                        if (result.source == AUDIO_SOURCE_HOTWORD && !inputDesc->isSoundTrigger()) {
+                            result.source = AUDIO_SOURCE_VOICE_RECOGNITION;
+                        }
+                        return result; }).
             //only one input device for now
-            deviceList.itemAt(0)->toAudioPortConfig(&patch.sources[0]);
-            patch.num_sources = 1;
-            ssize_t index;
-            if (patchHandle && *patchHandle != AUDIO_PATCH_HANDLE_NONE) {
-                index = mAudioPatches.indexOfKey(*patchHandle);
-            } else {
-                index = mAudioPatches.indexOfKey(inputDesc->getPatchHandle());
-            }
-            sp< AudioPatch> patchDesc;
-            audio_patch_handle_t afPatchHandle = AUDIO_PATCH_HANDLE_NONE;
-            if (index >= 0) {
-                patchDesc = mAudioPatches.valueAt(index);
-                afPatchHandle = patchDesc->mAfPatchHandle;
-            }
-
-            status_t status = mpClientInterface->createAudioPatch(&patch,
-                                                                  &afPatchHandle,
-                                                                  0);
-            ALOGV("setInputDevice() createAudioPatch returned %d patchHandle %d",
-                                                                          status, afPatchHandle);
-            if (status == NO_ERROR) {
-                if (index < 0) {
-                    patchDesc = new AudioPatch(&patch, mUidCached);
-                    addAudioPatch(patchDesc->mHandle, patchDesc);
-                } else {
-                    patchDesc->mPatch = patch;
-                }
-                patchDesc->mAfPatchHandle = afPatchHandle;
-                if (patchHandle) {
-                    *patchHandle = patchDesc->mHandle;
-                }
-                inputDesc->setPatchHandle(patchDesc->mHandle);
-                nextAudioPortGeneration();
-                mpClientInterface->onAudioPatchListUpdate();
-            }
+                    addSource(deviceList.itemAt(0));
+            status = installPatch(__func__, patchHandle, inputDesc.get(), patchBuilder.patch(), 0);
         }
     }
     return status;
@@ -5743,4 +5645,58 @@
     }
 }
 
+status_t AudioPolicyManager::installPatch(const char *caller,
+                                          audio_patch_handle_t *patchHandle,
+                                          AudioIODescriptorInterface *ioDescriptor,
+                                          const struct audio_patch *patch,
+                                          int delayMs)
+{
+    ssize_t index = mAudioPatches.indexOfKey(
+            patchHandle && *patchHandle != AUDIO_PATCH_HANDLE_NONE ?
+            *patchHandle : ioDescriptor->getPatchHandle());
+    sp<AudioPatch> patchDesc;
+    status_t status = installPatch(
+            caller, index, patchHandle, patch, delayMs, mUidCached, &patchDesc);
+    if (status == NO_ERROR) {
+        ioDescriptor->setPatchHandle(patchDesc->mHandle);
+    }
+    return status;
+}
+
+status_t AudioPolicyManager::installPatch(const char *caller,
+                                          ssize_t index,
+                                          audio_patch_handle_t *patchHandle,
+                                          const struct audio_patch *patch,
+                                          int delayMs,
+                                          uid_t uid,
+                                          sp<AudioPatch> *patchDescPtr)
+{
+    sp<AudioPatch> patchDesc;
+    audio_patch_handle_t afPatchHandle = AUDIO_PATCH_HANDLE_NONE;
+    if (index >= 0) {
+        patchDesc = mAudioPatches.valueAt(index);
+        afPatchHandle = patchDesc->mAfPatchHandle;
+    }
+
+    status_t status = mpClientInterface->createAudioPatch(patch, &afPatchHandle, delayMs);
+    ALOGV("%s() AF::createAudioPatch returned %d patchHandle %d num_sources %d num_sinks %d",
+            caller, status, afPatchHandle, patch->num_sources, patch->num_sinks);
+    if (status == NO_ERROR) {
+        if (index < 0) {
+            patchDesc = new AudioPatch(patch, uid);
+            addAudioPatch(patchDesc->mHandle, patchDesc);
+        } else {
+            patchDesc->mPatch = *patch;
+        }
+        patchDesc->mAfPatchHandle = afPatchHandle;
+        if (patchHandle) {
+            *patchHandle = patchDesc->mHandle;
+        }
+        nextAudioPortGeneration();
+        mpClientInterface->onAudioPatchListUpdate();
+    }
+    if (patchDescPtr) *patchDescPtr = patchDesc;
+    return status;
+}
+
 } // namespace android
diff --git a/services/audiopolicy/managerdefault/AudioPolicyManager.h b/services/audiopolicy/managerdefault/AudioPolicyManager.h
index 2b68882..21e258e 100644
--- a/services/audiopolicy/managerdefault/AudioPolicyManager.h
+++ b/services/audiopolicy/managerdefault/AudioPolicyManager.h
@@ -491,8 +491,8 @@
 
