Title: [212715] trunk/Source/WebCore
- Revision
- 212715
- Author
- [email protected]
- Date
- 2017-02-21 09:24:34 -0800 (Tue, 21 Feb 2017)
Log Message
Pulling too quickly from an AudioSampleDataSource should increase the pre-buffer amount
https://bugs.webkit.org/show_bug.cgi?id=168645
Reviewed by Eric Carlson.
If a pull operation runs past the end of the buffered range of a CARingBuffer, the underrun
is zero-filled, causing an audible glitch. In this case, bias m_outputSampleOffset by the
amount of the underrun, which should keep the underrun from reoccurring.
* platform/audio/mac/AudioSampleDataSource.cpp:
(WebCore::AudioSampleDataSource::pullSamplesInternal):
Modified Paths
Diff
Modified: trunk/Source/WebCore/ChangeLog (212714 => 212715)
--- trunk/Source/WebCore/ChangeLog 2017-02-21 17:19:10 UTC (rev 212714)
+++ trunk/Source/WebCore/ChangeLog 2017-02-21 17:24:34 UTC (rev 212715)
@@ -1,5 +1,19 @@
2017-02-21 Jer Noble <[email protected]>
+ Pulling too quickly from an AudioSampleDataSource should increase the pre-buffer amount
+ https://bugs.webkit.org/show_bug.cgi?id=168645
+
+ Reviewed by Eric Carlson.
+
+ If a pull operation runs past the end of the buffered range of a CARingBuffer, the underrun
+ is zero-filled, causing an audible glitch. In this case, bias m_outputSampleOffset by the
+ amount of the underrun, which should keep the underrun from reoccurring.
+
+ * platform/audio/mac/AudioSampleDataSource.cpp:
+ (WebCore::AudioSampleDataSource::pullSamplesInternal):
+
+2017-02-21 Jer Noble <[email protected]>
+
AudioSampleBufferList::zeroABL() takes a byte-count, not a sample-count.
https://bugs.webkit.org/show_bug.cgi?id=168635
Modified: trunk/Source/WebCore/platform/audio/mac/AudioSampleDataSource.cpp (212714 => 212715)
--- trunk/Source/WebCore/platform/audio/mac/AudioSampleDataSource.cpp 2017-02-21 17:19:10 UTC (rev 212714)
+++ trunk/Source/WebCore/platform/audio/mac/AudioSampleDataSource.cpp 2017-02-21 17:24:34 UTC (rev 212715)
@@ -253,7 +253,7 @@
LOG(MediaCaptureSamples, "** pullSamples: asking for %ld samples at time = %lld (was %lld)", sampleCount, timeStamp, timeStamp - m_outputSampleOffset);
- int64_t framesAvailable = sampleCount;
+ uint64_t framesAvailable = sampleCount;
if (timeStamp < startFrame || timeStamp + sampleCount > endFrame) {
if (timeStamp + sampleCount < startFrame || timeStamp > endFrame)
framesAvailable = 0;
@@ -264,6 +264,14 @@
LOG(MediaCaptureSamples, "** pullSamplesInternal: sample %lld is not completely in range [%lld .. %lld], returning %lld frames", timeStamp, startFrame, endFrame, framesAvailable);
+ if (framesAvailable < sampleCount) {
+ const double twentyMS = .02;
+ double sampleRate = m_outputDescription->sampleRate();
+ auto delta = static_cast<int64_t>(timeStamp) - endFrame;
+ if (delta > 0 && delta < sampleRate * twentyMS)
+ m_outputSampleOffset -= delta;
+ }
+
if (!framesAvailable) {
AudioSampleBufferList::zeroABL(buffer, byteCount);
return false;
_______________________________________________
webkit-changes mailing list
[email protected]
https://lists.webkit.org/mailman/listinfo/webkit-changes
