86 lines
2.8 KiB
Java
86 lines
2.8 KiB
Java
/*
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* Copyright 2015 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package android.media;
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/**
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* An immutable object that represents the linear correlation between the media time
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* and the system time. It contains the media clock rate, together with the media timestamp
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* of an anchor frame and the system time when that frame was presented or is committed
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* to be presented.
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* <p>
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* The phrase "present" means that audio/video produced on device is detectable by an external
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* observer off device.
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* The time is based on the implementation's best effort, using whatever knowledge
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* is available to the system, but cannot account for any delay unknown to the implementation.
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* The anchor frame could be any frame, including a just-rendered frame, or even a theoretical
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* or in-between frame, based on the source of the MediaTimestamp.
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* When the anchor frame is a just-rendered one, the media time stands for
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* current position of the playback or recording.
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*
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* @see MediaSync#getTimestamp
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* @see MediaPlayer#getTimestamp
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*/
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public final class MediaTimestamp
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{
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/**
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* Get the media time of the anchor in microseconds.
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*/
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public long getAnchorMediaTimeUs() {
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return mediaTimeUs;
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}
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/**
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* Get the {@link java.lang.System#nanoTime system time} corresponding to the media time
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* in nanoseconds.
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*/
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public long getAnchorSytemNanoTime() {
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return nanoTime;
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}
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/**
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* Get the rate of the media clock in relation to the system time.
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* <p>
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* It is 1.0 if media clock advances in sync with the system clock;
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* greater than 1.0 if media clock is faster than the system clock;
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* less than 1.0 if media clock is slower than the system clock.
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*/
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public float getMediaClockRate() {
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return clockRate;
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}
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/** @hide - accessor shorthand */
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public final long mediaTimeUs;
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/** @hide - accessor shorthand */
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public final long nanoTime;
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/** @hide - accessor shorthand */
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public final float clockRate;
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/** @hide */
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MediaTimestamp(long mediaUs, long systemNs, float rate) {
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mediaTimeUs = mediaUs;
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nanoTime = systemNs;
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clockRate = rate;
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}
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/** @hide */
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MediaTimestamp() {
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mediaTimeUs = 0;
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nanoTime = 0;
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clockRate = 1.0f;
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}
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}
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