libmediaplayerservice/nuplayer/NuPlayerRenderer.cpp

/*
 * Copyright (C) 2010 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.
 */

//#define LOG_NDEBUG 0
#define LOG_TAG "NuPlayerRenderer"
#include <utils/Log.h>

#include "NuPlayerRenderer.h"

#include <media/stagefright/foundation/ABuffer.h>
#include <media/stagefright/foundation/ADebug.h>
#include <media/stagefright/foundation/AMessage.h>
#include <media/stagefright/MediaErrors.h>
#include <media/stagefright/MetaData.h>

#include <inttypes.h>

namespace android {

// Maximum time in paused state when offloading audio decompression. When elapsed, the AudioSink
// is closed to allow the audio DSP to power down.
static const int64_t kOffloadPauseMaxUs = 60000000ll;

// static
const int64_t NuPlayer::Renderer::kMinPositionUpdateDelayUs = 100000ll;

NuPlayer::Renderer::Renderer(
        const sp<MediaPlayerBase::AudioSink> &sink,
        const sp<AMessage> &notify,
        uint32_t flags)
    : mAudioSink(sink),
      mNotify(notify),
      mFlags(flags),
      mNumFramesWritten(0),
      mDrainAudioQueuePending(false),
      mDrainVideoQueuePending(false),
      mAudioQueueGeneration(0),
      mVideoQueueGeneration(0),
      mFirstAnchorTimeMediaUs(-1),
      mAnchorTimeMediaUs(-1),
      mAnchorTimeRealUs(-1),
      mFlushingAudio(false),
      mFlushingVideo(false),
      mHasAudio(false),
      mHasVideo(false),
      mSyncQueues(false),
      mPaused(false),
      mVideoSampleReceived(false),
      mVideoRenderingStarted(false),
      mVideoRenderingStartGeneration(0),
      mAudioRenderingStartGeneration(0),
      mLastPositionUpdateUs(-1ll),
      mVideoLateByUs(0ll),
      mAudioOffloadPauseTimeoutGeneration(0),
      mAudioOffloadTornDown(false) {
}

NuPlayer::Renderer::~Renderer() {
    if (offloadingAudio()) {
        mAudioSink->stop();
        mAudioSink->flush();
        mAudioSink->close();
    }
}

void NuPlayer::Renderer::queueBuffer(
        bool audio,
        const sp<ABuffer> &buffer,
        const sp<AMessage> &notifyConsumed) {
    sp<AMessage> msg = new AMessage(kWhatQueueBuffer, id());
    msg->setInt32("audio", static_cast<int32_t>(audio));
    msg->setBuffer("buffer", buffer);
    msg->setMessage("notifyConsumed", notifyConsumed);
    msg->post();
}

void NuPlayer::Renderer::queueEOS(bool audio, status_t finalResult) {
    CHECK_NE(finalResult, (status_t)OK);

    sp<AMessage> msg = new AMessage(kWhatQueueEOS, id());
    msg->setInt32("audio", static_cast<int32_t>(audio));
    msg->setInt32("finalResult", finalResult);
    msg->post();
}

void NuPlayer::Renderer::flush(bool audio) {
    {
        Mutex::Autolock autoLock(mFlushLock);
        if (audio) {
            if (mFlushingAudio) {
                return;
            }
            mFlushingAudio = true;
        } else {
            if (mFlushingVideo) {
                return;
            }
            mFlushingVideo = true;
        }
    }

    sp<AMessage> msg = new AMessage(kWhatFlush, id());
    msg->setInt32("audio", static_cast<int32_t>(audio));
    msg->post();
}

void NuPlayer::Renderer::signalTimeDiscontinuity() {
    Mutex::Autolock autoLock(mLock);
    // CHECK(mAudioQueue.empty());
    // CHECK(mVideoQueue.empty());
    mFirstAnchorTimeMediaUs = -1;
    mAnchorTimeMediaUs = -1;
    mAnchorTimeRealUs = -1;
    mSyncQueues = false;
}

void NuPlayer::Renderer::signalAudioSinkChanged() {
    (new AMessage(kWhatAudioSinkChanged, id()))->post();
}

void NuPlayer::Renderer::signalDisableOffloadAudio() {
    (new AMessage(kWhatDisableOffloadAudio, id()))->post();
}

void NuPlayer::Renderer::pause() {
    (new AMessage(kWhatPause, id()))->post();
}

void NuPlayer::Renderer::resume() {
    (new AMessage(kWhatResume, id()))->post();
}

