[MPlayer-users] Sound issue with ac3 on PC speakers

[Tom Evans]

On Thu, Mar 13, 2014 at 1:22 PM, Ingo Brückl <ib at wupperonline.de> wrote:
> I've configured
>
>   ao=alsa
>   ac=hwac3,
>
> for my Soundblaster Live. With mp3, aac etc. I have sound with both my
> analogue PC stereo speakers and my digital surround receiver. With ac3 (both
> stereo and 5.1) I have sound only with my surround receiver, but none with my
> PC speakers.
>
> Isn't it possible to have both AC3 pass-through and a 2 channel downmix for
> the PC speakers simultaneously?

Yes, but not from mplayer I believe - mplayer can only output to one
audio device.

I didn't reply before because I only truly know how it behaves with
OSS. With OSS, each output is a separate device, so my digital output
is a completely different device and mixer to my analogue output on
the same card, and what you describe as happening with mp3 and aac
formats does not happen for me. I guess with alsa you get this
convenient fallback that pcm audio sent to the device is output on
both digital and analogue.

To make it work how you want, I think you would have to insert
pulseaudio in to the mix. Pulseaudio can take an ac3 track, send it as
a bitcopy to the digital output and simultaneously decode and output
it over analogue. You then get all the "features" of pulse to work
around too...

Cheers

Tom