Best Method to Import / Transcode AVCHD

[Rick Stuve]

I have read that FCP imports AVCHD at a better quality than FCE does. I have Imovie, FCE and Voltaic. Has anyone compared all these methods to import AVCHD? Does anyone know of any advantages of one over the other? I have listed some I can think of but still can not speak to the best quality.

Imovie:
Image Stabilization

Voltaic:
Do not have to leave camera connected will transcoding.

FCE:
More flexible than Imovie.


One thought I had is if there is not an issue with importing with Imovie you could import stabilize in Imovie and then import into FCE? Not sure this would cause problems though.

thanks for your input.

rick

[Rick Stuve]

Well I have a pretty untrained eye but since there seems to be little out on the internet about this and responses are a little thin, I have started to try to determine this answer myself.

i took some footage with My Canon Vixia HF10 recorded at 24P. So far I have taken the footage to the HD and converted using Voltaic 2. This version has 24P pulldown and from what I can read it De interlaces as it converts 24P if you tell it to. Results compared to standard transcode using 24P pulldown and not using that option and using the highest settings result in a sharper image with 24P pulldown enabled. I also noticed less blur in movement with the 24P pulldown vs. the interlaced version.

I did notice a difference in bit rate as the interlaced version had a higher bit rate file but it did not help it look better. :) I am going to try taking the footage in using Imove and FCE, although I do not think either support the 24P mode of the camera so if I understand it correctly the program will pull it in at 29.97 or 30P.

Not sure but Ill find out soon!

I welcome any suggestions or help in this endeavor.

[Predrag Vasic]

Here's what I know about AVCHD transcoding on Mac.

Final Cut Express and iMovie both transcode AVCHD into AIC (Apple Intermediate Codec). It is a very good codec, but not as good as Apple ProRes (which comes with FCP). Voltaic seems to be doing a great job of removing pulldown in addition to transcoding. It works more-or-less the same way as Cineform's NeoScene. The output format can be anything QuickTime can output, which means same as iMovie and FCE. It is my understanding that Voltaic can also output in ProRes, which doesn't normally come with iMovie, nor with FCE. ProRes supports 4:2:2 chroma sub-sampling (AVCHD, as well as AIC only do 4:2:0). While this doesn't improve colour resolution of original AVCHD footage upon transcoding, it allows better results after colour correction in FCE/FCP.

So, to make the long story short, if you're editing in iMovie or FCE, you get better results if you use Voltaic (or NeoScene) to transcode, rather that do it in iMovie, or via Log & Transfer in FCE.

IF your shots are 24p, then there's no question; removing pulldown via Voltaic gives you the original 24 progressive frames, getting rid of unnecessary duplicated fields that were littering the 60i stream in which they were inserted. However, neither iMovie, nor FCE support 24p timeline. On Mac, Premiere Pro and FCP are the only popular ones that will work with a proper 24p timeline. Therefore, you only have two options:

1. Shot in 30p nd edit as 30p (assuming you have US model of Vixia)
2. Buy FCP (or Premiere CS4) and edit in true 24p

Alternatively, you can shoot 24p, transcode into AIC or ProRes, but keep 24p inside 60i, place that 60i on a 60i timeline and edit the whole thing in 60i. When finished, deinterlace the final product and remove pulldown as best as possible. There may be some major issues with the pulldown removal here though, since your shots no longer begin with the original keyframes, so the pulldown cadence will be all over the place. I'm not sure how Voltaic detects that cadence and if it can notice when the cadence breaks in mid-stream. I know NeoScene only detects it at the beginning of an AVCHD clip and assumes it will continue consistently through the end of it. Incidentally, it takes a few fields for NeoScene to determine that cadence, so the pulldown may not be properly removed from the first few frames in NeoScene. I haven't tested this with Voltaic yet.

[Rick Stuve]

Predrag,
I can't tell you how much I appreciate the response. I am trying to learn and it's very nice that you took the time to respond. I may not of understood 100% of what you said but most of it made it through.

I will do some experimenting with 30P and see what results i can get with Imovie, FCE and Voltaic as I do not think there is a FCP in my future based on cost. I would like to just figure out the best settings for shooting and best method to transcode so i can focus more on putting it together.

Nothing fancy and all for friends and family but want it to look it's best. I read so much about 24P looking better but if I will not be able to utilize it in 24P with the editing software I have seems to me 30P is best way to go.

thank you again very much.

Rick

[Ron Evans]

Why do you want 24P? Unless you are going to transfer to film for projection it just creates a lot of issues. Requires film shooting technique, difficult to edit( as you have found), won't playback on displays that do not have a refresh rate a multiplay of 24 ( ie 72, 120, 240 etc and will in fact recognize 24p and display correctly. A lot of these sets interpolate extra frames and remove the film look!!!! ).
Unless you are looking for the look of 24p played back on TV WITH pulldown. i.e. the modified look of film and of course nothing like a film in a cinema. That look is easier to get by shooting and editing 60i and using a film filter!!!! Not the same but on most TV's both approaches are an effect!!!!
Also 30P isn't part of the Bluray spec. Bluray is 1920x1080i, 1280x720P60 and 24P. SD DVD's are basically interlaced so 24p recorded with pulldown needs a display able to decode correctly. A 60hz display cannot do this ,it is always an effect, hence the "film on TV" cadence people see. A 120 hz display has the capability to decode correctly emulating a projector with 5 blade shutter. A 72 hz TV a projector with 3 blades. Whether these sets all do decode this way is another issue.
Most PC's display at 60hz too so that will not display correctly either.

Ron Evans

[Rick Stuve]

Ron,
Great information, thank you so much for your input. I am fairly new to AVCHD as I have purchased a Canon vixia HF10 when they came out but really only worked with Imovie. i have been trying to branch out into new areas and learn about how to produce a better end product.
My first issues arose as I learned that the HF10 does not do 1080P but 1080i. So i started to learn more and now to work with those limitations. That's when i found out learning what I don't know really opened my eyes.
So many people speak about the great look of 24P and I read the camera supported that. With the new release of Voltaic 2.0 it now supports the 24P pulldown and i thought that would work with the software I used. "I have recently purchased FCE"
Any way to make a long drawn out story as short as possible, I am looking for the best way to record and process what I film. I will never transfer to film so perhaps my desire to use 24P is misplaced. I am pretty sure I will never use FCP either.
Thanks for your help, I appreciate you taking the time to respond.

rick