void NuPlayer::Renderer::onMessageReceived(const sp<AMessage> &msg) {
    switch (msg->what()) {
        case kWhatStopAudioSink:
        {
            mAudioSink->stop();
            break;
        }

        case kWhatDrainAudioQueue:
        {
            int32_t generation;
            CHECK(msg->findInt32("generation", &generation));
            if (generation != mAudioQueueGeneration) {
                break;
            }

            mDrainAudioQueuePending = false;

            if (onDrainAudioQueue()) {
                uint32_t numFramesPlayed;
                CHECK_EQ(mAudioSink->getPosition(&numFramesPlayed),
                         (status_t)OK);

                uint32_t numFramesPendingPlayout =
                    mNumFramesWritten - numFramesPlayed;

                // This is how long the audio sink will have data to
                // play back.
                int64_t delayUs =
                    mAudioSink->msecsPerFrame()
                        * numFramesPendingPlayout * 1000ll;

                // Let's give it more data after about half that time
                // has elapsed.
                // kWhatDrainAudioQueue is used for non-offloading mode,
                // and mLock is used only for offloading mode. Therefore,
                // no need to acquire mLock here.
                postDrainAudioQueue_l(delayUs / 2);
            }
            break;
        }

        case kWhatDrainVideoQueue:
        {
            int32_t generation;
            CHECK(msg->findInt32("generation", &generation));
            if (generation != mVideoQueueGeneration) {
                break;
            }

            mDrainVideoQueuePending = false;

            onDrainVideoQueue();

            postDrainVideoQueue();
            break;
        }

        case kWhatQueueBuffer:
        {
            onQueueBuffer(msg);
            break;
        }

        case kWhatQueueEOS:
        {
            onQueueEOS(msg);
            break;
        }

        case kWhatFlush:
        {
            onFlush(msg);
            break;
        }

        case kWhatAudioSinkChanged:
        {
            onAudioSinkChanged();
            break;
        }

        case kWhatDisableOffloadAudio:
        {
            onDisableOffloadAudio();
            break;
        }

        case kWhatPause:
        {
            onPause();
            break;
        }

        case kWhatResume:
        {
            onResume();
            break;
        }

        case kWhatAudioOffloadTearDown:
        {
            onAudioOffloadTearDown();
            break;
        }

        case kWhatAudioOffloadPauseTimeout:
        {
            int32_t generation;
            CHECK(msg->findInt32("generation", &generation));
            if (generation != mAudioOffloadPauseTimeoutGeneration) {
                break;
            }
            onAudioOffloadTearDown();
            break;
        }

        default:
            TRESPASS();
            break;
    }
}

void NuPlayer::Renderer::postDrainAudioQueue_l(int64_t delayUs) {
    if (mDrainAudioQueuePending || mSyncQueues || mPaused
            || offloadingAudio()) {
        return;
    }

    if (mAudioQueue.empty()) {
        return;
    }

    mDrainAudioQueuePending = true;
    sp<AMessage> msg = new AMessage(kWhatDrainAudioQueue, id());
    msg->setInt32("generation", mAudioQueueGeneration);
    msg->post(delayUs);
}

void NuPlayer::Renderer::prepareForMediaRenderingStart() {
    mAudioRenderingStartGeneration = mAudioQueueGeneration;
    mVideoRenderingStartGeneration = mVideoQueueGeneration;
}

void NuPlayer::Renderer::notifyIfMediaRenderingStarted() {
    if (mVideoRenderingStartGeneration == mVideoQueueGeneration &&
        mAudioRenderingStartGeneration == mAudioQueueGeneration) {
        mVideoRenderingStartGeneration = -1;
        mAudioRenderingStartGeneration = -1;

        sp<AMessage> notify = mNotify->dup();
        notify->setInt32("what", kWhatMediaRenderingStart);
        notify->post();
    }
}

