TV tuner, sound etc. -- what does this mean?

Michael Schwendt mschwendt at gmail.com
Fri Jul 31 10:18:00 UTC 2009


On Fri, 31 Jul 2009 04:47:29 -0400, William wrote:

> Hi Michael;
> 
> On Fri, 2009-07-31 at 07:54 +0200, Michael Schwendt wrote:
> > On Thu, 30 Jul 2009 21:52:00 -0400, William wrote:
> > 
> > > Mplayer gives me sound from both my DVD/CD drive (which RhythmBox fails
> > > to do) and video1 for tv (which tvtime fails to do).
> > 
> > It's not accurate to say "tvtime fails", because it doesn't even try to do
> > what you think it does [apparently]. The implementation in tvtime is
> > from 2005 and can only enable an analogue audio input channel.
> 
> I have understood from the first time that you told me that tvtime does
> not mix sound  -- except for the simplest kind of volume control; that
> ALSA is, or should be supplying the mixing.

For what?  If *you* run tvtime with *your* hardware configuration, there
is no audio available to be "mixed".  You may continue to point tvtime
at any of the available ALSA mixer devices, but it won't turn on any audio.

[The only scenario that would be possible is to abuse tvtime as
a volume control of e.g. the "Master" or "PCM" channels while using
a music player to play back audio tracks.]

> However, from a descriptive perspective, when I launch tvtime I get no
> sound.  I don't think anybody on "God's Green Earth" would misunderstand
> what I am saying. 

And still at least one other list subscriber has mentioned the cable
between tv card and audio board. ;) The obvious fix that doesn't
apply in your case. It doesn't become clear what you try to find out.

The condition "tvtime gives sound" does not exist with your h/w config.
That you get "no sound" with tvtime is _expected_. It's irrelevant to
continue with pointing out that tvtime "fails" or gives you "no sound".
tvtime works as expected. Your tv card driver provides the video signal
on /dev/video0, which is what tvtime displays correctly (with good
quality even, as you've pointed out). The mpeg encoded A/V stream on
/dev/video1 is nothing tvtime understands.

> What words would you suggest I choose to express that meaning?

To focus on the relevant details.

> Getting mplayer working as a replacement for tvtime is not the point of
> this exercise.  There is something clearly wrong with some drivers that
> are related to ALSA.

Maybe, but the message doesn't become clear at all anymore. What
exactly are you trouble-shooting? Music playback in application 1 or
television in application 2?
How about choosing a meaningful Subject line for the mails?

> My system's sound chips are not terribly unique.
> The whole world is going to the PCIe bus.  Having a tuner that includes
> both analogue and digital is not something that should be difficult to
> overcome.  As you point out, analogue is not being used.  As you have
> also pointed out, this is not about tvtime but about enabling one of the
> under lying chips or drivers.
> 
> Perhaps you can suggest another program that should be using alsa's
> analog sound capability (or lack of that capability) and I will try to
> get that going.

What kind of "analog sound capability" do you have in mind?
"Analog sound" refers to the Input ADC and Output DAC units. Since you
don't use your input (Line-in, or Microphone e.g.) where do you expect
analog audio input to come from?




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