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Video hang ups
I’ve been editing on FCP for 10 years, but very simple SD 4 camera shows. Now, I have a new gig and the company has a Mac 2 x 2.28 Quad-Core Mac running 6 GB of RAM and 10.5.8 and Premiere Pro CS4. Also installed is a Decklink Extreme card. I believe the video card is stock.
I’m importing footage shot with a Cineflex V14 HD aerial camera (which is based on a Sony 1500). Most footage is coming off DVCPro HD, and some off HDCam. Almost all has been shot 1080i, with a little bit 720p.
I’ve tried to capture footage through the Decklink, but it’s just not working. On playback, the files end up freezing up. So, I switched to capturing it to one of our AJA KiPro’s and transferring the data over to the mac. I can cut in Premiere, though have to render everything. However, in playback, my video is not at all smooth like my original tapes. It’s really jumpy. If I export a QT, it, too, is jumpy. HOWEVER, it seems that it’s jumpy in different places each time. I played the same clip repeatedly and the glitches are not consistent, so I think I’ve ruled out the capture.
I have three drives in the mac right now. All are in the SATA trays. One is a small drive with only the OS and Apps. The other two are 1 TB Seagates. They are NOT in a RAID.
I know it’s tough to diagnose remotely, but are there any red flags right off the bat? Our programmer here says I should run my OS and apps off a PATA drive (open connection on the DVD cable) and put four identical SATA drives in the trays and RAID them as one big drive (not sure of which RAID that is yet). Someone else has told me to do the same thing, but make the RAID into two drives with redundancy. Yet someone else told me that I don’t have to RAID my drives at all and it’s probably a video card issue (I haven’t run the HD-SDI output from the Decklink to my KiPro yet…doing that next to look at the video output…maybe that will shed some light).
Any thoughts would be appreciated.
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6 Replies
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I just ran the Disk Speed Test from Blackmagic. My results are:
HDTV 1080 fps Read: 17 Write: 16
Does this help?
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A single SATA drive alone cannot facilitate sustained HD playback.
Blackmagic recommend 2 x HDDs (La Cie) striped as raid0 for SD/HD 4:2:2 and 4 x HHDs for HD 4:4:4 or 2K.
As you have a BM Extreme card this should be doing most of the grunt work (as opposed to the GFX card) so your HDDs are the most likely suspects in their current guise.
best
andy
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For smooth HD video playback you want the BM disk utility to show your drive able to sustain at least 40fps preferably higher (60-75) and that goes for both read and write. This can only be achieved through RAID 0 or RAID 5 with fast SATA II series HDD Arrays.
Jon Barrie
aJBprods
http://www.jonbarrie.net
http://www.suiteskills.com -
Thank you all. Can these speeds be accomplished by filling the four internal drive trays or do I need to step up to an external array. I spoke with BM earlier and they recommend G Technologies or Stardom external raids. I’d prefer to go the cheaper route of using the PATA drive for OS/apps and four SATA trays for the array, HOWEVER, if this won’t work, I’ll try to sell the external raid upstairs.
Thanks again!
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this thread by Walter Biscardi covers the subject:
https://blogs.creativecow.net/blog/70/internal-vs-external-raid
Blackmagic recommendations are based on their own tests but it doesn’t mean that other alternatives won’t work. A colleague of mine has had more than one LaCie drive fail on him in the past so you pays your money and takes your chance.
best
andy
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Thank you all. We’ve decided to go ahead and bite the bullet and buy an external raid. I’m not liking my initial idea of using four internal trays because it’s still one controller. We’ll buy a raid controller card and a four drive raid. Currently looking at G-Force and Stardom. Will probably find more today to add to the list of considerations. I know SAS raids are faster, but I’m afraid SCSI drives won’t be around forever. Think SATA is a safer way to go.
…learning new stuff is good.
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