handle mono

stepmania/src/RageSound.cpp

@@ -281,7 +281,7 @@ void RageSound::RateChange(char *buf, int &cnt,
 
 /* Fill the buffer by about "bytes" worth of data.  (We might go a little
  * over, and we won't overflow our buffer.)  Return the number of bytes
- * actually read; 0 = EOF. */
+ * actually read; 0 = EOF.  Convert mono input to stereo. */
 int RageSound::FillBuf( int frames )
 {
 	ASSERT(Sample);
@@ -295,7 +295,6 @@ int RageSound::FillBuf( int frames )
 
 		char inbuf[10240];
 		unsigned read_size = read_block_size;
-		int cnt = 0;
 
 		if( m_Param.speed_input_samples != m_Param.speed_output_samples )
 		{
@@ -309,12 +308,36 @@ int RageSound::FillBuf( int frames )
 			ASSERT(read_size < sizeof(inbuf));
 		}
 
+		/* channels == 2; we want stereo.  If the input data is mono, read half as many
+		 * samples. */
+		if( Sample->GetNumChannels() == 1 )
+			read_size /= 2;
+
 		ASSERT(read_size < sizeof(inbuf));
 
-		cnt = Sample->Read(inbuf, read_size);
+		int cnt = Sample->Read(inbuf, read_size);
 		if(cnt == 0)
 			return got_something; /* EOF */
 
+		if( Sample->GetNumChannels() == 1 )
+		{
+			/* Dupe mono to stereo in-place; do it in reverse, to handle overlap. */
+			int num_samples = cnt / sizeof(int16_t);
+			float *input = (float *) inbuf;
+			float *output = input;
+			input += num_samples;
+			output += num_samples*2;
+			while( num_samples-- )
+			{
+				input -= 1;
+				output -= 2;
+				output[0] = input[0];
+				output[1] = input[0];
+			}
+
+			cnt *= 2;
+		}
+
 		if(cnt == -1)
 		{
 			Fail(Sample->GetError());

stepmania/src/RageSoundReader_Vorbisfile.cpp

@@ -54,8 +54,6 @@ static long OggRageFile_tell_func( void *datasource )
 	return f->Tell();
 }
 
-const int channels = 2;
-
 const int read_block_size = 1024;
 
 
@@ -131,6 +129,10 @@ SoundReader_FileReader::OpenResult RageSoundReader_Vorbisfile::Open(CString file
 	eof = false;
 	read_offset = (int) ov_pcm_tell(vf);
 
+	vorbis_info *vi = ov_info( vf, -1 );
+	ASSERT_M( vi->channels == 1 || vi->channels == 2, ssprintf("%i", vi->channels) );
+	channels = vi->channels;
+
     return OPEN_OK;
 }
 
@@ -183,9 +185,12 @@ bool RageSoundReader_Vorbisfile::FillBuf()
 
 	vorbis_info *vi = ov_info( vf, -1 );
 	ASSERT( vi != NULL );
-	const int bytes_per_frame = 2*vi->channels;
 
-	char tmpbuf[4096];
+	if( (unsigned) vi->channels != channels )
+		RageException::Throw( "File \"%s\" changes channel count from %i to %i; not supported", channels, vi->channels );
+
+	const int bytes_per_frame = sizeof(int16_t)*vi->channels;
+
 	int ret = 0;
 
 	{
@@ -207,9 +212,9 @@ bool RageSoundReader_Vorbisfile::FillBuf()
 			/* In bytes: */
 			int silence = (curofs - read_offset) * bytes_per_frame;
 			CHECKPOINT_M( ssprintf("p %i,%i: %i frames of silence needed", curofs, read_offset, silence) );
-			silence = min( silence, (int) sizeof(tmpbuf) );
+			silence = min( silence, (int) sizeof(buffer) );
 
-			memset( tmpbuf, 0, silence );
+			memset( buffer, 0, silence );
 			ret = silence;
 		}
 	}
@@ -218,9 +223,9 @@ bool RageSoundReader_Vorbisfile::FillBuf()
 	{
 		int bstream;
 #if defined(INTEGER_VORBIS)
-		ret = ov_read( vf, tmpbuf, sizeof(tmpbuf), &bstream );
+		ret = ov_read( vf, buffer, sizeof(buffer), &bstream );
 #else // float vorbis decoder
-		ret = ov_read( vf, tmpbuf, sizeof(tmpbuf), (BYTE_ORDER == BIG_ENDIAN)?1:0, 2, 1, &bstream );
+		ret = ov_read( vf, buffer, sizeof(buffer), (BYTE_ORDER == BIG_ENDIAN)?1:0, 2, 1, &bstream );
 #endif
 
 		if( ret == OV_HOLE )
@@ -242,17 +247,6 @@ bool RageSoundReader_Vorbisfile::FillBuf()
 
 	/* If we have a different number of channels, we need to convert. */
 	ASSERT( vi->channels == 1 || vi->channels == 2 );
-	if( vi->channels == 1 )
-	{
-		int16_t *indata = (int16_t *)tmpbuf;
-		int16_t *outdata = (int16_t *)buffer;
-		int size = ret / sizeof(int16_t);
-		for( unsigned pos = 0; pos < unsigned(size); ++pos )
-			outdata[pos*2] = outdata[pos*2+1] = indata[pos];
-		ret *= 2;
-	}
-	else
-		memcpy( buffer, tmpbuf, ret );
 
 	avail = ret;
 	return true;

stepmania/src/RageSoundReader_Vorbisfile.h

@@ -18,6 +18,7 @@ class RageSoundReader_Vorbisfile: public SoundReader_FileReader {
 	bool FillBuf();
 	CString filename;
 	int read_offset;
+	unsigned channels;
 
 public:
 	OpenResult Open(CString filename);
@@ -27,6 +28,7 @@ public:
 	int SetPosition_Fast(int ms) { return SetPosition(ms, false); }
 	int Read(char *buf, unsigned len);
 	int GetSampleRate() const;
+	unsigned GetNumChannels() const { return channels; }
 	RageSoundReader_Vorbisfile();
 	~RageSoundReader_Vorbisfile();
 	SoundReader *Copy() const;