Convert the OpenSL backend to C++

1 files changed, 1074 insertions, 0 deletions

diff --git a/Alc/backends/opensl.cpp b/Alc/backends/opensl.cpp
new file mode 100644
index 00000000..a8bb57eb
--- /dev/null
+++ b/Alc/backends/opensl.cpp
@@ -0,0 +1,1074 @@
+/*
+ * Copyright (C) 2011 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.
+ */
+
+/* This is an OpenAL backend for Android using the native audio APIs based on
+ * OpenSL ES 1.0.1. It is based on source code for the native-audio sample app
+ * bundled with NDK.
+ */
+
+#include "config.h"
+
+#include <stdlib.h>
+#include <jni.h>
+
+#include "alMain.h"
+#include "alu.h"
+#include "ringbuffer.h"
+#include "threads.h"
+#include "compat.h"
+
+#include "backends/base.h"
+
+#include <SLES/OpenSLES.h>
+#include <SLES/OpenSLES_Android.h>
+#include <SLES/OpenSLES_AndroidConfiguration.h>
+
+/* Helper macros */
+#define VCALL(obj, func)  ((*(obj))->func((obj), EXTRACT_VCALL_ARGS
+#define VCALL0(obj, func)  ((*(obj))->func((obj) EXTRACT_VCALL_ARGS
+
+
+static const ALCchar opensl_device[] = "OpenSL";
+
+
+static SLuint32 GetChannelMask(enum DevFmtChannels chans)
+{
+    switch(chans)
+    {
+        case DevFmtMono: return SL_SPEAKER_FRONT_CENTER;
+        case DevFmtStereo: return SL_SPEAKER_FRONT_LEFT|SL_SPEAKER_FRONT_RIGHT;
+        case DevFmtQuad: return SL_SPEAKER_FRONT_LEFT|SL_SPEAKER_FRONT_RIGHT|
+                                SL_SPEAKER_BACK_LEFT|SL_SPEAKER_BACK_RIGHT;
+        case DevFmtX51: return SL_SPEAKER_FRONT_LEFT|SL_SPEAKER_FRONT_RIGHT|
+                               SL_SPEAKER_FRONT_CENTER|SL_SPEAKER_LOW_FREQUENCY|
+                               SL_SPEAKER_SIDE_LEFT|SL_SPEAKER_SIDE_RIGHT;
+        case DevFmtX51Rear: return SL_SPEAKER_FRONT_LEFT|SL_SPEAKER_FRONT_RIGHT|
+                                   SL_SPEAKER_FRONT_CENTER|SL_SPEAKER_LOW_FREQUENCY|
+                                   SL_SPEAKER_BACK_LEFT|SL_SPEAKER_BACK_RIGHT;
+        case DevFmtX61: return SL_SPEAKER_FRONT_LEFT|SL_SPEAKER_FRONT_RIGHT|
+                               SL_SPEAKER_FRONT_CENTER|SL_SPEAKER_LOW_FREQUENCY|
+                               SL_SPEAKER_BACK_CENTER|
+                               SL_SPEAKER_SIDE_LEFT|SL_SPEAKER_SIDE_RIGHT;
+        case DevFmtX71: return SL_SPEAKER_FRONT_LEFT|SL_SPEAKER_FRONT_RIGHT|
+                               SL_SPEAKER_FRONT_CENTER|SL_SPEAKER_LOW_FREQUENCY|
+                               SL_SPEAKER_BACK_LEFT|SL_SPEAKER_BACK_RIGHT|
+                               SL_SPEAKER_SIDE_LEFT|SL_SPEAKER_SIDE_RIGHT;
+        case DevFmtAmbi3D:
+            break;
+    }
+    return 0;
+}
+
+#ifdef SL_DATAFORMAT_PCM_EX
+static SLuint32 GetTypeRepresentation(enum DevFmtType type)
+{
+    switch(type)
+    {
+        case DevFmtUByte:
+        case DevFmtUShort:
+        case DevFmtUInt:
+            return SL_PCM_REPRESENTATION_UNSIGNED_INT;
+        case DevFmtByte:
+        case DevFmtShort:
+        case DevFmtInt:
+            return SL_PCM_REPRESENTATION_SIGNED_INT;
+        case DevFmtFloat:
+            return SL_PCM_REPRESENTATION_FLOAT;
+    }
+    return 0;
+}
+#endif
+
+static const char *res_str(SLresult result)
+{
+    switch(result)
+    {
+        case SL_RESULT_SUCCESS: return "Success";
+        case SL_RESULT_PRECONDITIONS_VIOLATED: return "Preconditions violated";
+        case SL_RESULT_PARAMETER_INVALID: return "Parameter invalid";
+        case SL_RESULT_MEMORY_FAILURE: return "Memory failure";
+        case SL_RESULT_RESOURCE_ERROR: return "Resource error";
+        case SL_RESULT_RESOURCE_LOST: return "Resource lost";
+        case SL_RESULT_IO_ERROR: return "I/O error";
+        case SL_RESULT_BUFFER_INSUFFICIENT: return "Buffer insufficient";
+        case SL_RESULT_CONTENT_CORRUPTED: return "Content corrupted";
+        case SL_RESULT_CONTENT_UNSUPPORTED: return "Content unsupported";
+        case SL_RESULT_CONTENT_NOT_FOUND: return "Content not found";
+        case SL_RESULT_PERMISSION_DENIED: return "Permission denied";
+        case SL_RESULT_FEATURE_UNSUPPORTED: return "Feature unsupported";
+        case SL_RESULT_INTERNAL_ERROR: return "Internal error";
+        case SL_RESULT_UNKNOWN_ERROR: return "Unknown error";
