Visualizer: Add multichannel capability
Test: CTS VisualizerTest with multichannel USB devices
Bug: 118895139
Change-Id: I438708842f2d4cd490120c3a700047d96b93c3be
diff --git a/media/libeffects/visualizer/Android.mk b/media/libeffects/visualizer/Android.mk
index 3534149..35e2f3d 100644
--- a/media/libeffects/visualizer/Android.mk
+++ b/media/libeffects/visualizer/Android.mk
@@ -9,6 +9,7 @@
LOCAL_CFLAGS+= -O2 -fvisibility=hidden
LOCAL_CFLAGS += -Wall -Werror
+LOCAL_CFLAGS += -DBUILD_FLOAT -DSUPPORT_MC
LOCAL_SHARED_LIBRARIES := \
libcutils \
diff --git a/media/libeffects/visualizer/EffectVisualizer.cpp b/media/libeffects/visualizer/EffectVisualizer.cpp
index e2ccfb7..00bc371 100644
--- a/media/libeffects/visualizer/EffectVisualizer.cpp
+++ b/media/libeffects/visualizer/EffectVisualizer.cpp
@@ -32,8 +32,6 @@
#include <audio_effects/effect_visualizer.h>
#include <audio_utils/primitives.h>
-#define BUILD_FLOAT
-
#ifdef BUILD_FLOAT
static constexpr audio_format_t kProcessFormat = AUDIO_FORMAT_PCM_FLOAT;
@@ -157,7 +155,12 @@
if (pConfig->inputCfg.samplingRate != pConfig->outputCfg.samplingRate) return -EINVAL;
if (pConfig->inputCfg.channels != pConfig->outputCfg.channels) return -EINVAL;
if (pConfig->inputCfg.format != pConfig->outputCfg.format) return -EINVAL;
- if (pConfig->inputCfg.channels != AUDIO_CHANNEL_OUT_STEREO) return -EINVAL;
+ const uint32_t channelCount = audio_channel_count_from_out_mask(pConfig->inputCfg.channels);
+#ifdef SUPPORT_MC
+ if (channelCount < 1 || channelCount > FCC_8) return -EINVAL;
+#else
+ if (channelCount != FCC_2) return -EINVAL;
+#endif
if (pConfig->outputCfg.accessMode != EFFECT_BUFFER_ACCESS_WRITE &&
pConfig->outputCfg.accessMode != EFFECT_BUFFER_ACCESS_ACCUMULATE) return -EINVAL;
if (pConfig->inputCfg.format != kProcessFormat) return -EINVAL;
@@ -356,7 +359,7 @@
// store the measurement
pContext->mPastMeasurements[pContext->mMeasurementBufferIdx].mPeakU16 = (uint16_t)maxSample;
pContext->mPastMeasurements[pContext->mMeasurementBufferIdx].mRmsSquared =
- rmsSqAcc / (inBuffer->frameCount * pContext->mChannelCount);
+ rmsSqAcc / sampleLen;
pContext->mPastMeasurements[pContext->mMeasurementBufferIdx].mIsValid = true;
if (++pContext->mMeasurementBufferIdx >= pContext->mMeasurementWindowSizeInBuffers) {
pContext->mMeasurementBufferIdx = 0;
@@ -375,12 +378,17 @@
#ifdef BUILD_FLOAT
float maxSample = 0.f;
- for (size_t inIdx = 0; inIdx < sampleLen; ++inIdx) {
- maxSample = fmax(maxSample, fabs(inBuffer->f32[inIdx]));
+ for (size_t inIdx = 0; inIdx < sampleLen; ) {
+ // we reconstruct the actual summed value to ensure proper normalization
+ // for multichannel outputs (channels > 2 may often be 0).
+ float smp = 0.f;
+ for (int i = 0; i < pContext->mChannelCount; ++i) {
+ smp += inBuffer->f32[inIdx++];
+ }
+ maxSample = fmax(maxSample, fabs(smp));
}
if (maxSample > 0.f) {
- constexpr float halfish = 127.f / 256.f;
- fscale = halfish / maxSample;
+ fscale = 127.f / maxSample;
int exp; // unused
const float significand = frexp(fscale, &exp);
if (significand == 0.5f) {
@@ -412,7 +420,8 @@
} else {
assert(pContext->mScalingMode == VISUALIZER_SCALING_MODE_AS_PLAYED);
#ifdef BUILD_FLOAT
- fscale = 0.5f; // default divide by 2 to account for sum of L + R.
+ // Note: if channels are uncorrelated, 1/sqrt(N) could be used at the risk of clipping.
+ fscale = 1.f / pContext->mChannelCount; // account for summing all the channels together.
#else
shift = 9;
#endif // BUILD_FLOAT
@@ -422,17 +431,19 @@
uint32_t inIdx;
uint8_t *buf = pContext->mCaptureBuf;
for (inIdx = 0, captIdx = pContext->mCaptureIdx;
- inIdx < inBuffer->frameCount;
- inIdx++, captIdx++) {
- if (captIdx >= CAPTURE_BUF_SIZE) {
- // wrap around
- captIdx = 0;
- }
+ inIdx < sampleLen;
+ captIdx++) {
+ if (captIdx >= CAPTURE_BUF_SIZE) captIdx = 0; // wrap
+
#ifdef BUILD_FLOAT
- const float smp = (inBuffer->f32[2 * inIdx] + inBuffer->f32[2 * inIdx + 1]) * fscale;
- buf[captIdx] = clamp8_from_float(smp);
+ float smp = 0.f;
+ for (uint32_t i = 0; i < pContext->mChannelCount; ++i) {
+ smp += inBuffer->f32[inIdx++];
+ }
+ buf[captIdx] = clamp8_from_float(smp * fscale);
#else
- const int32_t smp = (inBuffer->s16[2 * inIdx] + inBuffer->s16[2 * inIdx + 1]) >> shift;
+ const int32_t smp = (inBuffer->s16[inIdx] + inBuffer->s16[inIdx + 1]) >> shift;
+ inIdx += FCC_2; // integer supports stereo only.
buf[captIdx] = ((uint8_t)smp)^0x80;
#endif // BUILD_FLOAT
}