Everything said so far is correct. so if i may add my experience in here...
technically it is much more challenging for an array to playback a sequence
of files, as against one large video file.
i.e one hundred x 7meg DPX files are more demanding to play than one x 700
meg video file.
And the type of drives make a big difference.
SATA have difficulty with single files (Flipbook), and FibreChannel do not
have difficulty. That is why Sata is cheaper.
The other technical consideration is the connection from the bus to the
drives.
I have a Quad 2Gb fibrechannel card on my Linux box, with 4 pairs of FC
connecting to a 32-drive Xyratex Raid X24 with true FC drives installed, and
I CAN playback targa images and dpx files in realtime.
But another system we have with dual FC and 16 spindles of SATA is NOT
realtime. But both systems are very happy to play uncomssed 10bit HD at
4:4:4 video files.
So the theoretical limits are only a rough guide
Barrie Williams
www.pixelfantastic.com
BTW the DDR system we are using is IFX Piranha.
----- Original Message -----
From: "Bob Friesenhahn" <bfriesen@simple.dallas.tx.us>
To: "Robin Rowe" <rower@movieeditor.com>
Cc: <cinepaint-users@lists.sourceforge.net>
Sent: Tuesday, February 07, 2006 7:56 PM
Subject: Re: [CinePaint] 100 frames max limit in flipbook
> On Tue, 7 Feb 2006, Robin Rowe wrote:
>
>> RAM is much faster. Without very fast drives, DI playback (12MB * 24 fps
>> => 288Mbyte/sec) will exceed the io bandwidth of the hard drive. A SATA
>> drive goes 300Mbyte/sec max, and Ultra ATA is just 100Mbyte/sec max. RAID
>> striping is typically used to increase disk io bandwidth.
|