I have been spending many months trying to get stutter-free HD with OSD up, on my combined frontend-backend R5E50 system, but before I admit defeat I would like to ask the help again of this forum.

I can’t help feeling that I am still missing an important step. I have researched this to death and despite everything I try I cannot get HD live TV to be stutter free when the OSD is up. I am currently using the latest Nvidia driver (9755) and have tried with and without XvMC, I have made sure to fix up the path in /etc/X11/XvMCConfig for XvMC, I have also made sure to include “Use Events “True� in my xorg.conf. I have also tried the previous driver, 9746.

From what a number of people have told me, my hardware should be up to the job and some users who have a very similar setup have been able to achieve stutter-free results when the OSD is up. Here is a description of my hardware:

KnoppMyth release: R5E50 (straight R5E50, I have not installed any of the mythtv patches/fixes)
Motherboard: ASUS M2NPV-VM (mATX GE6150-NF430)
CPU: AMD AM2 Athlon 64 3500+
Video: Nvidia 6150 (on the motherboard) Nvidia driver: 9755
Capture card1: Hauppauge PVR-500 (with Philips tuners)
Capture card2: Airstar HD-5000-PCI
RAM: 1G (2x512MB OCZ PC2-5400 Gold)
Hard drive: Maxtor 80GB 7200RPM ATA133S
DVD: Samsung SH-S182 IDE DVDRW with Lightscribe
Network: Dlink DWL-G122 Rev C1 USB dongle (wireless-G), Ralink RT73 driver

At the moment the best results are when I DONT use XvMC. I don’t know if I haven’t got XvMC set up correctly but I am still seeing grey OSD, whereas I have been told I should see color OSD if I have everything setup correctly.

I have been trying to optimize my setup to use OpenGL VSYNC. One area of confusion is what options I need to set in nvida-setup (from the KnoppMyth desktop). On gossamerthreads I read that the following gave one user the best results:

"Video Texture Adaptor" "Sync to Vblank" – ENABLED

"Blitter" – NOT enabled
"OpenGL settings" "Sync to VBlank" – NOT enabled

If someone can confirm (or otherwise) if the above is the correct nvidia-setting please let me know.

Finally, I would like to provide a full description of the steps which I took to install the latest Nvidia driver. This flow was derived from information obtained from this forum and other sources. If anyone can see a problem with this flow, please let me know.


Thanks in advance for your help,

Kevin



Details of the steps taken to install the Nvidia driver ..
=========================================

Note, the following steps must be run as root ..

(From: http://mysettopbox.tv/phpBB2/viewtopic.php?t=13281) ..

Get the kernel source ..

wget ftp://knoppmyth.net/R5/linux-source-2.6 ... om_all.deb
dpkg -i linux-source-2.6.18-chw-13_2.6.18-chw-13-10.00.Custom_all.deb
cd /usr/src
tar xjvf linux-source-2.6.18-chw-13.tar.bz2

(From: http://knoppmythwiki.org/index.php?page ... vtv-0.10.0) ..

These steps get the kernel source built and sym links correct (copied from the vmware server article, with
additional steps to correct a link in the lib/modules…). Note that running a ‘make’ on the Linux kernel can
take a long time.

cd /usr/src/linux-source-2.6.18-chw-13
cp /boot/config-2.6.18-chw-13 .config
make
cd /usr/src
rm linux
ln -s linux-source-2.6.18-chw-13 linux
cd /lib/modules/2.6.18-chw-13
rm build
ln -s /usr/src/linux-source-2.6.18-chw-13 build


(From: http://mysettopbox.tv/phpBB2/viewtopic. ... &highlight ) ..

You need to download the drivers from nVidia's website first.

