[opendtv] Re: Production Codecs

  • From: Craig Birkmaier <craig@xxxxxxxxx>
  • To: opendtv@xxxxxxxxxxxxx
  • Date: Mon, 14 Jul 2008 09:26:41 -0400

At 4:51 PM -0700 7/11/08, dan.grimes@xxxxxxxx wrote:
Anyone interested in talking about production codecs?

I would like to consider using a "house" video production codec for our new facility. The way I see it, the following are possibilities:

AVC-Intra
DVCProHD
XDCam-HD
XDCam-EX
DNxHD
JPEG-2000 (?)

Any others to consider?

Some information on our application:
-We want to be as file based as possible with solid-state media from the field and direct outputs whenever possible (see below). -We would like to produce in 720P and 1080i, depending on the client, 1080i for airing on PBS and 720P for all formats requiring deep encoding. -Our outputs include DVD (mostly standard DVDs but blu-ray in the future, I suppose), internet streaming, submission to an SD network (OSTN) in MPEG-2, an SD cable channel on Cox (live and automated output, with the hopes of maybe an HD channel in the future), and internet VOD.
-We edit using Avid Media Composer and do not plan to change.

I would prefer to work in 1920x1080 rather than a "thin" raster (Avid used that term for formats other than 1920x1080, if I understood them correctly). I don't think we can afford 1080@60P so will likely produce in 30P or 60i. We can work in 720@60P if need be. But I hear that it has unique qualities and not intermixable with other media.

So what are the brain-trust's thoughts and experiences?

I would say that your best choices are DNxHD and AVC-Intra. There are several other codecs in QuickTime that may be useful for specific tasks, but I would recommend using a lightly compressed, frame based codec as your house format.

JPEG-2000 is also very interesting, as the sub band nature "could" allow for partial decoding for proxy and low bandwidth networked viewing of files without needing to deal with the full HD quality and bit rate requirements. Unfortunately I am not aware of any commercial products that let you do this currently.

As for formats, 720@60P is my preference if you cannot use 1080@60P. You can convert 720@60P to 1080@30i with very little loss of quality. By this I mean lower horizontal detail; you will lose some vertical detail when interlacing to 1080i.

I do not know of any limitation of 720@60P as a mastering format, sans one. 1080i can carry more horizontal detail, but it offers less vertical detail and you must deal with interlace issue when re-encoding to other formats.

From your description, it looks like the only output that would require 1080i is for PBS. Given this you would be better off using 720@60P as your mastering format for everything else, and the quality difference for 1080i will be minimal...after mission encoding, which will take away most of the extra horizontal detail anyway.

Regards
Craig





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