AUDIO: Add rate adjustment functionality to Mixer

Extended the Mixer class to support manually setting the
sample rate of a channel.

audio/mixer.cpp

@@ -114,6 +114,26 @@ public:
 	 */
 	int8 getBalance();
 
+	/**
+	 * Set the channel's sample rate.
+	 * 
+	 * @param rate	The new sample rate. Must be less than 131072
+	*/
+	void setRate(uint32 rate);
+
+	/**
+	 * Get the channel's sample rate.
+	 * 
+	 * @return The current sample rate of the channel.
+	*/
+	uint32 getRate();
+
+	/**
+	 * Reset the sample rate of the channel back to its
+	 * AudioStream's native rate.
+	*/
+	void resetRate();
+
 	/**
 	 * Notifies the channel that the global sound type
 	 * volume settings changed.
@@ -401,6 +421,34 @@ int8 MixerImpl::getChannelBalance(SoundHandle handle) {
 	return _channels[index]->getBalance();
 }
 
+void MixerImpl::setChannelRate(SoundHandle handle, uint32 rate) {
+	Common::StackLock lock(_mutex);
+
+	const int index = handle._val % NUM_CHANNELS;
+	if (!_channels[index] || _channels[index]->getHandle()._val != handle._val)
+		return;
+
+	_channels[index]->setRate(rate);
+}
+
+uint32 MixerImpl::getChannelRate(SoundHandle handle) {
+	const int index = handle._val % NUM_CHANNELS;
+	if (!_channels[index] || _channels[index]->getHandle()._val != handle._val)
+		return 0;
+	
+	return _channels[index]->getRate();
+}
+
+void MixerImpl::resetChannelRate(SoundHandle handle) {
+	Common::StackLock lock(_mutex);
+
+	const int index = handle._val % NUM_CHANNELS;
+	if (!_channels[index] || _channels[index]->getHandle()._val != handle._val)
+		return;
+	
+	_channels[index]->resetRate();
+}
+
 uint32 MixerImpl::getSoundElapsedTime(SoundHandle handle) {
 	return getElapsedTime(handle).msecs();
 }
@@ -559,6 +607,24 @@ int8 Channel::getBalance() {
 	return _balance;
 }
 
+void Channel::setRate(uint32 rate) {
+	if (_converter)
+		_converter->setInputRate(rate);
+}
+
+uint32 Channel::getRate() {
+	if (_converter)
+		return _converter->getInputRate();
+	
+	return 0;
+}
+
+void Channel::resetRate() {
+	if (_converter && _stream) {
+		_converter->setInputRate(_stream->getRate());
+	}
+}
+
 void Channel::updateChannelVolumes() {
 	// From the channel balance/volume and the global volume, we compute
 	// the effective volume for the left and right channel. Note the

audio/mixer.h

@@ -254,6 +254,31 @@ public:
 	 */
 	virtual int8 getChannelBalance(SoundHandle handle) = 0;
 
+	/**
+	 * Set the sample rate for the given handle.
+	 * 
+	 * @param handle 	The sound to affect.
+	 * @param rate		The new sample rate. Must be less than 131072
+	*/
+	virtual void setChannelRate(SoundHandle handle, uint32 rate) = 0;
+
+	/**
+	 * Get the sample rate for the given handle.
+	 * 
+	 * @param handle 	The sound to affect.
+	 * 
+	 * @return The current sample rate of the channel.
+	*/
+	virtual uint32 getChannelRate(SoundHandle handle) = 0;
+
+	/**
+	 * Reset the sample rate of the channel back to its
+	 * AudioStream's native rate.
+	 * 
+	 * @param handle 	The sound to affect.
+	*/
+	virtual void resetChannelRate(SoundHandle handle) = 0;
+
 	/**
 	 * Get an approximation of for how long the channel has been playing.
 	 */

audio/mixer_intern.h

@@ -118,6 +118,9 @@ public:
 	virtual byte getChannelVolume(SoundHandle handle);
 	virtual void setChannelBalance(SoundHandle handle, int8 balance);
 	virtual int8 getChannelBalance(SoundHandle handle);
+	virtual void setChannelRate(SoundHandle handle, uint32 rate);
+	virtual uint32 getChannelRate(SoundHandle handle);
+	virtual void resetChannelRate(SoundHandle handle);
 
 	virtual uint32 getSoundElapsedTime(SoundHandle handle);
 	virtual Timestamp getElapsedTime(SoundHandle handle);