Skip to content

Commit

Permalink
Create AudioRecord by reflection as a fallback
Browse files Browse the repository at this point in the history 
Some devices (Vivo phones) fail to create an AudioRecord from an
AudioRecord.Builder (which throws a NullPointerException).

In that case, create an AudioRecord instance directly by reflection.

The AOSP version of AudioRecord constructor code can be found at:
 - Android 11 (R):
   <https://cs.android.com/android/platform/superproject/+/android-11.0.0_r1:frameworks/base/media/java/android/media/AudioRecord.java;l=335;drc=64ed2ec38a511bbbd048985fe413268335e072f8>
 - Android 12 (S):
   <https://cs.android.com/android/platform/superproject/+/android-12.0.0_r1:frameworks/base/media/java/android/media/AudioRecord.java;l=388;drc=2eebf929650e0d320a21f0d13677a27d7ab278e9>
 - Android 13 (T, functionally identical to Android 12):
   <https://cs.android.com/android/platform/superproject/+/android-13.0.0_r1:frameworks/base/media/java/android/media/AudioRecord.java;l=382;drc=ed242da52f975a1dd18671afb346b18853d729f2>
 - Android 14 (U): Not released, but expected to change

PR #3862 <#3862>
Fixes #3805 <#3805>

Signed-off-by: Romain Vimont <[email protected]>
  • Loading branch information
@yume-chan @rom1v
yume-chan authored and rom1v committed May 26, 2023
1 parent 597d2cc commit cab3541
Show file tree
Hide file tree
Showing 2 changed files with 154 additions and 1 deletion.
10 changes: 9 additions & 1 deletion server/src/main/java/com/genymobile/scrcpy/AudioCapture.java
View file
Original file line number Diff line number Diff line change
Expand Up @@ -22,6 +22,7 @@ public final class AudioCapture {
public static final int SAMPLE_RATE = 48000;
public static final int CHANNEL_CONFIG = AudioFormat.CHANNEL_IN_STEREO;
public static final int CHANNELS = 2;
public static final int CHANNEL_MASK = AudioFormat.CHANNEL_IN_LEFT | AudioFormat.CHANNEL_IN_RIGHT;
public static final int ENCODING = AudioFormat.ENCODING_PCM_16BIT;
public static final int BYTES_PER_SAMPLE = 2;

Expand Down Expand Up @@ -98,7 +99,14 @@ private void tryStartRecording(int attempts, int delayMs) throws AudioCaptureFor
}

private void startRecording() {
recorder = createAudioRecord();
try {
recorder = createAudioRecord();
} catch (NullPointerException e) {
// Creating an AudioRecord using an AudioRecord.Builder does not work on Vivo phones:
// - <https://github.com/Genymobile/scrcpy/issues/3805>
// - <https://github.com/Genymobile/scrcpy/pull/3862>
recorder = Workarounds.createAudioRecord(SOURCE, SAMPLE_RATE, CHANNEL_CONFIG, CHANNELS, CHANNEL_MASK, ENCODING);
}
recorder.startRecording();
}

Expand Down
145 changes: 145 additions & 0 deletions server/src/main/java/com/genymobile/scrcpy/Workarounds.java
View file
Original file line number Diff line number Diff line change
@@ -1,13 +1,22 @@
package com.genymobile.scrcpy;

import android.annotation.SuppressLint;
import android.annotation.TargetApi;
import android.app.Application;
import android.content.AttributionSource;
import android.content.ContextWrapper;
import android.content.pm.ApplicationInfo;
import android.media.AudioAttributes;
import android.media.AudioManager;
import android.media.AudioRecord;
import android.os.Build;
import android.os.Looper;
import android.os.Parcel;

import java.lang.ref.WeakReference;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.Method;

public final class Workarounds {

Expand Down Expand Up @@ -95,4 +104,140 @@ public static void fillAppContext() {
Ln.d("Could not fill app context: " + throwable.getMessage());
}
}

