[mythtv] jerky/jittery video on fast box?

John Joseph Roets jjr at sunflower.com
Tue Jan 21 14:47:32 EST 2003


Hello all.
I'm running Myth and getting jerky/jittery video.
Video is jittery to very jittery in live TV mode (and sometimes, in
playback mode).  It seems that the mpeg4 setting gives me better
quality, yet is much more jerky.  I've been recording with rtjpeg
settings below, and have gotten very large files (~3300-5400 KB/hr.) as
a result (I will ask that question next, after I see the file sizes
generated today with mpeg4 settings).
I was hoping that it was due to dma settings, but that is apparently not
the case.
Would I gain much in not compressing the audio?
Is there something in my system which inherently causes/allows this?

Any help would be greatly appreciated.
Thanks in advance.

I have:
IBM Netvista P4 @ 1.8 GHz 256MB RAM
ATI TV-Wonder VE
Intel i810 onboard sound with ALSA
nVidia Vanta/Vanta LT (AGP)
RH 8.0 -- Gnome
AVermedia AVerkey iMicro VGA to NTSC box
54 in. rear-projection bigscreen

- What version of MythTV are you running?
0.7

- settings file 
480x480
rtjpeg
 Quality=255
mpeg4
 TargetBitrate=2200
Deinterlace=1
All other settings in settings.txt are default, no change.

- What resolution?
480x480 (I've tried 640x480, as it should work fine with this box, and
while it is clearer, it causes much slowdown/jitter).

- What codec are you using?
rtjpeg -- less jitter, but still some.  Quality at 255
mpeg4 -- seems better quality, but certainly more jitter.  Target
bitrate at 2200.

- Are you using the nvidia binary driver?
nvidia module

- Is your mysql colocated on the server with mythtv?
Yes.

- What is your disk speed? 7200? 5400? Other?
7200

- HD info [hdparm -I /dev/hda]?
/dev/hda:

ATA device, with non-removable media
        Model Number:       MAXTOR 6L040J2
        Serial Number:      662205637151
        Firmware Revision:  A93.0500
Standards:
        Used: ATA/ATAPI-5 T13 1321D revision 1
        Supported: 5 4 3 2 & some of 6
Configuration:
        Logical         max     current
        cylinders       16383   16383
        heads           16      16
        sectors/track   63      63
        --
        CHS current addressable sectors:   16514064
        LBA    user addressable sectors:   78177792
        device size with M = 1024*1024:       38172 MBytes
        device size with M = 1000*1000:       40027 MBytes (40 GB)
Capabilities:
        LBA, IORDY(can be disabled)
        bytes avail on r/w long: 4      Queue depth: 1
        Standby timer values: spec'd by Vendor, no device specific
minimum
        R/W multiple sector transfer: Max = 16  Current = 16
        Recommended acoustic management value: 128, current value: 254
        DMA: mdma0 mdma1 mdma2 udma0 udma1 udma2 udma3 udma4 *udma5
udma6
             Cycle time: min=120ns recommended=120ns
        PIO: pio0 pio1 pio2 pio3 pio4
             Cycle time: no flow control=120ns  IORDY flow control=120ns
Commands/features:
        Enabled Supported:
           *    READ BUFFER cmd
           *    WRITE BUFFER cmd
           *    Host Protected Area feature set
           *    Look-ahead
           *    Write cache
           *    Power Management feature set
                Security Mode feature set
           *    SMART feature set
           *    Mandatory FLUSH CACHE command
           *    Device Configuration Overlay feature set
           *    Automatic Acoustic Management feature set
                SET MAX security extension
           *    DOWNLOAD MICROCODE cmd
           *    SMART self-test
           *    SMART error logging
Security:
        Master password revision code = 65534
                supported
        not     enabled
        not     locked
                frozen
        not     expired: security count
        not     supported: enhanced erase
        20min for SECURITY ERASE UNIT.
HW reset results:
        CBLID- above Vih
        Device num = 0 determined by CSEL
Checksum: correct

- What is your disk buffer size? 2MB? Other?
[ cat /proc/ide/hda/cache ]
1819

- What are your dma, multcount, and prefetch settings?
[ hdparm /dev/hda ]
/dev/hda:
 multcount    = 16 (on)
 IO_support   =  0 (default 16-bit)
 unmaskirq    =  0 (off)
 using_dma    =  1 (on)
 keepsettings =  0 (off)
 readonly     =  0 (off)
 readahead    =  8 (on)
 geometry     = 4866/255/63, sectors = 78177792, start = 0

