services/audioflinger/FastMixer.cpp - platform/frameworks/av - Git at Google

 /*
  * Copyright (C) 2012 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.
  */

 // <IMPORTANT_WARNING>
 // Design rules for threadLoop() are given in the comments at section "Fast mixer thread" of
 // StateQueue.h.  In particular, avoid library and system calls except at well-known points.
 // The design rules are only for threadLoop(), and don't apply to FastMixerDumpState methods.
 // </IMPORTANT_WARNING>

 #define LOG_TAG "FastMixer"
 //#define LOG_NDEBUG 0

 #define ATRACE_TAG ATRACE_TAG_AUDIO

 #include "Configuration.h"
 #include <time.h>
 #include <utils/Debug.h>
 #include <utils/Log.h>
 #include <utils/Trace.h>
 #include <system/audio.h>
 #ifdef FAST_THREAD_STATISTICS
 #include <cpustats/CentralTendencyStatistics.h>
 #ifdef CPU_FREQUENCY_STATISTICS
 #include <cpustats/ThreadCpuUsage.h>
 #endif
 #endif
 #include <audio_utils/mono_blend.h>
 #include <audio_utils/format.h>
 #include <media/AudioMixer.h>
 #include "FastMixer.h"

 namespace android {

 /*static*/ const FastMixerState FastMixer::sInitial;

 FastMixer::FastMixer() : FastThread("cycle_ms", "load_us"),
     // mFastTrackNames
     // mGenerations
     mOutputSink(NULL),
     mOutputSinkGen(0),
     mMixer(NULL),
     mSinkBuffer(NULL),
     mSinkBufferSize(0),
     mSinkChannelCount(FCC_2),
     mMixerBuffer(NULL),
     mMixerBufferSize(0),
     mMixerBufferFormat(AUDIO_FORMAT_PCM_16_BIT),
     mMixerBufferState(UNDEFINED),
     mFormat(Format_Invalid),
     mSampleRate(0),
     mFastTracksGen(0),
     mTotalNativeFramesWritten(0),
     // timestamp
     mNativeFramesWrittenButNotPresented(0),   // the = 0 is to silence the compiler
     mMasterMono(false)
 {
     // FIXME pass sInitial as parameter to base class constructor, and make it static local
     mPrevious = &sInitial;
     mCurrent = &sInitial;

     mDummyDumpState = &mDummyFastMixerDumpState;
     // TODO: Add channel mask to NBAIO_Format.
     // We assume that the channel mask must be a valid positional channel mask.
     mSinkChannelMask = audio_channel_out_mask_from_count(mSinkChannelCount);

     unsigned i;
     for (i = 0; i < FastMixerState::sMaxFastTracks; ++i) {
         mFastTrackNames[i] = -1;
         mGenerations[i] = 0;
     }
 #ifdef FAST_THREAD_STATISTICS
     mOldLoad.tv_sec = 0;
     mOldLoad.tv_nsec = 0;
 #endif
 }

 FastMixer::~FastMixer()
 {
 }

 FastMixerStateQueue* FastMixer::sq()
 {
     return &mSQ;
 }

 const FastThreadState *FastMixer::poll()
 {
     return mSQ.poll();
 }

 void FastMixer::setLog(NBLog::Writer *logWriter)
 {
     if (mMixer != NULL) {
         mMixer->setLog(logWriter);
     }
 }

 void FastMixer::onIdle()
 {
     mPreIdle = *(const FastMixerState *)mCurrent;
     mCurrent = &mPreIdle;
 }

 void FastMixer::onExit()
 {
     delete mMixer;
     free(mMixerBuffer);
     free(mSinkBuffer);
 }

 bool FastMixer::isSubClassCommand(FastThreadState::Command command)
 {
     switch ((FastMixerState::Command) command) {
     case FastMixerState::MIX:
     case FastMixerState::WRITE:
     case FastMixerState::MIX_WRITE:
         return true;
     default:
         return false;
     }
 }

 void FastMixer::onStateChange()
 {
     const FastMixerState * const current = (const FastMixerState *) mCurrent;
     const FastMixerState * const previous = (const FastMixerState *) mPrevious;
     FastMixerDumpState * const dumpState = (FastMixerDumpState *) mDumpState;
     const size_t frameCount = current->mFrameCount;

     // update boottime offset, in case it has changed
     mTimestamp.mTimebaseOffset[ExtendedTimestamp::TIMEBASE_BOOTTIME] =
             mBoottimeOffset.load();

     // handle state change here, but since we want to diff the state,
     // we're prepared for previous == &sInitial the first time through
     unsigned previousTrackMask;

     // check for change in output HAL configuration
     NBAIO_Format previousFormat = mFormat;
     if (current->mOutputSinkGen != mOutputSinkGen) {
         mOutputSink = current->mOutputSink;
         mOutputSinkGen = current->mOutputSinkGen;
         if (mOutputSink == NULL) {
             mFormat = Format_Invalid;
             mSampleRate = 0;
             mSinkChannelCount = 0;
             mSinkChannelMask = AUDIO_CHANNEL_NONE;
         } else {
             mFormat = mOutputSink->format();
             mSampleRate = Format_sampleRate(mFormat);
             mSinkChannelCount = Format_channelCount(mFormat);
             LOG_ALWAYS_FATAL_IF(mSinkChannelCount > AudioMixer::MAX_NUM_CHANNELS);

