The setting audio_output_format
forces
MPD to use one audio format for
all outputs. Doing that is usually not a good idea. The
values are the same as in format
in the audio_output
section.
Sometimes, music needs to be resampled before it can be played; for example, CDs use a sample rate of 44,100 Hz while many cheap audio chips can only handle 48,000 Hz. Resampling reduces the quality and consumes a lot of CPU. There are different options, some of them optimized for high quality and others for low CPU usage, but you can't have both at the same time. Often, the resampler is the component that is responsible for most of MPD's CPU usage. Since MPD comes with high quality defaults, it may appear that MPD consumes more CPU than other software.
Check the resampler plugin reference for a list of resamplers and how to configure them.