HD>SD downconversion Win/Premiere only

[Vincent Oliver]

After many days experimentation (excluding Christmas day, i'm not that sad), the best permutation I have achieved so far is to create a new SD project then bring in the HD footage, right click on it and select "Scale to Frame size".

I have experimented with 1920 x 1080 and 1440 x 1080, both are producing much better results than working in a HD timeline and rendering out to a SD DVD.

I am still not convinced I have acheived the best image quality, but I am one step nearer.

[Dominik Seibold]

1. edit on a HD-timeline
2. render out at HD
3. scale down with VirtualDubs lanczos-scaler.

[Perrone Ford]

Originally Posted by Dominik Seibold

1. edit on a HD-timeline
2. render out at HD
3. scale down with VirtualDubs lanczos-scaler.

We should write a book. It would be one page long!

[Vincent Oliver]

I will give VirtualDub a go and let you know. Who knows we may even get a book with two pages.

[Vincent Oliver]

Have just run some footage through VirtualDub using Lancos3 scaler. Not sure if our expectations are the same but to my eyes the end results are nowhere near acceptable, nor is the time consuming process that we would have to endure.

My original setting is still producing the best results, but it still needs to be better.

[Perrone Ford]

Vincent, would you mind explaining what type of file you input and what your settings were? i am especially interested in what you chose for output.

Have you seen my results with virtualdub? I've posted several examples here.

[Vincent Oliver]

From within Premierre CS3 I saved an EX3 1440 x 1080 NTSC file as an AVi file and imported the same into VirtualDub. I selected Filter and selected Resize. The file was resized to 16:9 format which produced an 720 x 405 file I also selected Lanczos3 and then saved the file as an AVI again. This was opened in a new Premierre NTSC SD project and the result was nowhere near acceptable.

I accept that I may have missed a vital step somewhere along the line, at least I hope I have, otherwise I may be trying to see the Emporers new clothing.

[Bo Skelmose]

Edit fx 720 25P in a CS3,2 EX 720 25P timeline - export to avi - size 720x576. Export to DVD via Vista ultimate DVD burner software makes great DVD's.
If you record progressive - remember to export avi file as progressive file. I have not tried 1080 50i but only 720 25P.
My recomendation would be always to import media to premiere into a project that mach the file codec and pixel size. Then export to a file in the propper size for further editing in fx. a DV SD timeline. Scale to framesize, do not make sharp video. I convert all my EX HD material that way before editing mixed HD/SD material for SD Broadcasting.

[Dominik Seibold]

Originally Posted by Vincent Oliver

The file was resized to 16:9 format which produced an 720 x 405 file I also selected Lanczos3 and then saved the file as an AVI again. This was opened in a new Premierre NTSC SD project and the result was nowhere near acceptable.

That's wrong. Resize not to 720x405, but to 720x576, because you want to make a standard-conform widescreen-PAL-DVD, which doesn't use square pixels. Encode the result directly with MediaEncoder to mpeg2 instead of using Premiere as an unnecessary fault-prone intermediate step.

Btw, are you using an intermediate codec like Cineform or DNxHD (can be freely downloaded)? I recommend to use that for the HD-export instead of uncompressed, to save harddisk-space and time because of too slow harddisks.

[Vincent Oliver]

Dominik,

Thank you for your suggestions.

I am actually working with NTSC files which should be 720 x 480, but for some reason these are 720 x 540.

"Encode the result directly with MediaEncoder to mpeg2 instead of using Premiere"

I couldn't find this option in VirtualDub. However, MediaEncoder is included within Premierre

[Dominik Seibold]

Originally Posted by Vincent Oliver

"Encode the result directly with MediaEncoder to mpeg2 instead of using Premiere"

I meant not to drop VirtualDubs result on Premiere (like you did it before), but on MediaEncoder for mpeg2-encoding.
But I just realized that MediaEncoder lacks an option to disable resizing (it thinks it should treat 720x480 as a square-pixel-format and resize it). Perhaps you shouldn't use MediaEncoder but a different mpeg2-encoder like TMPGEnc or CinemaCraftEncoder.