+        case SL_RESULT_OPERATION_ABORTED: return "Operation aborted";
+        case SL_RESULT_CONTROL_LOST: return "Control lost";
+#ifdef SL_RESULT_READONLY
+        case SL_RESULT_READONLY: return "ReadOnly";
+#endif
+#ifdef SL_RESULT_ENGINEOPTION_UNSUPPORTED
+        case SL_RESULT_ENGINEOPTION_UNSUPPORTED: return "Engine option unsupported";
+#endif
+#ifdef SL_RESULT_SOURCE_SINK_INCOMPATIBLE
+        case SL_RESULT_SOURCE_SINK_INCOMPATIBLE: return "Source/Sink incompatible";
+#endif
+    }
+    return "Unknown error code";
+}
+
+#define PRINTERR(x, s) do {                                                      \
+    if((x) != SL_RESULT_SUCCESS)                                                 \
+        ERR("%s: %s\n", (s), res_str((x)));                                      \
+} while(0)
+
+
+struct ALCopenslPlayback final : public ALCbackend {
+    /* engine interfaces */
+    SLObjectItf mEngineObj;
+    SLEngineItf mEngine;
+
+    /* output mix interfaces */
+    SLObjectItf mOutputMix;
+
+    /* buffer queue player interfaces */
+    SLObjectItf mBufferQueueObj;
+
+    ll_ringbuffer_t *mRing;
+    alsem_t mSem;
+
+    ALsizei mFrameSize;
+
+    ATOMIC(ALenum) mKillNow;
+    althrd_t mThread;
+};
+
+static void ALCopenslPlayback_process(SLAndroidSimpleBufferQueueItf bq, void *context);
+static int ALCopenslPlayback_mixerProc(void *arg);
+
+static void ALCopenslPlayback_Construct(ALCopenslPlayback *self, ALCdevice *device);
+static void ALCopenslPlayback_Destruct(ALCopenslPlayback *self);
+static ALCenum ALCopenslPlayback_open(ALCopenslPlayback *self, const ALCchar *name);
+static ALCboolean ALCopenslPlayback_reset(ALCopenslPlayback *self);
+static ALCboolean ALCopenslPlayback_start(ALCopenslPlayback *self);
+static void ALCopenslPlayback_stop(ALCopenslPlayback *self);
+static DECLARE_FORWARD2(ALCopenslPlayback, ALCbackend, ALCenum, captureSamples, void*, ALCuint)
+static DECLARE_FORWARD(ALCopenslPlayback, ALCbackend, ALCuint, availableSamples)
+static ClockLatency ALCopenslPlayback_getClockLatency(ALCopenslPlayback *self);
+static DECLARE_FORWARD(ALCopenslPlayback, ALCbackend, void, lock)
+static DECLARE_FORWARD(ALCopenslPlayback, ALCbackend, void, unlock)
+DECLARE_DEFAULT_ALLOCATORS(ALCopenslPlayback)
+
+DEFINE_ALCBACKEND_VTABLE(ALCopenslPlayback);
+
+
+static void ALCopenslPlayback_Construct(ALCopenslPlayback *self, ALCdevice *device)
+{
+    new (self) ALCopenslPlayback{};
+    ALCbackend_Construct(STATIC_CAST(ALCbackend, self), device);
+    SET_VTABLE2(ALCopenslPlayback, ALCbackend, self);
+
+    self->mEngineObj = NULL;
+    self->mEngine = NULL;
+    self->mOutputMix = NULL;
+    self->mBufferQueueObj = NULL;
+
+    self->mRing = NULL;
+    alsem_init(&self->mSem, 0);
+
+    self->mFrameSize = 0;
+
+    ATOMIC_INIT(&self->mKillNow, AL_FALSE);
+}
+
+static void ALCopenslPlayback_Destruct(ALCopenslPlayback* self)
+{
+    if(self->mBufferQueueObj != NULL)
+        VCALL0(self->mBufferQueueObj,Destroy)();
+    self->mBufferQueueObj = NULL;
+
+    if(self->mOutputMix)
+        VCALL0(self->mOutputMix,Destroy)();
+    self->mOutputMix = NULL;
+
+    if(self->mEngineObj)
+        VCALL0(self->mEngineObj,Destroy)();
+    self->mEngineObj = NULL;
+    self->mEngine = NULL;
+
+    ll_ringbuffer_free(self->mRing);
+    self->mRing = NULL;
+
+    alsem_destroy(&self->mSem);
+
+    ALCbackend_Destruct(STATIC_CAST(ALCbackend, self));
+    self->~ALCopenslPlayback();
+}
+
+
+/* this callback handler is called every time a buffer finishes playing */
+static void ALCopenslPlayback_process(SLAndroidSimpleBufferQueueItf UNUSED(bq), void *context)
+{
+    ALCopenslPlayback *self = static_cast<ALCopenslPlayback*>(context);
+
+    /* A note on the ringbuffer usage: The buffer queue seems to hold on to the
+     * pointer passed to the Enqueue method, rather than copying the audio.
+     * Consequently, the ringbuffer contains the audio that is currently queued
+     * and waiting to play. This process() callback is called when a buffer is
+     * finished, so we simply move the read pointer up to indicate the space is
+     * available for writing again, and wake up the mixer thread to mix and
+     * queue more audio.
