Merge "aaudio: offset MMAP timestamps" (b362012a) · Commits · e / os / android_frameworks_av

media/libaaudio/src/client/AudioStreamInternal.cpp

+20 −1

Original line number	Diff line number	Diff line
		@@ -232,6 +232,24 @@ aaudio_result_t AudioStreamInternal::open(const AudioStreamBuilder &builder) {
		mCallbackBuffer = new uint8_t[callbackBufferSize];
		}

		// For debugging and analyzing the distribution of MMAP timestamps.
		// For OUTPUT, use a NEGATIVE offset to move the CPU writes further BEFORE the HW reads.
		// For INPUT, use a POSITIVE offset to move the CPU reads further AFTER the HW writes.
		// You can use this offset to reduce glitching.
		// You can also use this offset to force glitching. By iterating over multiple
		// values you can reveal the distribution of the hardware timing jitter.
		if (mAudioEndpoint.isFreeRunning()) { // MMAP?
		int32_t offsetMicros = (getDirection() == AAUDIO_DIRECTION_OUTPUT)
		? AAudioProperty_getOutputMMapOffsetMicros()
		: AAudioProperty_getInputMMapOffsetMicros();
		// This log is used to debug some tricky glitch issues. Please leave.
		ALOGD_IF(offsetMicros, "%s() - %s mmap offset = %d micros",
		__func__,
		(getDirection() == AAUDIO_DIRECTION_OUTPUT) ? "output" : "input",
		offsetMicros);
		mTimeOffsetNanos = offsetMicros * AAUDIO_NANOS_PER_MICROSECOND;
		}

		setState(AAUDIO_STREAM_STATE_OPEN);

		return result;
		@@ -478,7 +496,8 @@ aaudio_result_t AudioStreamInternal::onTimestampService(AAudioServiceMessage *me
		#if LOG_TIMESTAMPS
		logTimestamp(*message);
		#endif
		processTimestamp(message->timestamp.position, message->timestamp.timestamp);
		processTimestamp(message->timestamp.position,
		message->timestamp.timestamp + mTimeOffsetNanos);
		return AAUDIO_OK;
		}

media/libaaudio/src/client/AudioStreamInternal.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -194,6 +194,7 @@ private:
		// By delaying slightly we can avoid waking up before other side is ready.
		const int32_t mWakeupDelayNanos; // delay past typical wakeup jitter
		const int32_t mMinimumSleepNanos; // minimum sleep while polling
		int32_t mTimeOffsetNanos = 0; // add to time part of an MMAP timestamp

		AudioEndpointParcelable mEndPointParcelable; // description of the buffers filled by service
		EndpointDescriptor mEndpointDescriptor; // buffer description with resolved addresses

media/libaaudio/src/utility/AAudioUtilities.cpp

+24 −0

Original line number	Diff line number	Diff line
		@@ -335,6 +335,30 @@ int32_t AAudioProperty_getHardwareBurstMinMicros() {
		return prop;
		}

		static int32_t AAudioProperty_getMMapOffsetMicros(const char *functionName,
		const char *propertyName) {
		const int32_t minMicros = -20000; // arbitrary
		const int32_t defaultMicros = 0; // arbitrary
		const int32_t maxMicros = 20000; // arbitrary
		int32_t prop = property_get_int32(propertyName, defaultMicros);
		if (prop < minMicros) {
		ALOGW("%s: clipped %d to %d", functionName, prop, minMicros);
		prop = minMicros;
		} else if (prop > maxMicros) {
		ALOGW("%s: clipped %d to %d", functionName, prop, minMicros);
		prop = maxMicros;
		}
		return prop;
		}

		int32_t AAudioProperty_getInputMMapOffsetMicros() {
		return AAudioProperty_getMMapOffsetMicros(__func__, AAUDIO_PROP_INPUT_MMAP_OFFSET_USEC);
		}

		int32_t AAudioProperty_getOutputMMapOffsetMicros() {
		return AAudioProperty_getMMapOffsetMicros(__func__, AAUDIO_PROP_OUTPUT_MMAP_OFFSET_USEC);
		}

		aaudio_result_t AAudio_isFlushAllowed(aaudio_stream_state_t state) {
		aaudio_result_t result = AAUDIO_OK;
		switch (state) {

media/libaaudio/src/utility/AAudioUtilities.h

+17 −10

Original line number	Diff line number	Diff line
		@@ -94,31 +94,26 @@ audio_flags_mask_t AAudioConvert_allowCapturePolicyToAudioFlagsMask(

		// Note that this code may be replaced by Settings or by some other system configuration tool.