@TargetApi(Build.VERSION_CODES.R)
@SuppressLint({"WrongConstant", "MissingPermission", "BlockedPrivateApi", "SoonBlockedPrivateApi"})
public static AudioRecord createAudioRecord(int source, int sampleRate, int channelConfig, int channels, int channelMask, int encoding) {
// Vivo (and maybe some other third-party ROMs) modified `AudioRecord`'s constructor, requiring `Context`s from real App environment.
//
// This method invokes the `AudioRecord(long nativeRecordInJavaObj)` constructor to create an empty `AudioRecord` instance, then uses
// reflections to initialize it like the normal constructor do (or the `AudioRecord.Builder.build()` method do).
// As a result, the modified code was not executed.
try {
// AudioRecord audioRecord = new AudioRecord(0L);
Constructor<AudioRecord> audioRecordConstructor = AudioRecord.class.getDeclaredConstructor(long.class);
audioRecordConstructor.setAccessible(true);
AudioRecord audioRecord = audioRecordConstructor.newInstance(0L);

// audioRecord.mRecordingState = RECORDSTATE_STOPPED;
Field mRecordingStateField = AudioRecord.class.getDeclaredField("mRecordingState");
mRecordingStateField.setAccessible(true);
mRecordingStateField.set(audioRecord, AudioRecord.RECORDSTATE_STOPPED);

Looper looper = Looper.myLooper();
if (looper == null) {
looper = Looper.getMainLooper();
}

// audioRecord.mInitializationLooper = looper;
Field mInitializationLooperField = AudioRecord.class.getDeclaredField("mInitializationLooper");
mInitializationLooperField.setAccessible(true);
mInitializationLooperField.set(audioRecord, looper);

// Create `AudioAttributes` with fixed capture preset
int capturePreset = source;
AudioAttributes.Builder audioAttributesBuilder = new AudioAttributes.Builder();
Method setInternalCapturePresetMethod = AudioAttributes.Builder.class.getMethod("setInternalCapturePreset", int.class);
setInternalCapturePresetMethod.invoke(audioAttributesBuilder, capturePreset);
AudioAttributes attributes = audioAttributesBuilder.build();

// audioRecord.mAudioAttributes = attributes;
Field mAudioAttributesField = AudioRecord.class.getDeclaredField("mAudioAttributes");
mAudioAttributesField.setAccessible(true);
mAudioAttributesField.set(audioRecord, attributes);

// audioRecord.audioParamCheck(capturePreset, sampleRate, encoding);
Method audioParamCheckMethod = AudioRecord.class.getDeclaredMethod("audioParamCheck", int.class, int.class, int.class);
audioParamCheckMethod.setAccessible(true);
audioParamCheckMethod.invoke(audioRecord, capturePreset, sampleRate, encoding);

// audioRecord.mChannelCount = channels
Field mChannelCountField = AudioRecord.class.getDeclaredField("mChannelCount");
mChannelCountField.setAccessible(true);
mChannelCountField.set(audioRecord, channels);

// audioRecord.mChannelMask = channelMask
Field mChannelMaskField = AudioRecord.class.getDeclaredField("mChannelMask");
mChannelMaskField.setAccessible(true);
mChannelMaskField.set(audioRecord, channelMask);

int minBufferSize = AudioRecord.getMinBufferSize(sampleRate, channelConfig, encoding);
int bufferSizeInBytes = minBufferSize * 8;

