[mythtv] No Sound...

[Chris Lack]

On Wednesday 29 January 2003 05:27 am, John wrote:
> Hey Chris,
>
> You da man!  I replaced that msp3400 module with the one from the mga dir
> and voila!  Working audio and video for the first time.  How cool!  I found
> a couple other modules (like bttv.o, tvaudio.o, videodev.o, tuner.o, and
> tvmixer.o) in there.  Should I look for replacements for those too or are
> they ok?

They're okay.  The only two mgavideo needs are tuner and videodev and those 
work fine.

> Another interesting thing.  I never realized that I wasn't
> supposed to use the audio output from the breakout box on the G200.  I mean
> I send that video to the TV but I have to take the audio from the soundcard
> output right?  I guess it's only when coming out of the soundcard that it's
> digitized, eh?  I assume that's the way you have it?

I have the audio in plug on the main cable that connects to the g200 plugged 
into the line-in of my soundcard, and my soundcard out going to the same 
destination as the video out on the marvel box.  The a/v inputs on the box 
are used by my vcr for some good ol fashion dubbing.  I don't use the 
audio-out ports on the box for anything.

> Now that it's working, I have some "fine tuning" to do and maybe you or
> others can help?
>
> 1) With the G200 (I've got a P3-800) what settings do you have for
> resolution, qual lvl, luma/chroma, etc?

I intend to use my bt878 for watching live tv as software playback of mjpeg is 
very costly.  I will use the g200 for recording important things I plan on 
archiving later because I'm quite impressed with the quality of mjpeg (it 
should be good as much space as it takes up).  For mjpeg recording I use 
decimation 2:1 with quality 70 and mp3 32000/q3.  For rtjpeg with my bt878 I 
use 352x480 q222 l0 c0, for mpeg4 I use 400x400 bitrate 2048 2/15/4 with my 
patch that deinterlaces before encoding so you don't have to re-filter the 
video later.  This is currently on a celeron 800 overclocked a hair 
(coppermine core, so very close to your p3).  I compile everything (using gcc 
3.2) with -march=pentium3 -mmmx -msse -mfpmath=sse . . . the mfpmath bit can 
speed up floating point heavy programs quite a bit.  I have a 1.3ghz celery 
on the way so I can get some breathing room for pip/recording+watching.

> 2) Do you do mjpeg or mpeg4?  I figured the main reason for buying the G200
> was built-in decoding but the mpeg4 looks better! ??  How about you?  Maybe
> something's not right about that yet.  Maybe you could attach your
> settings.txt and theme.txt?

I haven't used .7 in a looong time, so I can't really help you here.  For the 
g200 I will be using mjpeg exclusively.  As for mpeg4 looking better . . . I 
think that might be some anomoly with .7?  MJPEG at 2:2 (352x240) looks 
slightly better than a raw capture at 352x240 because MJPEGS are encoded with 
extra data that help them scale back up to the original sample size.

> 3) When my mythfrontend / mythtv fires up, it always goes to composite
> input first.  Where do you specify "Television" for the initial input?  I
> didn't see it in either .txt file (0.7).

Can't help you here either, but there is a setting for it in the current cvs 
from within the program.  There have been changes made to mjpeg capture that 
makes it more configurable as well.  You should try and upgrade if you can.

> 4) Here's a quirk... When I go to TV/Watch Live TV I get audio & video -
> cool.  If it hit ESC, it returns to the menu.  If I then return to watching
> live TV, my audio is gone (video still there) ???  However, if when
> watching TV I hit "M" I can go to the EPG just fine and move around and hit
> M again (or space) and everything is fine.  When I return that way to live
> TV audio is still going.  Any idea why the ESC key blows out my audio?

This happens to me too.  I'll look into it soon.

<snip>
> 6) One small easy UI question.  How do I simply record a minute of a
> program and then stop?  I want to compare quality settings for "record
> only".

Not easily done.  You could tell it to record a program that has already 
started and then kill the process a minute later.  I don't remember if .7 
will start recording a show that's already on though?