		#define AAUDIO_PROP_MMAP_POLICY "aaudio.mmap_policy"

		/**
		* Read system property.
		* @return AAUDIO_UNSPECIFIED, AAUDIO_POLICY_NEVER or AAUDIO_POLICY_AUTO or AAUDIO_POLICY_ALWAYS
		*/
		int32_t AAudioProperty_getMMapPolicy();

		#define AAUDIO_PROP_MMAP_EXCLUSIVE_POLICY "aaudio.mmap_exclusive_policy"
		#define AAUDIO_PROP_MMAP_POLICY "aaudio.mmap_policy"

		/**
		* Read system property.
		* @return AAUDIO_UNSPECIFIED, AAUDIO_POLICY_NEVER or AAUDIO_POLICY_AUTO or AAUDIO_POLICY_ALWAYS
		*/
		int32_t AAudioProperty_getMMapExclusivePolicy();

		#define AAUDIO_PROP_MIXER_BURSTS "aaudio.mixer_bursts"
		#define AAUDIO_PROP_MMAP_EXCLUSIVE_POLICY "aaudio.mmap_exclusive_policy"

		/**
		* Read system property.
		* @return number of bursts per AAudio service mixer cycle
		*/
		int32_t AAudioProperty_getMixerBursts();

		#define AAUDIO_PROP_HW_BURST_MIN_USEC "aaudio.hw_burst_min_usec"
		#define AAUDIO_PROP_MIXER_BURSTS "aaudio.mixer_bursts"

		/**
		* Read a system property that specifies the number of extra microseconds that a thread
		@@ -130,7 +125,6 @@ int32_t AAudioProperty_getMixerBursts();
		* @return number of microseconds to delay the wakeup.
		*/
		int32_t AAudioProperty_getWakeupDelayMicros();

		#define AAUDIO_PROP_WAKEUP_DELAY_USEC "aaudio.wakeup_delay_usec"

		/**
		@@ -139,7 +133,6 @@ int32_t AAudioProperty_getWakeupDelayMicros();
		* @return minimum number of microseconds to sleep.
		*/
		int32_t AAudioProperty_getMinimumSleepMicros();

		#define AAUDIO_PROP_MINIMUM_SLEEP_USEC "aaudio.minimum_sleep_usec"

		/**
		@@ -153,7 +146,21 @@ int32_t AAudioProperty_getMinimumSleepMicros();
		* @return minimum number of microseconds for a MMAP HW burst
		*/
		int32_t AAudioProperty_getHardwareBurstMinMicros();
		#define AAUDIO_PROP_HW_BURST_MIN_USEC "aaudio.hw_burst_min_usec"

		/**
		* Read a system property that specifies an offset that will be added to MMAP timestamps.
		* This can be used to correct bias in the timestamp.
		* It can also be used to analyze the time distribution of the timestamp
		* by progressively modifying the offset and listening for glitches.
		*
		* @return number of microseconds to offset the time part of an MMAP timestamp
		*/
		int32_t AAudioProperty_getInputMMapOffsetMicros();
		#define AAUDIO_PROP_INPUT_MMAP_OFFSET_USEC "aaudio.in_mmap_offset_usec"

		int32_t AAudioProperty_getOutputMMapOffsetMicros();
		#define AAUDIO_PROP_OUTPUT_MMAP_OFFSET_USEC "aaudio.out_mmap_offset_usec"

		/**
		* Is flush allowed for the given state?