audio: Prolong reading attempts from the remote submix pipe
In order to use the time interval for reading from the remote
submix pipe more efficiently, increase the deadline time
to the buffer duration minus a small amount. This should
minimize chances to have discontinuities in the remote submix
input.
Bug: 334363414
Test: atest --test-filter=".*RemoteSubmixTest#testRemoteSubmixRecordingContinuity" CtsMediaAudioTestCases
Change-Id: I02968d09afd8ecdad4d61e635393842d7280e55f
diff --git a/audio/aidl/default/r_submix/StreamRemoteSubmix.cpp b/audio/aidl/default/r_submix/StreamRemoteSubmix.cpp
index ca3f91a..a266b54 100644
--- a/audio/aidl/default/r_submix/StreamRemoteSubmix.cpp
+++ b/audio/aidl/default/r_submix/StreamRemoteSubmix.cpp
@@ -285,9 +285,12 @@
char* buff = (char*)buffer;
size_t actuallyRead = 0;
long remainingFrames = frameCount;
- const int64_t deadlineTimeNs =
- ::android::uptimeNanos() +
- getDelayInUsForFrameCount(frameCount) * NANOS_PER_MICROSECOND / 2;
+ // Try to wait as long as possible for the audio duration, but leave some time for the call to
+ // 'transfer' to complete. 'kReadAttemptSleepUs' is a good constant for this purpose because it
+ // is by definition "strictly inferior" to the typical buffer duration.
+ const long durationUs =
+ std::max(0L, getDelayInUsForFrameCount(frameCount) - kReadAttemptSleepUs);
+ const int64_t deadlineTimeNs = ::android::uptimeNanos() + durationUs * NANOS_PER_MICROSECOND;
while (remainingFrames > 0) {
ssize_t framesRead = source->read(buff, remainingFrames);
LOG(VERBOSE) << __func__ << ": frames read " << framesRead;