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What is the benefit of XDCam versus straight hard drive?
The gig I’m working on still shoots DVCPro tape and they want to transition to XDCam. We will likely be editing in an offline low-res codec and then upres-ing later (that’s what we do now with the tapes.) I just spent three hours reading forum posts about Avid-XDCam workflows and I’m still confused, so here I am.
From what I can tell, my options for offline-online editing with XDCam are this:
- AMA link and transcode each individual disc to a low resolution one-at-a-time. Edit. Upres by re-linking and re-transcoding each individual disc to a high resolution one-at-a-time.
(It seems very tedious to link and transcode each tape one-by-one as opposed to batch capturing the way we do with tapes now.) - Import the files from each individual disc at a low resolution. Edit. Upres by batch importing the files one disc at a time at a high resolution.
(It seems very tedious to bath import one-at-a-time, plus it would require importing an entire 20-minute clip if a few seconds were used in the sequence.) - Treat the discs like tapes and digitize real-time with a deck. Edit. Upres by decomposing and batch capturing the clips one-disc-at-a-time at a high resolution.
(This would be the easiest upres, but it seems ridiculous to capture digital video files in real-time.) - Back up each tape to a single hard drive. Link and transcode all files at once to low-res. Edit. Upres by relinking all-at-once and transcoding all-at-once to a high resolution.
(This is clearly the easiest and fastest workflow, but it requires a lot of disc space.)
SO MY QUESTION IS:
Assuming I use workflow #4, what is the point of shooting to XDcam as opposed to shooting straight to a card/drive? If we’re going to have to back up all of the media to a drive anyway, wouldn’t it be way cheaper to just use a second hard drive as a backup instead of a large collection of XDCam discs?Thanks!
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Using Avid MC 6.5 on Mac OSX 10.7 - AMA link and transcode each individual disc to a low resolution one-at-a-time. Edit. Upres by re-linking and re-transcoding each individual disc to a high resolution one-at-a-time.
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3 Replies
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If you have a computer and drive that’s fast enough, why not just AMA the source files and edit from those? I shoot using a Canon XF-300 i full MPEG-2 50 Mbit 1080p. I use the Canon XF utility to back my card(s) up to an external hard drive, then AMA link from that. I sequence all the raw clips, and edit straight from the sequence of AMA linked clips in full 1080p.
I think people over-complicate this stuff with all the off-line/on-line low-res/hi-res proxy stuff. I’m probably not the sharpest knife in the drawer but, for me, my workflow is pretty simple: Shoot. Edit. Export. Done. AMA gets me from start to finish with as little fuss as possible. 😉
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The offline/online choice in workflow is usually due to several reasons that force that decision and not because people want to:
1. Codec is not native to MC – XDCAM, DNxHD, ProRes and a few others are native, meaning they are part of Avid’s coded library and can be Avid managed in the Avid MediaFile structure. Also, because they are native, the decode playback performance is also optimized. Non-native codecs can be used directly, but when they no longer perform in real time to expectations is unknown.
2. Performance – related to #1. How complex is the timeline? Multicam? etc. As you expect more streams in real time, non-native codecs will have less performance.
3. Storage – Is the storage fast enough and big enough to hold everything? For example, it is one thing to have one 4TB drive and four 1TB drives in a RAID config as the more spindles give you more speed. How the drive or drives are connected is a factor – USB2, 3, etc. If the data rate is low enough, then the requirements go down. Also some productions like to bring dailies on to set and lower data rates allow a single drive to hold more media without the speed issue.
Understanding when and where the bottlenecks occur is key to getting a good start in post. Many can get away with native AMA linking – many others can’t.
Michael
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As usual, Mr. Phillips answers the question quite thoroughly.
I would only add that the future trend for ALL acquisition formats is AWAY from XDCAM type discs and TOWARDS file based formats recorded to a memory chip. Therefore, if you’re contemplating making a change, you may want to skip “step #4” and think about “step #5”, which is chip based media. The workflow for that would be to copy your camera chips to shared media and transcode to an Avid friendly format… or not and just use AMA. There’s too many variables to suggest a specific best practice, but
be aware that XDCAM disc may go the way of the dinosaur.You asked “what is the advantage” to Xdcam disc. One advantage is that you can box up all of the original source discs and turn them over to a network as a required “deliverable” element. For chip based media you’d have to hand over a drive (if acceptable) or LTO tape back up. Depending on the size of your media pool, this can be a BIG deal, and tilts in favor of XDCAM disc.
Good luck.
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