HD to SD Challenge

amendegw wrote on 11/24/2010, 1:24 PM

All,

There's been much discussion recently about how to downrez HD source for SD DVD production. I propose a challenge (I'd call it a contest, but there's no prizes).

I shot a short, 10 sec clip under (what I thought) were the worst conditions for downrezzing HD to SD: a stationary figure with a a moving, high contrast, fine detailed background. The clip is 1920x1080 60i AVCHD. The Challenge is to get the best balance of sharpness while eliminating the flicker in the background.

I tried to downrez this clip and got good sharpness, but horrible flicker/moire patterns by adding the Sharpen FX = zero. Adding a Vertical Gaussian Blur of .002 minimized the flicker/moire, but caused too much loss of resolution in the central figure. I uprezzed the results to 720p and sent them to YouTube:

So, here's the rules of the Challenge:

1) Download and start with the clip in this link: AVCHD.zip
2) Render the clip to an NTSC 720x480 Widescreen format for import to DVDA.
3) All work must be done within Vegas.
4) Render to an intermediate format is okay.
5) Masking and/or keyframing are not allowed.
6) The objective is to get the best resolution while eliminating the flicker.
7) If you are tempted to post, "Can't be done" or "start with a different format" or something similar, please don't post a reply.
8) Uprez the results of your efforts to the web and post the link in this thread (YouTube is nice because it can be embedded, but any web link is okay).
9) Tell us how you accomplished the results - Workflow, FX's applied, Project Settings, Render settings, etc.

Any takers?
...Jerry

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Comments

NickHope wrote on 12/15/2011, 6:05 AM

If you think that then my BS skills must be improving. I'm just a layman with an incurable perfectionist streak. Quiz me on the underlying science of deinterlacing and low-pass filtering and I'm going to flunk big time, trust me. I'm in awe of the doom9 types who have this stuff for breakfast.

I believe the floods have more or less receded. Luckily for me they never reached here in central Bangkok, but a lot of places were sacrificed in order to keep the central business areas dry.

dxdy wrote on 12/15/2011, 7:18 AM

Thanks for continuing the quest.

I gave this a try with my torture test clips (Brown herringbone wool vest, patterned dress, bridal hat and veil), and I don't see a difference between the Yadif and non-Yadif renders. I am still getting a lot of twitter.

I tried this in V11 64 bit. I also tried the script to apply the Media fx to all events and while it seemed to run, it did not actually add the fx.

With this test footage, the Lagarith - MC two step render is "twitterless".

Here is a sample of the output (I didn't have the crop or CK in place):

http://www.northvillenotices.com/UserPictures/YadifTestImage2.png

amendegw wrote on 12/15/2011, 7:43 AM

Hmmm... I can't tell much from your screen capture. Can you post a link to a few seconds of your footage and let me take a shot at it?

...Jerry

dxdy wrote on 12/15/2011, 5:08 PM

Thank you so much for offering to look at this. This is for the local historical society, with all volunteer actors, so I can only suggest that they wear uncomplicated clothes. This piece has twitter problems with the man's vest and the woman's bodice unless I go the Lagarith route. The ultimate deliverable is a widescreen DVD.

Here it is two different ways. Chromakeyed with background, on Vimeo (via MP4, which I made downloadable)...

http://vimeo.com/30742108

... and MXF without CK (only 10 seconds).

http://www.northvillenotices.com/UserPictures/10secondsample.mxf

Here is the Mediainfo on the original file:



General

ID                               : 1 (0x1)

Complete name                    : J:\CemWalk2011\GreenOct9Panny\00012.MTS

Format                           : BDAV

Format/Info                      : Blu-ray Video

File size                        : 132 MiB

Duration                         : 1mn 11s

Overall bit rate mode            : Variable

Overall bit rate                 : 15.5 Mbps

Maximum Overall bit rate         : 18.0 Mbps



Video

ID                               : 4113 (0x1011)