// static
size_t NuPlayer::Renderer::AudioSinkCallback(
        MediaPlayerBase::AudioSink * /* audioSink */,
        void *buffer,
        size_t size,
        void *cookie,
        MediaPlayerBase::AudioSink::cb_event_t event) {
    NuPlayer::Renderer *me = (NuPlayer::Renderer *)cookie;

    switch (event) {
        case MediaPlayerBase::AudioSink::CB_EVENT_FILL_BUFFER:
        {
            return me->fillAudioBuffer(buffer, size);
            break;
        }

        case MediaPlayerBase::AudioSink::CB_EVENT_STREAM_END:
        {
            me->notifyEOS(true /* audio */, ERROR_END_OF_STREAM);
            break;
        }

        case MediaPlayerBase::AudioSink::CB_EVENT_TEAR_DOWN:
        {
            me->notifyAudioOffloadTearDown();
            break;
        }
    }

    return 0;
}

size_t NuPlayer::Renderer::fillAudioBuffer(void *buffer, size_t size) {
    Mutex::Autolock autoLock(mLock);

    if (!offloadingAudio() || mPaused) {
        return 0;
    }

    bool hasEOS = false;

    size_t sizeCopied = 0;
    bool firstEntry = true;
    while (sizeCopied < size && !mAudioQueue.empty()) {
        QueueEntry *entry = &*mAudioQueue.begin();

        if (entry->mBuffer == NULL) { // EOS
            hasEOS = true;
            mAudioQueue.erase(mAudioQueue.begin());
            entry = NULL;
            break;
        }

        if (firstEntry && entry->mOffset == 0) {
            firstEntry = false;
            int64_t mediaTimeUs;
            CHECK(entry->mBuffer->meta()->findInt64("timeUs", &mediaTimeUs));
            ALOGV("rendering audio at media time %.2f secs", mediaTimeUs / 1E6);
            if (mFirstAnchorTimeMediaUs == -1) {
                mFirstAnchorTimeMediaUs = mediaTimeUs;
            }

            int64_t nowUs = ALooper::GetNowUs();
            mAnchorTimeMediaUs =
                mFirstAnchorTimeMediaUs + getPlayedOutAudioDurationUs(nowUs);
            mAnchorTimeRealUs = nowUs;

            notifyPosition();
        }

        size_t copy = entry->mBuffer->size() - entry->mOffset;
        size_t sizeRemaining = size - sizeCopied;
        if (copy > sizeRemaining) {
            copy = sizeRemaining;
        }

        memcpy((char *)buffer + sizeCopied,
               entry->mBuffer->data() + entry->mOffset,
               copy);

        entry->mOffset += copy;
        if (entry->mOffset == entry->mBuffer->size()) {
            entry->mNotifyConsumed->post();
            mAudioQueue.erase(mAudioQueue.begin());
            entry = NULL;
        }
        sizeCopied += copy;
        notifyIfMediaRenderingStarted();
    }

    if (hasEOS) {
        (new AMessage(kWhatStopAudioSink, id()))->post();
    }

    return sizeCopied;
}

bool NuPlayer::Renderer::onDrainAudioQueue() {
    uint32_t numFramesPlayed;
    if (mAudioSink->getPosition(&numFramesPlayed) != OK) {
        return false;
    }

    ssize_t numFramesAvailableToWrite =
        mAudioSink->frameCount() - (mNumFramesWritten - numFramesPlayed);

#if 0
    if (numFramesAvailableToWrite == mAudioSink->frameCount()) {
        ALOGI("audio sink underrun");
    } else {
        ALOGV("audio queue has %d frames left to play",
             mAudioSink->frameCount() - numFramesAvailableToWrite);
    }
#endif

    size_t numBytesAvailableToWrite =
        numFramesAvailableToWrite * mAudioSink->frameSize();

    while (numBytesAvailableToWrite > 0 && !mAudioQueue.empty()) {
        QueueEntry *entry = &*mAudioQueue.begin();

        if (entry->mBuffer == NULL) {
            // EOS
            int64_t postEOSDelayUs = 0;
            if (mAudioSink->needsTrailingPadding()) {
                postEOSDelayUs = getPendingAudioPlayoutDurationUs(ALooper::GetNowUs());
            }
            notifyEOS(true /* audio */, entry->mFinalResult, postEOSDelayUs);

            mAudioQueue.erase(mAudioQueue.begin());
            entry = NULL;
            return false;
        }

        if (entry->mOffset == 0) {
            int64_t mediaTimeUs;
            CHECK(entry->mBuffer->meta()->findInt64("timeUs", &mediaTimeUs));
            ALOGV("rendering audio at media time %.2f secs", mediaTimeUs / 1E6);
            if (mFirstAnchorTimeMediaUs == -1) {
                mFirstAnchorTimeMediaUs = mediaTimeUs;
            }
            mAnchorTimeMediaUs = mediaTimeUs;

            int64_t nowUs = ALooper::GetNowUs();
            mAnchorTimeRealUs = nowUs + getPendingAudioPlayoutDurationUs(nowUs);

