commit ec5746c10316a2a26022872d41c6002e8097caa7
author Haynes Mathew George <hgeorge@codeaurora.org> Mon Jan 14 16:17:36 2013 -0800
committer Ricardo Cerqueira <cyanogenmod@cerqueira.org> Sun Nov 03 02:47:04 2013 +0000
tree b11aa931aec5f38469e2d2f13daafc1fd900478b
parent 0868da69c72a30f46bd333adac86e93de7625709

libstagefright: Query AudioSystem for suggested record mute duration

- AudioSource mutes a pre-defined duration (defined by kAutoRampStartUs)
  at the beginning of a recording.
- Instead, query the audio system for any ongoing playback streams
  and use its output latency to calculate the duration to mute the incoming PCM stream.
- This assumes all current playback threads will be paused once recording
  is started.
CRs-Fixed: 438149

Change-Id: Ifaf59a9c09c0ece956379e10c801cad4dacfc8f3

include/media/stagefright/AudioSource.h

diff --git a/include/media/stagefright/AudioSource.h b/include/media/stagefright/AudioSource.h
index 4c9aaad..5e5137b 100644
--- a/include/media/stagefright/AudioSource.h
+++ b/include/media/stagefright/AudioSource.h
@@ -85,6 +85,7 @@
     int64_t mInitialReadTimeUs;
     int64_t mNumFramesReceived;
     int64_t mNumClientOwnedBuffers;
+    int64_t mAutoRampStartUs;
 
     List<MediaBuffer * > mBuffersReceived;
 

media/libstagefright/AudioSource.cpp

diff --git a/media/libstagefright/AudioSource.cpp b/media/libstagefright/AudioSource.cpp
index abbafd5..5396c14 100644
--- a/media/libstagefright/AudioSource.cpp
+++ b/media/libstagefright/AudioSource.cpp
@@ -83,6 +83,17 @@
                     this,
                     frameCount);
         mInitCheck = mRecord->initCheck();
+
+        //configure the auto ramp start duration
+        mAutoRampStartUs = kAutoRampStartUs;
+        uint32_t playbackLatencyMs = 0;
+        if (AudioSystem::getOutputLatency(&playbackLatencyMs,
+                                          AUDIO_STREAM_DEFAULT) == OK) {
+            if (2*playbackLatencyMs*1000LL > kAutoRampStartUs) {
+                mAutoRampStartUs = 2*playbackLatencyMs*1000LL;
+            }
+        }
+        ALOGD("Start autoramp from %lld", mAutoRampStartUs);
     } else {
         mInitCheck = status;
     }
@@ -236,14 +247,14 @@
     int64_t timeUs;
     CHECK(buffer->meta_data()->findInt64(kKeyTime, &timeUs));
     int64_t elapsedTimeUs = timeUs - mStartTimeUs;
-    if (elapsedTimeUs < kAutoRampStartUs) {
+    if (elapsedTimeUs < mAutoRampStartUs) {
         memset((uint8_t *) buffer->data(), 0, buffer->range_length());
-    } else if (elapsedTimeUs < kAutoRampStartUs + kAutoRampDurationUs) {
+    } else if (elapsedTimeUs < mAutoRampStartUs + kAutoRampDurationUs) {
         int32_t autoRampDurationFrames =
                     (kAutoRampDurationUs * mSampleRate + 500000LL) / 1000000LL;
 
         int32_t autoRampStartFrames =
-                    (kAutoRampStartUs * mSampleRate + 500000LL) / 1000000LL;
+                    (mAutoRampStartUs * mSampleRate + 500000LL) / 1000000LL;
 
         int32_t nFrames = mNumFramesReceived - autoRampStartFrames;
         rampVolume(nFrames, autoRampDurationFrames,