Menu ID                          : 1 (0x1)

Format                           : AVC

Format/Info                      : Advanced Video Codec

Format profile                   : High@L4.0

Format settings, CABAC           : Yes

Format settings, ReFrames        : 4 frames

Format settings, GOP             : M=3, N=15

Codec ID                         : 27

Duration                         : 1mn 11s

Bit rate mode                    : Variable

Bit rate                         : 14.6 Mbps

Maximum bit rate                 : 16.8 Mbps

Width                            : 1 920 pixels

Height                           : 1 080 pixels

Display aspect ratio             : 16:9

Frame rate                       : 29.970 fps

Color space                      : YUV

Chroma subsampling               : 4:2:0

Bit depth                        : 8 bits

Scan type                        : Interlaced

Scan order                       : Top Field First

Bits/(Pixel*Frame)               : 0.235

Stream size                      : 125 MiB (94%)



Audio

ID                               : 4352 (0x1100)

Menu ID                          : 1 (0x1)

Format                           : AC-3

Format/Info                      : Audio Coding 3

Mode extension                   : CM (complete main)

Codec ID                         : 129

Duration                         : 1mn 11s

Bit rate mode                    : Constant

Bit rate                         : 256 Kbps

Channel(s)                       : 2 channels

Channel positions                : Front: L R

Sampling rate                    : 48.0 KHz

Bit depth                        : 16 bits

Compression mode                 : Lossy

Delay relative to video          : -66ms

Stream size                      : 2.18 MiB (2%)



Text

ID                               : 4608 (0x1200)

Menu ID                          : 1 (0x1)

Format                           : PGS

Codec ID                         : 144

Duration                         : 1mn 11s

Delay relative to video          : -66ms

amendegw wrote on 12/15/2011, 6:06 PM

dxdy,

Okay, I rendered your clip the "standard" way to 720x480 60i and compared this to the 720x480 24p method. And, indeed, I see the moire/flicker in both cases.

However, I think I see the reason. The moire/flicker existed in your original clip. Therefore, it was reproduced in each render.

The original Hula Dancer clip had very little moire in the original 1080i. However we could see mucho moire in a 720x480 60i render (i.e. it was caused by the reszing during render).

Now, is seems that yours is the ideal case for adding a pinch of Gaussian Blur. In Vegas 11, Sony changed the Gaussian Blur effect to allow for 4 decimal places (vs. 3 in previous versions). So, in the following test, I added H=0.0000, V=0.0004 Of course, this somewhat softens the entire image.

dxdy24p-Blur.zip

...Jerry

dxdy wrote on 12/15/2011, 6:19 PM

Thanks for the hard look.

There is indeed moire in the original footage, although not as much as in the mxf sample.

Tomorrow morning, after my eyes are uncrossed, I shall devote some time to further experimentation.

dxdy wrote on 12/18/2011, 9:46 AM

I delved further into the Yadif/Lagarith/Pure Vegas options for rendering.

I am linking three renders that illustrate the effects.

And I had an AHA! moment after looking at these three samples.

I have been using the Lagarith-Main Concept 2 step process for the last six months, marvelling at the lack of artifacting. What I wasn't noticing was how much detail I had lost.

Here are the renders (each is about 4 megs). The sources are Panasonic HD from a 3-chip HDC-SD800 (mediainfo specs on a prior post).

1. An all-OEM render. Uses Clip has Reduce Interface Flicker checked:

http://www.northvillenotices.com/UserPictures/TestMC-RIFallVegas.mpg

Shows some good detail, but has some flicker

2. Using YADIF as interlacer:

http://www.northvillenotices.com/UserPictures/TestYADIF-MC.mpg

Looks very much like 1 above.

3. Render to a Lagarith intermediate, and then with MC to MPG2:

http://www.northvillenotices.com/UserPictures/TestFromLagarith.mpg

Shows no flicker, but it has been blurred. Akin to what Jerry suggested a couple of posts up, adding some blur and rendering with MC.

