| /* |
| * Copyright (C) 2016 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. |
| */ |
| |
| package com.android.tv.util; |
| |
| import java.util.concurrent.TimeUnit; |
| |
| /** A class that includes convenience methods for time shift plays. */ |
| public class TimeShiftUtils { |
| private static final String TAG = "TimeShiftUtils"; |
| private static final boolean DEBUG = false; |
| |
| private static final long SHORT_PROGRAM_THRESHOLD_MILLIS = TimeUnit.MINUTES.toMillis(46); |
| private static final int[] SHORT_PROGRAM_SPEED_FACTORS = new int[] {2, 4, 12, 48}; |
| private static final int[] LONG_PROGRAM_SPEED_FACTORS = new int[] {2, 8, 32, 128}; |
| |
| /** |
| * The maximum play speed level support by time shift play. In other words, the valid speed |
| * levels are ranged from 0 to MAX_SPEED_LEVEL (included). |
| */ |
| public static final int MAX_SPEED_LEVEL = SHORT_PROGRAM_SPEED_FACTORS.length - 1; |
| |
| /** |
| * Returns real speeds used in time shift play. This method is only for fast-forwarding and |
| * rewinding. The normal play speed is not addressed here. |
| * |
| * @param speedLevel the valid value is ranged from 0 to {@link #MAX_SPEED_LEVEL}. |
| * @param programDurationMillis the length of program under playing. |
| * @throws IndexOutOfBoundsException if speed level is out of its range. |
| */ |
| public static int getPlaybackSpeed(int speedLevel, long programDurationMillis) |
| throws IndexOutOfBoundsException { |
| return (programDurationMillis > SHORT_PROGRAM_THRESHOLD_MILLIS) |
| ? LONG_PROGRAM_SPEED_FACTORS[speedLevel] |
| : SHORT_PROGRAM_SPEED_FACTORS[speedLevel]; |
| } |
| |
| /** |
| * Returns the maxium possible play speed according to the program's length. |
| * |
| * @param programDurationMillis the length of program under playing. |
| */ |
| public static int getMaxPlaybackSpeed(long programDurationMillis) { |
| return (programDurationMillis > SHORT_PROGRAM_THRESHOLD_MILLIS) |
| ? LONG_PROGRAM_SPEED_FACTORS[MAX_SPEED_LEVEL] |
| : SHORT_PROGRAM_SPEED_FACTORS[MAX_SPEED_LEVEL]; |
| } |
| } |