Tag Archives: Dnxhd

Mastering codecs revisited

A lot of folks were excited by the release of the Windows ProRes 422 decoders for QuickTime last week. It does solve a workflow issue for editors needing to get ProRes material into third party Windows applications, but it doesn’t allow for roundtripping.

The lack of a Windows encoder is only part of the problem with ProRes. Its lack of alpha channel support remains a dealbreaker for many editors and motion graphics pros.

Looking for a reasonable bandwidth, all I-frame mastering codec? DNxHD remains the best cross-platform mastering solution.

New Avid DNxHD codecs

Avid has just made its latest version of the DNxHD codecs available on its Knowledge Base site. Scroll all the way to the bottom to get the codecs.

Import a QuickTime movie that has been compressed with this codec into an Avid editing application as DNxHD. You can “fast import” the movie if you select the 601/709 option in the Import Settings dialog box and import the video as DNxHD into an HD project of corresponding size and frame rate of the QuickTime movie.

Exporting from a non-Avid product: Export a movie at a size of 1920 x 1080 (1080i/p HD), 1280 x 720 (720p HD), or 1440 x 1080 (DNxHD-TR 1080i/p) for optimal quality.

Alpha: This codec supports alpha channels.

You read that correctly. The new DNxHD codecs now support alpha channels – a huge workflow enhancement for those of us using third party applications to create content for our Avid systems.

I haven’t tested them yet, but surely they are worth a try.

DNxHD vs. ProRes 422 redux

In a previous post on another blog I did a quick and dirty comparison of Avid’s DNxHD and Apple’s ProRes 422 codecs. The test was somewhat flawed in that I compared the codecs within Adobe After Effects CS3. This forced a YUV to RGB conversion. In that test, DNxHD outperformed ProRes. In essence all I was comparing was color space conversion capabilities.

In real world usage – ProRes within Final Cut Pro 6 and DNxHD within Avid Media Composer, the two codecs both performed very similarly. In other words, no one’s clients are going to complain about either codec.

So that means the codecs are pretty much the same? Yes and no. There are still real differences that pros in the trenches need to take into consideration.

Avid DNxHD colorspace options

Obviously my test proved that if you plan on doing anything in RGB space, such as After Effects or Photoshop work, you’re better off with DNxHD since the codec allows you to select the correct colorspace for rendering.

Just as Apple made a big deal about QuickTime being fully MPEG-4 compliant, Avid is working closely with SMPTE to make DNxHD fully VC-3 compliant.

In addition, Avid DNxHD is compliant with SMPTE draft standard VC-3, an HD video compression format in development that enables open media exchange. VC-3 is making excellent progress toward becoming a SMPTE Standard (to be identified as SMPTE 2019) and the effort is nearing completion. Pending VC-3 standardization by SMPTE, Avid DNxHD will be the world’s first codec fully compliant with VC-3 compression technology, and any manufacturer that licenses Avid DNxHD will have confidence knowing that it is working with a SMPTE standard.

That last line is interesting. Avid licenses DNxHD. Word on the street is that many developers don’t like the terms and pricing, but that’s still a step forward from closed and proprietary.

I can’t be talking about ProRes being closed and proprietary, can I? It’s in QuickTime, isn’t it? Yes, it is. But it’s only available on systems with Final Cut Studio installed, making it a $1,300 codec available only in Mac OS X. And that’s where working in ProRes can get ugly. No ability compress ProRes video on Windows workstation for FLV, WMV, MPEG-2, or 3gp. That’s a problem. Compressor 3 is very good, but it’s not the perfect solution for a lot of common compression tasks.

At the end of the day image quality it the most important feature a codec brings to the table, but it’s just one of several factors to consider when choosing a professional post workflow. For a good amount of the work I do, ProRes meets my needs. For a good amount more, DNxHD is the ideal codec.

Wouldn’t it just plain rock if AJA or Blackmagic would license DNxHD for Final Cut Pro capture hardware? Then I could choose an editing system based on the merits of the editor, instead of the codec’s required workflows.

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