• Apple Final Cut Pro Legacy

  “Lag” in Final Cut Pro and uncompressed video

  Posted by Erik Lindahl on November 24, 2005 at 9:14 pm

  I have a question that might have an answer. We just got a G5 for some editing and I’m experianceing a strange “lag” when it comes to playing back incompressed footage. The lag is not a A/V sync issue, it’s a playback-lag that comes when pressing “PLAY” in Final Cut och QuickTime player. I’ve found this on all uncompressed 8-bit PAL material I’ve used.

  To further explain this the lag only appers the first 0.5 to perhaps 1 or even two seconds. It varries quite a bit. I have not seen this issue on our system with DV or DV50 material. What I’m suspecting is to slow HD’s

  HARDWARE:
  – Dual G5/2.5 Ghz PCI-X
  – 3GB RAM
  – 2-port SATA PCI-X Card in 133Mhz slot
  – AJA Kona LS in 100Mhz PCI-X Slot

  DRIVES TESTED:
  – ACUTA 4-disk SATA RAID-5 (1 SATA connection to host computer, hardware RAID-5 in external disc cabinett)
  – Firmteck 2-disc SATA (software striped)

  SOFTWARE:
  – MacOSX Tiger 10.4.3
  – Final Cut Pro 5.0.3
  – AJA Kona LS 1.1.4 Drivers

  I’ve done system tests with Kona System Test and got:

  ACUTA: 75 MB/s read, 51 MB/s write
  Firmteck: 112 MB/s read, 103 MB/s write

  Still the “lag” is there. It’s a bit worse on the ACUTA, but it evident on the Firmteck and internal SATA-drives. It apper the first time I go to a clip usually. However, if I playback it so the lag disaperas, there is NO lag on that clip the next time I play it back (as long as I stay on the same clip). The same goes for playback of uncompressed files in QuickTime player. A slight, but very noticable lag beforce playback begins.

  I guess what I’m wonder is if this is normal OSX/FCP behavior or if it might be my drives or configuration. My suspision is some kind of cachine by the system or something

  Erik Lindahl replied 20 years, 5 months ago 2 Members · 2 Replies
• 2 Replies

• 

  Walter Biscardi

  November 25, 2005 at 12:43 am

  No lags here to speak of either with the FW 800’s (G-RAID and LaCie) or Fibre Channel array. Maybe with 10bit from time to time, but definitely not with 8 bit.

  Walter Biscardi, Jr.
  https://www.biscardicreative.com

  “The Rough Cut,” an original short film premiering December 7th in full High Definition in Atlanta.
  rsvp@biscardicreative.com to reserve seats.
  https://www.theroughcutmovie.com

  Now editing “Good Eats” in HD for the Food Network

  “I reject your reality and substitute my own!” – Adam Savage, Mythbusters
• 

  Erik Lindahl

  November 25, 2005 at 10:19 am

  Very strange I must admit. I don’t think my last workingstation (Dual 1Ghz G4 with a SCSI-RAID, softwarestriped) suffered from this.

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