             // TODO: Add channel mask to NBAIO_Format
             // We assume that the channel mask must be a valid positional channel mask.
             mSinkChannelMask = audio_channel_out_mask_from_count(mSinkChannelCount);
         }
         dumpState->mSampleRate = mSampleRate;
     }

     if ((!Format_isEqual(mFormat, previousFormat)) || (frameCount != previous->mFrameCount)) {
         // FIXME to avoid priority inversion, don't delete here
         delete mMixer;
         mMixer = NULL;
         free(mMixerBuffer);
         mMixerBuffer = NULL;
         free(mSinkBuffer);
         mSinkBuffer = NULL;
         if (frameCount > 0 && mSampleRate > 0) {
             // The mixer produces either 16 bit PCM or float output, select
             // float output if the HAL supports higher than 16 bit precision.
             mMixerBufferFormat = mFormat.mFormat == AUDIO_FORMAT_PCM_16_BIT ?
                     AUDIO_FORMAT_PCM_16_BIT : AUDIO_FORMAT_PCM_FLOAT;
             // FIXME new may block for unbounded time at internal mutex of the heap
             //       implementation; it would be better to have normal mixer allocate for us
             //       to avoid blocking here and to prevent possible priority inversion
             mMixer = new AudioMixer(frameCount, mSampleRate, FastMixerState::sMaxFastTracks);
             const size_t mixerFrameSize = mSinkChannelCount
                     * audio_bytes_per_sample(mMixerBufferFormat);
             mMixerBufferSize = mixerFrameSize * frameCount;
             (void)posix_memalign(&mMixerBuffer, 32, mMixerBufferSize);
             const size_t sinkFrameSize = mSinkChannelCount
                     * audio_bytes_per_sample(mFormat.mFormat);
             if (sinkFrameSize > mixerFrameSize) { // need a sink buffer
                 mSinkBufferSize = sinkFrameSize * frameCount;
                 (void)posix_memalign(&mSinkBuffer, 32, mSinkBufferSize);
             }
             mPeriodNs = (frameCount * 1000000000LL) / mSampleRate;    // 1.00
             mUnderrunNs = (frameCount * 1750000000LL) / mSampleRate;  // 1.75
             mOverrunNs = (frameCount * 500000000LL) / mSampleRate;    // 0.50
             mForceNs = (frameCount * 950000000LL) / mSampleRate;      // 0.95
             mWarmupNsMin = (frameCount * 750000000LL) / mSampleRate;  // 0.75
             mWarmupNsMax = (frameCount * 1250000000LL) / mSampleRate; // 1.25
         } else {
             mPeriodNs = 0;
             mUnderrunNs = 0;
             mOverrunNs = 0;
             mForceNs = 0;
             mWarmupNsMin = 0;
             mWarmupNsMax = LONG_MAX;
         }
         mMixerBufferState = UNDEFINED;
 #if !LOG_NDEBUG
         for (unsigned i = 0; i < FastMixerState::sMaxFastTracks; ++i) {
             mFastTrackNames[i] = -1;
         }
 #endif
         // we need to reconfigure all active tracks
         previousTrackMask = 0;
         mFastTracksGen = current->mFastTracksGen - 1;
         dumpState->mFrameCount = frameCount;
     } else {
         previousTrackMask = previous->mTrackMask;
     }

     // check for change in active track set
     const unsigned currentTrackMask = current->mTrackMask;
     dumpState->mTrackMask = currentTrackMask;
     if (current->mFastTracksGen != mFastTracksGen) {
         ALOG_ASSERT(mMixerBuffer != NULL);
         int name;

         // process removed tracks first to avoid running out of track names
         unsigned removedTracks = previousTrackMask & ~currentTrackMask;
         while (removedTracks != 0) {
             int i = __builtin_ctz(removedTracks);
             removedTracks &= ~(1 << i);
             const FastTrack* fastTrack = &current->mFastTracks[i];
             ALOG_ASSERT(fastTrack->mBufferProvider == NULL);
             if (mMixer != NULL) {
                 name = mFastTrackNames[i];
                 ALOG_ASSERT(name >= 0);
                 mMixer->deleteTrackName(name);
             }
 #if !LOG_NDEBUG
             mFastTrackNames[i] = -1;
 #endif
             // don't reset track dump state, since other side is ignoring it
             mGenerations[i] = fastTrack->mGeneration;
         }

         // now process added tracks
         unsigned addedTracks = currentTrackMask & ~previousTrackMask;
         while (addedTracks != 0) {
             int i = __builtin_ctz(addedTracks);
             addedTracks &= ~(1 << i);
             const FastTrack* fastTrack = &current->mFastTracks[i];
             AudioBufferProvider *bufferProvider = fastTrack->mBufferProvider;
             ALOG_ASSERT(bufferProvider != NULL && mFastTrackNames[i] == -1);
             if (mMixer != NULL) {
                 name = mMixer->getTrackName(fastTrack->mChannelMask,
                         fastTrack->mFormat, AUDIO_SESSION_OUTPUT_MIX);
                 ALOG_ASSERT(name >= 0);
                 mFastTrackNames[i] = name;
                 mMixer->setBufferProvider(name, bufferProvider);
                 mMixer->setParameter(name, AudioMixer::TRACK, AudioMixer::MAIN_BUFFER,
                         (void *)mMixerBuffer);
                 // newly allocated track names default to full scale volume
                 mMixer->setParameter(
                         name,
                         AudioMixer::TRACK,
                         AudioMixer::MIXER_FORMAT, (void *)mMixerBufferFormat);
                 mMixer->setParameter(name, AudioMixer::TRACK, AudioMixer::FORMAT,
                         (void *)(uintptr_t)fastTrack->mFormat);
                 mMixer->setParameter(name, AudioMixer::TRACK, AudioMixer::CHANNEL_MASK,
                         (void *)(uintptr_t)fastTrack->mChannelMask);
                 mMixer->setParameter(name, AudioMixer::TRACK, AudioMixer::MIXER_CHANNEL_MASK,
                         (void *)(uintptr_t)mSinkChannelMask);
                 mMixer->enable(name);
             }
             mGenerations[i] = fastTrack->mGeneration;
         }

