aaudio: improve accuracy of timestamps
Account for latency added by the AAudio service.
Fix input timestamps.
Bug: 37080396
Test: test_timestamps.cpp input_monitor.cpp
Change-Id: I1053cd21af722bb9b9371df4e5731bf4a0a57b0b
diff --git a/services/oboeservice/AAudioServiceEndpointPlay.cpp b/services/oboeservice/AAudioServiceEndpointPlay.cpp
index b83b918..20cc5b8 100644
--- a/services/oboeservice/AAudioServiceEndpointPlay.cpp
+++ b/services/oboeservice/AAudioServiceEndpointPlay.cpp
@@ -73,17 +73,31 @@
while (mCallbackEnabled.load() && getStreamInternal()->isActive() && (result >= 0)) {
// Mix data from each active stream.
mMixer.clear();
- { // use lock guard
+ { // brackets are for lock_guard
int index = 0;
+ int64_t mmapFramesWritten = getStreamInternal()->getFramesWritten();
+
std::lock_guard <std::mutex> lock(mLockStreams);
- for (sp<AAudioServiceStreamShared> sharedStream : mRegisteredStreams) {
- if (sharedStream->isRunning()) {
- FifoBuffer *fifo = sharedStream->getDataFifoBuffer();
+ for (sp<AAudioServiceStreamShared> clientStream : mRegisteredStreams) {
+ if (clientStream->isRunning()) {
+ FifoBuffer *fifo = clientStream->getDataFifoBuffer();
+ // Determine offset between framePosition in client's stream vs the underlying
+ // MMAP stream.
+ int64_t clientFramesRead = fifo->getReadCounter();
+ // These two indices refer to the same frame.
+ int64_t positionOffset = mmapFramesWritten - clientFramesRead;
+ clientStream->setTimestampPositionOffset(positionOffset);
+
float volume = 1.0; // to match legacy volume
bool underflowed = mMixer.mix(index, fifo, volume);
underflowCount += underflowed ? 1 : 0;
// TODO log underflows in each stream
- sharedStream->markTransferTime(AudioClock::getNanoseconds());
+
+ // This timestamp represents the completion of data being read out of the
+ // client buffer. It is sent to the client and used in the timing model
+ // to decide when the client has room to write more data.
+ Timestamp timestamp(fifo->getReadCounter(), AudioClock::getNanoseconds());
+ clientStream->markTransferTime(timestamp);
}
index++;
}