            notifyPosition();
        }

        size_t copy = entry->mBuffer->size() - entry->mOffset;
        if (copy > numBytesAvailableToWrite) {
            copy = numBytesAvailableToWrite;
        }

        ssize_t written = mAudioSink->write(entry->mBuffer->data() + entry->mOffset, copy);
        if (written < 0) {
            // An error in AudioSink write is fatal here.
            LOG_ALWAYS_FATAL("AudioSink write error(%zd) when writing %zu bytes", written, copy);
        }

        entry->mOffset += written;
        if (entry->mOffset == entry->mBuffer->size()) {
            entry->mNotifyConsumed->post();
            mAudioQueue.erase(mAudioQueue.begin());

            entry = NULL;
        }

        numBytesAvailableToWrite -= written;
        size_t copiedFrames = written / mAudioSink->frameSize();
        mNumFramesWritten += copiedFrames;

        notifyIfMediaRenderingStarted();

        if (written != (ssize_t)copy) {
            // A short count was received from AudioSink::write()
            //
            // AudioSink write should block until exactly the number of bytes are delivered.
            // But it may return with a short count (without an error) when:
            //
            // 1) Size to be copied is not a multiple of the frame size. We consider this fatal.
            // 2) AudioSink is an AudioCache for data retrieval, and the AudioCache is exceeded.

            // (Case 1)
            // Must be a multiple of the frame size.  If it is not a multiple of a frame size, it
            // needs to fail, as we should not carry over fractional frames between calls.
            CHECK_EQ(copy % mAudioSink->frameSize(), 0);

            // (Case 2)
            // Return early to the caller.
            // Beware of calling immediately again as this may busy-loop if you are not careful.
            ALOGW("AudioSink write short frame count %zd < %zu", written, copy);
            break;
        }
    }
    return !mAudioQueue.empty();
}

int64_t NuPlayer::Renderer::getPendingAudioPlayoutDurationUs(int64_t nowUs) {
    int64_t writtenAudioDurationUs =
        mNumFramesWritten * 1000LL * mAudioSink->msecsPerFrame();
    return writtenAudioDurationUs - getPlayedOutAudioDurationUs(nowUs);
}

void NuPlayer::Renderer::postDrainVideoQueue() {
    if (mDrainVideoQueuePending
            || mSyncQueues
            || (mPaused && mVideoSampleReceived)) {
        return;
    }

    if (mVideoQueue.empty()) {
        return;
    }

    QueueEntry &entry = *mVideoQueue.begin();

    sp<AMessage> msg = new AMessage(kWhatDrainVideoQueue, id());
    msg->setInt32("generation", mVideoQueueGeneration);

    int64_t delayUs;

    if (entry.mBuffer == NULL) {
        // EOS doesn't carry a timestamp.
        delayUs = 0;
    } else if (mFlags & FLAG_REAL_TIME) {
        int64_t mediaTimeUs;
        CHECK(entry.mBuffer->meta()->findInt64("timeUs", &mediaTimeUs));

        delayUs = mediaTimeUs - ALooper::GetNowUs();
    } else {
        int64_t mediaTimeUs;
        CHECK(entry.mBuffer->meta()->findInt64("timeUs", &mediaTimeUs));

        if (mFirstAnchorTimeMediaUs == -1 && !mHasAudio) {
            mFirstAnchorTimeMediaUs = mediaTimeUs;
        }
        if (mAnchorTimeMediaUs < 0) {
            delayUs = 0;

            if (!mHasAudio) {
                mAnchorTimeMediaUs = mediaTimeUs;
                mAnchorTimeRealUs = ALooper::GetNowUs();
                notifyPosition();
            }
        } else {
            int64_t realTimeUs =
                (mediaTimeUs - mAnchorTimeMediaUs) + mAnchorTimeRealUs;

            delayUs = realTimeUs - ALooper::GetNowUs();
        }
    }

    ALOGW_IF(delayUs > 500000, "unusually high delayUs: %" PRId64, delayUs);
    msg->post(delayUs);

    mDrainVideoQueuePending = true;
}

void NuPlayer::Renderer::onDrainVideoQueue() {
    if (mVideoQueue.empty()) {
        return;
    }

