From d7f1c3d69274fef8772a663ce1c792fd0466fcc5 Mon Sep 17 00:00:00 2001 From: James Dong Date: Thu, 26 Aug 2010 16:28:17 -0700 Subject: Suppress the video recording start signal - bug 2950297 Change-Id: I0044d07178691feb904cf81e87c1b6d4b714dc1a --- include/media/stagefright/AudioSource.h | 18 ++++++++++++- media/libstagefright/AudioSource.cpp | 46 +++++++++++++++++++++++++++++++++ 2 files changed, 63 insertions(+), 1 deletion(-) diff --git a/include/media/stagefright/AudioSource.h b/include/media/stagefright/AudioSource.h index 2597e9e..1af4254 100644 --- a/include/media/stagefright/AudioSource.h +++ b/include/media/stagefright/AudioSource.h @@ -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 &); }; diff --git a/media/libstagefright/AudioSource.cpp b/media/libstagefright/AudioSource.cpp index c8dfede..4c729e4 100644 --- a/media/libstagefright/AudioSource.cpp +++ b/media/libstagefright/AudioSource.cpp @@ -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); } -- cgit v1.1