For the 1.0-9746 driver, run ..

wget http://us.download.nvidia.com/XFree86/L ... 6-pkg1.run

For the 1.0-9755 driver, run ..

wget http://us.download.nvidia.com/XFree86/L ... 5-pkg1.run


Now we're ready to install the new driver. The easiest way to do this is the rename the startx script and reboot
so that X is not even trying to boot up.


mv /usr/bin/startx /usr/bin/startx.save


reboot


For some reason the NVidia install script isn't yanking out the original nvidia kernel module, so I manually pulled it
out with this command:


rmmod nvidia

The following command will let you verify that you no longer have the module loaded.


lsmod | grep nvidia

There was an install-nvidia-debian being called from /etc/init.d/ that would automatically overwrite my installation
of the latest nvidia drivers, so before installing the drivers, I ran

update-rc.d -f install-nvidia-debian remove


update-rc.d -f nvidia-glx remove


update-rc.d -f nvidia-kernel remove




Now we're actually ready to run the binary package from NVidia. It doesn't quite detect everything correctly, so
issue the command as such:


For the 1.0-9746 driver, run ..

sh NVIDIA-Linux-x86-1.0-9746-pkg1.run \


--kernel-source-path=/usr/src/linux-source-2.6.18-chw-13



For the 1.0-9755 driver, run ..


sh NVIDIA-Linux-x86-1.0-9755-pkg1.run \


--kernel-source-path=/usr/src/linux-source-2.6.18-chw-13



You will most likely get a message during the installation process that it had to make assumptions about the paths for
X.org. The assumptions that it made are fine.

During the installation I get the following message ..

“There appears to already be a driver installed on your system (version: 1.0-9746). As part of installing this driver
(version: 1.0-9755), the existing driver will be uninstalled. Are you sure you want to continue?�

.. I wasn’t expecting the installer to detect an existing driver, but hopefully this is ok.

Towards the end of the installation I get the following message ..

“Would you like to run the nvidia-xconfig utility to automatically update your X configuration file so that the NVIDIA
X driver will be used when you restart X? Any pre-existing configuration file will be backed up.� (default=No)

I chose the default (No) setting

(It then points me to the following document for help on updating the xorg.conf: /usr/share/doc/NVIDIA_GLX-1.0/README.txt)


Once the installer is finished you should be able to safely start X back up, but don't forget to rename your startx executable.


mv /usr/bin/startx.save /usr/bin/startx

reboot

Well I'm not sure how much this will help, but I'll give you my story...

I started with a FE/BE system with similar specs to yours. I had a socket 939 based Athlon 64 3700+ with 1 GB of memory. I could not get it to playback HD without stuttering. This was prior to the Nvidia driver with "Use Events" support. I purchased a new Athlon 64 X2 4400+ and all my problems went away.

I later used the 3700+ in a FE only system and it works ok with XvMC enabled, so it was not a complete waste. But, I will never buy another single core processor again. If the next Knoppmyth release results in more CPU usage, I'll upgrade the processor again...

Chris

Hi Chris,

thanks for sharing your experiences. I had thought I might need to upgrade my CPU at some point but wasn't sure if dual-core would help as much as having a higher clock speed.
Thinking about it, since I have three tuners (2xSD, 1x HD) and also I might be tieing up the CPU doing some transcoding to archive some recordings to DVD, perhaps a dual-core would make sense.

I wonder if I can just crank up the clock frequency on my single core CPU just as an experiment to see if it resolves the stuttering.

It's so frustrating, SD and HD without the OSD is absolutely fine, why having the OSD up takes so much more CPU is a mystery for me. Maybe the Nvidia architecture is not so good at doing overlays (If that's the right technical term),

Kevin

Kevin, I know you've probably done this already, but you've fixed the path in /etc/X11/XvMCCconfig , right?
It's just that you don't mention having fixed it and it's the easiest explanation for what you describe.

Mike

_________________
*********************
LinHES 7.4
Australian Dragon
*********************

Hi Mike,

yes, I have fixed the path in XvMCConfig, it now looks like ..

/usr/lib/libXvMCNVIDIA_dynamic.so.1

Actually, the best results I see are with XvMC off. With it on, the OSD goes grey (which I believe is an indication that XvMC is enabled), live HD viewing is ok until the OSD is up, then the audio stutters badly. I think that the video is also 'stuttering', although it is not that noticeable.

With XvMC off, both video and audio stutter, but the audio stutter is nowhere near as bad as when XvMc is enabled.

I do have extra audio buffering enabled.

BTW, at some point in the dim and distant past I think that I may have adjusted my ring buffer size, does anyone know what the 'recommended' setting is for the ring buffer size?

Kevin

Progress ..

as an experiment I went into my motherboards BIOS and used the Asus AI overclocking feature to increase the CPU clock by 10%, all audio and video stutter with OSD is gone!