         // finally process (potentially) modified tracks; these use the same slot
         // but may have a different buffer provider or volume provider
         unsigned modifiedTracks = currentTrackMask & previousTrackMask;
         while (modifiedTracks != 0) {
             int i = __builtin_ctz(modifiedTracks);
             modifiedTracks &= ~(1 << i);
             const FastTrack* fastTrack = &current->mFastTracks[i];
             if (fastTrack->mGeneration != mGenerations[i]) {
                 // this track was actually modified
                 AudioBufferProvider *bufferProvider = fastTrack->mBufferProvider;
                 ALOG_ASSERT(bufferProvider != NULL);
                 if (mMixer != NULL) {
                     name = mFastTrackNames[i];
                     ALOG_ASSERT(name >= 0);
                     mMixer->setBufferProvider(name, bufferProvider);
                     if (fastTrack->mVolumeProvider == NULL) {
                         float f = AudioMixer::UNITY_GAIN_FLOAT;
                         mMixer->setParameter(name, AudioMixer::VOLUME, AudioMixer::VOLUME0, &f);
                         mMixer->setParameter(name, AudioMixer::VOLUME, AudioMixer::VOLUME1, &f);
                     }
                     mMixer->setParameter(name, AudioMixer::RESAMPLE,
                             AudioMixer::REMOVE, NULL);
                     mMixer->setParameter(
                             name,
                             AudioMixer::TRACK,
                             AudioMixer::MIXER_FORMAT, (void *)mMixerBufferFormat);
                     mMixer->setParameter(name, AudioMixer::TRACK, AudioMixer::FORMAT,
                             (void *)(uintptr_t)fastTrack->mFormat);
                     mMixer->setParameter(name, AudioMixer::TRACK, AudioMixer::CHANNEL_MASK,
                             (void *)(uintptr_t)fastTrack->mChannelMask);
                     mMixer->setParameter(name, AudioMixer::TRACK, AudioMixer::MIXER_CHANNEL_MASK,
                             (void *)(uintptr_t)mSinkChannelMask);
                     // already enabled
                 }
                 mGenerations[i] = fastTrack->mGeneration;
             }
         }

         mFastTracksGen = current->mFastTracksGen;

         dumpState->mNumTracks = popcount(currentTrackMask);
     }
 }

 void FastMixer::onWork()
 {
     const FastMixerState * const current = (const FastMixerState *) mCurrent;
     FastMixerDumpState * const dumpState = (FastMixerDumpState *) mDumpState;
     const FastMixerState::Command command = mCommand;
     const size_t frameCount = current->mFrameCount;

     if ((command & FastMixerState::MIX) && (mMixer != NULL) && mIsWarm) {
         ALOG_ASSERT(mMixerBuffer != NULL);

         // AudioMixer::mState.enabledTracks is undefined if mState.hook == process__validate,
         // so we keep a side copy of enabledTracks
         bool anyEnabledTracks = false;

         // for each track, update volume and check for underrun
         unsigned currentTrackMask = current->mTrackMask;
         while (currentTrackMask != 0) {
             int i = __builtin_ctz(currentTrackMask);
             currentTrackMask &= ~(1 << i);
             const FastTrack* fastTrack = &current->mFastTracks[i];

             const int64_t trackFramesWrittenButNotPresented =
                 mNativeFramesWrittenButNotPresented;
             const int64_t trackFramesWritten = fastTrack->mBufferProvider->framesReleased();
             ExtendedTimestamp perTrackTimestamp(mTimestamp);

             // Can't provide an ExtendedTimestamp before first frame presented.
             // Also, timestamp may not go to very last frame on stop().
             if (trackFramesWritten >= trackFramesWrittenButNotPresented &&
                     perTrackTimestamp.mTimeNs[ExtendedTimestamp::LOCATION_KERNEL] > 0) {
                 perTrackTimestamp.mPosition[ExtendedTimestamp::LOCATION_KERNEL] =
                         trackFramesWritten - trackFramesWrittenButNotPresented;
             } else {
                 perTrackTimestamp.mPosition[ExtendedTimestamp::LOCATION_KERNEL] = 0;
                 perTrackTimestamp.mTimeNs[ExtendedTimestamp::LOCATION_KERNEL] = -1;
             }
             perTrackTimestamp.mPosition[ExtendedTimestamp::LOCATION_SERVER] = trackFramesWritten;
             fastTrack->mBufferProvider->onTimestamp(perTrackTimestamp);

             int name = mFastTrackNames[i];
             ALOG_ASSERT(name >= 0);
             if (fastTrack->mVolumeProvider != NULL) {
                 gain_minifloat_packed_t vlr = fastTrack->mVolumeProvider->getVolumeLR();
                 float vlf = float_from_gain(gain_minifloat_unpack_left(vlr));
                 float vrf = float_from_gain(gain_minifloat_unpack_right(vlr));