+     */
+    ll_ringbuffer_read_advance(self->mRing, 1);
+
+    alsem_post(&self->mSem);
+}
+
+
+static int ALCopenslPlayback_mixerProc(void *arg)
+{
+    ALCopenslPlayback *self = static_cast<ALCopenslPlayback*>(arg);
+    ALCdevice *device = STATIC_CAST(ALCbackend,self)->mDevice;
+    SLAndroidSimpleBufferQueueItf bufferQueue;
+    ll_ringbuffer_data_t data[2];
+    SLPlayItf player;
+    SLresult result;
+
+    SetRTPriority();
+    althrd_setname(althrd_current(), MIXER_THREAD_NAME);
+
+    result = VCALL(self->mBufferQueueObj,GetInterface)(SL_IID_ANDROIDSIMPLEBUFFERQUEUE,
+                                                       &bufferQueue);
+    PRINTERR(result, "bufferQueue->GetInterface SL_IID_ANDROIDSIMPLEBUFFERQUEUE");
+    if(SL_RESULT_SUCCESS == result)
+    {
+        result = VCALL(self->mBufferQueueObj,GetInterface)(SL_IID_PLAY, &player);
+        PRINTERR(result, "bufferQueue->GetInterface SL_IID_PLAY");
+    }
+
+    ALCopenslPlayback_lock(self);
+    if(SL_RESULT_SUCCESS != result)
+        aluHandleDisconnect(device, "Failed to get playback buffer: 0x%08x", result);
+
+    while(SL_RESULT_SUCCESS == result &&
+          !ATOMIC_LOAD(&self->mKillNow, almemory_order_acquire) &&
+          ATOMIC_LOAD(&device->Connected, almemory_order_acquire))
+    {
+        size_t todo;
+
+        if(ll_ringbuffer_write_space(self->mRing) == 0)
+        {
+            SLuint32 state = 0;
+
+            result = VCALL(player,GetPlayState)(&state);
+            PRINTERR(result, "player->GetPlayState");
+            if(SL_RESULT_SUCCESS == result && state != SL_PLAYSTATE_PLAYING)
+            {
+                result = VCALL(player,SetPlayState)(SL_PLAYSTATE_PLAYING);
+                PRINTERR(result, "player->SetPlayState");
+            }
+            if(SL_RESULT_SUCCESS != result)
+            {
+                aluHandleDisconnect(device, "Failed to start platback: 0x%08x", result);
+                break;
+            }
+
+            if(ll_ringbuffer_write_space(self->mRing) == 0)
+            {
+                ALCopenslPlayback_unlock(self);
+                alsem_wait(&self->mSem);
+                ALCopenslPlayback_lock(self);
+                continue;
+            }
+        }
+
+        ll_ringbuffer_get_write_vector(self->mRing, data);
+
+        aluMixData(device, data[0].buf, data[0].len*device->UpdateSize);
+        if(data[1].len > 0)
+            aluMixData(device, data[1].buf, data[1].len*device->UpdateSize);
+
+        todo = data[0].len+data[1].len;
+        ll_ringbuffer_write_advance(self->mRing, todo);
+
+        for(size_t i = 0;i < todo;i++)
+        {
+            if(!data[0].len)
+            {
+                data[0] = data[1];
+                data[1].buf = NULL;
+                data[1].len = 0;
+            }
+
+            result = VCALL(bufferQueue,Enqueue)(data[0].buf, device->UpdateSize*self->mFrameSize);
+            PRINTERR(result, "bufferQueue->Enqueue");
+            if(SL_RESULT_SUCCESS != result)
+            {
+                aluHandleDisconnect(device, "Failed to queue audio: 0x%08x", result);
+                break;
+            }
+
+            data[0].len--;
+            data[0].buf += device->UpdateSize*self->mFrameSize;
+        }
+    }
+    ALCopenslPlayback_unlock(self);
+
+    return 0;
+}
+
+
+static ALCenum ALCopenslPlayback_open(ALCopenslPlayback *self, const ALCchar *name)
+{
+    ALCdevice *device = STATIC_CAST(ALCbackend,self)->mDevice;
+    SLresult result;
+
+    if(!name)
+        name = opensl_device;
+    else if(strcmp(name, opensl_device) != 0)
+        return ALC_INVALID_VALUE;
+
+    // create engine
+    result = slCreateEngine(&self->mEngineObj, 0, NULL, 0, NULL, NULL);
+    PRINTERR(result, "slCreateEngine");
+    if(SL_RESULT_SUCCESS == result)
+    {
+        result = VCALL(self->mEngineObj,Realize)(SL_BOOLEAN_FALSE);
+        PRINTERR(result, "engine->Realize");
+    }
+    if(SL_RESULT_SUCCESS == result)
+    {
+        result = VCALL(self->mEngineObj,GetInterface)(SL_IID_ENGINE, &self->mEngine);
+        PRINTERR(result, "engine->GetInterface");
+    }
+    if(SL_RESULT_SUCCESS == result)
+    {
+        result = VCALL(self->mEngine,CreateOutputMix)(&self->mOutputMix, 0, NULL, NULL);
+        PRINTERR(result, "engine->CreateOutputMix");
+    }
+    if(SL_RESULT_SUCCESS == result)
+    {
+        result = VCALL(self->mOutputMix,Realize)(SL_BOOLEAN_FALSE);
+        PRINTERR(result, "outputMix->Realize");
+    }
+
+    if(SL_RESULT_SUCCESS != result)
+    {
+        if(self->mOutputMix != NULL)
+            VCALL0(self->mOutputMix,Destroy)();
+        self->mOutputMix = NULL;
+
+        if(self->mEngineObj != NULL)
+            VCALL0(self->mEngineObj,Destroy)();
+        self->mEngineObj = NULL;
+        self->mEngine = NULL;
+
+        return ALC_INVALID_VALUE;
+    }
+
+    alstr_copy_cstr(&device->DeviceName, name);
+
+    return ALC_NO_ERROR;
+}
+
+static ALCboolean ALCopenslPlayback_reset(ALCopenslPlayback *self)
+{
+    ALCdevice *device = STATIC_CAST(ALCbackend,self)->mDevice;
+    SLDataLocator_AndroidSimpleBufferQueue loc_bufq;
+    SLDataLocator_OutputMix loc_outmix;
+    SLDataSource audioSrc;
+    SLDataSink audioSnk;
+    ALuint sampleRate;
+    SLInterfaceID ids[2];
+    SLboolean reqs[2];
+    SLresult result;
+
+    if(self->mBufferQueueObj != NULL)
+        VCALL0(self->mBufferQueueObj,Destroy)();
+    self->mBufferQueueObj = NULL;
+
+    ll_ringbuffer_free(self->mRing);
+    self->mRing = NULL;
+
+    sampleRate = device->Frequency;
+#if 0
+    if(!(device->Flags&DEVICE_FREQUENCY_REQUEST))
+    {
+        /* FIXME: Disabled until I figure out how to get the Context needed for
+         * the getSystemService call.
+         */
+        JNIEnv *env = Android_GetJNIEnv();
+        jobject jctx = Android_GetContext();
+
+        /* Get necessary stuff for using java.lang.Integer,
+         * android.content.Context, and android.media.AudioManager.
