am bd240c27: media: add AudioTrack::getMinFrameCount(). (2ce999fc) · Commits · e / os / android_frameworks_base

include/media/AudioTrack.h

+11 −0

Original line number	Diff line number	Diff line
		@@ -102,6 +102,17 @@ public:

		typedef void (callback_t)(int event, void user, void *info);

		/* Returns the minimum frame count required for the successful creation of
		* an AudioTrack object.
		* Returned status (from utils/Errors.h) can be:
		* - NO_ERROR: successful operation
		* - NO_INIT: audio server or audio hardware not initialized
		*/

		static status_t getMinFrameCount(int* frameCount,
		int streamType =-1,
		uint32_t sampleRate = 0);

		/* Constructs an uninitialized AudioTrack. No connection with
		* AudioFlinger takes place.
		*/

+29 −0

Original line number	Diff line number	Diff line
		@@ -41,6 +41,35 @@
		#define UNLIKELY( exp ) (__builtin_expect( (exp) != 0, false ))

		namespace android {
		// ---------------------------------------------------------------------------

		// static
		status_t AudioTrack::getMinFrameCount(
		int* frameCount,
		int streamType,
		uint32_t sampleRate)
		{
		int afSampleRate;
		if (AudioSystem::getOutputSamplingRate(&afSampleRate, streamType) != NO_ERROR) {
		return NO_INIT;
		}
		int afFrameCount;
		if (AudioSystem::getOutputFrameCount(&afFrameCount, streamType) != NO_ERROR) {
		return NO_INIT;
		}
		uint32_t afLatency;
		if (AudioSystem::getOutputLatency(&afLatency, streamType) != NO_ERROR) {
		return NO_INIT;
		}

		// Ensure that buffer depth covers at least audio hardware latency
		uint32_t minBufCount = afLatency / ((1000 * afFrameCount) / afSampleRate);
		if (minBufCount < 2) minBufCount = 2;

		frameCount = (sampleRate == 0) ? afFrameCount minBufCount :
		afFrameCount * minBufCount * sampleRate / afSampleRate;
		return NO_ERROR;
		}

		// ---------------------------------------------------------------------------