Update of /cvsroot/audacity/audacity-src/src
In directory sc8-pr-cvs11.sourceforge.net:/tmp/cvs-serv5358
Modified Files:
AudioIO.cpp
Log Message:
Fix latency correction
Index: AudioIO.cpp
===================================================================
RCS file: /cvsroot/audacity/audacity-src/src/AudioIO.cpp,v
retrieving revision 1.164
retrieving revision 1.165
diff -u -d -r1.164 -r1.165
--- AudioIO.cpp 11 Jul 2007 06:18:43 -0000 1.164
+++ AudioIO.cpp 18 Sep 2007 07:20:33 -0000 1.165
@@ -1180,18 +1180,48 @@
//
// Offset all recorded tracks to account for latency
//
- double latencyCorrection = 0;
- gPrefs->Read(wxT("/AudioIO/LatencyCorrection"), &latencyCorrection);
-
if( mCaptureTracks.GetCount() > 0 )
{
+ //
+ // Note: Latency correction > 0 means there is more latency than
+ // expected. This means, more recorded audio must be thrown away
+ // to get it in sync with played back audio. Latency correction < 0
+ // means there is less latency than expected, this means, less
+ // recorded audio must be thrown away to get it in sync with played
+ // back audio.
+ //
+ // We also allow for the case of total latency being below zero, i.e.
+ // a negative latency. In this case, silence is inserted into the
+ // recorded track to bring it in sync with played back audio.
+ // However, it is unclear if there ever would be a technical reason
+ // for a negative latency.
+ //
+ // We also only apply latency correction when we actually played back
+ // tracks during the recording. If we did not play back tracks,
+ // there's nothing we could be out of sync with. This also covers the
+ // case that we do not apply latency correction when recording the
+ // first track in a project.
+ //
+ double latencyCorrection = 0;
+ gPrefs->Read(wxT("/AudioIO/LatencyCorrection"), &latencyCorrection);
+
+ double recordingOffset =
+ mLastRecordingOffset - latencyCorrection / 1000.0;
+
for( unsigned int i = 0; i < mCaptureTracks.GetCount(); i++ )
{
delete mCaptureBuffers[i];
- mCaptureTracks[i]->Flush();
- mCaptureTracks[i]->Trim(mLastRecordingOffset +
- latencyCorrection/1000.0,
- mCaptureTracks[i]->GetEndTime());
+
+ WaveTrack* track = mCaptureTracks[i];
+ track->Flush();
+
+ if (mPlaybackTracks.GetCount() > 0)
+ {
+ if (recordingOffset < 0)
+ track->Clear(0, -recordingOffset);
+ else
+ track->InsertSilence(0, recordingOffset);
+ }
}
delete[] mCaptureBuffers;
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