[mythtv-users] TVCards with chip Saa713x - Sound wrongly sampled; Image doubled and wrong color

"José Tomás @ Chico" jose.tomas at chico.mine.nu
Sun Oct 5 18:07:56 UTC 2008


A little story about my media center project with linux using 
Ubuntu/Mythbuntu (>=8,04) for better understand.

I have a _TV Card  ASUS My Cinema P7131_, which have the common _chip 
Saa713x_ aside the old btt chip at Portuguese market.
The _graphic display card_ is the very new _ASUS EAH3600 HD_, which has 
_ATI chip_.

With this two items I had image display drivers issues, some apps didn't 
work. Desktop gaphics effects didn't work or crash.
Showing TV was not acceptable since image at mythtv was doubled (see 
image) and sound wrong sampled. Only mplayer with some setings available 
on regular posts related to saa713x was able to do it fine.

Nevertheless I found posts with more then one year old and some 
suggestions not acceptable for some one need the thinks working with 
less of less tricks or workarounds. Like launching marginal processes 
like sox, auplay, etc etc.

So this mail is my contribution to clear some old and unappropriated 
suggestions since linux is getting better.

To be quick I'll not provide fine grain details, but I think enough to 
help any one who gets into same situation.

So, first, _this HD graphics card works better with ATI manufacturer 
driver for linux._ _These guys are updating very well._ So, usually 
posts suggested to use the XOrg or even envy driver... between this two, 
yes, the XOrg was better, but mythtv stand not working. ATI manufacturer 
driver has been the best.
For compiz you may turn off all performance and graphics improvements 
with the ati control center app. I did this test prior install mythtv, 
but remember to read that compiz and mythtv are not good friends.

This TVCard model has a good thing, provides internally an audio wire 
cdrom connection like, but I insisted on using DMA sound.
In my case DMA sound device is /dev/dsp2, as you may read at TVCad box 
or manual the sound is 32KHz, but saa7134_alsa module insists to config 
44KHz as you may see on boot up messages.
So, my battle was to do on app layer the setting for 32KHz. Mplayer 
worked like this, reason why I tested freevo mean while with success. 
But come back to mythtv, seamed to me that Mythtv had some features that 
I may need, and freevo doesn't have them. But I liked the freevo's 

So, the solutions using mythtv:
* for imaging is setting for Playback filter to the Default decoder plus 
xlib has renderer (ffmpeg->xlib), and linear blend for interlace issue. 
The oder options or gave to me wrong color or even worst, doubled view.
* for sound, regarding some log errors that were not totally 
understandable to me, at Setup>TV>Recording Profiles>Software Encoders 
change codec to Uncompres and Sampling to 32KHz.

For audio some posts sugested to go back using oss or sox or something 
like it, but I think linux is going into the battle front, not to back ;-).

By the way, the help given to me by posts related to thread 
"[mythtv-users] Doubled screen - Is this any interlace issue?" were 

Thanks to you all!
*José Tomás*
 MSN: jfht at netc.pt
 Skype: jfhtomas

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