<edit> scratch that. True the stuttering was gone initially, but after watching TV for ten minutes, then putting up the OSD the stutter is as bad as ever
It seems that by powering my system down, and booting it up, overclocking the CPU, etc perhaps initialised some sort of 'buffer', but after a while it goes back to the old stuttering behaviour - does this make any sense to anyone?
Could it be disk space related? (I only have an 80G drive on this combined front-end/backend)


This is using the Nvidia 9755 driver, I have the following settings in MythTV playback settings:

deinterlaced playback
Bob (2x)
Preferred mpeg decoder: standard
Enable OpenGL vertical sync for timing - enabled
Extra audio buffering - enabled

In nvidia-settings (from KM desktop) ..

X Server xvideo settings:
Video texture adapter, Sync to vBlank - enabled
Video blitter adapter, Sync to Vblank - not-enabled

OpenGL settings:
Sync to Vblank - not enabled
Allow Flipping - not enabled
Image setting - quality
Disable use of enhanced CPU instruction sets - not checked


I think the result of this experiment points to my CPU not quite being up to the job. I am using an AMD AM2 Athlon 64 3500+ as indicated in my first post.

I am not sure whether to just keep my CPU overclocked by 10% or whether to go out and buy something like a dual core, 4200

Kevin

Yep, you have the right XvMC setting.

Have you run top while it's all happening? Some statistics would be good at this point. I would try everything and write down the cpu usage. Since you're using an AMD CPU you may get some mileage out of ffmpeg instead of XvMC.

I'd heard of problems with the 64 bit AMD, but yours is fast. I ran my KM box on an (32 bit) XP 2500+ until yesterday, and it displayed HDTV easily.

The other thing is: if you just want to view HDTV on a plasma, I think you can get rid of deinterlace. try this, too. Removal of this overhead might make a difference, if it still looks OK that is.

I'd test each setting and run top, writing down each result etc.

Mike

_________________
*********************
LinHES 7.4
Australian Dragon
*********************

Your CPU isn't the problem. I'm all digital OTA and record lots of PBS HD. Dual tuners as well. I'm running a Sempron 2800+. Yes its overclocked, but not even in the same league as your Athlon. I get some stutter with OSD up, but nothing worse than you're describing and I have much less CPU power.

I use a graphics card with 256mb memory. Your onboard card might be stealing enough of your RAM that its causing the stutter. Your board can take a lot more RAM, that might be worth looking into.

Also, you have a tiny hard drive. If you're recording any HD that's just too small. The small size could be triggering more disk maintenance tasks than on a larger drive. And one more thing, open another term window (alt-x) and run the "top" command to see if you have some process running that's hogging the CPU cycles. For me, mythcommflag is a bad offender.

Have you tried going into the setup stuff and dialing down the OSD eye candy? Turning off the transparency and the like should reduce the GPU load.

I want to reiterate what tjc has said about turning off the options for the OSD.

Also have you checked your drive to ensure that it is using DMA, if your watching HD it probably is, but maybe it is slowing down.

You perhaps could also look at your backend log file around the time you put your OSD on to see if that indicates anything.

_________________
Girkers

thanks everyone for your help.

I have not tried dialing down the OSD settings, is there a discussion someone could point me to which will help me with what settings to change? I did ask around, and neutron68 gave me his OSD settings, which I replicated but it didn't help.

I do have DMA turned on, I have checked this.

Regarding the memory for video, I have set 256M in the BIOS, this is the maximum which I can set it. Earlier versions of the BIOS limited it at 128M. I have 1Gb RAM installed in my Myth box,

Tomorrow I will gather all the data points and post the results. Hockey should be on in HD, I have found that this gives quite consistent results so makes it easier to compare data points. And I will check the backen log file.

One thing I did want to mention about the OSD ..

If I go straight from the MythTV menu to watching a HD channel it comes up with the OSD up and stuttering (now I overclocked my CPU by 10%) is barely noticeable).

If, while watching the same HD channel I press the up button on my Streamzap remote the OSD come up with the 'browsing' message. Often (but not always) the screen completely freezes, and after a minute or so the audio starts to stutter really badly.

