[mythtv-users] HDTV digital static with DVB

Preston Crow pc-mythtv05b at crowcastle.net
Tue Nov 8 23:04:49 EST 2005


On Tue, 2005-11-08 at 20:35 -0500, Preston Crow wrote:
> I have two hard drives.  If I simply cat /dev/dvb/adapter0/dvr0 to a
> file on the SATA drive, I get some glitches.  If I do the same to a file
> on the PATA drive, I get tons of glitches.  If I do it to a ram disk, I
> get a perfect recording.

And one more update:  I've found the solution for the PATA drive is to
set the multisector I/O count to 16 (it was 0)
# hdparm -m16 /dev/hdc

Unfortunately, I don't seem to be able to set any useful parameters on
my SATA drive:
/dev/sda:
 IO_support   =  0 (default 16-bit)
 readonly     =  0 (off)
 readahead    = 16 (on)

Trying to change IO_support gives an error:
 setting 32-bit IO_support flag to 1
 HDIO_SET_32BIT failed: Invalid argument
It also doesn't seem to have a multisector I/O option.

So it does look like some performance improvements on the SATA drive are
what I need, but the tuning options aren't exposed.

--PC



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