Btw, did you examine VirtualDubs resizing-result? Didn't you see, how great the quality is?

[Vincent Oliver]

Just ran a couple of test files and it is a bit better than my earlier effort. However, there is a consideranle amount of twitter on the footage, blurring by a small amount does remove this, but then the footage is identical to just dropping in the MPEG file into a SD project. I am back at the start line now.

[Dominik Seibold]

Can you post a still of your result?

[Perrone Ford]

Vincent, you haven't told us anything. Let's examine a few troubling things.

1. You say you saved a 1440x1080 file from your EX3. Are you shooting HDV? If so, that's problem #1. Not to say the EX3 can't make nice HDV files, but why START with a lower quality source.

2. You then say you save it as AVI. What KIND of AVI. There are dozens. Some will retain every single pixel with no change, some will throw away 90% of the data you started with. This is CRITICAL. AVI is just a container for a codec. Please specify which one you used. And if you do this again, choose uncompressed.

3. So tou exported a non 16:9 file, brought it into Virtualdub, and stretched it 30%. I'm sure it looked awful. Then you downsized it to 720x405 which isn't in itself bad, but we can talk about that later. You say you saved it as an AVI file, but of course you don't say what kind again. Choose uncompressed if you can next time.

4. You opened a square pixel file (720x405) in premier NTSC timeline which was expecting non-square. So I'm sure it looked even worse.

Your trial here indicates the danger of video producers not understanding two basic concepts of working with video on computers

A. The lack of understanding of what codecs do and how they work.
B. The lack of understanding square and non-square pixels.

It's not your fault per se, because this stuff is not intuitive. But as you can see, they have a MASSIVE effect on quality when not understood. SDTV (PAL, NTSC) use and broadcast non-square pixels. Computers and HD have square pixels. HDV uses non-square pixels in the HD world which is why this is all so confusing. Somewhere along the path, you've got to standardize this stuff. For those working with HDV I recommend this:

First get your non-square 1440x1080 to a square shape. It's shape should be 1920x1080. Once you're there, you can then begin to use a normal HD workflow. You have a square pixel 16:9 image. Export that image uncompressed to Virtualdub. Open resize, select 720x480 if going to NTSC or 720x576 if going to PAL. Choose the Lanczos option. Open Video>compression and choose uncompressed. Open Video > Frame Rate > Frame Rate conversion and type in the selected frame rate. If it's already correct, don't do anything here. Make sure Audio is on Direct Stream Copy. Then save your new AVI file. This will create a PERFECT 720x480 or 720x576 to drop into your NLE on an NTSC or PAL timeline.

It really is easy once you know what you're looking for.

Hopefully this improves your results.

Originally Posted by Vincent Oliver

From within Premierre CS3 I saved an EX3 1440 x 1080 NTSC file as an AVi file and imported the same into VirtualDub. I selected Filter and selected Resize. The file was resized to 16:9 format which produced an 720 x 405 file I also selected Lanczos3 and then saved the file as an AVI again. This was opened in a new Premierre NTSC SD project and the result was nowhere near acceptable.

I accept that I may have missed a vital step somewhere along the line, at least I hope I have, otherwise I may be trying to see the Emporers new clothing.

[Vincent Oliver]

Reply to Dominick,

I have created two tiff files and one is with Virtual Dub, which I have to admit the edges are a lot cleaner on a still, but this is not evident when it is viewed as a movie on DVD. Not sure why at the moment.

ex3

Reply tp Perrone.

1. I am using the 1440x1080 because my Matrox RTX2 card will just downsample 1920x1080 to 1440, It can't work with the higher resolution - I will replace the card at a later date.

2. I save it as a Matrox AVI, this uses their own NTSC Matrox DV/DVCAM compressor, (or PAL Matrox DV/DVCAM).

Having read through your suggestions, I am going to give this another go.

I know I must be in a similar position to many other users, we are looking in this and other forums for pointers to help us understand what all the Codecs mean. There are so many other new names and techniques to learn, we all have to start somewhere.

I know I speak on behalf of many other readers of this forum and would like to thank both yourself and Dominick for your help and patience.