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-   -   High Action/Motion Video from HVR-V1U (https://www.dvinfo.net/forum/sony-hvr-v1-hdr-fx7/92806-high-action-motion-video-hvr-v1u.html)

Piotr Wozniacki June 12th, 2007 12:37 PM

Quote:

Originally Posted by John Cash (Post 695767)
next week I will be installing the Blackmagic HDMI capture card. No more MPEG 2 capture for me, so I hope that will do away with this problem

I guess you realize that only live HDMI capture will let you avoid HDV compression?

John Cash June 12th, 2007 12:44 PM

So, if I record to tape and watch it on HDTV via HDMI cable its still compressed at Mpeg2? And the only way to capture via HDMI without compression would be to use a hard drive instead of tape?

Piotr Wozniacki June 12th, 2007 12:48 PM

As I said, and Brandon confirmed - this is really weird. I do a lot of scrubbing of my HDV material in Vegas and have seen many things you can't notice when watching the normal speed video, but never came across such evident macroblocking.

Piotr Wozniacki June 12th, 2007 02:06 PM

Quote:

Originally Posted by John Cash (Post 695793)
So, if I record to tape and watch it on HDTV via HDMI cable its still compressed at Mpeg2? And the only way to capture via HDMI without compression would be to use a hard drive instead of tape?

John, HDMI is uncompressed. But, if you first compress in order to write to tape (or disk drive such as HVR-DR60 or Firestore), you're certainly not going to get rid of the compression artefacts, should any occure during the original compression process. HDV, or more generally MPEG-2, is not a lossless codec and what is lost, cannot be recovered.

Therefore, to avoid compression artefacts, one needs to capture uncompressed (HDMI with Blackmagic is one option) before, or without ever writing to tape/hdd recording unit.

Brandon Freeman June 12th, 2007 02:50 PM

Quote:

Originally Posted by Piotr Wozniacki (Post 695796)
As I said, and Brandon confirmed - this is really weird. I do a lot of scrubbing of my HDV material in Vegas and have seen many things you can't notice when watching the normal speed video, but never came across such evident macroblocking.

Correction -- I have seen macro blocking when shooting standard interlaced 60i or 50i, BUT when I shoot in CineFrame30 or CineFrame25*, the motion artifacts are gone. I had always figured that the interlacing added an extra burden for MPEG encoders, and thus don't do anything other than interviews in standard 60i.

*I understand that CF30 and CF25 are not true progressive, but it sure looks purty. :)

Bob Grant June 12th, 2007 05:14 PM

I attended the opening night of the Sydney Film Festival last Friday night. The movie was shown in the wrong aspect ratio.
At the party afterwards there was lots of discussion about the movie. Outside of a couple of people in our group no one mentioned the major projection stuff up. Those of us who did are all the kind of people who look at vision frame by frame.
Perhaps there's a lesson in this.


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