    QueueEntry *entry = &*mVideoQueue.begin();

    if (entry->mBuffer == NULL) {
        // EOS

        notifyEOS(false /* audio */, entry->mFinalResult);

        mVideoQueue.erase(mVideoQueue.begin());
        entry = NULL;

        mVideoLateByUs = 0ll;
        return;
    }

    int64_t realTimeUs;
    if (mFlags & FLAG_REAL_TIME) {
        CHECK(entry->mBuffer->meta()->findInt64("timeUs", &realTimeUs));
    } else {
        int64_t mediaTimeUs;
        CHECK(entry->mBuffer->meta()->findInt64("timeUs", &mediaTimeUs));

        realTimeUs = mediaTimeUs - mAnchorTimeMediaUs + mAnchorTimeRealUs;
    }

    bool tooLate = false;

    if (!mPaused) {
        mVideoLateByUs = ALooper::GetNowUs() - realTimeUs;
        tooLate = (mVideoLateByUs > 40000);

        if (tooLate) {
            ALOGV("video late by %lld us (%.2f secs)",
                 mVideoLateByUs, mVideoLateByUs / 1E6);
        } else {
            ALOGV("rendering video at media time %.2f secs",
                    (mFlags & FLAG_REAL_TIME ? realTimeUs :
                    (realTimeUs + mAnchorTimeMediaUs - mAnchorTimeRealUs)) / 1E6);
        }
    } else {
        mVideoLateByUs = 0ll;
    }

    entry->mNotifyConsumed->setInt32("render", !tooLate);
    entry->mNotifyConsumed->post();
    mVideoQueue.erase(mVideoQueue.begin());
    entry = NULL;

    mVideoSampleReceived = true;

    if (!mPaused) {
        if (!mVideoRenderingStarted) {
            mVideoRenderingStarted = true;
            notifyVideoRenderingStart();
        }
        notifyIfMediaRenderingStarted();
    }
}

void NuPlayer::Renderer::notifyVideoRenderingStart() {
    sp<AMessage> notify = mNotify->dup();
    notify->setInt32("what", kWhatVideoRenderingStart);
    notify->post();
}

void NuPlayer::Renderer::notifyEOS(bool audio, status_t finalResult, int64_t delayUs) {
    sp<AMessage> notify = mNotify->dup();
    notify->setInt32("what", kWhatEOS);
    notify->setInt32("audio", static_cast<int32_t>(audio));
    notify->setInt32("finalResult", finalResult);
    notify->post(delayUs);
}

void NuPlayer::Renderer::notifyAudioOffloadTearDown() {
    (new AMessage(kWhatAudioOffloadTearDown, id()))->post();
}

void NuPlayer::Renderer::onQueueBuffer(const sp<AMessage> &msg) {
    int32_t audio;
    CHECK(msg->findInt32("audio", &audio));

    if (audio) {
        mHasAudio = true;
    } else {
        mHasVideo = true;
    }

    if (dropBufferWhileFlushing(audio, msg)) {
        return;
    }

    sp<ABuffer> buffer;
    CHECK(msg->findBuffer("buffer", &buffer));

    sp<AMessage> notifyConsumed;
    CHECK(msg->findMessage("notifyConsumed", &notifyConsumed));

    QueueEntry entry;
    entry.mBuffer = buffer;
    entry.mNotifyConsumed = notifyConsumed;
    entry.mOffset = 0;
    entry.mFinalResult = OK;

    if (audio) {
        Mutex::Autolock autoLock(mLock);
        mAudioQueue.push_back(entry);
        postDrainAudioQueue_l();
    } else {
        mVideoQueue.push_back(entry);
        postDrainVideoQueue();
    }

    Mutex::Autolock autoLock(mLock);
    if (!mSyncQueues || mAudioQueue.empty() || mVideoQueue.empty()) {
        return;
    }

    sp<ABuffer> firstAudioBuffer = (*mAudioQueue.begin()).mBuffer;
    sp<ABuffer> firstVideoBuffer = (*mVideoQueue.begin()).mBuffer;

    if (firstAudioBuffer == NULL || firstVideoBuffer == NULL) {
        // EOS signalled on either queue.
        syncQueuesDone_l();
        return;
    }

    int64_t firstAudioTimeUs;
    int64_t firstVideoTimeUs;
    CHECK(firstAudioBuffer->meta()
            ->findInt64("timeUs", &firstAudioTimeUs));
    CHECK(firstVideoBuffer->meta()
            ->findInt64("timeUs", &firstVideoTimeUs));

    int64_t diff = firstVideoTimeUs - firstAudioTimeUs;

    ALOGV("queueDiff = %.2f secs", diff / 1E6);

    if (diff > 100000ll) {
        // Audio data starts More than 0.1 secs before video.
        // Drop some audio.

