fixed an audio glitch at the first note in exported mp3 file

Update the max samples per block for all sequences (rather than in each process call)

src/framework/vst/internal/synth/vstsynthesiser.cpp

@@ -199,6 +199,10 @@ samples_t VstSynthesiser::process(float* buffer, samples_t samplesPerChannel)
         return 0;
     }
 
+    if (samplesPerChannel > m_vstAudioClient->maxSamplesPerBlock()) {
+        m_vstAudioClient->setMaxSamplesPerBlock(samplesPerChannel);
+    }
+
     const msecs_t nextMsecs = samplesToMsecs(samplesPerChannel, m_sampleRate);
     const VstSequencer::EventSequenceMap sequences = m_sequencer.movePlaybackForward(nextMsecs);
     samples_t sampleOffset = 0;

src/framework/vst/internal/vstaudioclient.cpp

@@ -210,13 +210,18 @@ void VstAudioClient::allNotesOff()
     m_playingParams.clear();
 }
 
-void VstAudioClient::setMaxSamplesPerBlock(unsigned int samples)
+samples_t VstAudioClient::maxSamplesPerBlock() const
+{
+    return m_samplesInfo.maxSamplesPerBlock;
+}
+
+void VstAudioClient::setMaxSamplesPerBlock(samples_t samples)
 {
     if (m_samplesInfo.maxSamplesPerBlock == samples) {
         return;
     }
 
-    m_processData.numSamples = samples;
+    m_processData.numSamples = static_cast<Steinberg::int32>(samples);
     m_samplesInfo.maxSamplesPerBlock = samples;
     m_needUnprepareProcessData = true;
 

src/framework/vst/internal/vstaudioclient.h

@@ -47,15 +47,17 @@ class VstAudioClient
     void flush();
     void allNotesOff();
 
-    void setMaxSamplesPerBlock(unsigned int samples);
+    audio::samples_t maxSamplesPerBlock() const;
+    void setMaxSamplesPerBlock(audio::samples_t samples);
+
     void setSampleRate(unsigned int sampleRate);
 
     ParamsMapping paramsMapping(const std::set<Steinberg::Vst::CtrlNumber>& controllers) const;
 
 private:
     struct SamplesInfo {
         unsigned int sampleRate = 0;
-        unsigned int maxSamplesPerBlock = 0;
+        audio::samples_t maxSamplesPerBlock = 0;
 
         bool isValid()
         {