waveform: fixed precision issue when generating from sample data

Fixes #1664
2021-07-08 12:08:05 -07:00
parent 558d849d27
commit 1f0de6c5bb
1 changed files with 5 additions and 4 deletions
@@ -49,14 +49,15 @@ void AudioVisualWaveform::OverwriteSamplesFromBuffer(SampleBufferPtr samples, in
    data.resize(end_index);
  }

-  int chunk_size = sample_rate / target_rate;
+  double chunk_size = double(sample_rate) / double(target_rate);

  for (int i=0; i<samples_length; i+=channels_) {
-    int src_index = (i * chunk_size) / channels_;
+    int src_start = qRound((double(i) * chunk_size) / double(channels_));
+    int src_end = qMin(qRound((double(i + channels_) * chunk_size) / double(channels_)), samples->sample_count());

    Sample summary = SumSamples(samples,
-                                src_index,
-                                qMin(chunk_size, samples->sample_count() - src_index));
+                                src_start,
+                                src_end - src_start);

    memcpy(&data.data()[i + start_index],
        summary.constData(),