Set volume of ALSA stream

I need to be able to set the volume of my开发者_JS百科 ALSA stream (snd_pcm_t from the PCM Interface). This is a common operation and i don't understand why there is no easy way? How can i do this? Streaming attenuated data is not an option since this will cause choppy volume adjustments because data is buffered. In DirectSound and WinMM it's a simple function call. Have i missed something? Should i use the mixer interface? The control interface? I see no connection between snd_pcm_t and the control interface. Am i using the wrong API?

I am porting to PulseAudio instead, seems to be well performing and has better documentation.