                 mMixer->setParameter(name, AudioMixer::VOLUME, AudioMixer::VOLUME0, &vlf);
                 mMixer->setParameter(name, AudioMixer::VOLUME, AudioMixer::VOLUME1, &vrf);
             }
             // FIXME The current implementation of framesReady() for fast tracks
             // takes a tryLock, which can block
             // up to 1 ms.  If enough active tracks all blocked in sequence, this would result
             // in the overall fast mix cycle being delayed.  Should use a non-blocking FIFO.
             size_t framesReady = fastTrack->mBufferProvider->framesReady();
             if (ATRACE_ENABLED()) {
                 // I wish we had formatted trace names
                 char traceName[16];
                 strcpy(traceName, "fRdy");
                 traceName[4] = i + (i < 10 ? '0' : 'A' - 10);
                 traceName[5] = '\0';
                 ATRACE_INT(traceName, framesReady);
             }
             FastTrackDump *ftDump = &dumpState->mTracks[i];
             FastTrackUnderruns underruns = ftDump->mUnderruns;
             if (framesReady < frameCount) {
                 if (framesReady == 0) {
                     underruns.mBitFields.mEmpty++;
                     underruns.mBitFields.mMostRecent = UNDERRUN_EMPTY;
                     mMixer->disable(name);
                 } else {
                     // allow mixing partial buffer
                     underruns.mBitFields.mPartial++;
                     underruns.mBitFields.mMostRecent = UNDERRUN_PARTIAL;
                     mMixer->enable(name);
                     anyEnabledTracks = true;
                 }
             } else {
                 underruns.mBitFields.mFull++;
                 underruns.mBitFields.mMostRecent = UNDERRUN_FULL;
                 mMixer->enable(name);
                 anyEnabledTracks = true;
             }
             ftDump->mUnderruns = underruns;
             ftDump->mFramesReady = framesReady;
             ftDump->mFramesWritten = trackFramesWritten;
         }

         if (anyEnabledTracks) {
             // process() is CPU-bound
             mMixer->process();
             mMixerBufferState = MIXED;
         } else if (mMixerBufferState != ZEROED) {
             mMixerBufferState = UNDEFINED;
         }

     } else if (mMixerBufferState == MIXED) {
         mMixerBufferState = UNDEFINED;
     }
     //bool didFullWrite = false;    // dumpsys could display a count of partial writes
     if ((command & FastMixerState::WRITE) && (mOutputSink != NULL) && (mMixerBuffer != NULL)) {
         if (mMixerBufferState == UNDEFINED) {
             memset(mMixerBuffer, 0, mMixerBufferSize);
             mMixerBufferState = ZEROED;
         }

         if (mMasterMono.load()) {  // memory_order_seq_cst
             mono_blend(mMixerBuffer, mMixerBufferFormat, Format_channelCount(mFormat), frameCount,
                     true /*limit*/);
         }
         // prepare the buffer used to write to sink
         void *buffer = mSinkBuffer != NULL ? mSinkBuffer : mMixerBuffer;
         if (mFormat.mFormat != mMixerBufferFormat) { // sink format not the same as mixer format
             memcpy_by_audio_format(buffer, mFormat.mFormat, mMixerBuffer, mMixerBufferFormat,
                     frameCount * Format_channelCount(mFormat));
         }
         // if non-NULL, then duplicate write() to this non-blocking sink
         NBAIO_Sink* teeSink;
         if ((teeSink = current->mTeeSink) != NULL) {
             (void) teeSink->write(buffer, frameCount);
         }
         // FIXME write() is non-blocking and lock-free for a properly implemented NBAIO sink,
         //       but this code should be modified to handle both non-blocking and blocking sinks
         dumpState->mWriteSequence++;
         ATRACE_BEGIN("write");
         ssize_t framesWritten = mOutputSink->write(buffer, frameCount);
         ATRACE_END();
         dumpState->mWriteSequence++;
         if (framesWritten >= 0) {
             ALOG_ASSERT((size_t) framesWritten <= frameCount);
             mTotalNativeFramesWritten += framesWritten;
             dumpState->mFramesWritten = mTotalNativeFramesWritten;
             //if ((size_t) framesWritten == frameCount) {
             //    didFullWrite = true;
             //}
         } else {
             dumpState->mWriteErrors++;
         }
         mAttemptedWrite = true;
         // FIXME count # of writes blocked excessively, CPU usage, etc. for dump

         ExtendedTimestamp timestamp; // local
         status_t status = mOutputSink->getTimestamp(timestamp);
         if (status == NO_ERROR) {
             const int64_t totalNativeFramesPresented =
                     timestamp.mPosition[ExtendedTimestamp::LOCATION_KERNEL];
             if (totalNativeFramesPresented <= mTotalNativeFramesWritten) {
                 mNativeFramesWrittenButNotPresented =
                     mTotalNativeFramesWritten - totalNativeFramesPresented;
                 mTimestamp.mPosition[ExtendedTimestamp::LOCATION_KERNEL] =
                         timestamp.mPosition[ExtendedTimestamp::LOCATION_KERNEL];
                 mTimestamp.mTimeNs[ExtendedTimestamp::LOCATION_KERNEL] =
                         timestamp.mTimeNs[ExtendedTimestamp::LOCATION_KERNEL];
             } else {
                 // HAL reported that more frames were presented than were written
                 mNativeFramesWrittenButNotPresented = 0;
                 status = INVALID_OPERATION;
             }
         }
         if (status == NO_ERROR) {
             mTimestamp.mTimeNs[ExtendedTimestamp::LOCATION_SERVER] =
                     mTimestamp.mTimeNs[ExtendedTimestamp::LOCATION_KERNEL];
         } else {
             // fetch server time if we can't get timestamp
             mTimestamp.mTimeNs[ExtendedTimestamp::LOCATION_SERVER] =
                     systemTime(SYSTEM_TIME_MONOTONIC);
             // clear out kernel cached position as this may get rapidly stale
             // if we never get a new valid timestamp
             mTimestamp.mPosition[ExtendedTimestamp::LOCATION_KERNEL] = 0;
             mTimestamp.mTimeNs[ExtendedTimestamp::LOCATION_KERNEL] = -1;
         }
     }
 }

