[mythtv-users] Various teething problems setting up mythtv, comments wanted please ;-).

[Simon Iremonger]

Hello MythTv-users [writing to list for first time] ;-).

I would really appreciate the comments of some list-users out
   there on  MythTV setup using DVB-T [i.e. uk/Mendip] and
   acceptable TV-output onto a ''100hz'' digial-reprocessing-TV
   that only takes PAL/NTSC....

Apologies if this is a bit long; I'm going to describe the
   background of the machine/facts and then the problems I've
   been having!  Hopefully some of this may be of relevance
   to other people!

I have an appropriate machine/board with a reliable Astec PSU
   setup for quiet-running etc. anyhow... x86 machine...

** I have been using/experimenting-with Gentoo, and KnoppMyth
   R5A16.  KnoppMyth R5A16 includes Mythtv 0.18.1 with DVB-T
   support etc. built-in [no need to script filling the channel
   entries in mythconverg database manually as this is all
   catered for in MythTv-0.18.1].

[Currently got a an athlon-XP system basis with lov-voltage
   running CPU good for at least 2ghz, and can have 512mb or
   more memory... I believe this will be sufficient... This
   sort of thing is easily changed later ;-)].

I have 2* DVB-T cards with a cx23881 or similar (one is slightly
   different to the other) -- one is a "V-Stream" unit; other is
   an "LR6550" that indentifies as "conexant reference design".
In any case they both work ''perfectly'' seemingly, under 2.6.12
   kernel [or 2.6.11 with bytesex.org patches], which means you
   need to boot a separate kernel than that provided with
   KnoppMyth R5A16.

The only 'problem' I've been having with the cards is that the
   RF-passthrough on the LR6550 appears to be rubbish.. I.e.
   noticable patterning on Analogue TV reception using TV plugged
   through that card -- but I'll just accept this condition and
   daisy-chain that card off the V-stream card and not use the
   RF-out from the machine.

The machine has an onboard "cmipci" which works nicely, but I had
   to solder-on the 2-pin-headers for SPDIF in/out! [which does
   work, just the headers weren't fitted! -- all the surrounding
   resistors/capacitors feeding the outputs from the CMI chip were
   there already, how odd!].  The sound works beatifully using
   that connected to phonos on a backplate with ALSA drivers, and
   turning on "IEC958 output switch" in alsactl... So the sound
   can come from mini-jack (horrible connector!), or the phono
   SPDIF to external DAC.

I have maxtor 5400rpm ATA disk that seems to work fine, loads of
   capacity there, but it was being oddly noisy seeking around..
   Eventually I discovered that the 'acoustic management' value
   was set to "fastest but noisiest" mode... Now fixed.
   NB: see "hdparm -M" though this is marked as 'experimental'.
   Interestingly, under the current kernel, this value seems to
   be read-back as "0" always, whereas under a previous kernel
   I was using you could read this value okay seemingly... In
   any case it has been set to a sensible value which seems to
   be 'saved' in the drive okay... So this isn't really an
   issue now.

I have a plextor PX-712A cd/dvd read/writer with an RPC-1
   firmware which works nicely. However; even when continously
   reading a disk at a slow speed, it seems to 'insist' on
   spinning at a fast speed, which can be a bit noisy at times!
   I see 'hdparm' has an option for CD-drive speed...
   I notice there is a 'cdspeed' program too -- I can work this
   out anyway, not a large issue at the moment ;-).


I have a somewhat unusual partition layout, which is such that
   knoppmyth can be re-installed using a special config file
   without affecting the general boot partition or partition used
   for gentoo etc....


In any case...
Problems or areas of question ;-).


In particular, I would really appreciate comments on how to get
   TV output to RGB-scart behaving itself in a way appropriate for
   available mythtv ebuilds-in-gentoo or knoppmyth install.....
   If this presents a good reason to use a different distribution,
   then let me know ;-).

I have been using a Matrox-G400 with adapter wired-up for RGB-scart
   TV-output on G400... When this works, it works really well.  BUT
   I've been having ''issues''...  I do not have the original
   s-video/composite adapter that should have come with the card,
   but I do have, what I think is a similar composite/s-video
   adapter and quite possibly a compatible type [but I dont'
   want to use s-video/composite anyway!].

In any case, the properly wired up RGB adapter *does* work in e.g.
   DirectFB, and the wiring/card design is such that the TV
   'senses' the card is in S-video mode or RGB mode appropriately.
   (i.e. Either [Sync-on-video-pin, R, G, B] or
   [Sync-with-mono-video, Colour, n/a, n/a].  It also connects the
   "video dongle sense" such that the card can see the adapter is
   connected.  This is all wired to the SECOND head on the G400,
   as I understand is how it should be.

I have the PAL TV-output BIOS on the Card, but I've never suceeded
   in getting the TV output to work at boot-time ;-(.
I appear to have a 32mb dual-head G400-tv-out (i.e. with the 'Maven'
   chip).

I have also got wired-up a VGA-scart-rgb cable (with the resistors
   + transistor), and the tail-lead with 100ohms from 12v line
   [iirc].  I have an ATI-radeon card that is well supported and
   'does the job' for this purpose.
   I have been successful in making modelines that work, its' just
   fiddly to get the right width on the TV and never quite seems
   ''right''...
E.g. I have had this working on knoppmyth R5A16 install....

I am noticing many things...
Seemingly the video resultion of some DVB-T channels/programs is
   less than others, and the decoder 'scales' the resulting channel
   to the TV display [?]...

I seem to find that mythtv does not scale the video.... and hence
   appears to small on some channels, sometimes...  Is this normal??

I notice options on switching video mode in the mythtv setup menus.
   Does this actually work for anybody, so the X server display
   switches to different modes according to the video being played?
   Or is this not sensible??

You may see, I've been having a whole host of problems to solve...
   Mostly related to display with the TV-output!
The best G400 support is in DirectFB, but mythtv in DirectFB
   doesn't seem to be a particuarly viable solution!
I don't know if you can enable RGB TV on G400 in X.org X11 ??...

Of course, if you are just using the 'X on TV RGB cable' adapter,
   this is not an issue, since the output is normally RGB. the
   problems come with getting the right mode(s) setup in the
   X server...


********
I would really, really, appreciate some comments/examples on what
   'Actually works' and how to put it together right, particuarly
   in terms of RGB-TV-Output-at-PAL and mythtv fullscreen display
   that doesn't appear 'small', and any comments on the various
   distributions!
********

Please ;-)

I will be happy to provide any more relevant information from the
   machine, check things, test things... I just want to get it
   working properly !!!!

Thankyou in advance.


-- 'S Iremonger' <simon at businesswebsite.com>