aaudio: lower latency using MMAP capture
MMAP can be enabled by setting system properties.
Bug: 38267780
Test: input_monitor.cpp
Change-Id: I5e86fd1d9baef4fe59837ccbca7971acbb54d8b5
Signed-off-by: Phil Burk <philburk@google.com>
diff --git a/media/libaaudio/src/client/AudioStreamInternalCapture.h b/media/libaaudio/src/client/AudioStreamInternalCapture.h
new file mode 100644
index 0000000..17f37e8
--- /dev/null
+++ b/media/libaaudio/src/client/AudioStreamInternalCapture.h
@@ -0,0 +1,75 @@
+/*
+ * Copyright (C) 2017 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.
+ */
+#ifndef ANDROID_AAUDIO_AUDIO_STREAM_INTERNAL_CAPTURE_H
+#define ANDROID_AAUDIO_AUDIO_STREAM_INTERNAL_CAPTURE_H
+
+#include <stdint.h>
+#include <aaudio/AAudio.h>
+
+#include "binding/AAudioServiceInterface.h"
+#include "client/AudioStreamInternal.h"
+
+using android::sp;
+using android::IAAudioService;
+
+namespace aaudio {
+
+class AudioStreamInternalCapture : public AudioStreamInternal {
+public:
+ AudioStreamInternalCapture(AAudioServiceInterface &serviceInterface, bool inService = false);
+ virtual ~AudioStreamInternalCapture();
+
+ aaudio_result_t read(void *buffer,
+ int32_t numFrames,
+ int64_t timeoutNanoseconds) override;
+
+ int64_t getFramesRead() override;
+ int64_t getFramesWritten() override;
+
+ void *callbackLoop() override;
+
+ aaudio_direction_t getDirection() const override {
+ return AAUDIO_DIRECTION_INPUT;
+ }
+protected:
+
+/**
+ * Low level data processing that will not block. It will just read or write as much as it can.
+ *
+ * It passes back a recommended time to wake up if wakeTimePtr is not NULL.
+ *
+ * @return the number of frames processed or a negative error code.
+ */
+ aaudio_result_t processDataNow(void *buffer,
+ int32_t numFrames,
+ int64_t currentTimeNanos,
+ int64_t *wakeTimePtr) override;
+
+private:
+ /*
+ * Asynchronous read with data conversion.
+ * @param buffer
+ * @param numFrames
+ * @return frames written or negative error
+ */
+ aaudio_result_t readNowWithConversion(void *buffer, int32_t numFrames);
+
+ int64_t mLastFramesWritten = 0; // used to prevent retrograde motion
+};
+
+} /* namespace aaudio */
+
+#endif //ANDROID_AAUDIO_AUDIO_STREAM_INTERNAL_CAPTURE_H