From 92362bdba0d5cb33ed76f0af4bdcf91917837e54 Mon Sep 17 00:00:00 2001
From: Chris Cannam <cannam@all-day-breakfast.com>
Date: Fri, 2 Sep 2022 15:08:29 +0100
Subject: [PATCH] Resample in chunks as well, to avoid overrunning resample
 buffer

---
 src/finer/R3Stretcher.cpp | 86 ++++++++++++++++++++-------------------
 1 file changed, 44 insertions(+), 42 deletions(-)

diff --git a/src/finer/R3Stretcher.cpp b/src/finer/R3Stretcher.cpp
index 6ad9074..8cdbde2 100644
--- a/src/finer/R3Stretcher.cpp
+++ b/src/finer/R3Stretcher.cpp
@@ -309,7 +309,7 @@ R3Stretcher::createResampler()
         }
     } else {
         if (after) {
-            m_log.log(0, "createResampler: resampling after");
+            m_log.log(1, "createResampler: resampling after");
         }
     }
 }
@@ -660,33 +660,15 @@ R3Stretcher::process(const float *const *input, size_t samples, bool final)
         m_mode = ProcessMode::Processing;
     }
 
-    int channels = m_parameters.channels;
-    int toWrite = int(samples);
-
     bool resamplingBefore = false;
     areWeResampling(&resamplingBefore, nullptr);
-        
-    if (resamplingBefore) {
 
-        for (int c = 0; c < channels; ++c) {
-            auto &cd = m_channelData.at(c);
-            m_channelAssembly.resampled[c] = cd->resampled.data();
-        }
+    int channels = m_parameters.channels;
+    int inputIx = 0;
 
-        toWrite = m_resampler->resample
-            (m_channelAssembly.resampled.data(),
-             m_channelData.at(0)->resampled.size(),
-             input,
-             int(samples),
-             1.0 / m_pitchScale,
-             final);
-    }
-    
-    int written = 0;
-        
-    while (written < toWrite) {
+    while (inputIx < int(samples)) {
 
-        int remaining = toWrite - written;
+        int remaining = int(samples) - inputIx;
         int ws = m_channelData[0]->inbuf->getWriteSpace();
 
         if (ws == 0) {
@@ -695,8 +677,8 @@ R3Stretcher::process(const float *const *input, size_t samples, bool final)
         }
         
         if (ws == 0) {
-            m_log.log(0, "R3Stretcher::process: WARNING: Forced to increase input buffer size. Either setMaxProcessSize was not properly called, process is being called repeatedly without retrieve, or an internal error has led to an incorrect resampler output calculation. Samples to write", toWrite);
-            size_t newSize = m_channelData[0]->inbuf->getSize() + toWrite;
+            m_log.log(0, "R3Stretcher::process: WARNING: Forced to increase input buffer size. Either setMaxProcessSize was not properly called, process is being called repeatedly without retrieve, or an internal error has led to an incorrect resampler output calculation. Samples to write", remaining);
+            size_t newSize = m_channelData[0]->inbuf->getSize() + remaining;
             for (int c = 0; c < m_parameters.channels; ++c) {
                 auto newBuf = m_channelData[c]->inbuf->resized(newSize);
                 m_channelData[c]->inbuf =
@@ -704,27 +686,47 @@ R3Stretcher::process(const float *const *input, size_t samples, bool final)
             }
             continue;
         }
+        
+        if (resamplingBefore) {
 
-        int toWriteHere = remaining;
-        if (toWriteHere > ws) {
-            toWriteHere = ws;
-        }
-
-        for (int c = 0; c < m_parameters.channels; ++c) {
-            if (resamplingBefore) {
-                m_channelData[c]->inbuf->write
-                    (m_channelData.at(c)->resampled.data() + written,
-                     toWriteHere);
-            } else {
-                m_channelData[c]->inbuf->write
-                    (input[c] + written, toWriteHere);
+            for (int c = 0; c < channels; ++c) {
+                auto &cd = m_channelData.at(c);
+                m_channelAssembly.resampled[c] = cd->resampled.data();
             }
+
+            int resampleBufSize = int(m_channelData.at(0)->resampled.size());
+            int maxResampleOutput = std::min(ws, resampleBufSize);
+            
+            int maxResampleInput = int(floor(maxResampleOutput * m_pitchScale));
+            int resampleInput = std::min(remaining, maxResampleInput);
+            if (resampleInput == 0) resampleInput = 1;
+            
+            int resampleOutput = m_resampler->resample
+                (m_channelAssembly.resampled.data(),
+                 maxResampleOutput,
+                 input,
+                 resampleInput,
+                 1.0 / m_pitchScale,
+                 final);
+
+            inputIx += resampleInput;
+
+            for (int c = 0; c < m_parameters.channels; ++c) {
+                m_channelData[c]->inbuf->write
+                    (m_channelData.at(c)->resampled.data(),
+                     resampleOutput);
+            }
+
+        } else {
+            int toWrite = std::min(ws, remaining);
+            for (int c = 0; c < m_parameters.channels; ++c) {
+                m_channelData[c]->inbuf->write (input[c] + inputIx, toWrite);
+            }
+            inputIx += toWrite;
         }
-
-        written += toWriteHere;
+        
+        consume();
     }
-
-    consume();
 }
 
 int