 }   // namespace android
	/*
	* Copyright (C) 2012 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.
	*/

	// <IMPORTANT_WARNING>
	// Design rules for threadLoop() are given in the comments at section "Fast mixer thread" of
	// StateQueue.h. In particular, avoid library and system calls except at well-known points.
	// The design rules are only for threadLoop(), and don't apply to FastMixerDumpState methods.
	// </IMPORTANT_WARNING>

	#define LOG_TAG "FastMixer"
	//#define LOG_NDEBUG 0

	#define ATRACE_TAG ATRACE_TAG_AUDIO

	#include "Configuration.h"
	#include <time.h>
	#include <utils/Debug.h>
	#include <utils/Log.h>
	#include <utils/Trace.h>
	#include <system/audio.h>
	#ifdef FAST_THREAD_STATISTICS
	#include <cpustats/CentralTendencyStatistics.h>
	#ifdef CPU_FREQUENCY_STATISTICS
	#include <cpustats/ThreadCpuUsage.h>
	#endif
	#endif
	#include <audio_utils/mono_blend.h>
	#include <audio_utils/format.h>
	#include <media/AudioMixer.h>
	#include "FastMixer.h"

	namespace android {

	/static/ const FastMixerState FastMixer::sInitial;

	FastMixer::FastMixer() : FastThread("cycle_ms", "load_us"),
	// mFastTrackNames
	// mGenerations
	mOutputSink(NULL),
	mOutputSinkGen(0),
	mMixer(NULL),
	mSinkBuffer(NULL),
	mSinkBufferSize(0),
	mSinkChannelCount(FCC_2),
	mMixerBuffer(NULL),
	mMixerBufferSize(0),
	mMixerBufferFormat(AUDIO_FORMAT_PCM_16_BIT),
	mMixerBufferState(UNDEFINED),
	mFormat(Format_Invalid),
	mSampleRate(0),
	mFastTracksGen(0),
	mTotalNativeFramesWritten(0),
	// timestamp
	mNativeFramesWrittenButNotPresented(0), // the = 0 is to silence the compiler
	mMasterMono(false)
	{
	// FIXME pass sInitial as parameter to base class constructor, and make it static local
	mPrevious = &sInitial;
	mCurrent = &sInitial;

	mDummyDumpState = &mDummyFastMixerDumpState;
	// TODO: Add channel mask to NBAIO_Format.
	// We assume that the channel mask must be a valid positional channel mask.
	mSinkChannelMask = audio_channel_out_mask_from_count(mSinkChannelCount);

	unsigned i;
	for (i = 0; i < FastMixerState::sMaxFastTracks; ++i) {
	mFastTrackNames[i] = -1;
	mGenerations[i] = 0;
	}
	#ifdef FAST_THREAD_STATISTICS
	mOldLoad.tv_sec = 0;
	mOldLoad.tv_nsec = 0;
	#endif
	}

	FastMixer::~FastMixer()
	{
	}

	FastMixerStateQueue* FastMixer::sq()
	{
	return &mSQ;
	}

	const FastThreadState *FastMixer::poll()
	{
	return mSQ.poll();
	}

	void FastMixer::setLog(NBLog::Writer *logWriter)
	{
	if (mMixer != NULL) {
	mMixer->setLog(logWriter);
	}
	}

	void FastMixer::onIdle()
	{
	mPreIdle = (const FastMixerState )mCurrent;
	mCurrent = &mPreIdle;
	}

	void FastMixer::onExit()
	{
	delete mMixer;
	free(mMixerBuffer);
	free(mSinkBuffer);
	}

	bool FastMixer::isSubClassCommand(FastThreadState::Command command)
	{
	switch ((FastMixerState::Command) command) {
	case FastMixerState::MIX:
	case FastMixerState::WRITE:
	case FastMixerState::MIX_WRITE:
	return true;
	default:
	return false;
	}
	}

	void FastMixer::onStateChange()
	{
	const FastMixerState * const current = (const FastMixerState *) mCurrent;
	const FastMixerState * const previous = (const FastMixerState *) mPrevious;
	FastMixerDumpState * const dumpState = (FastMixerDumpState *) mDumpState;
	const size_t frameCount = current->mFrameCount;

	// update boottime offset, in case it has changed
	mTimestamp.mTimebaseOffset[ExtendedTimestamp::TIMEBASE_BOOTTIME] =
	mBoottimeOffset.load();

	// handle state change here, but since we want to diff the state,
	// we're prepared for previous == &sInitial the first time through
	unsigned previousTrackMask;

	// check for change in output HAL configuration
	NBAIO_Format previousFormat = mFormat;
	if (current->mOutputSinkGen != mOutputSinkGen) {
	mOutputSink = current->mOutputSink;
	mOutputSinkGen = current->mOutputSinkGen;
	if (mOutputSink == NULL) {
	mFormat = Format_Invalid;
	mSampleRate = 0;
	mSinkChannelCount = 0;
	mSinkChannelMask = AUDIO_CHANNEL_NONE;
	} else {
	mFormat = mOutputSink->format();
	mSampleRate = Format_sampleRate(mFormat);
	mSinkChannelCount = Format_channelCount(mFormat);
	LOG_ALWAYS_FATAL_IF(mSinkChannelCount > AudioMixer::MAX_NUM_CHANNELS);

