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-   -   I-Frame indicator?? (https://www.dvinfo.net/forum/convergent-design-odyssey/509278-i-frame-indicator.html)

Brian T. Young July 13th, 2012 04:38 PM

I-Frame indicator??
 
Greetings -
New NanoFlash owner here, so forgive if this is stupid.

I am looking to use the NF in a couple of ways: to replicate P2 AVC-Intra recording by putting the NF on a PDW-F800 and record in I-frame - and to replicate XDCAM 422 Long-GOP when using it on an HPX2700 Varicam and recording in Long-GOP. In basic words, to make an xdcam a p2 cam and vice versa.

My question is - in performing test recordings on the F-800 with the NF set to I-frame/100mb/1080/30p, and then playing back in both QuickTime Player 7 and FCP 7, I always see (under "format): Apple XDCAM HD422 50 Mb/s CBR when analyzing the clip.

is my mac/fcp/QT doing something to this upon playback??

thank you!
Brian

Jack Zhang July 13th, 2012 05:25 PM

Re: I-Frame indicator??
 
First off: MPEG-2 I-frame is less efficient than AVC-Intra so it requires more bitrate to be relatively equal. 220+Mbps I-frame MPEG-2 should be relatively equal to or superior to AVC-Intra at 100Mbps.

It is normal for QT to read 50Mbps as the codec. Your actual data rate shows in Movie Inspector as MB/s.

Brian T. Young July 13th, 2012 05:35 PM

Re: I-Frame indicator??
 
Jack,

Understood on I-frame/Intra efficiencies - thank you.

Strange for QT to incorrectly show the codec, isn't it?

Thanks again,
b

Billy Steinberg July 15th, 2012 09:20 PM

Re: I-Frame indicator??
 
The Apple XDCAM HD422 Quicktime codec can play any bitrate the nano can record, but the Quicktime codec can only encode to 50Mb. It's "title" includes the 50Mb part.


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