Merge "Suppress the video recording start signal - bug 2950297" into gingerbread (b86365ad) · Commits · e / os / android_frameworks_base

include/media/stagefright/AudioSource.h

+17 −1

Original line number	Diff line number	Diff line
		@@ -49,7 +49,17 @@ protected:
		virtual ~AudioSource();

		private:
		enum { kMaxBufferSize = 2048 };
		enum {
		kMaxBufferSize = 2048,

		// After the initial mute, we raise the volume linearly
		// over kAutoRampDurationUs.
		kAutoRampDurationUs = 300000,

		// This is the initial mute duration to suppress
		// the video recording signal tone
		kAutoRampStartUs = 700000,
		};

		AudioRecord *mRecord;
		status_t mInitCheck;
		@@ -67,6 +77,12 @@ private:

		void trackMaxAmplitude(int16_t *data, int nSamples);

		// This is used to raise the volume from mute to the
		// actual level linearly.
		void rampVolume(
		int32_t startFrame, int32_t rampDurationFrames,
		uint8_t *data, size_t bytes);

		AudioSource(const AudioSource &);
		AudioSource &operator=(const AudioSource &);
		};

media/libstagefright/AudioSource.cpp

+46 −0

Original line number	Diff line number	Diff line
		@@ -40,6 +40,7 @@ AudioSource::AudioSource(
		mGroup(NULL) {

		LOGV("sampleRate: %d, channels: %d", sampleRate, channels);
		CHECK(channels == 1 \|\| channels == 2);
		uint32_t flags = AudioRecord::RECORD_AGC_ENABLE \|
		AudioRecord::RECORD_NS_ENABLE \|
		AudioRecord::RECORD_IIR_ENABLE;
		@@ -158,6 +159,38 @@ static int skipFrame(int64_t timestampUs,

		}

		void AudioSource::rampVolume(
		int32_t startFrame, int32_t rampDurationFrames,
		uint8_t *data, size_t bytes) {

		const int32_t kShift = 14;
		int32_t fixedMultiplier = (startFrame << kShift) / rampDurationFrames;
		const int32_t nChannels = mRecord->channelCount();
		int32_t stopFrame = startFrame + bytes / sizeof(int16_t);
		int16_t frame = (int16_t ) data;
		if (stopFrame > rampDurationFrames) {
		stopFrame = rampDurationFrames;
		}

		while (startFrame < stopFrame) {
		if (nChannels == 1) { // mono
		frame[0] = (frame[0] * fixedMultiplier) >> kShift;
		++frame;
		++startFrame;
		} else { // stereo
		frame[0] = (frame[0] * fixedMultiplier) >> kShift;
		frame[1] = (frame[1] * fixedMultiplier) >> kShift;
		frame += 2;
		startFrame += 2;
		}

		// Update the multiplier every 4 frames
		if ((startFrame & 3) == 0) {
		fixedMultiplier = (startFrame << kShift) / rampDurationFrames;
		}
		}
		}

		status_t AudioSource::read(
		MediaBuffer *out, const ReadOptions options) {
		*out = NULL;
		@@ -242,6 +275,19 @@ status_t AudioSource::read(
		continue;
		}

		if (mPrevSampleTimeUs - mStartTimeUs < kAutoRampStartUs) {
		// Mute the initial video recording signal
		memset((uint8_t *) buffer->data(), 0, n);
		} else if (mPrevSampleTimeUs - mStartTimeUs < kAutoRampStartUs + kAutoRampDurationUs) {
		int32_t autoRampDurationFrames =
		(kAutoRampDurationUs * sampleRate + 500000LL) / 1000000LL;

		int32_t autoRampStartFrames =
		(kAutoRampStartUs * sampleRate + 500000LL) / 1000000LL;

		int32_t nFrames = numFramesRecorded - autoRampStartFrames;
		rampVolume(nFrames, autoRampDurationFrames, (uint8_t *) buffer->data(), n);
		}
		if (mTrackMaxAmplitude) {
		trackMaxAmplitude((int16_t *) buffer->data(), n >> 1);
		}