	// TODO: Add channel mask to NBAIO_Format
	// We assume that the channel mask must be a valid positional channel mask.
	mSinkChannelMask = audio_channel_out_mask_from_count(mSinkChannelCount);
	}
	dumpState->mSampleRate = mSampleRate;
	}

	if ((!Format_isEqual(mFormat, previousFormat)) \|\| (frameCount != previous->mFrameCount)) {
	// FIXME to avoid priority inversion, don't delete here
	delete mMixer;
	mMixer = NULL;
	free(mMixerBuffer);
	mMixerBuffer = NULL;
	free(mSinkBuffer);
	mSinkBuffer = NULL;
	if (frameCount > 0 && mSampleRate > 0) {
	// The mixer produces either 16 bit PCM or float output, select
	// float output if the HAL supports higher than 16 bit precision.
	mMixerBufferFormat = mFormat.mFormat == AUDIO_FORMAT_PCM_16_BIT ?
	AUDIO_FORMAT_PCM_16_BIT : AUDIO_FORMAT_PCM_FLOAT;
	// FIXME new may block for unbounded time at internal mutex of the heap
	// implementation; it would be better to have normal mixer allocate for us
	// to avoid blocking here and to prevent possible priority inversion
	mMixer = new AudioMixer(frameCount, mSampleRate, FastMixerState::sMaxFastTracks);
	const size_t mixerFrameSize = mSinkChannelCount
	* audio_bytes_per_sample(mMixerBufferFormat);
	mMixerBufferSize = mixerFrameSize * frameCount;
	(void)posix_memalign(&mMixerBuffer, 32, mMixerBufferSize);
	const size_t sinkFrameSize = mSinkChannelCount
	* audio_bytes_per_sample(mFormat.mFormat);
	if (sinkFrameSize > mixerFrameSize) { // need a sink buffer
	mSinkBufferSize = sinkFrameSize * frameCount;
	(void)posix_memalign(&mSinkBuffer, 32, mSinkBufferSize);
	}
	mPeriodNs = (frameCount * 1000000000LL) / mSampleRate; // 1.00
	mUnderrunNs = (frameCount * 1750000000LL) / mSampleRate; // 1.75
	mOverrunNs = (frameCount * 500000000LL) / mSampleRate; // 0.50
	mForceNs = (frameCount * 950000000LL) / mSampleRate; // 0.95
	mWarmupNsMin = (frameCount * 750000000LL) / mSampleRate; // 0.75
	mWarmupNsMax = (frameCount * 1250000000LL) / mSampleRate; // 1.25
	} else {
	mPeriodNs = 0;
	mUnderrunNs = 0;
	mOverrunNs = 0;
	mForceNs = 0;
	mWarmupNsMin = 0;
	mWarmupNsMax = LONG_MAX;
	}
	mMixerBufferState = UNDEFINED;
	#if !LOG_NDEBUG
	for (unsigned i = 0; i < FastMixerState::sMaxFastTracks; ++i) {
	mFastTrackNames[i] = -1;
	}
	#endif
	// we need to reconfigure all active tracks
	previousTrackMask = 0;
	mFastTracksGen = current->mFastTracksGen - 1;
	dumpState->mFrameCount = frameCount;
	} else {
	previousTrackMask = previous->mTrackMask;
	}

	// check for change in active track set
	const unsigned currentTrackMask = current->mTrackMask;
	dumpState->mTrackMask = currentTrackMask;
	if (current->mFastTracksGen != mFastTracksGen) {
	ALOG_ASSERT(mMixerBuffer != NULL);
	int name;

	// process removed tracks first to avoid running out of track names
	unsigned removedTracks = previousTrackMask & ~currentTrackMask;
	while (removedTracks != 0) {
	int i = __builtin_ctz(removedTracks);
	removedTracks &= ~(1 << i);
	const FastTrack* fastTrack = &current->mFastTracks[i];
	ALOG_ASSERT(fastTrack->mBufferProvider == NULL);
	if (mMixer != NULL) {
	name = mFastTrackNames[i];
	ALOG_ASSERT(name >= 0);
	mMixer->deleteTrackName(name);
	}
	#if !LOG_NDEBUG
	mFastTrackNames[i] = -1;
	#endif
	// don't reset track dump state, since other side is ignoring it
	mGenerations[i] = fastTrack->mGeneration;
	}

	// now process added tracks
	unsigned addedTracks = currentTrackMask & ~previousTrackMask;
	while (addedTracks != 0) {
	int i = __builtin_ctz(addedTracks);
	addedTracks &= ~(1 << i);
	const FastTrack* fastTrack = &current->mFastTracks[i];
	AudioBufferProvider *bufferProvider = fastTrack->mBufferProvider;
	ALOG_ASSERT(bufferProvider != NULL && mFastTrackNames[i] == -1);
	if (mMixer != NULL) {
	name = mMixer->getTrackName(fastTrack->mChannelMask,
	fastTrack->mFormat, AUDIO_SESSION_OUTPUT_MIX);
	ALOG_ASSERT(name >= 0);
	mFastTrackNames[i] = name;
	mMixer->setBufferProvider(name, bufferProvider);
	mMixer->setParameter(name, AudioMixer::TRACK, AudioMixer::MAIN_BUFFER,
	(void *)mMixerBuffer);
	// newly allocated track names default to full scale volume
	mMixer->setParameter(
	name,
	AudioMixer::TRACK,
	AudioMixer::MIXER_FORMAT, (void *)mMixerBufferFormat);
	mMixer->setParameter(name, AudioMixer::TRACK, AudioMixer::FORMAT,
	(void *)(uintptr_t)fastTrack->mFormat);
	mMixer->setParameter(name, AudioMixer::TRACK, AudioMixer::CHANNEL_MASK,
	(void *)(uintptr_t)fastTrack->mChannelMask);
	mMixer->setParameter(name, AudioMixer::TRACK, AudioMixer::MIXER_CHANNEL_MASK,
	(void *)(uintptr_t)mSinkChannelMask);
	mMixer->enable(name);
	}
	mGenerations[i] = fastTrack->mGeneration;
	}

