“Recompress all frames”

[Rafael Amador]

Hi Alexander,
That means that on exporting everything is rendered even if is not necessary because the footage match the Sequence Setting.
When you should use it: NEVER.
If you recompress any kind of compressed format, you always loose a generation.
let it always unchec, you know that FC will always render what is necessary to render on exporting.
Cheers,
rafael

http://www.nagavideo.com

(and here some clips for the friends: https://www.vimeo.com/2694745 )

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[Alexander Kallas]

…so why is it an option?

Cheers
Alexander

[Tom Wolsky]

It allows you to force a re-render of your sequence when you make a self-contained movie. Normally if you’ve rendered items in the sequence those get copied into the export file. If you rendered at reduced resolution for speed those low res files will get copied into the master, even if you change the render settings. If you change the render settings to full quality and check Recompress it will re-render at full res. At least that’s my understand. Otherwise forget about it.

All the best,

Tom

Class on Demand DVDs “Complete Training for FCP6,” “Basic Training for FCS2” and “Final Cut Express Made Easy”
Author: “Final Cut Pro 5 Editing Essentials” and “Final Cut Express 4 Editing Workshop”

[Alexander Kallas]

Thanks Tom,
That’s the best and only logical explanation.

Cheers
Alexander

[Dennis Couzin]

Tom, doesn’t your explanation imply that Apple used the wrong term? Rerendering all frames doesn’t mean recompressing all frames.
I thought Apple offered the “Recompress all frames” option in order make the QT export more uniform in quality. For example, suppose I capture DV and set the timeline as DV. Suppose the edit goes from from a shot to the same shot mirrored left to right. The second shot required FCP rendering, so it will be recompressed DV in the export. There will be an appearance difference between the consecutive shots unless “Recompress all frames” is chosen.

[Dennis Couzin]

Sorry for the lame example of the mirrored shot. A better example would be a cut to slow motion or a cut to the same shot with something inserted into it.
Years ago, low budget films would shift quality at the beginning and end of every effect. To save money, they optically printed just the effect, not the whole shot. Recompression today is not as lossy as optical printing was then, but I think “Recompress All Frames” is to solve that same problem.
Incidentally, recompression of a compressed video doesn’t necessarily change it at all. It depends on the type of compression. There’s a fun experiment for testing what decode/code does for a particular codec. Make a QT with the “Recompress All Frames” option. Import it to the timeline and make another QT with the “Recompress All Frames” option. After several iterations, do you see a difference with the original?

[Rafael Amador]

Hi Dennis,
i don’t think your eyes will be able to tell when a clip have overcome one more generation.
i’ve made tests with DV, and you can make few re-compression without much visual degradation

[Dennis Couzin] ” Rerendering all frames doesn’t mean recompressing all frames. “
This is true only when you are working Uncompress. Working with any other codec means re-compression and quality lost.
rafael

http://www.nagavideo.com

(and here some clips for the friends: https://www.vimeo.com/2694745 )

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[Dennis Couzin]

[Rafael Amador] “i don’t think your eyes will be able to tell when a clip have overcome one more generation.
i’ve made tests with DV, and you can make few re-compression without much visual degradation”

Hi Rafael, it’s good you found that because it tends to confirm that “recompression of a compressed video doesn’t necessarily change it at all.” Many in this forum have the heebie-jeebies about all recompression. This isn’t helped by the FCP User Manual’s blanket statement “not recompressing frames reduc[es] unnecessary artifacts when exporting to the same video codec.”

[Rafael Amador]

Hi Dennis,
i think that when working with high compressed formats is important to try to avoid multiple rendering.
I try to do everything at once and if I have to make any kind of round tryp (Color, AE, Shake,..) from the first export work Uncompress if possible.
rafael

http://www.nagavideo.com

[Mario Vivanco]

Sorry for being late, but I am newbie on that. Of course should be noticed a big difference beteween the original and the recompressed for 5ht. time, really? I didn’t make the experiment but I think so…

I would ask, that , even if we don† notice the diference, does it mean that that re-compressed QTMovie has good video quality (at sight) and more light (because of the recompression) and will be converted to MPEG2 for example to make a DVD and is it an acceptable professional workflow?