Sony EX1 - EX1r - EX3 720/60p is better for interlaced downconverting to SD

adamr316

adamr316

Well-known member
Hey guys,

I think I've posted this on another forum but not in its own thread. Through browsing various forums and with my own tests here are my conclusions on what to shoot for best downconversion to standard definition on a DVD. So when anyone googles this they'll find this info.


For 60i standard definition - Shoot 720/60p

For 24p standard definition - Shoot 1080/24p and edit natively at 23.98p (no 2:3 pulldown or any of that stuff)

For 30p footage - Shoot natively if shooting exclusively for the web or shoot 1080/60i and use VirtualDub's YADIF deinterlace method.


In whatever software you have make sure 16:9 flags and 23.98p>29.97 flags are set properly. This is vitally important to storing 24p footage on a DVD. When done properly 24p footage (which is 480p lines of resolution in NTSC countries) looks damn good and almost indistinguishable from HD on smaller TVs with a Blu Ray, HD DVD or similar upconverting player. With larger HDTVs close-up and medium shots look almost-HD...you can really only tell with wide establishing shots and the like.

The reason it's better to shoot 720/60p if going to interlaced standard def is two-fold. First, you are starting at a closer resolution to standard def. Second, you are shooting in a progressive format. Both of these technical specs make for easier math, which software downconversion must do. The math on interlaced to interlaced is not so good and may never be.

The only exception to this rule is if you own a hardware downconverter. It may be better shooting 1080/60i but you should and probably already have done your own tests.

480i footage from 720p looks darn good. Not as good as 24p footage but as good as high end SD cameras. At least that's my opinion on it.

On a side note make sure you're converting your colorspace from Rec. 709 (HD) to ITU-R BT. Rec. 601 (SD). Your software may or not do it without you knowing so you may need to consult the user manual or contact your software maker.

I personally use VirtualDub and the Lanczos3 resize filter with "interlace" unchecked in the dialog box. If I do shoot 1080/60i or receive this material I resize (again in VirtualDub with the "interlaced" box checked) and resize to 480i. I experimented with using yadif like with my 30p web video method but there was way too much flicker.
 
Last edited:
Forgot mention one other thing. Unless you are on a time crunch and you own an EX1r it is better to shoot HD and downres to SD in-software rather than shoot the built in SD mode. From what I've read it doesn't look too good. That's hearsay though EX1r owners feel free to chime in and correct me.
 
adamr316 said:
I personally use VirtualDub and the Lancos3 resize filter with "interlace" unchecked in the dialog box. If I do shoot 1080/60i or receive this material I deinterlace with Yadif (again in VirtualDub) and resize to 480i. The idea is yadiff retains better resolution than interpolation (default method for deinterlacing) would and therefore results in a better looking downconvert.
Click to expand...

Hi, adamr316,

I am a little confused... In case of 1080/i60 - how exactly are you doing deinterlacing? I see the first option for deinterlacing in VirtualDub is 'interpolate using Yadif algorithm' on top left for Deinterlacing method (it is selected by default because it is on top), and many options on right for Field order. Which options to choose? Also, do you deinterlace and resize to 480i at the same time? I guess, "interlace" with Lancos3 resize filter is unchecked in this case too. Please, clarify...

Thanks.
 
Last edited:
OK my exact steps/settings in Virtual Dub for 1080/60i videos are as follows:

1. Open your video file.

2. Video>Filters (or control+F)

3. Click Add>resize.

4. Use the following settings:



New size: Absolute (pixels) 720 x 480 (for NTSC)

Aspect Ratio: Disabled (you may need to change this first before changing the above setting)

Filter mode: Lanczos3 (or if you're not n a rush choose Precise bilinear. Experiment with the various modes for your likeness towards sharpening).

MAKE SURE Interlaced is CHECKED. Very VERY important!

Framing options: Do not letterbox or crop.

Codec-friendly sizing: Do not adjust


5. Click Save as default so you don't have to mess with this stuff next time. Then click OK.

6. At the Filters dialog box click OK. Except if you want 4:3 center crop instead of 16:9 single-click the resize filter line and click the Cropping button and enter 180 into both X1 and X2 offset. Be careful not to enter 180 into Y1...X2 is the box at the upper-right corner of the Crop window. If you just enter 180 into X1 and press the Tab key it will take you to X2.

7. Back at the main screen click Video>Compression. Use a video compressor that is relatively uncompressed and can use AVI as a container format. I use Canopus Lossless (I'm using Canopus Edius/Procoder)

8. Back at the main screen again click File>Save as AVI. Type in a file name and save to the directory you want. Click OK and your video will start processing.


You will now have a 720x480i file.

9. Drop your new AVI file into your MPEG-2 conversion software. Let it do its thing then...

10. Profit.


Also if you are deinterlacing 1080/60i for the web change use the VirtualDub deinterlace filter and use yadif. Keep top field, interpolate/discard bottom field for the settings. This will effectively turn the footage into 1080/30p.
 
Last edited:
adamr316,

Thank you very much for your detailed description! Before I was using this recommendation from the Edius forum, which did not use deinterlacing. With VirtualDub, it was just direct re-sizing interlaced to interlaced:
http://www.videoproductions.com.au/html/virtualdub-hd-sd.html

For better results it was then recommended to use TMPGEnc Express 4.0:
http://www.videoproductions.com.au/html/t4-hd-sd.html

I got good results with VirtualDub (did not try Express 4.0) but, I think, your workflow will be even better. I will definitely try it.

Thanks again!
 
xpycm said:
adamr316,

Thank you very much for your detailed description! Before I was using this recommendation from the Edius forum, which did not use deinterlacing. With VirtualDub, it was just direct re-sizing interlaced to interlaced:
http://www.videoproductions.com.au/html/virtualdub-hd-sd.html

For better results it was then recommended to use TMPGEnc Express 4.0:
http://www.videoproductions.com.au/html/t4-hd-sd.html

I got good results with VirtualDub (did not try Express 4.0) but, I think, your workflow will be even better. I will definitely try it.

Thanks again!
Click to expand...


Definitely compare my method with any others you may have found. Mine is based off one that was posted over on the Grass Valley forums for downconverting ( http://ediusforum.grassvalley.com/forum/showthread.php?t=5141 ).

I just found some old downconverted footage I shot last year with the edius method. It was 4:3 cropped and compared to my YADIF method it appears to lose a lot of sharpness. I don't know I'm going to mess around with some more footage and see what I come up with before I draw any definitive conclusions. But so far YADIF seems to be the way to go for 1080/60i downconverts.
 
After some more testing there is definitely a need for a 709 to 601 colorspace filter within VirtualDub. Anyone know how to do it?
 
OK, I hate being wrong but when I am take no issue admitting it.

Yadif deinterlacing is not the way to go for 1080/60i --> 480/60i material.

Just use the resize filter in VirtualDub and check the "interlaced" box. Done. There was too much flicker on the footage and although yadif may be a bit more sharper in appearance going through the resize filter gives fine results.

HOWEVER, for 1080/60i --> 1080/30p conversions for web video yadif seems to be the way to go. I've updated the first post on the thread to reflect these new findings.
 
You must log in or register to reply here.
Back
Top