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-   -   Down Conversion of HDV to SD Media Manager (http://www.dvinfo.net/forum/final-cut-suite/103112-down-conversion-hdv-sd-media-manager.html)

Dave Beaty September 8th, 2007 01:13 PM

Down Conversion of HDV to SD Media Manager

I am cutting a feature doc with 720p30 and SD archival footage. I am cutting in HDV but I need to deliver in NTSC letterbox.

I 've read that exporting to QT or compressor is the best method to do this as copying into an NTSC sequence results in very poor resolution and pixelation of HDV source due to FCPro's inadequate method of scaling.

Yet, Tim and others have mentioned using media manager in the past. Because I need to continue editing the SD archival material in the NTSC sequence, this may be the only option I have. Once the edit is locked, I plan to use media manager to recompress all the HDV content in my sequence to NTSC 10 bit.

Are there any problems that are known bugs when doing this? I have 60 minutes of content and I worry about audio sync and poor results when under a tight deadline.



Jim Fields September 8th, 2007 10:47 PM

I wrote an article for Ken Stone just for this very reason.

Here you go.


Dave Beaty September 9th, 2007 07:53 AM

Jim, thanks for that link, it's a great tutorial. Very helpful.

But I still need a way to get my HDV footage into an SD sequence in an editable format. Right now I'm using SD and HD footage in an HDV sequence and I have to replace proxy SD material later. So, If I export the entire sequence to QT conversion or Compressor and reimport, it will not allow further editing of those shots.

My work flow and plan:

Edit in HD Sequence with 720p30 material
Add low rez NTSC Shots and uprez them in the sequence
When edit is locked create a SD sequence with all material
Downconvert HD material to SD
replace the NTSC shots in full rez.

The reason I want to do this is because I don't want to scale up all the NTSC footage into an HD sequence to match the 16:9 HDV material and then turn around and down convert the same material back to NTSC. I'd rather wait until I'm almost complete in the edit and then convert all the HDV material to SD, replace the new NTSC shots at full rez and master in NTSC.

I've never used Media Manager to do a recompress of all footage in a sequence. I assume it should work as Tim Dashwood explained a while back.

The other thing I could do is batch convert every shot externally of FCPro and then relink. I have not tested this, as the media attributes certainly would change, so I don't know if it would work.

If apple programmers could find a way to allow better down conversion in the sequence we wouldn't have to worry about all this. (sigh)

Dave B

Dave Beaty September 10th, 2007 09:57 AM

Good news, I did tests this morning using Media Manager to Recompress the HDV material into a new SD timeline. The results are startling.

First I copied and pasted the HDV edited clips into an Uncompressed NTSC sequence and rendered. Looks terrrible. Lot's of aliasing on all edges. Shimmers and looks soft.

Next, I used media manager to copy and recompress all clips into a new uncompressed NTSC sequence. Looks good with no aliasing. Switching between the recompressed project and the original down converted sequence with HDV clips showed noticeable differences. The recompressed SD sequence looked much better.

But then I had a thought, perhaps the problem FCPro has dealing with 720p HDV has to do with the interlace vs progressive timelines. I changed the original problem sequence to none for interlacing in the settings and the problem dissapears.
That fixed the shots with aliasing and it was now a carbon copy of the recompressed sequence when I switched back and forth.

But the issue isn't solved. Now the problem is with source NTSC material that IS interlaced. You can't put this material into the non-interlaced timeline without it looking terrible. So, for now, recompressing is the only answer for mixed format down conversions.

Dave B

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