+         */
+        jclass int_cls = JCALL(env,FindClass)("java/lang/Integer");
+        jmethodID int_parseint = JCALL(env,GetStaticMethodID)(int_cls,
+            "parseInt", "(Ljava/lang/String;)I"
+        );
+        TRACE("Integer: %p, parseInt: %p\n", int_cls, int_parseint);
+
+        jclass ctx_cls = JCALL(env,FindClass)("android/content/Context");
+        jfieldID ctx_audsvc = JCALL(env,GetStaticFieldID)(ctx_cls,
+            "AUDIO_SERVICE", "Ljava/lang/String;"
+        );
+        jmethodID ctx_getSysSvc = JCALL(env,GetMethodID)(ctx_cls,
+            "getSystemService", "(Ljava/lang/String;)Ljava/lang/Object;"
+        );
+        TRACE("Context: %p, AUDIO_SERVICE: %p, getSystemService: %p\n",
+              ctx_cls, ctx_audsvc, ctx_getSysSvc);
+
+        jclass audmgr_cls = JCALL(env,FindClass)("android/media/AudioManager");
+        jfieldID audmgr_prop_out_srate = JCALL(env,GetStaticFieldID)(audmgr_cls,
+            "PROPERTY_OUTPUT_SAMPLE_RATE", "Ljava/lang/String;"
+        );
+        jmethodID audmgr_getproperty = JCALL(env,GetMethodID)(audmgr_cls,
+            "getProperty", "(Ljava/lang/String;)Ljava/lang/String;"
+        );
+        TRACE("AudioManager: %p, PROPERTY_OUTPUT_SAMPLE_RATE: %p, getProperty: %p\n",
+              audmgr_cls, audmgr_prop_out_srate, audmgr_getproperty);
+
+        const char *strchars;
+        jstring strobj;
+
+        /* Now make the calls. */
+        //AudioManager audMgr = (AudioManager)getSystemService(Context.AUDIO_SERVICE);
+        strobj = JCALL(env,GetStaticObjectField)(ctx_cls, ctx_audsvc);
+        jobject audMgr = JCALL(env,CallObjectMethod)(jctx, ctx_getSysSvc, strobj);
+        strchars = JCALL(env,GetStringUTFChars)(strobj, NULL);
+        TRACE("Context.getSystemService(%s) = %p\n", strchars, audMgr);
+        JCALL(env,ReleaseStringUTFChars)(strobj, strchars);
+
+        //String srateStr = audMgr.getProperty(AudioManager.PROPERTY_OUTPUT_SAMPLE_RATE);
+        strobj = JCALL(env,GetStaticObjectField)(audmgr_cls, audmgr_prop_out_srate);
+        jstring srateStr = JCALL(env,CallObjectMethod)(audMgr, audmgr_getproperty, strobj);
+        strchars = JCALL(env,GetStringUTFChars)(strobj, NULL);
+        TRACE("audMgr.getProperty(%s) = %p\n", strchars, srateStr);
+        JCALL(env,ReleaseStringUTFChars)(strobj, strchars);
+
+        //int sampleRate = Integer.parseInt(srateStr);
+        sampleRate = JCALL(env,CallStaticIntMethod)(int_cls, int_parseint, srateStr);
+
+        strchars = JCALL(env,GetStringUTFChars)(srateStr, NULL);
+        TRACE("Got system sample rate %uhz (%s)\n", sampleRate, strchars);
+        JCALL(env,ReleaseStringUTFChars)(srateStr, strchars);
+
+        if(!sampleRate) sampleRate = device->Frequency;
+        else sampleRate = maxu(sampleRate, MIN_OUTPUT_RATE);
+    }
+#endif
+
+    if(sampleRate != device->Frequency)
+    {
+        device->NumUpdates = (device->NumUpdates*sampleRate + (device->Frequency>>1)) /
+                             device->Frequency;
+        device->NumUpdates = maxu(device->NumUpdates, 2);
+        device->Frequency = sampleRate;
+    }
+
+    device->FmtChans = DevFmtStereo;
+    device->FmtType = DevFmtShort;
+
+    SetDefaultWFXChannelOrder(device);
+    self->mFrameSize = FrameSizeFromDevFmt(device->FmtChans, device->FmtType, device->AmbiOrder);
+
+
+    loc_bufq.locatorType = SL_DATALOCATOR_ANDROIDSIMPLEBUFFERQUEUE;
+    loc_bufq.numBuffers = device->NumUpdates;
+
+#ifdef SL_DATAFORMAT_PCM_EX
+    SLDataFormat_PCM_EX format_pcm;
+    format_pcm.formatType = SL_DATAFORMAT_PCM_EX;
+    format_pcm.numChannels = ChannelsFromDevFmt(device->FmtChans, device->AmbiOrder);
+    format_pcm.sampleRate = device->Frequency * 1000;
+    format_pcm.bitsPerSample = BytesFromDevFmt(device->FmtType) * 8;
+    format_pcm.containerSize = format_pcm.bitsPerSample;
+    format_pcm.channelMask = GetChannelMask(device->FmtChans);
+    format_pcm.endianness = IS_LITTLE_ENDIAN ? SL_BYTEORDER_LITTLEENDIAN :
+                                               SL_BYTEORDER_BIGENDIAN;
+    format_pcm.representation = GetTypeRepresentation(device->FmtType);
+#else
+    SLDataFormat_PCM format_pcm;
+    format_pcm.formatType = SL_DATAFORMAT_PCM;
+    format_pcm.numChannels = ChannelsFromDevFmt(device->FmtChans, device->AmbiOrder);
+    format_pcm.samplesPerSec = device->Frequency * 1000;
+    format_pcm.bitsPerSample = BytesFromDevFmt(device->FmtType) * 8;
+    format_pcm.containerSize = format_pcm.bitsPerSample;
+    format_pcm.channelMask = GetChannelMask(device->FmtChans);
+    format_pcm.endianness = IS_LITTLE_ENDIAN ? SL_BYTEORDER_LITTLEENDIAN :
+                                               SL_BYTEORDER_BIGENDIAN;
+#endif
+
+    audioSrc.pLocator = &loc_bufq;
+    audioSrc.pFormat = &format_pcm;
+
+    loc_outmix.locatorType = SL_DATALOCATOR_OUTPUTMIX;