        (*mAudioQueue.begin()).mNotifyConsumed->post();
        mAudioQueue.erase(mAudioQueue.begin());
        return;
    }

    syncQueuesDone_l();
}

void NuPlayer::Renderer::syncQueuesDone_l() {
    if (!mSyncQueues) {
        return;
    }

    mSyncQueues = false;

    if (!mAudioQueue.empty()) {
        postDrainAudioQueue_l();
    }

    if (!mVideoQueue.empty()) {
        postDrainVideoQueue();
    }
}

void NuPlayer::Renderer::onQueueEOS(const sp<AMessage> &msg) {
    int32_t audio;
    CHECK(msg->findInt32("audio", &audio));

    if (dropBufferWhileFlushing(audio, msg)) {
        return;
    }

    int32_t finalResult;
    CHECK(msg->findInt32("finalResult", &finalResult));

    QueueEntry entry;
    entry.mOffset = 0;
    entry.mFinalResult = finalResult;

    if (audio) {
        Mutex::Autolock autoLock(mLock);
        if (mAudioQueue.empty() && mSyncQueues) {
            syncQueuesDone_l();
        }
        mAudioQueue.push_back(entry);
        postDrainAudioQueue_l();
    } else {
        if (mVideoQueue.empty() && mSyncQueues) {
            Mutex::Autolock autoLock(mLock);
            syncQueuesDone_l();
        }
        mVideoQueue.push_back(entry);
        postDrainVideoQueue();
    }
}

void NuPlayer::Renderer::onFlush(const sp<AMessage> &msg) {
    int32_t audio;
    CHECK(msg->findInt32("audio", &audio));

    {
        Mutex::Autolock autoLock(mFlushLock);
        if (audio) {
            mFlushingAudio = false;
        } else {
            mFlushingVideo = false;
        }
    }

    // If we're currently syncing the queues, i.e. dropping audio while
    // aligning the first audio/video buffer times and only one of the
    // two queues has data, we may starve that queue by not requesting
    // more buffers from the decoder. If the other source then encounters
    // a discontinuity that leads to flushing, we'll never find the
    // corresponding discontinuity on the other queue.
    // Therefore we'll stop syncing the queues if at least one of them
    // is flushed.
    {
         Mutex::Autolock autoLock(mLock);
         syncQueuesDone_l();
    }

    ALOGV("flushing %s", audio ? "audio" : "video");
    if (audio) {
        {
            Mutex::Autolock autoLock(mLock);
            flushQueue(&mAudioQueue);

            ++mAudioQueueGeneration;
            prepareForMediaRenderingStart();

            if (offloadingAudio()) {
                mFirstAnchorTimeMediaUs = -1;
            }
        }

        mDrainAudioQueuePending = false;

        if (offloadingAudio()) {
            mAudioSink->pause();
            mAudioSink->flush();
            mAudioSink->start();
        }
    } else {
        flushQueue(&mVideoQueue);

        mDrainVideoQueuePending = false;
        ++mVideoQueueGeneration;

        prepareForMediaRenderingStart();
    }

    mVideoSampleReceived = false;
    notifyFlushComplete(audio);
}

void NuPlayer::Renderer::flushQueue(List<QueueEntry> *queue) {
    while (!queue->empty()) {
        QueueEntry *entry = &*queue->begin();

        if (entry->mBuffer != NULL) {
            entry->mNotifyConsumed->post();
        }

        queue->erase(queue->begin());
        entry = NULL;
    }
}

void NuPlayer::Renderer::notifyFlushComplete(bool audio) {
    sp<AMessage> notify = mNotify->dup();
    notify->setInt32("what", kWhatFlushComplete);
    notify->setInt32("audio", static_cast<int32_t>(audio));
    notify->post();
}

bool NuPlayer::Renderer::dropBufferWhileFlushing(
        bool audio, const sp<AMessage> &msg) {
    bool flushing = false;

