With longer process sizes we can end up with insufficient space in the inbuf, but enough in the outbuf following the previous retrieve call for a consume to be possible before writing to the inbuf

main/main.cpp

@@ -673,6 +673,7 @@ int main(int argc, char **argv)
         RubberBandStretcher ts(sfinfo.samplerate, channels, options,
                                ratio, frequencyshift);
         ts.setExpectedInputDuration(sfinfo.frames);
+        ts.setMaxProcessSize(bs);
 
         int frame = 0;
         int percent = 0;

src/finer/R3Stretcher.cpp

@@ -647,6 +647,11 @@ R3Stretcher::process(const float *const *input, size_t samples, bool final)
     }
     
     size_t ws = m_channelData[0]->inbuf->getWriteSpace();
+    if (samples > ws) {
+        m_log.log(2, "R3Stretcher::process: insufficient space in input buffer, attempting consume before write");
+        consume();
+        ws = m_channelData[0]->inbuf->getWriteSpace();
+    }
     if (samples > ws) {
         m_log.log(0, "R3Stretcher::process: WARNING: Forced to increase input buffer size. Either setMaxProcessSize was not properly called or process is being called repeatedly without retrieve. Write space and samples", ws, samples);
         size_t newSize = m_channelData[0]->inbuf->getSize() - ws + samples;