I am wondering what the difference is between these two very similar OSD screens. Maybe ‘browsing’ + OSD uses more CPU?

BTW, thought that I would mention that I capture using clear-QAM 256, not OTA. I have heard some say that QAM is problematic, and I wondered if this was making the load on my CPU much higher compared to other users Myth boxes.

Kevin

Hello all,

I have some datapoints which I would like to share. I am not sure if a straight ‘top’ is preferred or whether there are some switches to ‘top’ which I should be using, anyway here is what I have to report so far. Note, this is still with my CPU overclocked by 10% ..

‘top’ while watching HD channel with no OSD ..

top - 19:20:30 up 22 min, 1 user, load average: 4.31, 3.95, 2.77
Tasks: 90 total, 2 running, 86 sleeping, 0 stopped, 2 zombie
Cpu(s): 49.0%us, 1.7%sy, 0.0%ni, 46.7%id, 0.7%wa, 1.0%hi, 1.0%si, 0.0%st
Mem: 771952k total, 763504k used, 8448k free, 1188k buffers
Swap: 1157680k total, 143600k used, 1014080k free, 420564k cached

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
3292 mythtv 0 0 435m 251m 121m S 43.6 33.3 5:41.66 mythfrontend
3227 root 0 0 264m 192m 100m S 7.3 25.5 0:53.54 Xorg
3159 mythtv 0 0 306m 26m 11m S 1.3 3.5 0:11.50 mythbackend
1048 root 0 -5 0 0 0 S 0.3 0.0 0:00.03 kjournald
1 root 0 0 1948 636 540 S 0.0 0.1 0:00.84 init
2 root RT 0 0 0 0 S 0.0 0.0 0:00.00 migration/0
3 root 0 19 0 0 0 S 0.0 0.0 0:00.00 ksoftirqd/0
4 root RT 0 0 0 0 S 0.0 0.0 0:00.00 watchdog/0
5 root 0 -5 0 0 0 S 0.0 0.0 0:00.09 events/0
6 root 0 -5 0 0 0 S 0.0 0.0 0:00.00 khelper
7 root 0 -5 0 0 0 S 0.0 0.0 0:00.00 kthread

‘top’ while watching HD channel with OSD up, after first starting MythTV (stuttering is barely noticeable) ..

top - 19:23:22 up 25 min, 1 user, load average: 4.03, 4.03, 3.00
Tasks: 90 total, 2 running, 86 sleeping, 0 stopped, 2 zombie
Cpu(s): 96.0%us, 1.7%sy, 0.0%ni, 0.0%id, 0.0%wa, 1.0%hi, 1.3%si, 0.0%st
Mem: 771952k total, 762624k used, 9328k free, 2328k buffers
Swap: 1157680k total, 143584k used, 1014096k free, 421568k cached

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
3292 mythtv 0 0 360m 188m 68m S 92.9 25.0 7:07.07 mythfrontend
3227 root 0 0 211m 143m 49m S 6.3 19.1 1:01.15 Xorg
3159 mythtv 0 0 300m 28m 11m S 0.3 3.8 0:14.19 mythbackend
1 root 0 0 1948 636 540 S 0.0 0.1 0:00.84 init
2 root RT 0 0 0 0 S 0.0 0.0 0:00.00 migration/0
3 root 0 19 0 0 0 S 0.0 0.0 0:00.00 ksoftirqd/0
4 root RT 0 0 0 0 S 0.0 0.0 0:00.00 watchdog/0
5 root 0 -5 0 0 0 S 0.0 0.0 0:00.10 events/0
6 root 0 -5 0 0 0 S 0.0 0.0 0:00.00 khelper
7 root 0 -5 0 0 0 S 0.0 0.0 0:00.00 kthread

‘top’ while watching HD channel with OSD up, using ‘up; button on remote ‘browsing’ message on screen,
Frozen screen, until OSD disappears. (note, most of the time, browsing in this way does not freeze the screen, I am not sure what triggers this phenomena) ..

top - 19:21:18 up 23 min, 1 user, load average: 4.52, 4.06, 2.86
Tasks: 90 total, 2 running, 86 sleeping, 0 stopped, 2 zombie
Cpu(s): 97.3%us, 1.1%sy, 0.0%ni, 0.0%id, 0.0%wa, 1.5%hi, 0.0%si, 0.0%st
Mem: 771952k total, 764336k used, 7616k free, 1276k buffers
Swap: 1157680k total, 143600k used, 1014080k free, 421196k cached