    {
        Mutex::Autolock autoLock(mFlushLock);
        if (audio) {
            flushing = mFlushingAudio;
        } else {
            flushing = mFlushingVideo;
        }
    }

    if (!flushing) {
        return false;
    }

    sp<AMessage> notifyConsumed;
    if (msg->findMessage("notifyConsumed", &notifyConsumed)) {
        notifyConsumed->post();
    }

    return true;
}

void NuPlayer::Renderer::onAudioSinkChanged() {
    if (offloadingAudio()) {
        return;
    }
    CHECK(!mDrainAudioQueuePending);
    mNumFramesWritten = 0;
    uint32_t written;
    if (mAudioSink->getFramesWritten(&written) == OK) {
        mNumFramesWritten = written;
    }
}

void NuPlayer::Renderer::onDisableOffloadAudio() {
    Mutex::Autolock autoLock(mLock);
    mFlags &= ~FLAG_OFFLOAD_AUDIO;
    ++mAudioQueueGeneration;
}

void NuPlayer::Renderer::notifyPosition() {
    // notifyPosition() must be called only after setting mAnchorTimeRealUs
    // and mAnchorTimeMediaUs, and must not be paused as it extrapolates position.
    //CHECK_GE(mAnchorTimeRealUs, 0);
    //CHECK_GE(mAnchorTimeMediaUs, 0);
    //CHECK(!mPaused || !mHasAudio);  // video-only does display in paused mode.

    int64_t nowUs = ALooper::GetNowUs();

    if (mLastPositionUpdateUs >= 0
            && nowUs < mLastPositionUpdateUs + kMinPositionUpdateDelayUs) {
        return;
    }
    mLastPositionUpdateUs = nowUs;

    int64_t positionUs = (nowUs - mAnchorTimeRealUs) + mAnchorTimeMediaUs;

    //ALOGD("notifyPosition: positionUs(%lld) nowUs(%lld) mAnchorTimeRealUs(%lld)"
    //        " mAnchorTimeMediaUs(%lld) mFirstAnchorTimeMediaUs(%lld)",
    //        (long long)positionUs, (long long)nowUs, (long long)mAnchorTimeRealUs,
    //        (long long)mAnchorTimeMediaUs, (long long)mFirstAnchorTimeMediaUs);

    // Due to adding the latency to mAnchorTimeRealUs in onDrainAudioQueue(),
    // positionUs may be less than the first media time.  This is avoided
    // here to prevent potential retrograde motion of the position bar
    // when starting up after a seek.
    if (positionUs < mFirstAnchorTimeMediaUs) {
        positionUs = mFirstAnchorTimeMediaUs;
    }
    sp<AMessage> notify = mNotify->dup();
    notify->setInt32("what", kWhatPosition);
    notify->setInt64("positionUs", positionUs);
    notify->setInt64("videoLateByUs", mVideoLateByUs);
    notify->post();
}

void NuPlayer::Renderer::onPause() {
    if (mPaused) {
        ALOGW("Renderer::onPause() called while already paused!");
        return;
    }
    {
        Mutex::Autolock autoLock(mLock);
        ++mAudioQueueGeneration;
        ++mVideoQueueGeneration;
        prepareForMediaRenderingStart();
        mPaused = true;
    }

    mDrainAudioQueuePending = false;
    mDrainVideoQueuePending = false;

    if (mHasAudio) {
        mAudioSink->pause();
        startAudioOffloadPauseTimeout();
    }

    ALOGV("now paused audio queue has %d entries, video has %d entries",
          mAudioQueue.size(), mVideoQueue.size());
}

void NuPlayer::Renderer::onResume() {
    if (!mPaused) {
        return;
    }

    if (mHasAudio) {
        cancelAudioOffloadPauseTimeout();
        mAudioSink->start();
    }

    Mutex::Autolock autoLock(mLock);
    mPaused = false;

    if (!mAudioQueue.empty()) {
        postDrainAudioQueue_l();
    }

    if (!mVideoQueue.empty()) {
        postDrainVideoQueue();
    }
}

// TODO: Remove unnecessary calls to getPlayedOutAudioDurationUs()
// as it acquires locks and may query the audio driver.
//
// Some calls are not needed since notifyPosition() doesn't always deliver a message.
// Some calls could conceivably retrieve extrapolated data instead of
// accessing getTimestamp() or getPosition() every time a data buffer with
// a media time is received.
//
int64_t NuPlayer::Renderer::getPlayedOutAudioDurationUs(int64_t nowUs) {
    uint32_t numFramesPlayed;
    int64_t numFramesPlayedAt;
    AudioTimestamp ts;
    static const int64_t kStaleTimestamp100ms = 100000;

