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Commit 9025cc09 authored by Andy Hung's avatar Andy Hung
Browse files

AudioTrack: Enable deep buffer under certain conditions 

Under certain conditions, i.e. USAGE_MEDIA and
CONTENT_TYPE UNKNOWN, MUSIC, MOVIE and large buffers
we route the AudioTrack to deep buffer to save power.

Change-Id: Ibc8a31750999da842e36156f939448989ee50511
Test: Play Movies, CTS
Bug: 30687201
parent e9b83480

media/java/android/media/AudioTrack.java

+64 −1
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ import java.util.Collection; 


import android.annotation.IntDef;

import android.annotation.NonNull;

import android.annotation.Nullable;

import android.app.ActivityThread;

import android.content.Context;

import android.os.Handler;
@@ -538,6 +539,15 @@ public class AudioTrack extends PlayerBase 
            throw new IllegalArgumentException("Illegal null AudioFormat");

        }



        // Check if we should enable deep buffer mode

        if (shouldEnablePowerSaving(mAttributes, format, bufferSizeInBytes, mode)) {

            mAttributes = new AudioAttributes.Builder(mAttributes)

                .replaceFlags((mAttributes.getAllFlags()

                        | AudioAttributes.FLAG_DEEP_BUFFER)

                        & ~AudioAttributes.FLAG_LOW_LATENCY)

                .build();

        }



        // remember which looper is associated with the AudioTrack instantiation

        Looper looper;

        if ((looper = Looper.myLooper()) == null) {
@@ -861,7 +871,10 @@ public class AudioTrack extends PlayerBase 
                    .build();

                break;

            case PERFORMANCE_MODE_NONE:

                break;

                if (!shouldEnablePowerSaving(mAttributes, mFormat, mBufferSizeInBytes, mMode)) {

                    break; // do not enable deep buffer mode.

                }

                // permitted to fall through to enable deep buffer

            case PERFORMANCE_MODE_POWER_SAVING:

                mAttributes = new AudioAttributes.Builder(mAttributes)

                .replaceFlags((mAttributes.getAllFlags()
@@ -912,6 +925,56 @@ public class AudioTrack extends PlayerBase 
            AudioFormat.CHANNEL_OUT_SIDE_LEFT |

            AudioFormat.CHANNEL_OUT_SIDE_RIGHT;



    // Returns a boolean whether the attributes, format, bufferSizeInBytes, mode allow

    // power saving to be automatically enabled for an AudioTrack. Returns false if

    // power saving is already enabled in the attributes parameter.

    private static boolean shouldEnablePowerSaving(

            @Nullable AudioAttributes attributes, @Nullable AudioFormat format,

            int bufferSizeInBytes, int mode) {

        // If no attributes, OK

        // otherwise check attributes for USAGE_MEDIA and CONTENT_UNKNOWN, MUSIC, or MOVIE.

        if (attributes != null &&

                (attributes.getAllFlags() != 0  // cannot have any special flags

                || attributes.getUsage() != AudioAttributes.USAGE_MEDIA

                || (attributes.getContentType() != AudioAttributes.CONTENT_TYPE_UNKNOWN

                    && attributes.getContentType() != AudioAttributes.CONTENT_TYPE_MUSIC

                    && attributes.getContentType() != AudioAttributes.CONTENT_TYPE_MOVIE))) {

            return false;

        }



        // Format must be fully specified and be linear pcm

        if (format == null

                || format.getSampleRate() == AudioFormat.SAMPLE_RATE_UNSPECIFIED

                || !AudioFormat.isEncodingLinearPcm(format.getEncoding())

                || !AudioFormat.isValidEncoding(format.getEncoding())

                || format.getChannelCount() < 1) {

            return false;

        }



        // Mode must be streaming

        if (mode != MODE_STREAM) {

            return false;

        }



        // A buffer size of 0 is always compatible with deep buffer (when called from the Builder)

        // but for app compatibility we only use deep buffer power saving for large buffer sizes.

        if (bufferSizeInBytes != 0) {

            final long BUFFER_TARGET_MODE_STREAM_MS = 100;

            final int MILLIS_PER_SECOND = 1000;

            final long bufferTargetSize =

                    BUFFER_TARGET_MODE_STREAM_MS

                    * format.getChannelCount()

                    * format.getBytesPerSample(format.getEncoding())

                    * format.getSampleRate()

                    / MILLIS_PER_SECOND;

            if (bufferSizeInBytes < bufferTargetSize) {

                return false;

            }

        }



        return true;

    }



    // Convenience method for the constructor's parameter checks.

    // This is where constructor IllegalArgumentException-s are thrown

    // postconditions: