• Apple Final Cut Pro Legacy

  Stuttery HDV Playback

  Posted by Mark Curry on January 31, 2008 at 9:02 pm

  Hello,
  I’m editing a 720p60 piece that consists of a continuous, very smooth motion dolly (on tracks) pan. However, on QuickTime playback the video exhibits occasional stutters. These stutters are not consistent temporally (i.e. stutters aren’t always in same place). These stutters appear similar to dropped frames (i.e. the video jumps ahead a small amount). However, the system is keeping up as tested by FCP’s dropped frames detection, and QuickTime’s Playing FPS Info window reports a consistent frame rate.

  On playback from tape to an HDTV there are no stutters. Also, tape printed from FCP (this footage which is sttutery in FCP and QT) also exhibits smooth playback on the HDTV. Clearly, this is some software playback issue. Thinking that the complex MPEG-2 data was being misinterpreted by QT, I downconverted to Apple Intermediate Codec, ProRes 4:2:2 and various low data rate SD files always with the same sttutery result. At this point, I am approaching being stumped. This work is intended for QuickTime SD downconverted playback (as well as HD ProRes 4:2:2 archiving) so I cannot avoid the issue. Help …

  Specs:
  HDV 720p60
  JVC GY-HD200U camera
  QT 7.3.1 (and also tried QT 7.4)
  Leopard 10.5.1
  FCP 6.0.2
  Easy Setup 720p60
  iMac 2.4GHz Duo

  chimpybits

  Mark Curry replied 18 years, 6 months ago 2 Members · 3 Replies
• 3 Replies

• 

  Jeff Carpenter

  January 31, 2008 at 9:12 pm

  What kind of hard drive is the media on?
• 

  Mark Curry

  January 31, 2008 at 9:28 pm

  Tried:
  – External Macally Firewire 400 7200rpm drive (not Oxford bridge)
  – Internal aluminum iMac SATA2 drive
  – G-Tech G-RAID Mini

  I can’t vouch for the G-RAID as it was a quick test on an unfamiliar system. However, I will test more carefully on a Mac Pro internal SATA RAID.
• 

  Mark Curry

  February 2, 2008 at 2:26 am

  Just had a new idea. As our final output is letterbox SD (.h264), how about we try doing a hardware downconvert via the camera. As round-tripping to HDV via the camera is fine, perhaps downconversion via the camera will also be fine. It is quite possible that the camera conforms the footage properly (in a way that the software doesn’t). I believe this camera’s (JVC GY-HD200U) downconverts to DV? This DV file we would then transcode to h264. In light of the stuttering issue, this extra DV compression is acceptable if the result doesn’t have this issue.

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