HD to SD downconversion

barfnuts9000 wrote on 11/29/2012, 1:45 AM

I know that the topic of having multiple types of target media for the same project (HD BluRay and SD DVD) is a bit of a touchy subject for some people -- in terms of how you can reliably get optimal video quality results for both BluRay and SD-DVD media when shooting in interlaced formats..

When I shot a wedding for a friend a few months ago, I was oblivious to the fact that there was such a painstaking process for shooting for multiple formats. I assumed (wrongly) that if you shot in HD, then downgrading to an inferior format would be a piece of cake. Seems that I thought wrong.

Editing and rendering the master format of the native video (XDCAM 1920x1080i @ 29.97) was not a problem. Unfortunately, it seems that the majority of the target "customers" that I will be sending this video to have still not jumped into the 21st century and purchased BluRay players, so when it came to the time to render the DVD copy of the project, I was a bit stumped as to why the video quality had taken such a horrific downturn since the master format was far superior.

Aside from the issues of choosing the proper field order for the SD render (original footage is upper field, DVD default is lower field), I found that motion artifacts and poor video quality came along with it. Trying both upper and lower field orders produced the obvious disgusting botched interlacing issues, so I just rendered the project to progressive MPEG-2.

After researching on the internet for possible suggestions or solutions, it seems that a successful tried-and-true process has yet to be found.

After looking through several options that didn't involve installing several different 3rd party programs, the only process that seemed to work well for me involved rendering each frame into a seperate TIFF file in the native format (essentially removing the interlacing, it seems), then re-rendering it to MPEG-2 Widescreen/Architect. The results were amazing compared to the stock Vegas downsampling. The problem is, I don't have a trillion GB to render my entire project to TIFF, then to SD-DVD.

So, my question is, is there any sort of plugin, or 3rd party program that can take the master render of my HD file, and put it through a "temporary TIFF intermediate" process, where it will render the full HD interlaced frame to a temp file, then automatically render it to an MPEG-2 file in the same process? Forgive me if that request/suggestion sounds preposterous as this is my first foray into this type of situation. It just seems that it would be the easiest way to go for someone in my situation who has limited HD space and wants optimal results.

Any suggestions/pointers would be appreciated!

Thanks,
Travis

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VidMus wrote on 10/8/2013, 4:08 PM

"Finally, the whole business of using Cineform here is because VirtualDub reads only avi files and it, not Vegas, has the superior Lanczos3 resizing algorithm."

Ok, I downloaded VirtualDUD and I cannot figure out to save my life how to use it to convert an AVI file to mpeg!

I searched google and get nothing helpful.

One person gave a step by step instructions that assumed one had the needed whatever mpeg thing to do it and said if one did not have mpeg thing then one can download it. DUH!!! What does one download and how does one install it?

Anyway, I deleted virtualdud and gave up. GRRRRRRR!!!

Now a question, Does AVS-Video-Converter have what I need? It does not say anywhere what it uses to convert the video from avi to mpeg such as Lanczos3.

My mind is too stressed and tired to figure this out anymore!

Just a SIMPLE, EASY step by step of what I need, what I do and so on.

vtxrocketeer wrote on 10/8/2013, 4:56 PM

VidMus, deep breath. I've been there. ;)

Here is the logjam for you, I think: VirtualDub will open and render only avi files. Period. You can apply any number of filters to the avi within VD, including the resize filter that I mentioned, but VD does not convert an avi to any other file type, including any flavor of MPEG. So you MUST work with only avi files in "my" workflow for the HD-->SD down convert.

Once you render an avi out of VD, for instance a down-rezzed version of your HD avi, you then drop the rendered avi into Vegas. Then within Vegas, you render to a DVD Architect-compliant MPEG-2 to make your DVD.

Here is a very rough "word" picture of what I've been trying to explain:

Obtain HD source footage --> edit/CC/grade in Vegas --> render to HD avi master out of Vegas --> open HD avi within VD --> apply resize filter --> render SD avi from VD --> place SD avi onto new Vegas timeline --> render MPEG-2 out of Vegas.

Why don't you give it another whirl? VD is a dandy program with a small footprint.

I swear I'm going to type this into a mini-tutorial. I poached the main idea years ago from a forum post not remotely related to Vegas (Edius? Adobe? I don't recall), and a few minutes on Google last night did not reveal the post. Maybe it's gone forever, but I'm not going anywhere. ;)

VidMus wrote on 10/8/2013, 5:50 PM

Thanks much!

I will clone my system drive and try it again.

VidMus wrote on 10/8/2013, 6:20 PM

Sorry but VD leaves me BEGGING to know how to use it.

There are no resize filters. In fact no filters of any type.

I click on 'Video" then 'Filters' and there is nothing there.

What do I click on to render?

I have it running with my AVI file opened and I cannot do anything with it.

vtxrocketeer wrote on 10/8/2013, 6:34 PM

@VidMus: VD apparently doesn't come with a manual. I found it more or less intuitive to use. Still, I can appreciate that the interface isn't terribly user-friendly.

Within VD, go to Video along the menu bar, select Filters. A box entitled "Filters" then opens. It is empty. Apparently this is how far you got and then stopped. Am I right?

Now click on the "Add" button along the right side. A second box opens entitled "Add filter." There you will find a large menu of filters. Scroll down to find "resize." Highlight it and click on the OK button.

Then another box opens entitled "Filter: Resize." There you will find all sorts of settings for resizing. Select Absolute, enter 720 x 405 (in the example of my workflow), select Lanczos3 in the Filter Mode dropdown menu, and leave everything else at default values. Click OK, the box closes. Back to the "Filters" box, you'll see a summary of the filter that you just specified. Click OK.