So, I have a choice, given my flawed input: Some detail with a little twitter, or no twitter but it is blurred or softened. Since this is a historic piece, I can explain away the blur. For other pieces, not so much.

AHA! Moment:
Envying the look of Hollywood DVDs on my consumer screens (and even discounting their cameras and lenses costing more than my house), after looking at these three tests:

The wardrobe department did it. (Not an original thought, I realize, and credit goes to the poster who said it months ago.)

Working with volunteer actors who have to provide their own costumes, I have to work with what I get. I was also crammed into a too-small room for the green screen vids (only 20 feet long, 30 would have been better...but again, that is what the client wanted.)

I do appreciate the efforts of all who have posted before...thank you thank you thank you.

Fred

amendegw wrote on 12/18/2011, 11:22 AM

Ha! Fred, that is definitely an "AHA! Moment" Every time I see a network news interview where someone is wearing a herringbone jacket or striped shirt, I think, "Who the he11 let them on set?"

...Jerry

MikeLV wrote on 8/11/2016, 6:29 PM

"In Pan/Crop, both Maintain Aspect and Stretch to Fill should be set to Yes."

When I do this, I end up with thin vertical black bars on the left and right of the video. Actually, the thin black bars start on the top and bottom of the video in Vegas, and then in the mpeg2 file, they're on the left and right. Is there something else I'm missing?

OldSmoke wrote on 8/11/2016, 8:04 PM

Render to 704x480 instead of 720x480 and you won't have any problems. 704x480 is a DVD standard and will display 16x9 in the correct aspect ratio too.

MikeLV wrote on 8/12/2016, 2:29 PM

I was hoping the 704 would be the fix but no such luck. I set the pan/crop to 1920x1056

Maintain Aspect Ratio: Yes
Stretch to Fill frame: Yes
Changed the DVD-A Widescreen video template to 704x480

When I play the video in VLC, I see the thin black bars on top, as well as when I preview video in DVD-A. Black bars look to be the same size in both the 704x480 and 720x480 videos.

Is there something else that could be causing the bars?

Former user wrote on 8/12/2016, 3:01 PM

Do you see them on your TV?

craftech wrote on 8/12/2016, 3:09 PM

Uncheck Maintain Aspect Ratio.

John

OldSmoke wrote on 8/12/2016, 3:11 PM

You have to check the playback on your TV. With 704x480 you don't need any pan/crop and you can uncheck the "stretch" checkbox on the render dialog too. Just make sure your project settings are 1920x1080 with 1:1 PAR.
If you make short clip of your source available for download I can render it for you with my usual settings.

Former user wrote on 8/12/2016, 3:44 PM

With 704 x 480, you are shortchanging your resolution just a bit. I have found that 720 x 480 with "stretch" checked gives me a good full screen video.

I am not saying your way is wrong, just I prefer to keep as much resolution as possible.

OldSmoke wrote on 8/12/2016, 4:09 PM

Yes, you are trading resolution for bitrate. At the same bitrate setting, 704 has a higher bitrate. You will not see the difference between the two settings.

Former user wrote on 8/12/2016, 4:27 PM

Probably not, just my own prejudice. :)

MikeLV wrote on 8/12/2016, 5:04 PM

Got it, I did 704x480 without any pan/crop and the MPG has no black bars on the top or bottom in VLC player, nor in the preview in DVD-A and it's not flagged for recompress either so that looks like the way to go!

That resolution isn't going to cause an issue on any DVD players will it?

Would I then also set the DVD-A project properties to 16:9 and 704x480?

Thanks for the help and sorry to resurrect an ancient thread (again)

Former user wrote on 8/12/2016, 5:17 PM

No, there shouldn't be any problems. that is a valid DVD resolution. You are correct in how to set up the DVD project.

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