    status_t res = mAudioSink->getTimestamp(ts);
    if (res == OK) {                 // case 1: mixing audio tracks and offloaded tracks.
        numFramesPlayed = ts.mPosition;
        numFramesPlayedAt =
            ts.mTime.tv_sec * 1000000LL + ts.mTime.tv_nsec / 1000;
        const int64_t timestampAge = nowUs - numFramesPlayedAt;
        if (timestampAge > kStaleTimestamp100ms) {
            // This is an audio FIXME.
            // getTimestamp returns a timestamp which may come from audio mixing threads.
            // After pausing, the MixerThread may go idle, thus the mTime estimate may
            // become stale. Assuming that the MixerThread runs 20ms, with FastMixer at 5ms,
            // the max latency should be about 25ms with an average around 12ms (to be verified).
            // For safety we use 100ms.
            ALOGW("getTimestamp: returned stale timestamp nowUs(%lld) numFramesPlayedAt(%lld)",
                    (long long)nowUs, (long long)numFramesPlayedAt);
            numFramesPlayedAt = nowUs - kStaleTimestamp100ms;
        }
        //ALOGD("getTimestamp: OK %d %lld", numFramesPlayed, (long long)numFramesPlayedAt);
    } else if (res == WOULD_BLOCK) { // case 2: transitory state on start of a new track
        numFramesPlayed = 0;
        numFramesPlayedAt = nowUs;
        //ALOGD("getTimestamp: WOULD_BLOCK %d %lld",
        //        numFramesPlayed, (long long)numFramesPlayedAt);
    } else {                         // case 3: transitory at new track or audio fast tracks.
        res = mAudioSink->getPosition(&numFramesPlayed);
        CHECK_EQ(res, (status_t)OK);
        numFramesPlayedAt = nowUs;
        numFramesPlayedAt += 1000LL * mAudioSink->latency() / 2; /* XXX */
        //ALOGD("getPosition: %d %lld", numFramesPlayed, numFramesPlayedAt);
    }

    // TODO: remove the (int32_t) casting below as it may overflow at 12.4 hours.
    //CHECK_EQ(numFramesPlayed & (1 << 31), 0);  // can't be negative until 12.4 hrs, test
    int64_t durationUs = (int32_t)numFramesPlayed * 1000LL * mAudioSink->msecsPerFrame()
            + nowUs - numFramesPlayedAt;
    if (durationUs < 0) {
        // Occurs when numFramesPlayed position is very small and the following:
        // (1) In case 1, the time nowUs is computed before getTimestamp() is called and
        //     numFramesPlayedAt is greater than nowUs by time more than numFramesPlayed.
        // (2) In case 3, using getPosition and adding mAudioSink->latency() to
        //     numFramesPlayedAt, by a time amount greater than numFramesPlayed.
        //
        // Both of these are transitory conditions.
        ALOGW("getPlayedOutAudioDurationUs: negative timestamp %lld set to zero", (long long)durationUs);
        durationUs = 0;
    }
    ALOGV("getPlayedOutAudioDurationUs(%lld) nowUs(%lld) frames(%u) framesAt(%lld)",
            (long long)durationUs, (long long)nowUs, numFramesPlayed, (long long)numFramesPlayedAt);
    return durationUs;
}

void NuPlayer::Renderer::onAudioOffloadTearDown() {
    if (mAudioOffloadTornDown) {
        return;
    }
    mAudioOffloadTornDown = true;

    int64_t firstAudioTimeUs;
    {
        Mutex::Autolock autoLock(mLock);
        firstAudioTimeUs = mFirstAnchorTimeMediaUs;
    }

    int64_t currentPositionUs =
        firstAudioTimeUs + getPlayedOutAudioDurationUs(ALooper::GetNowUs());

    mAudioSink->stop();
    mAudioSink->flush();

    sp<AMessage> notify = mNotify->dup();
    notify->setInt32("what", kWhatAudioOffloadTearDown);
    notify->setInt64("positionUs", currentPositionUs);
    notify->post();
}

void NuPlayer::Renderer::startAudioOffloadPauseTimeout() {
    if (offloadingAudio()) {
        sp<AMessage> msg = new AMessage(kWhatAudioOffloadPauseTimeout, id());
        msg->setInt32("generation", mAudioOffloadPauseTimeoutGeneration);
        msg->post(kOffloadPauseMaxUs);
    }
}

void NuPlayer::Renderer::cancelAudioOffloadPauseTimeout() {
    if (offloadingAudio()) {
        ++mAudioOffloadPauseTimeoutGeneration;
    }
}

}  // namespace android