+    loc_outmix.outputMix = self->mOutputMix;
+    audioSnk.pLocator = &loc_outmix;
+    audioSnk.pFormat = NULL;
+
+
+    ids[0]  = SL_IID_ANDROIDSIMPLEBUFFERQUEUE;
+    reqs[0] = SL_BOOLEAN_TRUE;
+    ids[1]  = SL_IID_ANDROIDCONFIGURATION;
+    reqs[1] = SL_BOOLEAN_FALSE;
+
+    result = VCALL(self->mEngine,CreateAudioPlayer)(&self->mBufferQueueObj,
+        &audioSrc, &audioSnk, COUNTOF(ids), ids, reqs
+    );
+    PRINTERR(result, "engine->CreateAudioPlayer");
+    if(SL_RESULT_SUCCESS == result)
+    {
+        /* Set the stream type to "media" (games, music, etc), if possible. */
+        SLAndroidConfigurationItf config;
+        result = VCALL(self->mBufferQueueObj,GetInterface)(SL_IID_ANDROIDCONFIGURATION, &config);
+        PRINTERR(result, "bufferQueue->GetInterface SL_IID_ANDROIDCONFIGURATION");
+        if(SL_RESULT_SUCCESS == result)
+        {
+            SLint32 streamType = SL_ANDROID_STREAM_MEDIA;
+            result = VCALL(config,SetConfiguration)(SL_ANDROID_KEY_STREAM_TYPE,
+                &streamType, sizeof(streamType)
+            );
+            PRINTERR(result, "config->SetConfiguration");
+        }
+
+        /* Clear any error since this was optional. */
+        result = SL_RESULT_SUCCESS;
+    }
+    if(SL_RESULT_SUCCESS == result)
+    {
+        result = VCALL(self->mBufferQueueObj,Realize)(SL_BOOLEAN_FALSE);
+        PRINTERR(result, "bufferQueue->Realize");
+    }
+    if(SL_RESULT_SUCCESS == result)
+    {
+        self->mRing = ll_ringbuffer_create(device->NumUpdates,
+            self->mFrameSize*device->UpdateSize, true
+        );
+        if(!self->mRing)
+        {
+            ERR("Out of memory allocating ring buffer %ux%u %u\n", device->UpdateSize,
+                device->NumUpdates, self->mFrameSize);
+            result = SL_RESULT_MEMORY_FAILURE;
+        }
+    }
+
+    if(SL_RESULT_SUCCESS != result)
+    {
+        if(self->mBufferQueueObj != NULL)
+            VCALL0(self->mBufferQueueObj,Destroy)();
+        self->mBufferQueueObj = NULL;
+
+        return ALC_FALSE;
+    }
+
+    return ALC_TRUE;
+}
+
+static ALCboolean ALCopenslPlayback_start(ALCopenslPlayback *self)
+{
+    SLAndroidSimpleBufferQueueItf bufferQueue;
+    SLresult result;
+
+    ll_ringbuffer_reset(self->mRing);
+
+    result = VCALL(self->mBufferQueueObj,GetInterface)(SL_IID_ANDROIDSIMPLEBUFFERQUEUE,
+                                                       &bufferQueue);
+    PRINTERR(result, "bufferQueue->GetInterface");
+    if(SL_RESULT_SUCCESS != result)
+        return ALC_FALSE;
+
+    result = VCALL(bufferQueue,RegisterCallback)(ALCopenslPlayback_process, self);
+    PRINTERR(result, "bufferQueue->RegisterCallback");
+    if(SL_RESULT_SUCCESS != result)
+        return ALC_FALSE;
+
+    ATOMIC_STORE_SEQ(&self->mKillNow, AL_FALSE);
+    if(althrd_create(&self->mThread, ALCopenslPlayback_mixerProc, self) != althrd_success)
+    {
+        ERR("Failed to start mixer thread\n");
+        return ALC_FALSE;
+    }
+
+    return ALC_TRUE;
+}
+
+
+static void ALCopenslPlayback_stop(ALCopenslPlayback *self)
+{
+    SLAndroidSimpleBufferQueueItf bufferQueue;
+    SLPlayItf player;
+    SLresult result;
+    int res;
+
+    if(ATOMIC_EXCHANGE_SEQ(&self->mKillNow, AL_TRUE))
+        return;
+
+    alsem_post(&self->mSem);
+    althrd_join(self->mThread, &res);
+
+    result = VCALL(self->mBufferQueueObj,GetInterface)(SL_IID_PLAY, &player);
+    PRINTERR(result, "bufferQueue->GetInterface");
+    if(SL_RESULT_SUCCESS == result)
+    {
+        result = VCALL(player,SetPlayState)(SL_PLAYSTATE_STOPPED);
+        PRINTERR(result, "player->SetPlayState");
+    }
+
+    result = VCALL(self->mBufferQueueObj,GetInterface)(SL_IID_ANDROIDSIMPLEBUFFERQUEUE,
+                                                       &bufferQueue);
+    PRINTERR(result, "bufferQueue->GetInterface");
+    if(SL_RESULT_SUCCESS == result)
+    {
+        result = VCALL0(bufferQueue,Clear)();
+        PRINTERR(result, "bufferQueue->Clear");
+    }
+    if(SL_RESULT_SUCCESS == result)
+    {
+        result = VCALL(bufferQueue,RegisterCallback)(NULL, NULL);
+        PRINTERR(result, "bufferQueue->RegisterCallback");
+    }
+    if(SL_RESULT_SUCCESS == result)
+    {
+        SLAndroidSimpleBufferQueueState state;
+        do {
+            althrd_yield();
+            result = VCALL(bufferQueue,GetState)(&state);
+        } while(SL_RESULT_SUCCESS == result && state.count > 0);
+        PRINTERR(result, "bufferQueue->GetState");
+    }
+}
+
+static ClockLatency ALCopenslPlayback_getClockLatency(ALCopenslPlayback *self)
+{
+    ALCdevice *device = STATIC_CAST(ALCbackend, self)->mDevice;
+    ClockLatency ret;
+
+    ALCopenslPlayback_lock(self);
+    ret.ClockTime = GetDeviceClockTime(device);
