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-   -   HDV export to tape lossless? (https://www.dvinfo.net/forum/adobe-creative-suite/90089-hdv-export-tape-lossless.html)

Michael Barrette March 27th, 2007 06:36 PM

HDV export to tape lossless?
 
If importing HDV then exporting back to tape, is the footage as high quality as the original footage after it's gone through both the import and the export transcoding to make it HDV? Or is the only way to keep it lossless quality to import and export using HDMI?

Thanks!
Michael

Steven Gotz March 27th, 2007 07:21 PM

There will be loss, but less loss if you use Cineform Aspect HD. In any case, there is loss when encoding it back to HDV.

Don Blish March 27th, 2007 09:23 PM

Loss at scene boundaries
 
As you can see from this post, the export back to tape is tripped up by scene boundaries.

http://www.dvinfo.net/conf/showthread.php?t=89585

The original footage always starts with a full "I frame", thats one reason why our HDV cameras take a few heartbeats to start recording. On reexport, scene boundaries will often badly miss "I frame boundaries". At least thats my interpretation. In Blu-Ray authoring, using VBR lets software ramp up speed for such.

Pete Bauer March 27th, 2007 09:24 PM

Steve is definitely correct if you've edited and then rendered out for export to tape.

I was under the impression that if you just captured and then exported back to tape without doing anything more than cuts -- (no color correction, etc that would require a render), you shouldn't lose image quality. There's probably a caveat for HDV, though, in that if you've cut in the middle of a GOP, it presumably would force a render of at least some adjacent frames to create new GOP's, but this is about as far as I can go with it. Steve and others can probably write more authoritatively on that.

EDIT: That was fast...see Don's post just before mine!


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