Playback on a mac

[onion]

My Mac mini can edit GH13 footage (converted to prores) using fcp without any problem. If I save the timeline as a self-contained QT movie, it struggles to play it back without stutter (using QT player)

Is the computer too slow? Or is there another player that might be able to handle playback better than QT?

I never had this problem with the lower bit rate GH1 footage

[GraemeH]

Hi Onion

it seems strange that your converted prores clips play ok - but your final prores export doesn't

if the movie is stuttering then it sounds like Hard drive speed issue, is your self contained QT export on a different drive to your source material? like USB external drive? or perhaps your hard drive is very full?

If that doesn't - help perhaps explain your set up in detail including the Prores type you are converting to and the prores type in your FCP sequence settings.

and your original source material Motion Jpeg or AVC and frame size etc.

Graeme

[onion]

Cheers

Looks like it might be something up with my OS installation. QT7 (pro) plays it fine. It's the version of QT player bundled with snow leopard that doesn't play so nice

The original was AVCHD, all files are on the same external HDD (fw800)

[GraemeH]

QTX should play it back ok, but it's not up to much yet.

Your right to stick with QT7- which still drives FCP.

If you convert Lumix Motion Jpeg footage (an i frame codec) to pro res the data rate will stay very similar to the original, however converting AVCHD (long GOP codec) to Prores will increase the data-rate 3 or 4 fold, as Prores is an iframe codec.

if you don't understand the iframe thing- ill explain more.

But basically AVCHD to prores conversion creates a larger more edit friendly file but of course larger file- higher data rate.

Prores conversion is a good idea with this footage when editing in Final cut pro

[meego]

FCP can dynamically reduce quality/framerate of preview playback. Maybe that's the reason why you get better performance in FCP than in QT.

[onion]

I'm sure you're right. The FCP preview doesn't look as sharp as the MTS file. Not really an issue when editing tbh.

QT7 pro does play the file back at full quality. It is an issue with QTX playback of the high bit rate file as GraemeH suggests.

[GraemeH]

FCP can dynamically reduce quality/framerate of preview playback. Maybe that's the reason why you get better performance in FCP than in QT.

Thats also a good point that meego makes, and if your playing the exported file from the same Hard drive as your source files - dynamic playback could account for the discrepancy.

just to add, the FCP Canvas window doesn't give a great indication of the final quality, colour tones or final output of your video, thats one of the reasons you need an external monitor (calibrated) to properly make colour/look adjustments for final output. If you don't have an external monitor then previewing in quicktime is i guess the next best thing.

Expect it's the speed of your hardrive that is the issue with QT, but since people rarely deliver in prores (expect you then compress to H.264 or the like) then expect you can live with the limitation.

if you want to explore further, open the Video in QT - with movie inspector open and note the data rate for the file in kbit/s or mbit/s , also note down the size, manufacture of your hard disk and it's model number (we can work out it's rpm 5,400 or 7,200, and wether it's internal or external (if external whats the connection? firewire, usb...) if that sounds like hard work don't worry.

I generally playback prores files from a Hard drive (7,200rpm) raid set up- internally or external via firewire 400/800 or esata. this can be expensive but there are some reasonably priced kit around for this now. as i said the issue might not bug you too much and the best option might be to export to proress (for archiving and transcoding) then create your delivery file from that and use that delivery file for local playback.