Avid Media Composer Forum
XDCAM Media from disks to DNXHD145?
XDCAM Media from disks to DNXHD145?
by Diego Garza on Jan 29, 2013 at 11:55:53 pm

I will be receiving xdcam media that essentially needs to be imported to avid at dnxhd145 and then export some selects as h264 QTs. Easy enough?

I'm running Avid 6.5 on a Macbook Pro on OS 10.8.2, 2.6 ghz core i7, 8bg of ram (fyi).

I initially created an avid project at 1080/23.98 since the footage they shot is at 23.98 fps. When linking to the footage via AMA, it came up, and I was going to select a clip as a test to transcode. But, I didn't see a DNXH145 option:

So, I created another project, this time at 1080/59.94 and did the same process, link via AMA, brought a clip in, and I can now trandscode to dnxhd145 but it asks me to convert the rate. I did so, and when I went to export an h264 it came out with 29.97 fps and not 23.98 because of the transcode.

What step or setting am I missing here? I want to be able to transcode the 23.98 media to DNXH145 and then export an h264 that still has 23.98 frame rate.

Just to note, I have installed the AMA xdcam plug ins as well as all of the DNXHD codecs needed. Any suggestions would be appreciated!

Re: XDCAM Media from disks to DNXHD145?
by Job ter Burg on Jan 30, 2013 at 12:46:16 am

There is no 145 for 23/24p projects. This is because the data rate (per second) is lower when the frame rate is lower, when using the same compression.

So DNxHD115 (23/25) equals DNxHD120 (25) and DNxHD145 (29), and DNxHD175 (23/24) equals DNxHD185 (25) and DNxHD220 (29).

You can transcode to 29.97, as you did, and then you'll have sources that are 23.976 with a pulldown added. If you cut those, you are likely to break pulldown phase. Not problematic in some cases, but not the cleanest workflow.

Guess you got stuck on the number 145, which is understandable, but is just named differently in a 23.976 project.

Re: XDCAM Media from disks to DNXHD145?
by Diego Garza on Jan 30, 2013 at 12:49:32 am

AH! Bingo. OK, understood. Thank you so much for the explanation. Very helpful!

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