HD to SD at DVinfo.net

Jeremy Spruston · October 27th, 2006, 01:37 PM

Hey guys,

I'm currently finishing up the first episode of a television series shot with the F350. Everything was shot and edited at 35Mbp/s interlaced. I am cutting in Final Cut Pro.

The station we are delivering to still broadcasts in standard definition and I was wondering what the best method to down-convert from HD to SD is?

I have tried the nesting method (dropping my HD timeline into an SD timeline and rendering) which does the trick but seems to have some weird interlace issues when played back on an SD monitor. I applied the de-interlace filter, which helped a little bit but didn't eliminate the problem completely.

Is there a better method of down-converting?

Nate Weaver · October 27th, 2006, 10:22 PM

If you're cutting HDV, and can downconvert after you have picture lock, use Compressor. The timeline method works also, but doesn't give you a ton of options.

Add sharpening at 3.0 or 4.0

The only problem with this method that I can find is that you can get interlace twitter because the downconverted detail is so fine. You can add a directional gaussian blur in the vertical to help with this, but it only needs maybe a .5 pixel blur.

Daniel Weber · October 28th, 2006, 09:20 PM

Will a Decklink or AJA card give you a downconvert path like from uncompressed HD? I am able to do it with HDV footage and it looks great. I have not heard if either card will work with the Sony 35mbs codec. It would be great it they did.

Dan Weber

Jeremy Spruston · October 30th, 2006, 11:49 AM

Quote:

Originally Posted by Daniel Weber

Will a Decklink or AJA card give you a downconvert path like from uncompressed HD? I am able to do it with HDV footage and it looks great. I have not heard if either card will work with the Sony 35mbs codec. It would be great it they did.

Dan Weber

What would the be the methodology for this? I have an Kona II card and board, so I could give it a shot. I'm looking to attain the best quality possible.

Nate Weaver · October 30th, 2006, 11:56 AM

Using a Decklink or Kona card for downconversions, in my opinion, is cool for quick client approval DVDs and the like, but the RT downconversion at least on my Decklink card leaves a lot to be desired. I can see scaling artifacts pretty easily, and again, it doesn't do any sharpening.

Kona is usually ahead of Decklink when it comes to issues like this, but I've only worked on SD Kona rigs. I still wouldn't expect Kona to be doing anything stellar in real time for the prices they charge.

So RT downconversion, at least for me, is cool for approvals. But not for final outputs.

Greg Boston · October 30th, 2006, 12:07 PM

Quote:

Originally Posted by Daniel Weber

Will a Decklink or AJA card give you a downconvert path like from uncompressed HD? I am able to do it with HDV footage and it looks great. I have not heard if either card will work with the Sony 35mbs codec. It would be great it they did.

Dan Weber

Dan, if you're capturing uncompressed HDSDI via Decklink or AJA, you're aren't using the 35mb codec for capture. You are using uncompressed codecs that would be supplied via the card manufacturer or your NLE app.

The 35mb VBR codec is for bringing the material in via file access mode because that's what format they are in.

Also, if you are needing to downconvert to SD, the camera can do this for you very nicely either 16:9 or cropped to 4:3. In this method, you capture to your NLE like you would any DVCAM capable camera.

If you capture uncompressed via a AJA or Decklink, then you can set up an SD timeine and your NLE would downsize for you. Or you might want to run a stand alone product or plug-in whose results might be better than what the NLE would give you.

-gb-

Jeremy Spruston · October 30th, 2006, 12:27 PM

Greg,

I've captured everything via FAM at 35 mbp/s so I'll have an HD master ready to go for future use. Is the current method of nesting my HD timeline into and SD timeline in Final Cut the best method of downconverting? As I mentioned in the beginning of this post, I get some noticeable interlacing when the footage is played back on an SD monitor.

I'm just trying to figure out the best possible method of getting my HD into SD at the highest quality. Want to make sure that f350 mage still looks fantastic!

Greg Boston · October 30th, 2006, 12:37 PM

Quote:

Originally Posted by Jeremy Spruston

Greg,

I've captured everything via FAM at 35 mbp/s so I'll have an HD master ready to go for future use. Is the current method of nesting my HD timeline into and SD timeline in Final Cut the best method of downconverting? As I mentioned in the beginning of this post, I get some noticeable interlacing when the footage is played back on an SD monitor.

I'm just trying to figure out the best possible method of getting my HD into SD at the highest quality. Want to make sure that f350 mage still looks fantastic!

I think if you are going to go this route, Nate's advice might work best.

Another option you might wish to consider for quality assessment is to EXPORT -> XDCAM and then use your deck/camera's downconvert to re-ingest the footage as SD. I know this is a longer round trip, but as I said, it's to assess who does a better quality downconvert...the software, or the hardware.