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
3292 mythtv 0 0 435m 251m 121m S 99.2 33.3 6:07.29 mythfrontend
3159 mythtv 0 0 306m 26m 11m S 1.5 3.5 0:12.08 mythbackend
3351 root 0 0 2236 1136 856 R 0.4 0.1 0:00.86 top
1 root 0 0 1948 636 540 S 0.0 0.1 0:00.84 init
2 root RT 0 0 0 0 S 0.0 0.0 0:00.00 migration/0
3 root 0 19 0 0 0 S 0.0 0.0 0:00.00 ksoftirqd/0
4 root RT 0 0 0 0 S 0.0 0.0 0:00.00 watchdog/0
5 root 0 -5 0 0 0 S 0.0 0.0 0:00.09 events/0
6 root 0 -5 0 0 0 S 0.0 0.0 0:00.00 khelper
7 root 0 -5 0 0 0 S 0.0 0.0 0:00.00 kthread



After first starting MythTV it comes up on a SD channel as it defaults to my PVR-500 card, I then select CH180 (HD channel, using Airstar card), I see the following appear in the backend logfile (/var/log/mythtv/mythbackend.log) ..

2007-05-09 19:44:54.759 adding: mythtv as a client (events: 0)
2007-05-09 19:44:54.761 TVRec(3): Changing from None to WatchingLiveTV
2007-05-09 19:44:54.762 TVRec(3): HW Tuner: 3->3
2007-05-09 19:44:55.272 Finished recording Hindenburg: Titanic of the Skies: channel 1621
2007-05-09 19:44:55.308 Finished recording Hindenburg: Titanic of the Skies: channel 1621
2007-05-09 19:44:55.340 Preview Error: Previewer file '/myth/tv/1621_20070509194454.mpg' is not valid.
2007-05-09 19:46:39.138 Expiring Hindenburg: Titanic of the Skies from Wed May 9 18:00:00 2007, 0 MBytes, forced expire (LiveTV recording)
2007-05-09 19:46:39.173 Expiring Hindenburg: Titanic of the Skies from Wed May 9 18:00:00 2007, 35 MBytes, forced expire (LiveTV recording)
2007-05-09 19:46:39.177 Expiring Malcolm in the Middle "Forbidden Girlfriend" from Wed May 9 19:30:00 2007, 4 MBytes, forced expire (LiveTV recording)


Also, after watching TV for about an hour, I see the following appear in the log and the "Error Was encountered while displaying video" message appear on the screen (note the preview error and the pointer to non-existent .mpg file). Although this is annoying as hell I don’t think it is directly related to the OSD stuttering problem. I have discussed this error in an existing post to this forum but it seems that no one has any answers yet.

(See http://mysettopbox.tv/phpBB2/viewtopic. ... highlight=)

