audio: use sample rate rather than timebase now they aren't interchangeable

app/render/audioparams.cpp

@@ -105,7 +105,7 @@ qint64 AudioParams::time_to_samples(const double &time) const
 
   // NOTE: Not sure if we should round or ceil, but I've gotten better results with ceil.
   //       Specifically, we seem to occasionally get straggler ranges that never cache with round.
-  return qCeil(time_base().flipped().toDouble() * time);
+  return qCeil(double(sample_rate()) * time);
 }
 
 qint64 AudioParams::time_to_samples(const rational &time) const
@@ -122,7 +122,7 @@ qint64 AudioParams::samples_to_bytes(const qint64 &samples) const
 
 rational AudioParams::samples_to_time(const qint64 &samples) const
 {
-  return time_base() * samples;
+  return sample_rate_as_time_base() * samples;
 }
 
 qint64 AudioParams::bytes_to_samples(const qint64 &bytes) const

app/widget/timelinewidget/timelinewidget.cpp

@@ -1003,7 +1003,7 @@ void TimelineWidget::SetViewTimestamp(const int64_t &ts)
     if (use_audio_time_units_ && i == Track::kAudio) {
       view->view()->SetTime(Timecode::rescale_timestamp(ts,
                                                         timebase(),
-                                                        GetConnectedNode()->GetAudioParams().time_base()));
+                                                        GetConnectedNode()->GetAudioParams().sample_rate_as_time_base()));
     } else {
       view->view()->SetTime(ts);
     }
@@ -1014,7 +1014,7 @@ void TimelineWidget::ViewTimestampChanged(int64_t ts)
 {
   if (use_audio_time_units_ && sender() == views_.at(Track::kAudio)) {
     ts = Timecode::rescale_timestamp(ts,
-                                     GetConnectedNode()->GetAudioParams().time_base(),
+                                     GetConnectedNode()->GetAudioParams().sample_rate_as_time_base(),
                                      timebase());
   }
 
@@ -1048,7 +1048,7 @@ void TimelineWidget::UpdateViewTimebases()
     TimelineAndTrackView* view = views_.at(i);
 
     if (use_audio_time_units_ && i == Track::kAudio) {
-      view->view()->SetTimebase(GetConnectedNode()->GetAudioParams().time_base());
+      view->view()->SetTimebase(GetConnectedNode()->GetAudioParams().sample_rate_as_time_base());
     } else {
       view->view()->SetTimebase(timebase());
     }

app/widget/viewer/audiowaveformview.cpp

@@ -55,7 +55,7 @@ void AudioWaveformView::SetViewer(AudioPlaybackCache *playback)
     connect(playback_, &AudioPlaybackCache::Validated, this, &AudioWaveformView::ForceUpdateOfRange);
     connect(playback_, &AudioPlaybackCache::ParametersChanged, this, &AudioWaveformView::BackendParamsChanged);
 
-    SetTimebase(playback_->GetParameters().time_base());
+    SetTimebase(playback_->GetParameters().sample_rate_as_time_base());
   }
 
   ForceUpdate();
@@ -171,7 +171,7 @@ QPixmap AudioWaveformView::DrawWaveform(QIODevice* fs, CachedWaveformInfo info,
 
 void AudioWaveformView::BackendParamsChanged()
 {
-  SetTimebase(playback_->GetParameters().time_base());
+  SetTimebase(playback_->GetParameters().sample_rate_as_time_base());
 }
 
 void AudioWaveformView::ForceUpdate()