[mythtv-users] qt-mysql on mandrake

[Daniel Dunning]

Greetings.  First off I want to thank Isaac and all the Myth developers, 
this application really rocks and certainly rivals (and surpasses in 
many areas) the functionality of my TiVo.  

I have been setting up a MythTV system for video distribution around my 
house.  I have been having problems with numerous different elements.  I 
am hoping that documenting my system with this post will help me get it 
in order.  Hopefully people will spot my weak areas and help me fortify 
the system.  I am currently in the setup and testing phase of the MythTV 
experience.  Here is how I am currently set up:

Master Backend:
Debian Stable (2.4.20)
Athlon 1 GHz processor (unstable at 1 GHz [7.5 X 133Mhz], running at 7.5 
x 125Mhz [937MHz])
Asus A7v133 Motherboard
256 MB PC133 SDRAM
Mounted storage via NFS
Disk: Maxtor 91080D5 10GB
#hdparm /dev/hda
/dev/hda:
 multcount    = 16 (on)
 I/O support  =  1 (32-bit)
 unmaskirq    =  1 (on)
 using_dma    =  1 (on)
 keepsettings =  0 (off)
 nowerr       =  0 (off)
 readonly     =  0 (off)
 readahead    =  8 (on)
 geometry     = 1313/255/63, sectors = 21095424, start = 0
 busstate     =  1 (on)
#hdparm -tT /dev/hda
/dev/hda:
 Timing buffer-cache reads:   128 MB in  0.75 seconds =170.67 MB/sec
 Timing buffered disk reads:  64 MB in  4.32 seconds = 14.81 MB/sec

Audio: es1371 based
Video: Savage 2000 64MB composite out
Tuner: Hauppauge WinTV-Go (mono)


File/Database Server
RedHat 7.3 (2.4.18-3)
Athlon 1.2 GHz processor
Asus A7v Motherboard
512 MB PC133 SDRAM
Storage Disks:
/dev/md0: 136 GB RAID5 (4 x 45GB ATA 100/133)
/dev/md1: 194 GB RAID5 (8 x 27GB ATA 100/133)
#hdparm -tT /dev/md[0-1]
/dev/md0:
 Timing buffer-cache reads:   128 MB in  0.63 seconds =203.17 MB/sec
 Timing buffered disk reads:  64 MB in  1.43 seconds = 44.76 MB/sec
/dev/md1:
 Timing buffer-cache reads:   128 MB in  0.62 seconds =206.45 MB/sec
 Timing buffered disk reads:  64 MB in  0.90 seconds = 71.11 MB/sec


Frontend Candidate 1:
AMD k6-2 @ 375 MHz

Frontend Candidate 2:
Pentium II @ 275 MHz

Frontend Candidate 3:
Celeron A @ 300 MHz

Frontend/Backend Candidate 4:
Pentium II @ 333 MHz X 2

Misc Frontend Parts:
Remote: Creative CIMR 100 IR reciever x 3
Video: S3 Savage 2000 64MB Composite out x 2
Video: ATI Radeon 7500 Svid + Composite
Video: ATI Rage 128 SVid + Comp out, Comp in
Video: ATI Rage II+DVD Svid + Composite
Tuner: AI Tech WaveWatcher NeTV-PCI (Zoran zr36120 + Phillips 7110A)
Capture: Generic BT848 Capture with SVid+Composite in
Audio: ymfpci, es1370, es1371, oplSAx, opti
Various Hard Drives, Memory, etc.

Issues:

I am having issues in quite a few areas (and have worked through more 
problems than I can count to get where I am already) so I will try to 
categorize the issues:

1. System Performance: The main issue is performance problems with video 
playback.  I am unsure whether the issue is with the frontend or backend 
machines, but I suspect the problem is on the frontend.  The only 
configuration where I was able to get any acceptable playback was using 
frontend #2 with the radeon video card.  Also, I am only able to get 
acceptable playback for live TV, if I am trying to record the show and 
watch it on the frontend, the playback stalls every .5-1.5 seconds and 
the audio stutters and cuts out.  The backend is set up to use it's 
local disk for live TV buffering, but to use the file server via NFS for 
recordings.  The load on the file server while these operations are 
happening is negligible.  The processor on the backend machine is 
usually 50-80% utilization if it is recording and a frontend is 
playing.  The processor on the frontend machines ranges by machine, but 
none of them seem to use full utilization during playback.  However, on 
machines 1 and 3 the playback freezes every second or so, with 
corresponding audio dropout.  Frontend system 4 has not yet been tested 
with myth.  Frontend #1 was used as a freevo system in the past, with 
acceptable performance playing back MPEG2 files exported from a TiVo.  
One of the drives has MythVideo on it, but it has not yet been tested 
with the TiVo files.  I am using the default settings for recording live 
TV and scheduled recordings.  

So I guess my question in this area is what are the minimum system 
requirements for a frontend system?  Are any of the candidates listed 
above going to be able to cut it in the performance arena?  Do I just 
need to optimize the way things are set up on the systems that can't 
play video well (or the backend system) or are they simply too 
underpowered and no amount of optimization will suffice?