-gb-

Jeremy Spruston · October 30th, 2006, 01:03 PM

Quote:

Originally Posted by Greg Boston

I think if you are going to go this route, Nate's advice might work best.

Another option you might wish to consider for quality assessment is to EXPORT -> XDCAM and then use your deck/camera's downconvert to re-ingest the footage as SD. I know this is a longer round trip, but as I said, it's to assess who does a better quality downconvert...the software, or the hardware.

-gb-

Thanks for the help!

I tried downconverting back through the camera, as I thought this would be the best method (using hardware and all), but as I have a 16:9 image, it seems to cut off the sides (similiar to pan & scan) instead of placing it withing a 16:9 frame as Final Cut does. Is there any method to get the camera to retain the image properly?

Alister Chapman · October 30th, 2006, 01:21 PM

There is an HD-SD downconvert menu setting on the camera that allows you to select whether the downconverted output is 16:9 or cropped to 4:3.

If you have a decklink card and are working in a 1080i project the decklink card will give you realtime downconversion of the 35Mb XDCAM files.

As Nate has said using compressor to create the final clip is the best quality option.

October 27th, 2006, 01:37 PM	#1
Jeremy Spruston Regular Crew Join Date: May 2006 Location: Victoria Canada Posts: 34	HD to SD Hey guys, I'm currently finishing up the first episode of a television series shot with the F350. Everything was shot and edited at 35Mbp/s interlaced. I am cutting in Final Cut Pro. The station we are delivering to still broadcasts in standard definition and I was wondering what the best method to down-convert from HD to SD is? I have tried the nesting method (dropping my HD timeline into an SD timeline and rendering) which does the trick but seems to have some weird interlace issues when played back on an SD monitor. I applied the de-interlace filter, which helped a little bit but didn't eliminate the problem completely. Is there a better method of down-converting?

October 27th, 2006, 10:22 PM	#2
Nate Weaver Wrangler Join Date: Oct 2002 Location: Los Angeles, CA Posts: 2,100	If you're cutting HDV, and can downconvert after you have picture lock, use Compressor. The timeline method works also, but doesn't give you a ton of options. Add sharpening at 3.0 or 4.0 The only problem with this method that I can find is that you can get interlace twitter because the downconverted detail is so fine. You can add a directional gaussian blur in the vertical to help with this, but it only needs maybe a .5 pixel blur. __________________ My Work: nateweaver.net

October 30th, 2006, 11:56 AM	#5
Nate Weaver Wrangler Join Date: Oct 2002 Location: Los Angeles, CA Posts: 2,100	Using a Decklink or Kona card for downconversions, in my opinion, is cool for quick client approval DVDs and the like, but the RT downconversion at least on my Decklink card leaves a lot to be desired. I can see scaling artifacts pretty easily, and again, it doesn't do any sharpening. Kona is usually ahead of Decklink when it comes to issues like this, but I've only worked on SD Kona rigs. I still wouldn't expect Kona to be doing anything stellar in real time for the prices they charge. So RT downconversion, at least for me, is cool for approvals. But not for final outputs. __________________ My Work: nateweaver.net

October 30th, 2006, 01:21 PM	#10
Alister Chapman Inner Circle Join Date: Dec 2005 Location: Bracknell, Berkshire, UK Posts: 4,957	There is an HD-SD downconvert menu setting on the camera that allows you to select whether the downconverted output is 16:9 or cropped to 4:3. If you have a decklink card and are working in a 1080i project the decklink card will give you realtime downconversion of the 35Mb XDCAM files. As Nate has said using compressor to create the final clip is the best quality option. __________________ Alister Chapman, Film-Maker/Stormchaser http://www.xdcam-user.com/alisters-blog/ My XDCAM site and blog. http://www.hurricane-rig.com

October 28th, 2006, 09:20 PM	#3
Daniel Weber Major Player Join Date: Mar 2005 Location: Maryland, USA Posts: 696	Will a Decklink or AJA card give you a downconvert path like from uncompressed HD? I am able to do it with HDV footage and it looks great. I have not heard if either card will work with the Sony 35mbs codec. It would be great it they did. Dan Weber

October 30th, 2006, 12:27 PM	#7
Jeremy Spruston Regular Crew Join Date: May 2006 Location: Victoria Canada Posts: 34	Greg, I've captured everything via FAM at 35 mbp/s so I'll have an HD master ready to go for future use. Is the current method of nesting my HD timeline into and SD timeline in Final Cut the best method of downconverting? As I mentioned in the beginning of this post, I get some noticeable interlacing when the footage is played back on an SD monitor. I'm just trying to figure out the best possible method of getting my HD into SD at the highest quality. Want to make sure that f350 mage still looks fantastic!