Dropped Frames and/or Jerky Playback with HD material

Question

Level 1

0 points

Dropped Frames and/or Jerky Playback with HD material

We have a project due very soon that needs to be Hd, so we updated from our G5 PowerPC to a iMac 27" i5 with 4GB ram, 6770m 512 video card and a Blackmagic Ultra Studio 3d. Running Final Cut Pro X.

I've exported from Boris RED and Motion in both SD and HD. HD 1080i footage plays back jerky on both Quicktime player and FCP..resembles dropped frames...to both the iMac screen and an external monitor.

SD seems to play well.

720p is very jerky too.

I'm wondering this is a hardrive speed issue? I ran the Blackmagic Speed Test and it said read was only at about 100 mbs.

Any help would be greatly appreciated.

iMac, Mac OS X (10.7.2), Blackmagic Ultra Studio 3d

Posted on Dec 6, 2011 6:17 PM

Reply

Answer 1

MattMPA Author

Level 1

0 points

Dec 6, 2011 6:32 PM in response to MattMPA

A bit more info as I work more and more with this...

It seems when playing back in Quicktime Player...the jerky part changes on repeated playbacks.

Reply

Answer 2

MattMPA Author

Level 1

0 points

Dec 6, 2011 6:53 PM in response to MattMPA

OK...last time I post tonight....but have figured more out. It seemsin Quicktime player that the smaller the file, the better it plays.

Does this sound like RAM or harddrive speed?

Reply

Answer 3

Tom Wolsky

Level 10

152,815 points

Dec 6, 2011 6:56 PM in response to MattMPA

4G RAM is base specs for HD.

HD 1080i footage plays back jerky on both Quicktime player

Very likely unless you have a fast computer and fast drives. We can't tell without the exact specifications of the media.

100mbps is very low.

Reply

Answer 4

Tom Wolsky

Level 10

152,815 points

Dec 6, 2011 6:57 PM in response to MattMPA

Depending on the exact specs of the media it can be either or both.

Reply

Answer 5

MattMPA Author

Level 1

0 points

Dec 6, 2011 7:10 PM in response to Tom Wolsky

Thanks Tom.

I've tried many different compressions, the one that seems to work best is 1920x1080, h.264. This file is a 5 sec. video clip that is 52.2 MB. I have exported the same piece with different compression and one is over 1 GB...this one plays terribly.

The play worse from FCP X, than from QT player, which I suppose makes sense since the program is also using resources.

The machine is an iMac 2.7 GHz Intel Core i5.

Thanks again....I was assured this machine would do the job.

Reply

Answer 6

Dec 7, 2011 8:24 AM in response to MattMPA

The dropped frames are due to the bitrate of the source video. Essentially your computer cannot deliver the video data fast enough. Is the data on the boot drive? If so you may want to consider a high speed external drive for all of your video data. Your iMac should have Thunderbolt, which is a compelling new otion for external data.

The problem happens on the boot drive because your video playback is competing for data with the operating system. It may also help to work off a fresh reboot, and be sure you have no other applications running at the same time as FCP. HTH.

Reply

Answer 7

MattMPA Author

Level 1

0 points

Dec 7, 2011 3:38 PM in response to John Vargo

Well guys...here's the answer and I'm amazed.

Turns out that the UltraStudio 3d equipment cannot output clean video to an external monitor in FCP X. They don't know when they'll ber able to correct this.

It WOULD work with FCP 7....but with Apple no longer selling this....I'm SOL.

Reply

Answer 8

MattMPA Author

Level 1

0 points

Dec 8, 2011 4:00 AM in response to MattMPA

I was able to get FCP7... So we should be good once that arrives.

According to the folks at Blackmagic, it has some thing to do with FCP X not supporting external video playback. They have to set it up as an extended desktop to get around this, but having the video upscaled causes heavy CPU use, thus causing the video to stumble. FCP 7 supports external video for NTSC playback.

After more testing, I see that when I drag QuickTime player to the external monitor...even this plays back choppy....but clean in the iMac screen.

Reply