+    ret.Latency = ll_ringbuffer_read_space(self->mRing)*device->UpdateSize *
+                  DEVICE_CLOCK_RES / device->Frequency;
+    ALCopenslPlayback_unlock(self);
+
+    return ret;
+}
+
+
+struct ALCopenslCapture final : public ALCbackend {
+    /* engine interfaces */
+    SLObjectItf mEngineObj;
+    SLEngineItf mEngine;
+
+    /* recording interfaces */
+    SLObjectItf mRecordObj;
+
+    ll_ringbuffer_t *mRing;
+    ALCuint mSplOffset;
+
+    ALsizei mFrameSize;
+};
+
+static void ALCopenslCapture_process(SLAndroidSimpleBufferQueueItf bq, void *context);
+
+static void ALCopenslCapture_Construct(ALCopenslCapture *self, ALCdevice *device);
+static void ALCopenslCapture_Destruct(ALCopenslCapture *self);
+static ALCenum ALCopenslCapture_open(ALCopenslCapture *self, const ALCchar *name);
+static DECLARE_FORWARD(ALCopenslCapture, ALCbackend, ALCboolean, reset)
+static ALCboolean ALCopenslCapture_start(ALCopenslCapture *self);
+static void ALCopenslCapture_stop(ALCopenslCapture *self);
+static ALCenum ALCopenslCapture_captureSamples(ALCopenslCapture *self, ALCvoid *buffer, ALCuint samples);
+static ALCuint ALCopenslCapture_availableSamples(ALCopenslCapture *self);
+static DECLARE_FORWARD(ALCopenslCapture, ALCbackend, ClockLatency, getClockLatency)
+static DECLARE_FORWARD(ALCopenslCapture, ALCbackend, void, lock)
+static DECLARE_FORWARD(ALCopenslCapture, ALCbackend, void, unlock)
+DECLARE_DEFAULT_ALLOCATORS(ALCopenslCapture)
+DEFINE_ALCBACKEND_VTABLE(ALCopenslCapture);
+
+
+static void ALCopenslCapture_Construct(ALCopenslCapture *self, ALCdevice *device)
+{
+    new (self) ALCopenslCapture{};
+    ALCbackend_Construct(STATIC_CAST(ALCbackend, self), device);
+    SET_VTABLE2(ALCopenslCapture, ALCbackend, self);
+
+    self->mEngineObj = NULL;
+    self->mEngine = NULL;
+
+    self->mRecordObj = NULL;
+
+    self->mRing = NULL;
+    self->mSplOffset = 0;
+
+    self->mFrameSize = 0;
+}
+
+static void ALCopenslCapture_Destruct(ALCopenslCapture *self)
+{
+    if(self->mRecordObj != NULL)
+        VCALL0(self->mRecordObj,Destroy)();
+    self->mRecordObj = NULL;
+
+    if(self->mEngineObj != NULL)
+        VCALL0(self->mEngineObj,Destroy)();
+    self->mEngineObj = NULL;
+    self->mEngine = NULL;
+
+    ll_ringbuffer_free(self->mRing);
+    self->mRing = NULL;
+
+    ALCbackend_Destruct(STATIC_CAST(ALCbackend, self));
+    self->~ALCopenslCapture();
+}
+
+
+static void ALCopenslCapture_process(SLAndroidSimpleBufferQueueItf UNUSED(bq), void *context)
+{
+    ALCopenslCapture *self = static_cast<ALCopenslCapture*>(context);
+    /* A new chunk has been written into the ring buffer, advance it. */
+    ll_ringbuffer_write_advance(self->mRing, 1);
+}
+
+
+static ALCenum ALCopenslCapture_open(ALCopenslCapture *self, const ALCchar *name)
+{
+    ALCdevice *device = STATIC_CAST(ALCbackend, self)->mDevice;
+    SLDataLocator_AndroidSimpleBufferQueue loc_bq;
+    SLAndroidSimpleBufferQueueItf bufferQueue;
+    SLDataLocator_IODevice loc_dev;
+    SLDataSource audioSrc;
+    SLDataSink audioSnk;
+    SLresult result;
+
+    if(!name)
+        name = opensl_device;
+    else if(strcmp(name, opensl_device) != 0)
+        return ALC_INVALID_VALUE;
+
+    result = slCreateEngine(&self->mEngineObj, 0, NULL, 0, NULL, NULL);
+    PRINTERR(result, "slCreateEngine");
+    if(SL_RESULT_SUCCESS == result)
+    {
+        result = VCALL(self->mEngineObj,Realize)(SL_BOOLEAN_FALSE);
+        PRINTERR(result, "engine->Realize");
+    }
+    if(SL_RESULT_SUCCESS == result)
+    {
+        result = VCALL(self->mEngineObj,GetInterface)(SL_IID_ENGINE, &self->mEngine);
+        PRINTERR(result, "engine->GetInterface");
+    }
+    if(SL_RESULT_SUCCESS == result)
+    {
+        /* Ensure the total length is at least 100ms */
+        ALsizei length = maxi(device->NumUpdates * device->UpdateSize,
+                              device->Frequency / 10);
+        /* Ensure the per-chunk length is at least 10ms, and no more than 50ms. */
+        ALsizei update_len = clampi(device->NumUpdates*device->UpdateSize / 3,
+                                    device->Frequency / 100,
+                                    device->Frequency / 100 * 5);
+
+        device->UpdateSize = update_len;
+        device->NumUpdates = (length+update_len-1) / update_len;
+
+        self->mFrameSize = FrameSizeFromDevFmt(device->FmtChans, device->FmtType, device->AmbiOrder);
+    }
+    loc_dev.locatorType = SL_DATALOCATOR_IODEVICE;
+    loc_dev.deviceType = SL_IODEVICE_AUDIOINPUT;
+    loc_dev.deviceID = SL_DEFAULTDEVICEID_AUDIOINPUT;
+    loc_dev.device = NULL;
+
+    audioSrc.pLocator = &loc_dev;
+    audioSrc.pFormat = NULL;
+
+    loc_bq.locatorType = SL_DATALOCATOR_ANDROIDSIMPLEBUFFERQUEUE;
+    loc_bq.numBuffers = device->NumUpdates;
+
+#ifdef SL_DATAFORMAT_PCM_EX
+    SLDataFormat_PCM_EX format_pcm;