Again on the Video sub-menu, select compression. The default is uncompressed. Here is where I choose my Cineform codec. You choose whatever you want.

To render: File | Save as avi. Give it a name, click OK. Rendering begins.

Is this detailed enough? Kind of bare bones instructional here, I know, but in essence that's what you need to do inside Virtual Dub.

VidMus wrote on 10/8/2013, 6:46 PM

Since my last reply I used Google to figure most of this out. I did miss a step in there.

Thanks much for the help. I should now be able to get this done.

I am using the 'raw' video type.

I try to keep my system lean by installing the absolute minimum of stuff.

Mindmatter wrote on 10/10/2013, 8:53 AM

I' really don't like to abuse of your help , but I got 2 more questions for you Rocketeer., if you don't mind...

why is there a need for compression on the .avi from VD? If I use it, which one should I use , Lagarith?

you say you sharpen the final mpeg2 render from Vegas to DVDA. How much exactly do you set the sharpen plugin? Or do you do it on sight, depending on the source material?
Thanks again!

vtxrocketeer wrote on 10/10/2013, 3:12 PM

@Mindmatter, I don't mind at all.

1. Compression: there is no need, but I suggested you use compression, such as is available via the Cineform or Lagarith codecs, for the same reason(s) you would elsewhere in a workflow: save HDD space (relative to uncompressed) and Vegas timeline preview ease (uncompressed requires your disk drive(s) to sling around a LOT of data quickly. Compressed formats less so.)

a. Cineform is lossy, but visually lossless. Also, file sizes are tidy.

b. Lagarith is lossless and it's file sizes are roughly 3x the size of corresponding Cineform files. It's free. I use Cineform exclusively. It just works. But either of these are fine.

The only time when I MIGHT use a truly lossless codec such as Lagarith is for dealing with multi-generational renders of animations or motion graphics. (For these, however, I use Photoshop sequences, so the concern is rather moot for me.)

2. Sharpen: reasonable minds will offer different recipes for this one, though most would agree it's a good idea to sharpen a little on the MPEG-2 compression render. Some use Sharpen, others Unsharp Mask. I use Convolution Kernel with excellent effects.

a. Add Convolution Kernel as an FX to your down-rezzed avi on the Vegas timeline. Select "sharpen" from the dropdown menu of presets.

b. You need to tweak this preset to the following values, most of which will be dialed in already:

Row 1 | Col 1 | -1.000
Row 1 | Col 2 | -2.000
Row 1 | Col 3 | -1.000

Row 2 | Col 1 | -2.000
Row 2 | Col 2 | 33.000
Row 2 | Col 3 | -2.000

Row 3 | Col 1 | -1.000
Row 3 | Col 2 | -2.000
Row 3 | Col 3 | -1.000

The key parameter is Row2 | Col2: reducing this value from 33 will gradually sharpen the image, then turn very strange close to zero. Play with it. I typically set this value from 28 - 33. The sharpening effect is very subtle, almost organic. To my eyes, the sharpened image does not scream "video."

I shoot with some to very little in-camera sharpening (again, reasonable minds would differ on this point), so I go easy on the sharpening here. I can't think of a DVD production for which I did NOT sharpen in post, regardless of source.

Finally, I find sharpening to make text and clean motion graphics look a bit harsh or artifact-laden. Hence, if I have text on my down-rezzed avi, I'll simply split it into multiple events to separate out titles, credits, motion graphics, and the like. Thus, only video footage gets the sharpening treatment.

Hope this helps!

larry-peter wrote on 10/10/2013, 4:43 PM

@vfxrocketeer, just wanted to thank you for the suggestion of using Convolution Kernel for sharpening. Completely overlooked it! I have despised Vegas' Unsharp Mask, and usually settled for Sharpen when I absolutely had to. Your technique isn't like a stick poking me in the eye. Very pleasing.

Mindmatter wrote on 10/10/2013, 5:13 PM

Again, thanks Rocketeer for your abundant willingness to help! I tried sharpen at a level of 300, in between medium and subtle, and will test burn a DVD so see the outcome on my TV. So far , following your workflow, i have definitely noticed an improvement , like the disappearing of strange horizontal artifacts compared to downsizing directly in Vegas.

It's still is a real shame tho to downgrade all that nice HD material to an SD DVD, but the decision has been made to release it on DVD, so I'll try to save what I can...

vtxrocketeer wrote on 10/10/2013, 8:13 PM

Glad this is working for you. (Seriously, how many of us have ever understood what Convolution Kernel does? It was a joy to discover that little gem that ships with Vegas.)

@Mindmatter: I didn't quite follow your mention of sharpening at 300. Did you mean 30?

Chucking loads of quality on the down-rezzing is a fact of life. However, if any of your clients/customers/friends/family have a Blu-ray player that does hardware-based uprezzing, the DVD's can actually look quite stunning. (I know, why would an owner of a Blu-ray player buy a DVD?) I have a high end Oppo Blu-ray player that does this kind of uprezzing. My DVD's look just spectacular, so much so that one time a neighbor asked me if it was a Blu-ray.

"My" workflow, so far as I have discerned over the years, is the best that I can do for wringing all the quality possible in post-production for delivering DVD's from HD source material.

Mindmatter wrote on 10/11/2013, 2:48 AM

Rocketeer, on the "sharpen" FX, there is just one slider with a preset value of 500, which I set back to around 300. But I just checked the convolution kernel with your settings, and it really looks less harsh. Thanks for another great hint!