SD MXF Files from Rocket?

[Richard Bradbury]

Is it possible to create Avid MXF files at SD resolutions with RocketCine-X? Specifically I need 720x576 FHA, 25P, DV50/DV25.

 

[MichaelP]

Not at this time.

Michael

 

[Richard Bradbury]

Can you suggest an alternative SD Avid workflow that uses the Red Rocket? Is it possible to make DNxHD36 files at SD resolution? Is there a way to do it through quicktime?

 

[Marcus Vasques Osorio]

U have the option to create a AVID-DV or DV-PAL quicktimes in REDCine-X, this can then be transcoded into the AVID, realtime. You will need to create a ALE for the ingest and to link to clips.

RocketCine has not got the resolution unfortunately also has not go the option to customise size of export...

Marcus

 

[M Most]

Can you suggest an alternative SD Avid workflow that uses the RED Rocket™™™? Is it possible to make DNxHD36 files at SD resolution? Is there a way to do it through quicktime?

Generating SD files from R3ds has been a real time or faster process on most modern computers without the Rocket for quite some time. The only thing Rocket would bring to the table would be full debayer, but frankly, you can't see the difference between quarter debayer and full debayer in a standard definition image. So the answer to your question is that the alternative workflow is probably to generate standard def Quicktime files - either compressed or uncompressed - and import them into Avid, which should happen pretty quickly. If they're 24fps Quicktimes, you can use the ALE generated by Red's tools and batch import at whatever compression ratio (or 1:1) you want. The suggestion above to use Avid DV is a good approach as well, as it should fast import.

As for DNxHD, there's a reason the "HD" is part of the codec name.

 

[Marcus Vasques Osorio]

agreed, the full debayering leads to alot of aliasing as well in the SD material, so definately less debayring if possible. RedRocket does not make the process much quicker...

Marcus

 

[MichaelP]

I will try this later today but you could try...

Out of RED tools use QT wrapped Avid format for 14:1. The ALE needs to be created to properly represent 24fps sources inside 30fps and 25fps formats. Try MetaCheater on the resulting QT's to see if that works.

Once in an SD project, you need to ensure tracking of original 24fps TC - duplicate START timecode column into TC24 and do the conversion.

Michael

 

[Graeme Nattress]

What leads to aliasing is poor downsample filters - not a full demosaic. Whenever you downsample, especially to SD, it's vital you properly downsample.

Graeme

 

[M Most]

What leads to aliasing is poor downsample filters - not a full demosaic. Whenever you downsample, especially to SD, it's vital you properly downsample.

Do you have an example of a "proper downsample filter?" When one is making SD elements, one usually doesn't have the time to investigate everything available, one usually uses what one has already, be it hardware or software. And since most of the time the original transcode is for HD, the SD version is usually done through hardware, such as an Aja or Blackmagic card, in part because it's real time. That's often - if not usually - a lot more important than seeing a bit of aliasing.

 

[MichaelP]

OK - I got it to work, but it takes a couple steps. In REDCINE-X create a setting and select QuickTime and the Meridien codec of your choice (I used 14:1). Create a custom size of 720x486 for NTSC. I also maintained SMPTE color. I used a 1/8th debayer from the 4K file, but play around yourself for speed versus quality. Add burn-ins as needed.

Once the QT files were created, I used MetaCheater to create the ALE file making sure to check 24->30 in the bottom right hand side. This is to ensure proper timecode management when entering the world of SD since 24fps is not a native SMPTE recognized format. At this point, the steps are very much like the original workflow - import ALE, batch import QT files with setting to 601/709 color and image sized to fit. This will be a fast import. Once imported, highlight the entire START column and do a command-D or control-D and select the TC24 column. It will reverse telecine the metadata to the original 24fps timecode. Make all EDL's on that column.

Michael