+    format_pcm.formatType = SL_DATAFORMAT_PCM_EX;
+    format_pcm.numChannels = ChannelsFromDevFmt(device->FmtChans, device->AmbiOrder);
+    format_pcm.sampleRate = device->Frequency * 1000;
+    format_pcm.bitsPerSample = BytesFromDevFmt(device->FmtType) * 8;
+    format_pcm.containerSize = format_pcm.bitsPerSample;
+    format_pcm.channelMask = GetChannelMask(device->FmtChans);
+    format_pcm.endianness = IS_LITTLE_ENDIAN ? SL_BYTEORDER_LITTLEENDIAN :
+                                               SL_BYTEORDER_BIGENDIAN;
+    format_pcm.representation = GetTypeRepresentation(device->FmtType);
+#else
+    SLDataFormat_PCM format_pcm;
+    format_pcm.formatType = SL_DATAFORMAT_PCM;
+    format_pcm.numChannels = ChannelsFromDevFmt(device->FmtChans, device->AmbiOrder);
+    format_pcm.samplesPerSec = device->Frequency * 1000;
+    format_pcm.bitsPerSample = BytesFromDevFmt(device->FmtType) * 8;
+    format_pcm.containerSize = format_pcm.bitsPerSample;
+    format_pcm.channelMask = GetChannelMask(device->FmtChans);
+    format_pcm.endianness = IS_LITTLE_ENDIAN ? SL_BYTEORDER_LITTLEENDIAN :
+                                               SL_BYTEORDER_BIGENDIAN;
+#endif
+
+    audioSnk.pLocator = &loc_bq;
+    audioSnk.pFormat = &format_pcm;
+
+    if(SL_RESULT_SUCCESS == result)
+    {
+        const SLInterfaceID ids[2] = { SL_IID_ANDROIDSIMPLEBUFFERQUEUE, SL_IID_ANDROIDCONFIGURATION };
+        const SLboolean reqs[2] = { SL_BOOLEAN_TRUE, SL_BOOLEAN_FALSE };
+
+        result = VCALL(self->mEngine,CreateAudioRecorder)(&self->mRecordObj,
+            &audioSrc, &audioSnk, COUNTOF(ids), ids, reqs
+        );
+        PRINTERR(result, "engine->CreateAudioRecorder");
+    }
+    if(SL_RESULT_SUCCESS == result)
+    {
+        /* Set the record preset to "generic", if possible. */
+        SLAndroidConfigurationItf config;
+        result = VCALL(self->mRecordObj,GetInterface)(SL_IID_ANDROIDCONFIGURATION, &config);
+        PRINTERR(result, "recordObj->GetInterface SL_IID_ANDROIDCONFIGURATION");
+        if(SL_RESULT_SUCCESS == result)
+        {
+            SLuint32 preset = SL_ANDROID_RECORDING_PRESET_GENERIC;
+            result = VCALL(config,SetConfiguration)(SL_ANDROID_KEY_RECORDING_PRESET,
+                &preset, sizeof(preset)
+            );
+            PRINTERR(result, "config->SetConfiguration");
+        }
+
+        /* Clear any error since this was optional. */
+        result = SL_RESULT_SUCCESS;
+    }
+    if(SL_RESULT_SUCCESS == result)
+    {
+        result = VCALL(self->mRecordObj,Realize)(SL_BOOLEAN_FALSE);
+        PRINTERR(result, "recordObj->Realize");
+    }
+
+    if(SL_RESULT_SUCCESS == result)
+    {
+        self->mRing = ll_ringbuffer_create(device->NumUpdates,
+            device->UpdateSize*self->mFrameSize, false
+        );
+
+        result = VCALL(self->mRecordObj,GetInterface)(SL_IID_ANDROIDSIMPLEBUFFERQUEUE,
+                                                      &bufferQueue);
+        PRINTERR(result, "recordObj->GetInterface");
+    }
+    if(SL_RESULT_SUCCESS == result)
+    {
+        result = VCALL(bufferQueue,RegisterCallback)(ALCopenslCapture_process, self);
+        PRINTERR(result, "bufferQueue->RegisterCallback");
+    }
+    if(SL_RESULT_SUCCESS == result)
+    {
+        ALsizei chunk_size = device->UpdateSize * self->mFrameSize;
+        ll_ringbuffer_data_t data[2];
+        size_t i;
+
+        ll_ringbuffer_get_write_vector(self->mRing, data);
+        for(i = 0;i < data[0].len && SL_RESULT_SUCCESS == result;i++)
+        {
+            result = VCALL(bufferQueue,Enqueue)(data[0].buf + chunk_size*i, chunk_size);
+            PRINTERR(result, "bufferQueue->Enqueue");
+        }
+        for(i = 0;i < data[1].len && SL_RESULT_SUCCESS == result;i++)
+        {
+            result = VCALL(bufferQueue,Enqueue)(data[1].buf + chunk_size*i, chunk_size);
+            PRINTERR(result, "bufferQueue->Enqueue");
+        }
+    }
+
+    if(SL_RESULT_SUCCESS != result)
+    {
+        if(self->mRecordObj != NULL)
+            VCALL0(self->mRecordObj,Destroy)();
+        self->mRecordObj = NULL;
+
+        if(self->mEngineObj != NULL)
+            VCALL0(self->mEngineObj,Destroy)();
+        self->mEngineObj = NULL;
+        self->mEngine = NULL;
+
+        return ALC_INVALID_VALUE;
+    }
+
+    alstr_copy_cstr(&device->DeviceName, name);
+
+    return ALC_NO_ERROR;
+}
+
+static ALCboolean ALCopenslCapture_start(ALCopenslCapture *self)
+{
+    SLRecordItf record;
+    SLresult result;
+
+    result = VCALL(self->mRecordObj,GetInterface)(SL_IID_RECORD, &record);
+    PRINTERR(result, "recordObj->GetInterface");
+
+    if(SL_RESULT_SUCCESS == result)
+    {
+        result = VCALL(record,SetRecordState)(SL_RECORDSTATE_RECORDING);
+        PRINTERR(result, "record->SetRecordState");
+    }
