Apple Hardware For Editing 50Mbps Files?

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Ron Jackson
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I've been thinking about either the forthcoming Canon XLH1 replacement or adding a NanoFlash to my XLH1.

I own an iMac with a 2.93GHz Intel Core 2 duo processor and 4 gigs of RAM.

Will this have sufficient grunt to edit 50Mbps files via FCP7, XDCAM off the Nano?

Ron

Ron Jackson

MAGLINK
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It will Ron but probably only one or two streams so if you do any FX or inlays you will need to render!

I am running a mac pro 8-core with 8gig ram and a blackmagic extreem HD card and I still need to render certain things when editing AVC intra 50 or 100 at pro res HQ rates.

dominicwitherow
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Ron, your machine should be fine with the footage, as Gary says. However, to make it even easier to work with, I would strongly recommend transcoding to ProRes prior to editing. If you use ProRes HQ the machine will find it hard to keep up with everything, but normal ProRes will be a breeze. This is because the MPEG2 Long GOP codec of the XDCAM will be replaced by the i-frame ProRes, which is much easier for the computer to work with.
Dominic

Ron Jackson
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Thanks for the replies. It seems nowadays that the first thing one checks when contemplating upgrades to video kit, apart from one's wallet, is one's NLE and the computer itself.
Canon haven't given out much info on their new cams. nothing about the codec and recording medium other than that "50Mbps" capability and that they are in discussion with the main NLE software producers.
Dominic, please can you give a brief description of "Pro-Res". I've seen plenty of references to it without feeling in the know.

Ron

Ron Jackson

dominicwitherow
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Ron

ProRes is an Apple proprietary codec specifically designed to make the gazillions of other codecs available to professional users all play happily together in the post production process. It is very high quality and visually lossless when compared to most standard formats. It also comes in various versions. The basic versions are ProRes 422 and ProRes 422 HQ (the latter being a 10-bit codec, suitable for high-end delivery / effects etc). In FCP7 there are several other versions available, but I have not used FCP7 so can't tell you much about them, other than that they are aimed at offline work and where computer resources are limited.

The main facet of ProRes, with regard to using it when the original video is in one of the popular MPEG2 or AVC codecs (HDV, XDCAM, EXCAM, AVCHD etc) is that each frame is independent to the last, whereas the more highly compressed capture codecs are based on groups of pictures (Long GOP), which are then decoded by the computer to make a stream of frames. Not only does this require a lot of computer grunt to decode and playback at a decent rate, but it means that the pictures are essentially interpretations, rather than photographs. What transcoding to Prores does is it translates these GOPs into individual frames and so future playback does not require any of the computing needed for the original footage, thus freeing up valuable computer resources. As this process is conducted without having to play back the video at the same time, the resultant Prores video is pristine and very easy to work with.

It used to be common to transcode HDV, for instance, into DVCProHD which was essentially the same thing. The key difference between ProRes and DVCProHD is that ProRes is a Full HD codec (1920 x 1080 or 1280 x 720) with square pixels, so there is also no worry about the pictures coming out looking slightly squashed or stretched, as is sometimes the case when using DVCProHD, as it is 1440 x 1080 or 960 x 720.

So, in short - ProRes makes it easier for the computer to interpret footage that was originally aquired in a highly compressed format. Also, any footage can be made into Prores, making a mixed timeline work better too.

I hope that makes some sort of sense!

Dominic

Ron Jackson
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Thanks Dominic, as always a succint and understandable explanation.
Some of you forum members should be employed by Apple Corp. to write their guff in"proper English".

Ron

Ron Jackson

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Just to add FCP also has pro res proxy and LT.

Proxy is an off line codec designed to be used with very high bit rate material such as RED and 2k cinema. It is very low bit rate and will work on just about anything but you have to then re-conform a master from the original material.

LT is also lower bit rate than std pro res and HQ and is ideal for working with AVCHD or HDV bit rates of around 12-25mbs.

I personally use two camera codecs:

1: 1920x1080 AVC Intra 100mbs and this is re-wrapped to pro res HQ as it is a 10 bit 4.2.2 codec.

2: 1920x1080 AVCHD from a canon HF11 at 24mbs I transcode to pro res LT for this.

Ron Jackson
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Thanks again. Will FCP(Studio) then do something "extra" for my HDV footage via an XLH1 that iMovie and FCE cannot manage being limited to A.I.C. (I think!).

Ron

Ron Jackson

PaulD
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Hi
AIC is not a very good codec for anybody other than iMovie/FCE users. ProRes is an excellent high-resolution codec suitable for professional use.

ProRes HQ doesn't really offer any advantage over the ordinary ProRes codec - unless you start with camera footage with greater-than 10-bit recorded colour fidelity - ie Red and Viper.