解决一个隐晦的问题。

QMultimedia Audio Input 在Qt6 下，QIODevice::readAll()返回的长度为奇数。如果默认返回长度是short的整数倍，则会出现严重的问题。

modules/sources/source_soundcard/dialogsoundcard.cpp

@@ -160,12 +160,6 @@ void DialogSoundCard::CreateAudioInput()
 }
 
 
-int DialogSoundCard::ApplyVolumeToSample(short iSample)
-{
-	//Calculate volume, Volume limited to  max 30000 and min -30000
-	return std::max(std::min(((iSample * miVolume) / 50) ,30000), -30000);
-}
-
 void DialogSoundCard::OnSliderValueChanged(int value)
 {
 	miVolume = value;
@@ -182,39 +176,26 @@ void DialogSoundCard::OnReadMore()
 	const int nins = m_cmdline->toInt("instance",0);
 	const int channel = m_cmdline->toInt("channel",2);
 	//Read sound samples from input device to buffer
+	//注意！Qt6下，这里返回的 mBuffer 字节个数可能是奇数。因此需要额外的处理。
 	QByteArray mBuffer = mpInputDevSound->readAll();
-	qint64 l = mBuffer.length();
+	m_buffer.append(mBuffer);
+	qint64 l = m_buffer.length();
 	if(l > 0) {
-		//Assign sound samples to short array
-		short* resultingData = (short*)mBuffer.data();
-		const int len = l/2;
-
-		short *outdata=resultingData;
-		outdata[ 0 ] = resultingData [ 0 ];
-		int iIndex;
-		miMaxValue = 0;
-		for ( iIndex=0; iIndex < len; iIndex++ ) {
-			//Change volume to each integer data in a sample
-			int value = ApplyVolumeToSample( outdata[ iIndex ]);
-			outdata[ iIndex ] = value;
-
-			miMaxValue = miMaxValue>=value ? miMaxValue : value;
-		}
-
-
 		if (m_batch_size<=0)
 		{
+			int len = m_buffer.size() / 2 / channel;
 			//write modified sound sample to outputdevice for playback audio
+			ApplyVolumeToSample((short *)m_buffer.data(),len * channel);
 			if (nid_timestamp)
 				TASKBUS::push_subject(nid_timestamp,nins,sizeof(quint64),(unsigned char *)&m_nTotalSps);
 			if (nid_wav>0)
-				TASKBUS::push_subject(nid_wav,nins,len*2,(unsigned char *)outdata);
-			m_nTotalSps += len*2;
+				TASKBUS::push_subject(nid_wav,nins,len*2*channel,(unsigned char *)m_buffer.data());
+			m_nTotalSps += len*2*channel;
 			QTimer::singleShot(1000, this, SLOT(OnTimeOut()));
+			m_buffer.remove(0,len*2*channel);
 		}
 		else
 		{
-			m_buffer.append((char *)outdata,len*2);
 			const int groupBytes = channel*m_batch_size*2;
 			const int groups = m_buffer.size()/groupBytes;
 			const char * pdata = m_buffer.constData();
@@ -224,6 +205,10 @@ void DialogSoundCard::OnReadMore()
 				if ((m_nTotalSps - listen_thread::m_refTms )<=19200*16 ||
 						listen_thread::m_refTms==0)
 				{
+					ApplyVolumeToSample(
+								(short *)(pdata+i*groupBytes),
+								groupBytes/2
+								);
 					//write modified sound sample to outputdevice for playback audio
 					if (nid_timestamp)
 						TASKBUS::push_subject(nid_timestamp,nins,sizeof(quint64),(unsigned char *)&m_nTotalSps);
@@ -238,6 +223,7 @@ void DialogSoundCard::OnReadMore()
 			//tail
 			m_buffer.remove(0,groups*groupBytes);
 		}
+
 	}
 }
 

modules/sources/source_soundcard/dialogsoundcard.h

@@ -30,7 +30,20 @@ private:
 
 private:
 	int AddWavHeader(char *);
-	int ApplyVolumeToSample(short iSample);
+
+	inline int ApplyVolumeToSample(short * iSample, int len)
+	{
+		//Calculate volume, Volume limited to  max 30000 and min -30000
+		miMaxValue = 0;
+		for (int i=0;i<len;++i)
+		{
+			iSample[i] = std::max(std::min(((iSample[i] * miVolume) / 50) ,30000), -30000);
+			if (miMaxValue < abs(iSample[i]))
+				miMaxValue = abs(iSample[i]);
+		}
+		return miMaxValue;
+	}
+
 	void InitMonitor();
 	void CreateAudioInput();
 private slots: