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Carbon Coder h.264 issue

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Brian Wheeler
Carbon Coder h.264 issue
on Jun 25, 2010 at 5:42:02 pm

Okay, I'm really not sure where to put this since the COW doesn't have a MCO section (well, not that I've found at any rate).

My station is in the midst of going tapeless (huzzah), but we're encountering some strange issues with transferring spots into our media exchange. Our setup, as I am aware, is as such:

We are transferring spots manually from an FTP into a carbon coder system which then trans-codes said spots into our Omneon servers preferred MPEG2 format (we'd do this ourselves, but it takes MPEG2 with a Quicktime reference wrapper who's metadata I can't quite figure out).

We store all of our spots in Quicktime h264 compression. The Carbon Coder seems to like this format as it transfers in well, but the problem arises in that when it trans-codes it seems to double the time it shows in our media prep station. So, for example, a 30 second spot will show up as being 60 seconds long; with the spot good but followed by a mirror amount of time in black.

My concern is that the system may be encoding this black as actual video and thus chewing up space on our servers. If this is just a program aberration and it's not truly encoding extra black than we're good and can just work around it.

I've tried talking with the tech support people at Avid and the consensus from them was "Uhhhhh... what now?" so I'm hoping my fellow COW readers may have some advice on how to diagnose this issue or resolve it. I can get more specific with the setup, but since just edit the stuff right now this is all I know.

Thank you in advance for your help!

Brian Wheeler
Senior Editor
KXRM / KXTU


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Dave LaRonde
Re: Carbon Coder h.264 issue
on Jun 28, 2010 at 4:25:35 pm

Personally, I'm leery of H.264; it's extremely processor-intensive, and definitely a delivery rather than an archival codec. It can also tend to give some transcoding applications fits.

As a test, I'd recommend making a test spot using something that does NOT use long-gop compression like H.264 does. Photo JPEG at 100% is good, PNG (the codec -- you'll find it in QT) is VERY good, and then there that good ol' standby, Animation.

Run the test and see what happens. If you still get black, you've then eliminated the possibility that it's the codec at fault and you can focus your attention on other causes.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


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Brian Wheeler
Re: Carbon Coder h.264 issue
on Jun 28, 2010 at 4:38:55 pm

We've tried DV NTSC and it works fine (the system won't even recognize the new ProRes codec, which sucks but whatchagonnado?). The problem would seem to be in how it handles the transcoding of H.264 files. This doesn't make a lot of sense for me because the Omneon server we're using says it prefers long GOP compression schemes.

We used to archive everything in ProRes HQ, but when space became an issue we had to switch to H264 for archive. Its small file size and great quality make it ideal for keeping a record of spots.

And thanks for the response!

Brian Wheeler
Senior Editor
KXRM / KXTU


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Dave LaRonde
Re: Carbon Coder h.264 issue
on Jun 28, 2010 at 6:22:22 pm

[Brian Wheeler] "...the system won't even recognize the new ProRes codec, which sucks but whatchagonnado?"

The newest ProRes codecs are available only to machines with FCP 7 installed.

And unless you're working with RED footage or something, ProRes HQ is pretty much overkill.
Regular ol' ProRes 422 is just fine 80 times out of 100.

Now, Apple also has a QT ProRes READER for non-FCP machines, in both Mac and Win versions. You can't use it to encode to ProRes, but you can eliminate the White Screen of Death when opening ProRes files on the wrong machine and encode to different codecs:
http://support.apple.com/downloads/Apple_ProRes_QuickTime_Decoder_1_0_for_W...
http://support.apple.com/downloads/Apple_ProRes_QuickTime_Decoder_1_0_for_M...


Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


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