+
+    if(SL_RESULT_SUCCESS != result)
+    {
+        ALCopenslCapture_lock(self);
+        aluHandleDisconnect(STATIC_CAST(ALCbackend, self)->mDevice,
+                            "Failed to start capture: 0x%08x", result);
+        ALCopenslCapture_unlock(self);
+        return ALC_FALSE;
+    }
+
+    return ALC_TRUE;
+}
+
+static void ALCopenslCapture_stop(ALCopenslCapture *self)
+{
+    SLRecordItf record;
+    SLresult result;
+
+    result = VCALL(self->mRecordObj,GetInterface)(SL_IID_RECORD, &record);
+    PRINTERR(result, "recordObj->GetInterface");
+
+    if(SL_RESULT_SUCCESS == result)
+    {
+        result = VCALL(record,SetRecordState)(SL_RECORDSTATE_PAUSED);
+        PRINTERR(result, "record->SetRecordState");
+    }
+}
+
+static ALCenum ALCopenslCapture_captureSamples(ALCopenslCapture *self, ALCvoid *buffer, ALCuint samples)
+{
+    ALCdevice *device = STATIC_CAST(ALCbackend, self)->mDevice;
+    ALsizei chunk_size = device->UpdateSize * self->mFrameSize;
+    SLAndroidSimpleBufferQueueItf bufferQueue;
+    ll_ringbuffer_data_t data[2];
+    SLresult result;
+    ALCuint i;
+
+    result = VCALL(self->mRecordObj,GetInterface)(SL_IID_ANDROIDSIMPLEBUFFERQUEUE,
+                                                  &bufferQueue);
+    PRINTERR(result, "recordObj->GetInterface");
+
+    /* Read the desired samples from the ring buffer then advance its read
+     * pointer.
+     */
+    ll_ringbuffer_get_read_vector(self->mRing, data);
+    for(i = 0;i < samples;)
+    {
+        ALCuint rem = minu(samples - i, device->UpdateSize - self->mSplOffset);
+        memcpy((ALCbyte*)buffer + i*self->mFrameSize,
+               data[0].buf + self->mSplOffset*self->mFrameSize,
+               rem * self->mFrameSize);
+
+        self->mSplOffset += rem;
+        if(self->mSplOffset == device->UpdateSize)
+        {
+            /* Finished a chunk, reset the offset and advance the read pointer. */
+            self->mSplOffset = 0;
+
+            ll_ringbuffer_read_advance(self->mRing, 1);
+            result = VCALL(bufferQueue,Enqueue)(data[0].buf, chunk_size);
+            PRINTERR(result, "bufferQueue->Enqueue");
+            if(SL_RESULT_SUCCESS != result) break;
+
+            data[0].len--;
+            if(!data[0].len)
+                data[0] = data[1];
+            else
+                data[0].buf += chunk_size;
+        }
+
+        i += rem;
+    }
+
+    if(SL_RESULT_SUCCESS != result)
+    {
+        ALCopenslCapture_lock(self);
+        aluHandleDisconnect(device, "Failed to update capture buffer: 0x%08x", result);
+        ALCopenslCapture_unlock(self);
+        return ALC_INVALID_DEVICE;
+    }
+
+    return ALC_NO_ERROR;
+}
+
+static ALCuint ALCopenslCapture_availableSamples(ALCopenslCapture *self)
+{
+    ALCdevice *device = STATIC_CAST(ALCbackend, self)->mDevice;
+    return ll_ringbuffer_read_space(self->mRing) * device->UpdateSize;
+}
+
+
+struct ALCopenslBackendFactory final : public ALCbackendFactory {
+    ALCopenslBackendFactory() noexcept;
+};
+
+static ALCboolean ALCopenslBackendFactory_init(ALCopenslBackendFactory* UNUSED(self))
+{
+    return ALC_TRUE;
+}
+
+static void ALCopenslBackendFactory_deinit(ALCopenslBackendFactory* UNUSED(self))
+{
+}
+
+static ALCboolean ALCopenslBackendFactory_querySupport(ALCopenslBackendFactory* UNUSED(self), ALCbackend_Type type)
+{
+    if(type == ALCbackend_Playback || type == ALCbackend_Capture)
+        return ALC_TRUE;
+    return ALC_FALSE;
+}
+
+static void ALCopenslBackendFactory_probe(ALCopenslBackendFactory* UNUSED(self), enum DevProbe type, al_string *outnames)
+{
+    switch(type)
+    {
+        case ALL_DEVICE_PROBE:
+        case CAPTURE_DEVICE_PROBE:
+            alstr_append_range(outnames, opensl_device, opensl_device+sizeof(opensl_device));
+            break;
+    }
+}
+
+static ALCbackend* ALCopenslBackendFactory_createBackend(ALCopenslBackendFactory* UNUSED(self), ALCdevice *device, ALCbackend_Type type)
+{
+    if(type == ALCbackend_Playback)
+    {
+        ALCopenslPlayback *backend;
+        NEW_OBJ(backend, ALCopenslPlayback)(device);
+        if(!backend) return NULL;
+        return STATIC_CAST(ALCbackend, backend);
+    }
+    if(type == ALCbackend_Capture)
+    {
+        ALCopenslCapture *backend;
+        NEW_OBJ(backend, ALCopenslCapture)(device);
+        if(!backend) return NULL;
+        return STATIC_CAST(ALCbackend, backend);
+    }
+
+    return NULL;
+}
+
+DEFINE_ALCBACKENDFACTORY_VTABLE(ALCopenslBackendFactory);
+
+
+ALCopenslBackendFactory::ALCopenslBackendFactory() noexcept
+  : ALCbackendFactory{GET_VTABLE2(ALCopenslBackendFactory, ALCbackendFactory)}
+{ }
+
+ALCbackendFactory *ALCopenslBackendFactory_getFactory(void)
+{
+    static ALCopenslBackendFactory factory{};
+    return STATIC_CAST(ALCbackendFactory, &factory);
+}