media/libstagefright/MediaClock.cpp

/*
 * Copyright (C) 2015 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 "MediaClock"
#include <utils/Log.h>

#include <media/stagefright/MediaClock.h>

#include <media/stagefright/foundation/ADebug.h>
#include <media/stagefright/foundation/ALooper.h>

namespace android {

MediaClock::MediaClock()
    : mAnchorTimeMediaUs(-1),
      mAnchorTimeRealUs(-1),
      mMaxTimeMediaUs(INT64_MAX),
      mStartingTimeMediaUs(-1),
      mPlaybackRate(1.0) {
}

MediaClock::~MediaClock() {
}

void MediaClock::setStartingTimeMedia(int64_t startingTimeMediaUs) {
    Mutex::Autolock autoLock(mLock);
    mStartingTimeMediaUs = startingTimeMediaUs;
}

void MediaClock::clearAnchor() {
    Mutex::Autolock autoLock(mLock);
    mAnchorTimeMediaUs = -1;
    mAnchorTimeRealUs = -1;
}

void MediaClock::updateAnchor(
        int64_t anchorTimeMediaUs,
        int64_t anchorTimeRealUs,
        int64_t maxTimeMediaUs) {
    if (anchorTimeMediaUs < 0 || anchorTimeRealUs < 0) {
        ALOGW("reject anchor time since it is negative.");
        return;
    }

    Mutex::Autolock autoLock(mLock);
    int64_t nowUs = ALooper::GetNowUs();
    int64_t nowMediaUs =
        anchorTimeMediaUs + (nowUs - anchorTimeRealUs) * (double)mPlaybackRate;
    if (nowMediaUs < 0) {
        ALOGW("reject anchor time since it leads to negative media time.");
        return;
    }
    mAnchorTimeRealUs = nowUs;
    mAnchorTimeMediaUs = nowMediaUs;
    mMaxTimeMediaUs = maxTimeMediaUs;
}

void MediaClock::updateMaxTimeMedia(int64_t maxTimeMediaUs) {
    Mutex::Autolock autoLock(mLock);
    mMaxTimeMediaUs = maxTimeMediaUs;
}

void MediaClock::setPlaybackRate(float rate) {
    CHECK_GE(rate, 0.0);
    Mutex::Autolock autoLock(mLock);
    if (mAnchorTimeRealUs == -1) {
        mPlaybackRate = rate;
        return;
    }

    int64_t nowUs = ALooper::GetNowUs();
    mAnchorTimeMediaUs += (nowUs - mAnchorTimeRealUs) * (double)mPlaybackRate;
    if (mAnchorTimeMediaUs < 0) {
        ALOGW("setRate: anchor time should not be negative, set to 0.");
        mAnchorTimeMediaUs = 0;
    }
    mAnchorTimeRealUs = nowUs;
    mPlaybackRate = rate;
}

float MediaClock::getPlaybackRate() const {
    Mutex::Autolock autoLock(mLock);
    return mPlaybackRate;
}

status_t MediaClock::getMediaTime(
        int64_t realUs, int64_t *outMediaUs, bool allowPastMaxTime) const {
    if (outMediaUs == NULL) {
        return BAD_VALUE;
    }

    Mutex::Autolock autoLock(mLock);
    return getMediaTime_l(realUs, outMediaUs, allowPastMaxTime);
}

status_t MediaClock::getMediaTime_l(
        int64_t realUs, int64_t *outMediaUs, bool allowPastMaxTime) const {
    if (mAnchorTimeRealUs == -1) {
        return NO_INIT;
    }

    int64_t mediaUs = mAnchorTimeMediaUs
            + (realUs - mAnchorTimeRealUs) * (double)mPlaybackRate;
    if (mediaUs > mMaxTimeMediaUs && !allowPastMaxTime) {
        mediaUs = mMaxTimeMediaUs;
    }
    if (mediaUs < mStartingTimeMediaUs) {
        mediaUs = mStartingTimeMediaUs;
    }
    if (mediaUs < 0) {
        mediaUs = 0;
    }
    *outMediaUs = mediaUs;
    return OK;
}

status_t MediaClock::getRealTimeFor(
        int64_t targetMediaUs, int64_t *outRealUs) const {
    if (outRealUs == NULL) {
        return BAD_VALUE;
    }

    Mutex::Autolock autoLock(mLock);
    if (mPlaybackRate == 0.0) {
        return NO_INIT;
    }

    int64_t nowUs = ALooper::GetNowUs();
    int64_t nowMediaUs;
    status_t status =
            getMediaTime_l(nowUs, &nowMediaUs, true /* allowPastMaxTime */);
    if (status != OK) {
        return status;
    }
    *outRealUs = (targetMediaUs - nowMediaUs) / (double)mPlaybackRate + nowUs;
    return OK;
}

}  // namespace android