2007-05-09 20:00:40.120 Expiring Tsunami: Facing the Wave from Tue May 8 19:00:00 2007, 449 MBytes, forced expire (LiveTV recording)
2007-05-09 20:10:40.919 Expiring American Idol from Tue May 8 20:00:00 2007, 1048 MBytes, forced expire (LiveTV recording)
2007-05-09 20:10:45.461 TFW, Error: Write() -- IOBOUND begin cnt(9400) free(1515)
2007-05-09 20:10:46.510 TFW, Error: Write() -- IOBOUND end
2007-05-09 21:00:01.190 Finished recording Destroyer: Forged in Steel: channel 1621
2007-05-09 21:00:01.393 TVRec(3): Enabling Full LiveTV UI.
2007-05-09 21:00:03.001 TVRec(3): RingBufferChanged()
2007-05-09 21:00:03.023 Finished recording Hindenburg: Titanic of the Skies: channel 1621
2007-05-09 21:00:03.039 TVRec(3): Enabling Full LiveTV UI.
2007-05-09 21:00:03.041 Preview Error: Previewer file '/myth/tv/1621_20070509210001.mpg' is not valid.
2007-05-09 21:00:03.070 Finished recording Destroyer: Forged in Steel: channel 1621
2007-05-09 21:00:03.101 TVRec(3): RingBufferChanged()
2007-05-09 21:00:03.123 Finished recording Hindenburg: Titanic of the Skies: channel 1621
2007-05-09 21:00:03.170 TFW, Error: Write() -- IOBOUND begin cnt(9400) free(1515)
2007-05-09 21:00:03.191 TFW, Error: Write() -- IOBOUND end
0: start_time: 7384.532 duration: 323.955
1: start_time: 7384.532 duration: 323.955
stream: start_time: 82050.350 duration: 3599.496 bitrate=14775 kb/s
2007-05-09 21:00:04.987 AFD: Opened codec 0x8252c00, id(MPEG2VIDEO) type(Video)
2007-05-09 21:00:04.990 AFD: Opened codec 0x825a6c0, id(AC3) type(Audio)
2007-05-09 21:00:04.994 NVP: Recording does not have position map.
Run 'mythcommflag --file 1621_20070509200001.mpg --rebuild' to fix
2007-05-09 21:00:12.510 TVRec(3): Changing from WatchingLiveTV to None
2007-05-09 21:00:12.724 Finished recording Hindenburg: Titanic of the Skies: channel 1621
2007-05-09 21:00:44.555 Expiring Daily Planet from Tue May 8 20:00:00 2007, 1805 MBytes, forced expire (LiveTV recording)


I will now go away and research how I go about dialing down the eye candy for my OSD,

Thanks everyone for your help,

Kevin

Some other interesting errors in the backend logfile when I went in to delete recordings and clear out some disk space ..

2007-05-09 21:44:29.425 DevRdB(0) Error: Driver buffers overflowed
2007-05-09 21:44:29.527 TFW, Error: Write() -- IOBOUND begin cnt(9400) free(6591)
2007-05-09 21:44:30.204 TFW, Error: Write() -- IOBOUND end
2007-05-09 21:44:36.598 TFW, Error: Write() -- IOBOUND begin cnt(9400) free(2643)
2007-05-09 21:44:38.148 TFW, Error: Write() -- IOBOUND end
2007-05-09 21:44:46.485 TFW, Error: Write() -- IOBOUND begin cnt(9400) free(1891)
2007-05-09 21:45:03.546 TFW, Error: Write() -- IOBOUND end
2007-05-09 21:45:03.689 DevRdB(0) Error: Driver buffers overflowed
2007-05-09 21:45:03.783 TFW, Error: Write() -- IOBOUND begin cnt(6204) free(1139)
2007-05-09 21:45:04.449 TFW, Error: Write() -- IOBOUND end
2007-05-09 21:45:29.483 TFW, Error: Write() -- IOBOUND begin cnt(9400) free(2079)
2007-05-09 21:46:07.019 TFW, Error: Write() -- IOBOUND end
2007-05-09 21:46:07.129 DevRdB(0) Error: Driver buffers overflowed
2007-05-09 21:46:07.217 TFW, Error: Write() -- IOBOUND begin cnt(9400) free(4711)
2007-05-09 21:46:07.776 TFW, Error: Write() -- IOBOUND end

probably not related to the original stuttering/OSD problem but thought I would report it here just in case,

Kevin

Them's extraordinary figures, Kevin.

I've never seen such high CPU usage for mythfrontend.
It's now obvious the stuttering is due to your system running out of puff, but why is mythfrontend using all the cpu? With a 64 bit 3500, there's clearly something wrong. My XP2500+ used about 36% on HD.

I'll probably have to say I can't help you any further with this. Can't think of any reason a beefy CPU would be dying like this. If you've turned all the eye candy (OpenGL) stuff off, I'd suspect the NVIDIA driver install, since it all started going pear shaped when you updated the driver.

Good luck finding the cause.

Mike

_________________
*********************
LinHES 7.4
Australian Dragon
*********************

Hmmm. Kevin, I would also suspect the NVidia drivers. Maybe try several different versions.

Since the frontend is using large amounts of RAM and CPU, I would try looking for anything interesting in its output. Have a look in ~mythtv/.xsession-errors

If nothing obvious, try running the frontend with -vplayback.

_________________
| Nigel Pearson, nigel.pearson.au@gmail.com
| "Things you own end up owning you" - Tyler, Fight Club