2.  Network Performance.  As I stated above, I am attempting to use a 
remote NFS server for storing recordings.  When I am trying to record 
something and watch it on frontend 2 (which can watch live TV with 
almost acceptable performance) the video stutters as described above.  I 
am wondering if these problems are related to network performace.  The 
NFS server and the backend server are connected via a 24 port netgear 
100 Mb rackmount hub.  During the testing phase the frontends have been 
connected to a 8 port 100 Mb D-link switch.  Is it possible that my 
problems viewing programs that are recording are related to network 
performance?  What are the bandwidth requirements for recording (and 
playing back) programs?  Are there other people who are using NFS mounts 
to record programs?  With so many variables (backend performance, 
frontend performance, network performance, file server performance, 
etc.) it is hard to narrow down where the problems are.  Is it possible 
that I need to upgrade to a switched network for the backend servers (or 
even gigabit??).  Or are my problems related to system performance and 
not network performance?

3.  Video Out.  As you can see from the array of video cards listed 
above, I have tried quite a few things trying to get the video signal to 
my television.  I need either s-vid or composite output that works in X, 
but so far, none of the listed video cards can give me that.  Has anyone 
used any of the cards listed above for output to a television?  When I 
was using system #1 for freevo, I used one of the savage 2000 cards 
listed above.  I was enthusiastic about this card, because it gave 
acceptable video playback under freevo and the composite output worked 
automatically under X, as opposed to all the ATI cards listed above, 
which seem to have problems displaying X on the alternate outputs.  So 
enthusiastic in fact, that I bought another one for use in my envisioned 
video network.  Unfortunately, once I tried to use this card with MythTV 
I discovered that it did not support XV accelerated output and on 
further investigation, I don't know if they ever will have XV support.  
Does anyone else have this card, and are there any workarounds for using 
MythTV with cards that don't have XV support?  The card really does a 
good job of outputting X to the TV, and I would love to be able to use 
the two cards that I have in some capacity.  The ATI cards all have 
tv-out support under windows, but so far I have been unable to get them 
to work at all under Linux.  Are there alternate drivers available that 
might help me out on the ATI front?  I have looked at the Gatos drivers, 
but the documentation is unclear on what cards are supported and what 
features are supported with each card.  Is there anyone that is using 
one of the above ATI cards that successfully uses the TV-out under 
Linux?  Or does everyone use scan converters?  All the scan converters I 
have seen are quite expensive and I am reluctant to purchase one (or 
many) when I have all these video cards that have the hardware to output 
a composite signal.  None of the frontends are going to be used for 
fancy displays, they just need to be able to output a decent composite 
or s-video signal to a normal television.  I would certainly prefer to 
use the many cards I have listed, but if I am unable to, can someone 
recommend a card that will work flawlessly for tv-out under Linux?  I 
would like to spend as little money as possible, as I have already sunk 
a ton of money into this and I am likely to end up with a bunch of 
hardware that I cannot use.  I have seen many posts about the NVidia 
cards, will something like the 440 mx (or similar) give me the TV output 
that I need?

4.  Audio.  When I am watching video on the system that nominally works 
(frontend 2) the audio is out of sync.  When I start watching the video, 
the terminal gives an error to the effect of "Can't query audio buffers 
on this card, audio will be out of sync".  I believe the card was the 
Yamaha using the ymfpci module.  Is there something I can do to fix 
this, or am I just out of luck with this sound card?  Would it suffice 
for the backend machine (which is currently using an es1371 card)?  

Also, I was wondering about the btaudio module.  Has anyone used the 
WinTV-go with btaudio successfully?  I have loaded the module, and it 
sets up /dev/dsp2 and 3 (digital and analog), but piping the output from 
those dsps to the sound card only gives popping or nothing.  Currently, 
I am using the analog output into the sound card line in, but I would 
love to dump the sound card on the backend to make room for additional 
tuners.   

I also have an alternate video feed that has a single channel that I 
would like to distribute with Myth.  I was thinking of purchasing an old 
secondhand VCR (or cable box) and piping the channel onto the composite 
input of the generic bt848 card that I have.  How should this be set 
up?  I obviously need to set this up as a second video input, but how do 
I set up the listings side of it.  I pull the XMLTV listings manually 
for another application, and have been using mythfilldatabase --file to 
load the file (which also contains the channel on the second cable 
feed).  Do I need to do a second xmltv pull that gets just this channel 
and create a input entry for it?  How will it appear in the EPG?  Will 
it be on the very end since it is a different input source or will the 
channel number sort itself in with the existing channels?

Concerning the AI Tech WaveWatcher NeTV-PCI (Zoran zr36120 + Phillips 
7110A), has anyone used this thing?  There are drivers in the kernel 
source, but they are seriously broken and set up to use the old i2c 
interface.  Does anyone know if there has been any effort to port the 
drivers to the new i2c interface?  Or are these drivers going to fall by 
the wayside and I will have another useless piece of hardware.  
I know this is a hugely rambling post, and I apologise.  I am just 
hoping by posting it I would able to get input on my setup from people 
who have more experience with Myth than I, and also to rudimentarily 
document my setup.  I appreciate any and all input on my setup, from 
"you're an idiot" to "this is exactly what you need to do to make this 
work effectively".

TIA for any advice.