Nano and Avid

[Glenn Selig]

I am recording on the Nano Firmware version 1.1.154, File Format MXF, I-Frame, 100 Mbps.
Then I am importing them into the Avid, DNxHD 145 setting. The files import and are listed as XDCAM HD 50 Mbits files. When I complete my edit, I need to Transcode to have the sequence playback at the best quality. Any ideas how I can import without have to Transcode later? Thanks

[Dave Chalmers]

Hi there,

You don't tell us what version of Avid SW you are using?
It makes a big difference.

Dave

[Glenn Selig]

Sorry, Avid 4.02

[John Mitchell]

For a start I'd upgrade to 4.0.5 - it is free for owners of version 4.

Secondly the Avid software recognises the metadata attached to the files and flags them as XDCam 50Mb/s - this is a way to get Avid to use the Sony codec to decode the files. The files are in fact whatever you recorded them at. This is because Avid doesn't officially recognise or support the various XDcam flavours that CD has developed. The byproduct of this is Avid fast imports these files in their native format - it does not transcode them even if you set your target res as DnxHD.

With the I frame codecs you can transcode at any stage to DnxHD. With the Long GOP codecs 100Mb/s you must transcode immediately after you import to avoid the buffer overflow error that Avid has with the higher data rate.

I would suggest you transcode immediately after import and delete the original native import files. You aren't really losing much as the original import only takes the amount of time it would to transfer the files - BTW you don't need to transcode at all unless you need QT ref export. You can still export a full QT but it is slow if you are working on long sequences.

My workflow - compact flash drives on location to Nexto extreme ND2700. Nexto extreme hooked up via eSata to a second external eSata drive. Import to Avid on to a separate media drive. At this point with a backup on an external drive and a separate media drive I feel comfortable clearing the cards and the Nexto. It is worth noting that my media drives are mirrored. A lot of my projects run 45 mins to 90 mins so I will generally transcode to DnxHD after import so I can use QTref for crunching to DVD.

However I just shot a project which has over 12 hours of footage (3 cams x 4 hours) so to save space I'll cut it native and do a video mixdown to DnxHD of the final approved timeline. Video mixdowns in my tests are much faster and safer than exporting a full QT. For a start if a video mixdown fails it will keep th media up to that point so you can pick it up, a QT export failure will leave you with an unreadable QT and you'll have to start from scratch. For some reason video mixdown is almost realtime while QT export is about 3 x realtime on my dual quadcore PC..

HTH

John

[Mark Job]

Hi John & Glenn:
I suggest you consider upgrading to the latest Avid Media Composer CPR (Customer Patch Release), which fixes a number of specific problems with how Media Composer deals specifically with Sony XDCAM HD 4:2:2 video files. (A La Convergent Design's Hardware Encoder Engine on the nano & XDR).

1. Header misreading with Long GOP XDCAM HD files has been improved.
2. A Major Mixdown bug (Which will jump up and drive you nutz !) with Sony XDCAM HD 4:2:2 files has been fixed.

*What would happen with 4.0.5 is you would transcode or simply video mixdown to DnxHD resolution, then when exporting to QT Ref for DVD crunching, Media Composer would forget to render whatever embedded effects or transitions or titles you had in your timeline. Then once you had your DVD encoded you would notice scenes and clips suddenly disappearing to black whenever there was a title or effect on a clip. This has been fixed. Anytime Avid improves its handling of Sony XDCAM HD files, then this is good for those of use using the Convergent Design CF Card media recorders since this is the codec they use. The link to download the latest patch is here at http://www.avid.com/support/download...torPatches.asp

[Dan Keaton]

Dear John and Mark,

Thank you very much for your very helpful posts, they are greatly appreciated.