- What are your "elevator" settings? [ elvtune /dev/hda1 ]
/dev/hda1 elevator ID           0
        read_latency:           8192
        write_latency:          16384
        max_bomb_segments:      6

- What is your CPU and bus speed? [ cat /proc/cpuinfo ]
processor       : 0
vendor_id       : GenuineIntel
cpu family      : 15
model           : 1
model name      : Intel(R) Pentium(R) 4 CPU 1.80GHz
stepping        : 2
cpu MHz         : 1794.252
cache size      : 256 KB
fdiv_bug        : no
hlt_bug         : no
f00f_bug        : no
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 2
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge
mca cmov
pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm
bogomips        : 3567.44

- What is your memory type, speed, configuration, and size?
256MB

- What is your motherboard chipset? [ a function of `cat /proc/pci` ]
[root at mythtv root]# cat /proc/pci
PCI devices found:
  Bus  0, device   0, function  0:
    Host bridge: Intel Corp. 82845 845 (Brookdale) Chipset Host Bridge
(rev 3).
      Prefetchable 32 bit memory at 0xf4000000 [0xf7ffffff].
  Bus  0, device   1, function  0:
    PCI bridge: Intel Corp. 82845 845 (Brookdale) Chipset AGP Bridge
(rev 3).
      Master Capable.  Latency=96.  Min Gnt=12.
  Bus  0, device  30, function  0:
    PCI bridge: Intel Corp. 82801BA/CA/DB PCI Bridge (rev 18).
      Master Capable.  No bursts.  Min Gnt=6.
  Bus  0, device  31, function  0:
    ISA bridge: Intel Corp. 82801BA ISA Bridge (LPC) (rev 18).
  Bus  0, device  31, function  1:
    IDE interface: Intel Corp. 82801BA IDE U100 (rev 18).
      I/O at 0x1800 [0x180f].
  Bus  0, device  31, function  2:
    USB Controller: Intel Corp. 82801BA/BAM USB (Hub #1) (rev 18).
      IRQ 11.
      I/O at 0x1820 [0x183f].
  Bus  0, device  31, function  3:
    SMBus: Intel Corp. 82801BA/BAM SMBus (rev 18).
      IRQ 5.
      I/O at 0x1810 [0x181f].
  Bus  0, device  31, function  4:
    USB Controller: Intel Corp. 82801BA/BAM USB (Hub #2) (rev 18).
      IRQ 10.
      I/O at 0x1840 [0x185f].
  Bus  0, device  31, function  5:
    Multimedia audio controller: Intel Corp. 82801BA/BAM AC'97 Audio
(rev 18).
      IRQ 5.?
      I/O at 0x1c00 [0x1cff].
      I/O at 0x1880 [0x18bf].
  Bus  1, device   0, function  0:
    VGA compatible controller: nVidia Corporation Vanta [NV6] (rev 21).
      IRQ 5.
      Master Capable.  Latency=248.  Min Gnt=5.Max Lat=1.
      Non-prefetchable 32 bit memory at 0xf0000000 [0xf0ffffff].
      Prefetchable 32 bit memory at 0xf8000000 [0xf9ffffff].
  Bus  2, device   8, function  0:
    Ethernet controller: Intel Corp. 82801BA/BAM/CA/CAM Ethernet
Controller (rev 3).
      IRQ 11.
      Master Capable.  Latency=66.  Min Gnt=8.Max Lat=56.
      Non-prefetchable 32 bit memory at 0xf2000000 [0xf2000fff].
      I/O at 0x2000 [0x203f].
  Bus  2, device  14, function  0:
    Multimedia video controller: Brooktree Corporation Bt878 (rev 17).
      IRQ 5.
      Master Capable.  Latency=132.  Min Gnt=16.Max Lat=40.
      Prefetchable 32 bit memory at 0xfb000000 [0xfb000fff].
  Bus  2, device  14, function  1:
    Multimedia controller: Brooktree Corporation Bt878 (rev 17).
      IRQ 5.
      Master Capable.  Latency=33.  Min Gnt=4.Max Lat=255.
      Prefetchable 32 bit memory at 0xfb001000 [0xfb001fff].

- What is your kernel version? [ uname -a ]
Linux mythtv 2.4.18-19.8.0 #1 Thu Dec 12 05:39:29 EST 2002 i686 i686
i386 GNU/Linux

-- 

/**
 * john joseph roets
 * createTank
 * www.createtank.com
 * 785.550.3654
 * joe at createtank.com
 */ 



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