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Studdering DVD
http://forums.linhes.org/viewtopic.php?f=17&t=19207
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Author:  jmckeown2 [ Fri Nov 14, 2008 3:44 pm ]
Post subject:  Studdering DVD

Hey all,
I'm running KM5.5 on a AMD X2 4000+ w an nVidia card (8500GT) driving an older Sony TV at 720p over DVI. This should be plenty of horsepower for DVD playback, but I get stuttering video on playback; audio is fine.
Any idea where to start?

Thanks,

Joe

Author:  mihanson [ Fri Nov 14, 2008 7:28 pm ]
Post subject: 

Is DMA turned on?

For how to:
Code:
man hdparm

Author:  cecil [ Sat Nov 15, 2008 12:58 am ]
Post subject: 

What are you using to play the DVDs? We include 4 options out the box... You aren't trying to use XvMC are you? XvMC doesn't work w/ the 8xzy series...

Author:  jmckeown2 [ Sat Nov 15, 2008 11:46 am ]
Post subject: 

mihanson wrote:
Is DMA turned on?

Yes, it is.
cecil wrote:
What are you using to play the DVDs? We include 4 options out the box... You aren't trying to use XvMC are you?

The DVD player is mythtv's "Internal"

I didn't realize that about the 8xxx and XvMC, I did some googling around and learned from here xvmc is controlled by playback profiles. My playpack profile is "CPU++" which the docs I read say does not use xvmc. So I guess I unwittingly did the right thing there; If I had known it was off I would have tried turning it on :oops:

Author:  marc.aronson [ Sat Nov 15, 2008 1:18 pm ]
Post subject: 

Stuttering can occur for many reasons. Check you CPU utilization on playback to be sure that you aren't maxing out the CPU. (I agree that you probably are not). Check to be sure that the bob2x deinterlacer is being used.

Marc

Author:  jmckeown2 [ Sat Nov 15, 2008 1:27 pm ]
Post subject: 

I did an experiment. I took an iso of a DVD; and loaded it in MythVideo. It played fine with the internal player. A physical DVD burned form that iso stutters.
So I'm guessing there's something wrong with the drive configuration, or maybe with the drive itself?

Drive information:
Code:
root@mythtv:~# hdparm -I /dev/hda

/dev/hda:

ATAPI CD-ROM, with removable media
        Model Number:       SONY    DVD RW DW-Q120A
        Serial Number:
        Firmware Revision:  PYS2
Standards:
        Used: ATAPI for CD-ROMs, SFF-8020i, r2.5
        Supported: CD-ROM ATAPI-2
Configuration:
        DRQ response: 50us.
        Packet size: 12 bytes
Capabilities:
        LBA, IORDY(cannot be disabled)
        DMA: *sdma0 *sdma1 *sdma2 sdma3 sdma4 sdma7 mdma0 mdma1 mdma2 udma0 udma1 udma2 udma3 *udma4 (?)
             Cycle time: min=120ns recommended=120ns
        PIO: pio0 pio1 pio2 pio3 pio4
             Cycle time: no flow control=240ns  IORDY flow control=120ns
Commands/features:
        Enabled Supported:
           *    PACKET command feature set
           *    DEVICE_RESET command
           *    Mandatory FLUSH_CACHE
HW reset results:
        CBLID- below Vih
        Device num = 0


Current setup:
Code:
root@mythtv:~# hdparm -acdkru /dev/hda

/dev/hda:
 IO_support   =  1 (32-bit)
 unmaskirq    =  1 (on)
 using_dma    =  1 (on)
 keepsettings =  0 (off)
 readonly     =  0 (off)
 readahead    = 256 (on)

Anything obviously wrong? Anything I should look at?

Author:  brfransen [ Sat Nov 15, 2008 6:38 pm ]
Post subject: 

I had a problem about a year ago with one of my DVD drives studdering and I solved it by setting IO_support and unmaskirq to 0. This is my hdparm for my DVD drive.
Code:
hdparm -acdkru /dev/hdc

/dev/hdc:
 IO_support   =  0 (default 16-bit)
 unmaskirq    =  0 (off)
 using_dma    =  1 (on)
 keepsettings =  0 (off)
 readonly     =  0 (off)
 readahead    = 256 (on)


Britney

Author:  marc.aronson [ Sat Nov 15, 2008 7:07 pm ]
Post subject: 

I just checked and my NEC IDE burner has DMA turned off. I then used hdparm to turn DMA on and access to the drive became very unstable. I then turned DMA mode off and now things are working well again.

I did a google search and found many references to people haivng problems with DMA turned on with DVD drives on various flavors of Linux. I didn't read the details.

So I agree with brfransen -- try turning off DMA mode.

Marc

Author:  jmckeown2 [ Tue Nov 18, 2008 8:04 pm ]
Post subject: 

I turned off DMA and it did the trick!!!

Now how do I make it last across a reboot? I'm not seeing where hdparm is called initially. There's an /etc/init.d/hdparm, but no links in /etc/rc?.d

Author:  brfransen [ Tue Nov 18, 2008 9:50 pm ]
Post subject: 

Look in /etc/init.d/bootmisc.sh If it is not listed you should be able to disable it there.

Britney

Author:  manicmike [ Wed Nov 19, 2008 3:46 am ]
Post subject: 

From memory, there is an /etc/hdparm.conf

Mike

Author:  elgordo123 [ Wed Nov 19, 2008 1:43 pm ]
Post subject: 

I normally put that at the end of /etc/init.d/bootmisc.sh

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