Enable 8 bit and float pcm record formats for AudioFlinger
Update sampling rate handling as well.
Bug: 19570772
Change-Id: I872248e64c0578b2e48869a68fee0d51bd0640c3
diff --git a/include/media/AudioResamplerPublic.h b/include/media/AudioResamplerPublic.h
index b705efa..0634741 100644
--- a/include/media/AudioResamplerPublic.h
+++ b/include/media/AudioResamplerPublic.h
@@ -17,6 +17,8 @@
#ifndef ANDROID_AUDIO_RESAMPLER_PUBLIC_H
#define ANDROID_AUDIO_RESAMPLER_PUBLIC_H
+#include <stdint.h>
+
// AUDIO_RESAMPLER_DOWN_RATIO_MAX is the maximum ratio between the original
// audio sample rate and the target rate when downsampling,
// as permitted in the audio framework, e.g. AudioTrack and AudioFlinger.
@@ -26,6 +28,12 @@
// TODO: replace with an API
#define AUDIO_RESAMPLER_DOWN_RATIO_MAX 256
+// AUDIO_RESAMPLER_UP_RATIO_MAX is the maximum suggested ratio between the original
+// audio sample rate and the target rate when upsampling. It is loosely enforced by
+// the system. One issue with large upsampling ratios is the approximation by
+// an int32_t of the phase increments, making the resulting sample rate inexact.
+#define AUDIO_RESAMPLER_UP_RATIO_MAX 65536
+
// Returns the source frames needed to resample to destination frames. This is not a precise
// value and depends on the resampler (and possibly how it handles rounding internally).
// Nevertheless, this should be an upper bound on the requirements of the resampler.
@@ -39,4 +47,15 @@
size_t((uint64_t)dstFramesRequired * srcSampleRate / dstSampleRate + 1 + 1);
}
+// An upper bound for the number of destination frames possible from srcFrames
+// after sample rate conversion. This may be used for buffer sizing.
+static inline size_t destinationFramesPossible(size_t srcFrames, uint32_t srcSampleRate,
+ uint32_t dstSampleRate) {
+ if (srcSampleRate == dstSampleRate) {
+ return srcFrames;
+ }
+ uint64_t dstFrames = (uint64_t)srcFrames * dstSampleRate / srcSampleRate;
+ return dstFrames > 2 ? dstFrames - 2 : 0;
+}
+
#endif // ANDROID_AUDIO_RESAMPLER_PUBLIC_H