[mythtv-users] how many concurrent recordings possible? in HD?

mrwester mrwester at gmail.com
Sat Dec 10 01:14:32 EST 2005


On 12/9/05, John P Poet <jppoet at gmail.com > wrote:
>
> On 12/9/05, mrwester <mrwester at gmail.com> wrote:
> > Hi-
> >  My mythtv system has 1xPVR-350, 1xPVR-500 using ivtv 0.4, and a newly
> added
> > DViCO FusionHDTV 5 Lite using DVB drivers.   1x200GB seagate+1x300GB
> seagate
> > HD LVM with XFS for /video and 1x40GB seagate for FC4 OS. I have DMA
> > enabled. DVI out via fx5200 at 1280x768.  Chaintech nforce2 mobo,
> AMD2900
> > with 1gb ram.  All 4 tuners can capture on their own with no
> problems.  I
> > can capture with all 3 Hauppauge tuners at the same time no problems.
> > Trying to capture HDTV while capturing with the Hauppuge cards results
> in
> > normal analog recordings but the digital recording has dropouts and
> > scrambled bars across it.  I need to double check if capturing digital
> NTSC
> > with the DViCO card also has the dropouts when one or more PVR cards are
> in
> > use.
> >
> >  I'm new to the HDTV part of mythtv and looking for feedback to tell me
> if
> > what I'm trying to do is realistic or not.   And if it is realistic,
> where
> > should I look to troubleshoot.  Thanks for any insight.
> >
> >  Mike
>
> I have four HD-3000 cards writing to a 5 disk software RAID5 formatted
> as XFS.  I can record on all four cards simultaneously without any
> problem.  I do *not* use LVM -- which I believe adds some overhead.
> Software raid5 on a 3GHz Pentium 4 system results in very good disk
> throughput.
>
> As a test, I tried turning OFF hyperthreading on my 3.0GHz P4, and
> started having problems recording more than two HD programs at a time.
> Don't know how Athlons perform, but HT is a win for Pentiums.
>
> Another datapoint - My raid5 had to rebuild one of the disks.  During
> this rebuild, I could still record one HD stream without a problem,
> but two resulted in a LOT of corruption, and a lot of messages about
> it taking a LONG time to get data from the HD tuner card.
>
> I noticed that Daniel add a ringbuffer into myth's DVB processing
> today, so that should help any system which is marginal.
>
> Don't know if any of this helps you, but thought it might...



Thanks for all the replies, they give me some idea of what is possible- if
capture of 4 HD streams is possible, then I'd think the  17gb/hr that the
3xhauppauge + the DViCO are writing to disk when recording 1080i should be
pretty easily attainable.

Currently, I've got the 2 tuners of the 500 as 1 and 2, the pvr-350 as 3 and
the fusionHDTV 5 lite as #4.  I only see issues when the pvr-350 and the
fusionHDTV 5 lite are both capturing...  If I have all 4 tuners capturing-
which will give me recording corruption on the fusionHDTV5 lite, and then
systematically stop recording on any of the other tuners, only the PVR-350
makes a difference, and stopping capture by this tuner will clear up the
fusionHDTV capture, irregardless of what the pvr-500 is doing.

Relevant bits of lspci -v indicate that the 350 and the fusionHDTV 5 lite
are not sharing and IRQ, so that's not an issue...


01:0a.0 Multimedia video controller: Brooktree Corporation Bt878 Video
Capture (rev 11)
        Subsystem: DViCO Corporation DViCO FusionHDTV5 Lite
        Flags: bus master, medium devsel, latency 32, IRQ 11
        Memory at e4000000 (32-bit, prefetchable) [size=4K]
        Capabilities: [44] Vital Product Data
        Capabilities: [4c] Power Management version 2

01:0a.1 Multimedia controller: Brooktree Corporation Bt878 Audio Capture
(rev 11)
        Subsystem: DViCO Corporation DViCO FusionHDTV5 Lite
        Flags: bus master, medium devsel, latency 32, IRQ 11
        Memory at e4001000 (32-bit, prefetchable) [size=4K]
        Capabilities: [44] Vital Product Data
        Capabilities: [4c] Power Management version 2

01:0b.0 Ethernet controller: Realtek Semiconductor Co., Ltd.
RTL-8139/8139C/8139C+ (rev 10)
        Subsystem: Realtek Semiconductor Co., Ltd. RT8139
        Flags: bus master, medium devsel, latency 32, IRQ 5
        I/O ports at d000 [size=256]
        Memory at ea010000 (32-bit, non-prefetchable) [size=256]
        [virtual] Expansion ROM at e4010000 [disabled] [size=64K]
        Capabilities: [50] Power Management version 2

02:08.0 Multimedia video controller: Internext Compression Inc iTVC16
(CX23416) MPEG-2 Encoder (rev 01)
        Subsystem: Hauppauge computer works Inc.: Unknown device e807
        Flags: bus master, medium devsel, latency 64, IRQ 9
        Memory at dc000000 (32-bit, prefetchable) [size=64M]
        Capabilities: [44] Power Management version 2

02:09.0 Multimedia video controller: Internext Compression Inc iTVC16
(CX23416) MPEG-2 Encoder (rev 01)
        Subsystem: Hauppauge computer works Inc.: Unknown device e817
        Flags: bus master, medium devsel, latency 64, IRQ 11
        Memory at e0000000 (32-bit, prefetchable) [size=64M]
        Capabilities: [44] Power Management version 2

If I get a chance to switch some cards/slots around tomorrow, I'll see if it
makes any difference, but from lspci, it appears that the PVR-350 is sharing
with tuner 1 of the PVR-500 and the fusionHDTV 5 lite is sharing with tuner
2 of the PVR-500.  I've got to re-do the experiment and go to the logs to
see what's going on, but my wife wanted to catch up on a few days of
unwatched shows, so the system was in use all evening...  If anyone has
ideas, I'm open to suggestions.   Thanks,

Mike
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