Latest post Sat, May 30 2015 8:31 PM by cuervo. 3 replies.
Page 1 of 1 (4 items)
Sort Posts: Previous Next
  • Tue, Jan 14 2014 3:43 AM

    DNxHD 444 350x

    Hello all,

    I have what I'm hoping is a quick question about the DNxHD 444 350x codec, and 4:4:4 in Avid in general.  Here's my scenario:

    I'm working on an animated TV movie that needs to be delievered at 23.98 in 4:4:4.  I'm working on the final delivery, and all the editing and animation is being done out of house.  I recieve an Avid bin from the editors, and .mov media from the animation company.  All this media is 24P (yes, 24, not 23.98) at 4:2:2.  To get the media up to 4:4:4 (I know there's no actual benefit to this given the 4:2:2 source, but no one is wavering on it), what I'm doing is exporting an RGB Same As Source QT and then importing that into a seperate 1080p/23.98 RGB 709 Avid project.

    The problem I'm having is being confident that the media is 4:4:4.  I've tried importing the clip using DNxHD 444 350x, 1:1 10bit RGB, and Apple ProRes 4444, and within the Colour Space column the only one that clearly states RGB is 1:1 10bit RGB.  I've done a Same as Source export of all three of these conversions and had a look at them in MediaInfo, hoping that would clear things up, but the 1:1 file doesn't give me any Chroma info at all.  The DNX and ProRes files both end up 4:2:2.

    If anyone can clarify the exact differences between the DNX, 1:1, and ProRes codecs and how they treat colour space that would be great.  Also, if there's something I'm doing wrong, it would be super helpful to know that as well.  All the work I've done in Avid so far has just been 4:2:2, so I am a bit out of me element right now.  Oh, and if this is any help, we're using MC6.0.1.

    Filed under: , , , , ,
  • Tue, Jan 14 2014 6:54 AM In reply to

    Re: DNxHD 444 350x

    shenanigans:
    To get the media up to 4:4:4 , what I'm doing is exporting an RGB Same As Source QT and then importing that into a seperate 1080p/23.98 RGB 709 Avid project.

    I suspect you are being misled by the confusing use of the term RGB. If you export Same As Source, and tick the RGB button, that is only remapping the luma levels from 16-235 to 0-255, there is nothing 4:4:4 RGB about that process. I'm not sure why you are doing that RGB export in between. Here's more on the RGB import and export option.

    If you want to get this into 23.976 properly, you would need to slow the 24p source down. If this is a regular File->Import, you can force a frame-by-frame import if you open the console (CMD-6) and type IgnoreQTRate True before you import. If you are using AMA to bring the file in, you can use SetAMAQTForcedFrameRate true 23.976 before you AMA-link. If you do not use such a slowdown, MC will just interpolate from 24 to 23.976, meaning that it will just drop a frame every now and then. Generally, that is not what you want.

    Note that IgnoreQTRate and SetAMAQTForcedFrameRate will not manage audio, so if you have slowed down the picture, you will need to slow down the sound mix (or have them deliver a slowed down audio mix to you). If you need to do this yourself, you could use Sound Devices' Wave Agent, open the WAV files from the mix there, restamp the sample rate to 47952Hz, save, the import the result into MC, with the check box "change sample rate to project rate" ticked.

    I'm pretty sure that whenever you are in a 444 project, you can only create 444 media, so if you import the source file into your 23.976 RGB project, choosing any of the 444 codecs will result in 444 media. AFAIK, exporting that Same As Source should result in a 444 export.

    I'm not familiar with MediaInfo, but I just downloaded and installed it, then checked a ProRess 4444 clip from an Alexa camera, and that did not show anywhere that the clip is 444. But if I open the same clip in Quicktime Player and do a Get Info, there is a clear indication that this is ProRes 4444.

     

    P.S. IgnoreQTRate False will reset. As will SetAMAQTForcedFrameRate false 0.

    Media Composer /w Symphony option | PT-HD | Win7Pro64 HP | OSX MBP | ISIS5000 | Nitris DX | Artist Mix & Transport & Color | AJA T-Tap | Decklink... [view my complete system specs]
  • Tue, Jan 14 2014 9:10 PM In reply to

    Re: DNxHD 444 350x

    I do the export step in between because I'm not doing a straight File>Import, so to speak, nor am I linking to AMA.  I'm doing a Clip>Batch Import of the offline sequence I recieve from the editors, which I'm unable to open in the 23.98 project.

    But my question isn't about my method of converting 24 to 23.98 (less of a concern with the client) and more about converting 422 to 444.  If this help illustrate my concerns more, here are screenshots of the three different exports out of the 23.98 RGB sequence.

    Apple ProRes 4444
     

    DNxHD 444 350x

    1:1 10bit RGB
     

  • Sat, May 30 2015 8:31 PM In reply to

    • cuervo
    • Top 100 Contributor
    • Joined on Fri, May 2 2008
    • Santa Fe, NM
    • Posts 1,174
    • Points 15,595

    Re: DNxHD 444 350x

    shenanigans,

    did u ever get an answer? I have the same question about DNxHD 444

    SYS1:ASUS Z97, Haswell 4.0GHz CPU, 32GB RAM, Quadro 4200 + GTX1070, Thunderbolt II -DNxIO-FSI CM171 ///SYS2:ASUS Maximus Extreme V, Sandy Bridge 3.1GHz... [view my complete system specs]

    M-Power Independent Video and Film Services, Sony PMW-F5--Sony FS700U--Canon 7d--Odyssey 7Q

Page 1 of 1 (4 items)

© Copyright 2011 Avid Technology, Inc.  Terms of Use |  Privacy Policy |  Site Map |  Find a Reseller