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Re: [pulseaudio-discuss] Auto-switching to and from HDMI ports (audio)


On 03/16/2012 03:06 AM, Tanu Kaskinen wrote:
On Fri, 2012-03-16 at 02:48 +0100, David Henningsson wrote:
As I see it we have a couple of options.

   * no auto switching between HDMI and analog outputs at all. This is
probably the simplest option. But maybe this is not the most user
friendly option?

   * full switching. This requires not only profile switching on plug and
unplug, but also switching between cards, i e moving streams between
cards, and updating the default sink. More work, but definitely doable.
I get the feeling that we want to avoid updating the default sink when
it's not a direct user action though?

I guess you are more familiar with the use cases, but wouldn't it be
common to attach a monitor without wanting to use the monitor's audio
output? If that's the case, I think auto-switching isn't really a good

I don't know how common it is to want to use, vs does not want to use, the audio output of an HDMI monitor. That's part of why I'm asking :-)

Also, I don't know if it's possible/common that the HDMI monitor lies to us about its audio capabilities, so that it would say that it has audio capabilities when it does not. I did however test connecting my DVI monitor over HDMI and that one correctly did not show up as having audio capabilities.

If you are going to do the auto-switching anyway, I think the default
sink should be changed too. Behaving differently with existing and
not-yet-existing streams doesn't make sense to me.

   * switching only if the HDMI outputs are on the same card as the
analog output. This is also simple to achieve, but might be confusing
for users and support engineers?

   * switching from HDMI but never to HDMI: assuming we're not certain
that the user wants to use HDMI audio just because (s)he plugged it in,
we could quite safely assume that (s)he does not want to use an
unplugged HDMI cable. However, if we want to do this consistently, we
still suffer from having to set the default sink.

What do you think?

For what it's worth (I'm not a usability expert), to me the last option
sounds the best policy, with default sink updating.

Cool, thanks for the input. What do others think?

David Henningsson, Canonical Ltd.

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