         uint32_t updateCallRouting(audio_devices_t rxDevice, uint32_t delayMs = 0);
         sp<AudioPatch> createTelephonyPatch(bool isRx, audio_devices_t device, uint32_t delayMs);
-        sp<DeviceDescriptor> fillAudioPortConfigForDevice(
-                const DeviceVector& devices, audio_devices_t device, audio_port_config *config);
+        sp<DeviceDescriptor> findDevice(
+                const DeviceVector& devices, audio_devices_t device);
 
         // if argument "device" is different from AUDIO_DEVICE_NONE,  startSource() will force
         // the re-evaluation of the output device.
@@ -664,6 +664,18 @@
             param.addInt(String8(AudioParameter::keyMonoOutput), (int)mMasterMono);
             mpClientInterface->setParameters(output, param.toString());
         }
+        status_t installPatch(const char *caller,
+                audio_patch_handle_t *patchHandle,
+                AudioIODescriptorInterface *ioDescriptor,
+                const struct audio_patch *patch,
+                int delayMs);
+        status_t installPatch(const char *caller,
+                ssize_t index,
+                audio_patch_handle_t *patchHandle,
+                const struct audio_patch *patch,
+                int delayMs,
+                uid_t uid,
+                sp<AudioPatch> *patchDescPtr);
 
         bool soundTriggerSupportsConcurrentCapture();
         bool mSoundTriggerSupportsConcurrentCapture;
diff --git a/services/audiopolicy/tests/audiopolicymanager_tests.cpp b/services/audiopolicy/tests/audiopolicymanager_tests.cpp
index a9593b8..2d9260e 100644
--- a/services/audiopolicy/tests/audiopolicymanager_tests.cpp
+++ b/services/audiopolicy/tests/audiopolicymanager_tests.cpp
@@ -19,6 +19,8 @@
 
 #include <gtest/gtest.h>
 
+#include <media/PatchBuilder.h>
+
 #include "AudioPolicyTestClient.h"
 #include "AudioPolicyTestManager.h"
 
@@ -166,29 +168,14 @@
 }
 
 TEST_F(AudioPolicyManagerTest, CreateAudioPatchFromMix) {
-    audio_patch patch{};
     audio_patch_handle_t handle = AUDIO_PATCH_HANDLE_NONE;
     uid_t uid = 42;
     const size_t patchCountBefore = mClient->getActivePatchesCount();
-    patch.num_sources = 1;
-    {
-        auto& src = patch.sources[0];
-        src.role = AUDIO_PORT_ROLE_SOURCE;
-        src.type = AUDIO_PORT_TYPE_MIX;
-        src.id = mManager->getConfig().getAvailableInputDevices()[0]->getId();
-        // Note: these are the parameters of the output device.
-        src.sample_rate = 44100;
-        src.format = AUDIO_FORMAT_PCM_16_BIT;
-        src.channel_mask = AUDIO_CHANNEL_OUT_STEREO;
-    }
-    patch.num_sinks = 1;
-    {
-        auto& sink = patch.sinks[0];
-        sink.role = AUDIO_PORT_ROLE_SINK;
-        sink.type = AUDIO_PORT_TYPE_DEVICE;
-        sink.id = mManager->getConfig().getDefaultOutputDevice()->getId();
-    }
-    ASSERT_EQ(NO_ERROR, mManager->createAudioPatch(&patch, &handle, uid));
+    ASSERT_FALSE(mManager->getConfig().getAvailableInputDevices().isEmpty());
+    PatchBuilder patchBuilder;
+    patchBuilder.addSource(mManager->getConfig().getAvailableInputDevices()[0]).
+            addSink(mManager->getConfig().getDefaultOutputDevice());
+    ASSERT_EQ(NO_ERROR, mManager->createAudioPatch(patchBuilder.patch(), &handle, uid));
     ASSERT_NE(AUDIO_PATCH_HANDLE_NONE, handle);
     ASSERT_EQ(patchCountBefore + 1, mClient->getActivePatchesCount());
 }