DVD Library on Firewire drive.

[SGtheArtist]

I know some of you have similar setups so maybe you can answer this question, though it has nothing to do with SageTV.

I have recently purchased an 8-bay (w/mobile HDD racks) External Firewire 400 Enclosure (50MB/s bandwidth). This box has four Oxford 911 Firewire to IDE controllers installed, which I have daisy-chained (w/ three 6pin-6pin Firewire cables) and ran a single cable (6pin-4pin) to my laptop.

I have 7200rpm HDDs installed in the external enclosure and have copied some of my DVD’s using DVD Decrypter (default settings) to the external enclosure. I watched one of the movies off of the external enclosure last night and noticed that there appeared to be some lag in the film from time to time.

I only had the HDD with the movie I was viewing locked and on in the External Enclosure. All other drives were off and no other data was being transferred over the Firewire.

I ensured that no programs were running except VideoLAN (default settings), using EndItAll. The network connection was also disabled to ensure no Internet activity. I also noticed that when the film didn’t lag it appeared to have a very small choppiness to it. This looked to me like VideoLAN playing the chunks of data as they were received.

The HDD’s in the external enclosure are formatted using the standard NTFS by Windows XP Pro. My laptop has a 1.8GHz A64, 512MB & a GF4 Go (w/64MB dedicated memory) and a 15.4” widescreen LCD. It is running Windows XP Pro, SP2 with the latest updates.

Does anyone have any ideas as to what could be causing the lag?

[Wheemer]

I would think is has to do with the 6-4 pin cable... in order to get the max from firewire you'd need a 6-6 pin...

[SGtheArtist]

I thought the only difference between the 4pin & 6pin Firewire cables was the fact that the 4pin does not supply power and therefore the 2 additional wires are missing.

Is there a difference in bandwidth between 4pin & 6pin Firewire?

[Wheemer]

I thought that was the case, maybe I'm wrong though...

[SGtheArtist]

I'm searching for a free HD benchmark utility to test the bandwidth I did see an article that stated that 1394 was designed for 100, 200 & 400 mbps. I'll report back when I find something.

[SGtheArtist]

I installed and used SiSoftware Sandra to test the bandwidth and Sandra says that the bandwidth is 29MB/s.

Shouldn't this be plenty for DVD which uses 6Mbps (0.75MB/s)?

http://www.infotelesys.com/dvd_bandwidth.htm

[Wheemer]

you may want to take a look at your cpu usage during that test... although the throughput could be adequate, maybe it's using too much CPU to accomplish it????

[SGtheArtist]

During DVD playback from the external enclosure I noticed a 20-30% CPU usage. Or did you mean check the CPU while testing the throughput with Sandra?

I've read that SageTV works best with (i think) 64K block size do you think this may have anything to do with it?

[SGtheArtist]

Alright I've researched some more and have found the following. I read the article on Doom9.org about playing DVDs from the HDD, here:

http://www.doom9.org/index.html?/mpg/hd-playback.htm

Original Problem:
VideoLAN playing DVD files on Firewire HDD.
-Significant Lag every 15 minutes & slight stutter.

Tests:
1) VideoLAN playing DVD ISO on Firewire HDD.
-Significant Lag noticed twice (specifically at layer change), slight stutter.

2) VideoLAN playing DVD in DVD-ROM Drive.
-Significant Lag noticed every 5-15 seconds.

3) VideoLAN playing DVD ISO on Firewire HDD using a 5 second cache.
-Significant Lag noticed at layer change, slight stutter not noticable.

It appears that this is a problem with the DVD Playing software. I will try some other player and report back.

[SGtheArtist]

Test:
4) PowerDVD 6 playing DVD files from Firewire HDD
- smooth as glass no lag or stutter noticable.



Thats too bad I was hoping VideoLAN could perform as well as the commercial players