	// finally process (potentially) modified tracks; these use the same slot
	// but may have a different buffer provider or volume provider
	unsigned modifiedTracks = currentTrackMask & previousTrackMask;
	while (modifiedTracks != 0) {
	int i = __builtin_ctz(modifiedTracks);
	modifiedTracks &= ~(1 << i);
	const FastTrack* fastTrack = &current->mFastTracks[i];
	if (fastTrack->mGeneration != mGenerations[i]) {
	// this track was actually modified
	AudioBufferProvider *bufferProvider = fastTrack->mBufferProvider;
	ALOG_ASSERT(bufferProvider != NULL);
	if (mMixer != NULL) {
	name = mFastTrackNames[i];
	ALOG_ASSERT(name >= 0);
	mMixer->setBufferProvider(name, bufferProvider);
	if (fastTrack->mVolumeProvider == NULL) {
	float f = AudioMixer::UNITY_GAIN_FLOAT;
	mMixer->setParameter(name, AudioMixer::VOLUME, AudioMixer::VOLUME0, &f);
	mMixer->setParameter(name, AudioMixer::VOLUME, AudioMixer::VOLUME1, &f);
	}
	mMixer->setParameter(name, AudioMixer::RESAMPLE,
	AudioMixer::REMOVE, NULL);
	mMixer->setParameter(
	name,
	AudioMixer::TRACK,
	AudioMixer::MIXER_FORMAT, (void *)mMixerBufferFormat);
	mMixer->setParameter(name, AudioMixer::TRACK, AudioMixer::FORMAT,
	(void *)(uintptr_t)fastTrack->mFormat);
	mMixer->setParameter(name, AudioMixer::TRACK, AudioMixer::CHANNEL_MASK,
	(void *)(uintptr_t)fastTrack->mChannelMask);
	mMixer->setParameter(name, AudioMixer::TRACK, AudioMixer::MIXER_CHANNEL_MASK,
	(void *)(uintptr_t)mSinkChannelMask);
	// already enabled
	}
	mGenerations[i] = fastTrack->mGeneration;
	}
	}

	mFastTracksGen = current->mFastTracksGen;

	dumpState->mNumTracks = popcount(currentTrackMask);
	}
	}

	void FastMixer::onWork()
	{
	const FastMixerState * const current = (const FastMixerState *) mCurrent;
	FastMixerDumpState * const dumpState = (FastMixerDumpState *) mDumpState;
	const FastMixerState::Command command = mCommand;
	const size_t frameCount = current->mFrameCount;

	if ((command & FastMixerState::MIX) && (mMixer != NULL) && mIsWarm) {
	ALOG_ASSERT(mMixerBuffer != NULL);

	// AudioMixer::mState.enabledTracks is undefined if mState.hook == process__validate,
	// so we keep a side copy of enabledTracks
	bool anyEnabledTracks = false;

	// for each track, update volume and check for underrun
	unsigned currentTrackMask = current->mTrackMask;
	while (currentTrackMask != 0) {
	int i = __builtin_ctz(currentTrackMask);
	currentTrackMask &= ~(1 << i);
	const FastTrack* fastTrack = &current->mFastTracks[i];

	const int64_t trackFramesWrittenButNotPresented =
	mNativeFramesWrittenButNotPresented;
	const int64_t trackFramesWritten = fastTrack->mBufferProvider->framesReleased();
	ExtendedTimestamp perTrackTimestamp(mTimestamp);

	// Can't provide an ExtendedTimestamp before first frame presented.
	// Also, timestamp may not go to very last frame on stop().
	if (trackFramesWritten >= trackFramesWrittenButNotPresented &&
	perTrackTimestamp.mTimeNs[ExtendedTimestamp::LOCATION_KERNEL] > 0) {
	perTrackTimestamp.mPosition[ExtendedTimestamp::LOCATION_KERNEL] =
	trackFramesWritten - trackFramesWrittenButNotPresented;
	} else {
	perTrackTimestamp.mPosition[ExtendedTimestamp::LOCATION_KERNEL] = 0;
	perTrackTimestamp.mTimeNs[ExtendedTimestamp::LOCATION_KERNEL] = -1;
	}
	perTrackTimestamp.mPosition[ExtendedTimestamp::LOCATION_SERVER] = trackFramesWritten;
	fastTrack->mBufferProvider->onTimestamp(perTrackTimestamp);

	int name = mFastTrackNames[i];
	ALOG_ASSERT(name >= 0);
	if (fastTrack->mVolumeProvider != NULL) {
	gain_minifloat_packed_t vlr = fastTrack->mVolumeProvider->getVolumeLR();
	float vlf = float_from_gain(gain_minifloat_unpack_left(vlr));
	float vrf = float_from_gain(gain_minifloat_unpack_right(vlr));

