1/* 2 * Copyright 2015 The WebRTC Project Authors. All rights reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11package org.appspot.apprtc; 12 13import android.widget.SeekBar; 14import android.widget.TextView; 15 16import org.webrtc.CameraEnumerationAndroid.CaptureFormat; 17 18import java.util.Arrays; 19import java.util.Collections; 20import java.util.Comparator; 21import java.util.List; 22 23/** 24 * Control capture format based on a seekbar listener. 25 */ 26public class CaptureQualityController implements SeekBar.OnSeekBarChangeListener { 27 private final List<CaptureFormat> formats = Arrays.asList( 28 new CaptureFormat(1280, 720, 0, 30000), 29 new CaptureFormat(640, 480, 0, 30000), 30 new CaptureFormat(320, 240, 0, 30000), 31 new CaptureFormat(256, 144, 0, 30000)); 32 // Prioritize framerate below this threshold and resolution above the threshold. 33 private static final int FRAMERATE_THRESHOLD = 15; 34 private TextView captureFormatText; 35 private CallFragment.OnCallEvents callEvents; 36 private int width = 0; 37 private int height = 0; 38 private int framerate = 0; 39 private double targetBandwidth = 0; 40 41 public CaptureQualityController( 42 TextView captureFormatText, CallFragment.OnCallEvents callEvents) { 43 this.captureFormatText = captureFormatText; 44 this.callEvents = callEvents; 45 } 46 47 private final Comparator<CaptureFormat> compareFormats = new Comparator<CaptureFormat>() { 48 @Override 49 public int compare(CaptureFormat first, CaptureFormat second) { 50 int firstFps = calculateFramerate(targetBandwidth, first); 51 int secondFps = calculateFramerate(targetBandwidth, second); 52 53 if (firstFps >= FRAMERATE_THRESHOLD && secondFps >= FRAMERATE_THRESHOLD 54 || firstFps == secondFps) { 55 // Compare resolution. 56 return first.width * first.height - second.width * second.height; 57 } else { 58 // Compare fps. 59 return firstFps - secondFps; 60 } 61 } 62 }; 63 64 @Override 65 public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) { 66 if (progress == 0) { 67 width = 0; 68 height = 0; 69 framerate = 0; 70 captureFormatText.setText("Muted"); 71 return; 72 } 73 74 // Extract max bandwidth (in millipixels / second). 75 long maxCaptureBandwidth = java.lang.Long.MIN_VALUE; 76 for (CaptureFormat format : formats) { 77 maxCaptureBandwidth = Math.max(maxCaptureBandwidth, 78 (long) format.width * format.height * format.maxFramerate); 79 } 80 81 // Fraction between 0 and 1. 82 double bandwidthFraction = (double) progress / 100.0; 83 // Make a log-scale transformation, still between 0 and 1. 84 final double kExpConstant = 3.0; 85 bandwidthFraction = 86 (Math.exp(kExpConstant * bandwidthFraction) - 1) / (Math.exp(kExpConstant) - 1); 87 targetBandwidth = bandwidthFraction * maxCaptureBandwidth; 88 89 // Choose the best format given a target bandwidth. 90 final CaptureFormat bestFormat = Collections.max(formats, compareFormats); 91 width = bestFormat.width; 92 height = bestFormat.height; 93 framerate = calculateFramerate(targetBandwidth, bestFormat); 94 captureFormatText.setText(width + "x" + height + " @ " + framerate + "fps"); 95 } 96 97 @Override 98 public void onStartTrackingTouch(SeekBar seekBar) { 99 } 100 101 @Override 102 public void onStopTrackingTouch(SeekBar seekBar) { 103 callEvents.onCaptureFormatChange(width, height, framerate); 104 } 105 106 // Return the highest frame rate possible based on bandwidth and format. 107 private int calculateFramerate(double bandwidth, CaptureFormat format) { 108 return (int) Math.round(Math.min(format.maxFramerate, 109 (int) Math.round(bandwidth / (format.width * format.height))) / 1000.0); 110 } 111} 112 113