// audioRecord.audioBuffSizeCheck(bufferSizeInBytes)
Method audioBuffSizeCheckMethod = AudioRecord.class.getDeclaredMethod("audioBuffSizeCheck", int.class);
audioBuffSizeCheckMethod.setAccessible(true);
audioBuffSizeCheckMethod.invoke(audioRecord, bufferSizeInBytes);

final int channelIndexMask = 0;

int[] sampleRateArray = new int[]{sampleRate};
int[] session = new int[]{AudioManager.AUDIO_SESSION_ID_GENERATE};

int initResult;
if (Build.VERSION.SDK_INT < Build.VERSION_CODES.S) {
// private native final int native_setup(Object audiorecord_this,
// Object /*AudioAttributes*/ attributes,
// int[] sampleRate, int channelMask, int channelIndexMask, int audioFormat,
// int buffSizeInBytes, int[] sessionId, String opPackageName,
// long nativeRecordInJavaObj);
Method nativeSetupMethod = AudioRecord.class.getDeclaredMethod("native_setup", Object.class, Object.class, int[].class, int.class,
int.class, int.class, int.class, int[].class, String.class, long.class);
nativeSetupMethod.setAccessible(true);
initResult = (int) nativeSetupMethod.invoke(audioRecord, new WeakReference<AudioRecord>(audioRecord), attributes, sampleRateArray,
channelMask, channelIndexMask, audioRecord.getAudioFormat(), bufferSizeInBytes, session, FakeContext.get().getOpPackageName(),
0L);
} else {
// Assume `context` is never `null`
AttributionSource attributionSource = FakeContext.get().getAttributionSource();

// Assume `attributionSource.getPackageName()` is never null

// ScopedParcelState attributionSourceState = attributionSource.asScopedParcelState()
Method asScopedParcelStateMethod = AttributionSource.class.getDeclaredMethod("asScopedParcelState");
asScopedParcelStateMethod.setAccessible(true);

try (AutoCloseable attributionSourceState = (AutoCloseable) asScopedParcelStateMethod.invoke(attributionSource)) {
Method getParcelMethod = attributionSourceState.getClass().getDeclaredMethod("getParcel");
Parcel attributionSourceParcel = (Parcel) getParcelMethod.invoke(attributionSourceState);

// private native int native_setup(Object audiorecordThis,
// Object /*AudioAttributes*/ attributes,
// int[] sampleRate, int channelMask, int channelIndexMask, int audioFormat,
// int buffSizeInBytes, int[] sessionId, @NonNull Parcel attributionSource,
// long nativeRecordInJavaObj, int maxSharedAudioHistoryMs);
Method nativeSetupMethod = AudioRecord.class.getDeclaredMethod("native_setup", Object.class, Object.class, int[].class, int.class,
int.class, int.class, int.class, int[].class, Parcel.class, long.class, int.class);
nativeSetupMethod.setAccessible(true);
initResult = (int) nativeSetupMethod.invoke(audioRecord, new WeakReference<AudioRecord>(audioRecord), attributes, sampleRateArray,
channelMask, channelIndexMask, audioRecord.getAudioFormat(), bufferSizeInBytes, session, attributionSourceParcel, 0L, 0);
}
}

if (initResult != AudioRecord.SUCCESS) {
Ln.e("Error code " + initResult + " when initializing native AudioRecord object.");
throw new RuntimeException("Cannot create AudioRecord");
}

// mSampleRate = sampleRate[0]
Field mSampleRateField = AudioRecord.class.getDeclaredField("mSampleRate");
mSampleRateField.setAccessible(true);
mSampleRateField.set(audioRecord, sampleRateArray[0]);

// audioRecord.mSessionId = session[0]
Field mSessionIdField = AudioRecord.class.getDeclaredField("mSessionId");
mSessionIdField.setAccessible(true);
mSessionIdField.set(audioRecord, session[0]);

// audioRecord.mState = AudioRecord.STATE_INITIALIZED
Field mStateField = AudioRecord.class.getDeclaredField("mState");
mStateField.setAccessible(true);
mStateField.set(audioRecord, AudioRecord.STATE_INITIALIZED);

return audioRecord;
} catch (Exception e) {
Ln.e("Failed to invoke AudioRecord.<init>.", e);
throw new RuntimeException("Cannot create AudioRecord");
}
}
}

0 comments on commit cab3541

Please sign in to comment.