	mMixer->setParameter(name, AudioMixer::VOLUME, AudioMixer::VOLUME0, &vlf);
	mMixer->setParameter(name, AudioMixer::VOLUME, AudioMixer::VOLUME1, &vrf);
	}
	// FIXME The current implementation of framesReady() for fast tracks
	// takes a tryLock, which can block
	// up to 1 ms. If enough active tracks all blocked in sequence, this would result
	// in the overall fast mix cycle being delayed. Should use a non-blocking FIFO.
	size_t framesReady = fastTrack->mBufferProvider->framesReady();
	if (ATRACE_ENABLED()) {
	// I wish we had formatted trace names
	char traceName[16];
	strcpy(traceName, "fRdy");
	traceName[4] = i + (i < 10 ? '0' : 'A' - 10);
	traceName[5] = '\0';
	ATRACE_INT(traceName, framesReady);
	}
	FastTrackDump *ftDump = &dumpState->mTracks[i];
	FastTrackUnderruns underruns = ftDump->mUnderruns;
	if (framesReady < frameCount) {
	if (framesReady == 0) {
	underruns.mBitFields.mEmpty++;
	underruns.mBitFields.mMostRecent = UNDERRUN_EMPTY;
	mMixer->disable(name);
	} else {
	// allow mixing partial buffer
	underruns.mBitFields.mPartial++;
	underruns.mBitFields.mMostRecent = UNDERRUN_PARTIAL;
	mMixer->enable(name);
	anyEnabledTracks = true;
	}
	} else {
	underruns.mBitFields.mFull++;
	underruns.mBitFields.mMostRecent = UNDERRUN_FULL;
	mMixer->enable(name);
	anyEnabledTracks = true;
	}
	ftDump->mUnderruns = underruns;
	ftDump->mFramesReady = framesReady;
	ftDump->mFramesWritten = trackFramesWritten;
	}

	if (anyEnabledTracks) {
	// process() is CPU-bound
	mMixer->process();
	mMixerBufferState = MIXED;
	} else if (mMixerBufferState != ZEROED) {
	mMixerBufferState = UNDEFINED;
	}

	} else if (mMixerBufferState == MIXED) {
	mMixerBufferState = UNDEFINED;
	}
	//bool didFullWrite = false; // dumpsys could display a count of partial writes
	if ((command & FastMixerState::WRITE) && (mOutputSink != NULL) && (mMixerBuffer != NULL)) {
	if (mMixerBufferState == UNDEFINED) {
	memset(mMixerBuffer, 0, mMixerBufferSize);
	mMixerBufferState = ZEROED;
	}

	if (mMasterMono.load()) { // memory_order_seq_cst
	mono_blend(mMixerBuffer, mMixerBufferFormat, Format_channelCount(mFormat), frameCount,
	true /limit/);
	}
	// prepare the buffer used to write to sink
	void *buffer = mSinkBuffer != NULL ? mSinkBuffer : mMixerBuffer;
	if (mFormat.mFormat != mMixerBufferFormat) { // sink format not the same as mixer format
	memcpy_by_audio_format(buffer, mFormat.mFormat, mMixerBuffer, mMixerBufferFormat,
	frameCount * Format_channelCount(mFormat));
	}
	// if non-NULL, then duplicate write() to this non-blocking sink
	NBAIO_Sink* teeSink;
	if ((teeSink = current->mTeeSink) != NULL) {
	(void) teeSink->write(buffer, frameCount);
	}
	// FIXME write() is non-blocking and lock-free for a properly implemented NBAIO sink,
	// but this code should be modified to handle both non-blocking and blocking sinks
	dumpState->mWriteSequence++;
	ATRACE_BEGIN("write");
	ssize_t framesWritten = mOutputSink->write(buffer, frameCount);
	ATRACE_END();
	dumpState->mWriteSequence++;
	if (framesWritten >= 0) {
	ALOG_ASSERT((size_t) framesWritten <= frameCount);
	mTotalNativeFramesWritten += framesWritten;
	dumpState->mFramesWritten = mTotalNativeFramesWritten;
	//if ((size_t) framesWritten == frameCount) {
	// didFullWrite = true;
	//}
	} else {
	dumpState->mWriteErrors++;
	}
	mAttemptedWrite = true;
	// FIXME count # of writes blocked excessively, CPU usage, etc. for dump

	ExtendedTimestamp timestamp; // local
	status_t status = mOutputSink->getTimestamp(timestamp);
	if (status == NO_ERROR) {
	const int64_t totalNativeFramesPresented =
	timestamp.mPosition[ExtendedTimestamp::LOCATION_KERNEL];
	if (totalNativeFramesPresented <= mTotalNativeFramesWritten) {
	mNativeFramesWrittenButNotPresented =
	mTotalNativeFramesWritten - totalNativeFramesPresented;
	mTimestamp.mPosition[ExtendedTimestamp::LOCATION_KERNEL] =
	timestamp.mPosition[ExtendedTimestamp::LOCATION_KERNEL];
	mTimestamp.mTimeNs[ExtendedTimestamp::LOCATION_KERNEL] =
	timestamp.mTimeNs[ExtendedTimestamp::LOCATION_KERNEL];
	} else {
	// HAL reported that more frames were presented than were written
	mNativeFramesWrittenButNotPresented = 0;
	status = INVALID_OPERATION;
	}
	}
	if (status == NO_ERROR) {
	mTimestamp.mTimeNs[ExtendedTimestamp::LOCATION_SERVER] =
	mTimestamp.mTimeNs[ExtendedTimestamp::LOCATION_KERNEL];
	} else {
	// fetch server time if we can't get timestamp
	mTimestamp.mTimeNs[ExtendedTimestamp::LOCATION_SERVER] =
	systemTime(SYSTEM_TIME_MONOTONIC);
	// clear out kernel cached position as this may get rapidly stale
	// if we never get a new valid timestamp
	mTimestamp.mPosition[ExtendedTimestamp::LOCATION_KERNEL] = 0;
	mTimestamp.mTimeNs[ExtendedTimestamp::LOCATION_KERNEL] = -1;
	}
	}
	}

	} // namespace android