[MPlayer-users] What output driver for USB DAC?

[Erik Auerswald]

Hi John,

On 02/04/2018 09:32 AM, John Long wrote:
> Does anybody know how to get mplayer to send the correct signal to a
> USB DAC?

I've never done this and don't have that kind of device, so I cannot 
give you a definitive answer.

Anyway, I used to have a Hi-Fi DAC connected via S/PDIF fibre optics 
cable. I could use this with the MPlayer option:

     -ao alsa:device=iec958=1.0

You can look at the documentation for "passthrough":

http://mplayerhq.hu/DOCS/HTML/en/advaudio-surround.html#advaudio-surround-passthrough

http://mplayerhq.hu/DOCS/HTML/en/advaudio-surround.html#hwmpa-surround-passthrough

You can get a list of audio outputs supported by you MPlayer executable 
using:

     mplayer -ao help

> If I play the file normally (mplayer filename) it appears mplayer
> decodes the file before sending it to the DAC.

Yes, that is the MPlayer default behaviour, you need to explicitly stop 
MPlayer from decoding and tell it to send the digital data to the device 
if you want to override this default.

> I am trying to get
> mplayer to send whatever type of signal to the DAC it needs so that the
> DAC itself will decode the music, not mplayer.

I hope that the documentation pointers above help you getting closer to 
that.

Thanks,
Erik