Any stand-alone aspect ratio converters worth trying?

[Präsi]

Hi!
I restore vintage pre-recorded VHS tapes in my past-time. Most of them are documentaries, so they were shot in 4:3 at the time. But there are also a few letterboxed ones.
My intermediate medium is DVCAM, my output media can also be DVD.
I’d like to see the 4:3 sources pillar-boxed in a 16:9 frame and the letterboxed sources expanded to full height in the 16:9 frame. The point is to play the recordings back on a system that has a pixel-to-pixel representation on a widescreen monitor, aka zero overscan.
I’ve uses an AXON ARC2000, but did not like the results. Also, operation was quirky. And the thing is noisy. So, I put it away. (If anyone is interested in it, drop me a line.)
There was one feature on the Axon that did not work as intended. It caused the problems it claimed to avoid: When you scale an interlaced picture vertically (as in converting letterboxed to anamorphic) your scaler needs to know if both fields belong to the same frame (i.e. point in time) or not. If they are, you can scale the deinterlaced frame without problems. If they don’t you have to make a case distinction if the source was video or 3:2 pull-down film. In the former case, you need to scale both fields separately, but also apply some vertical filtering to it, I guess. In the latter case, you must remove the pull-down, calculate the full progressive frame, scale and then re-interlace with pull-down re-applied. Follow me up to here? Anyway, the Axon does have a setting that biases the vertical filtering algorithm to favor Video, Film, Mixed, and Field. However, the results were always awful, with line twitter and other artifacts. The manufacturer was not able to comment.
I’m looking for a flexible solution that explicitly takes care of these issues in NTSC or PAL. I’ve read the Snell & Wilcox ARC 20:20 manual but there is no indication that they made provisions for the above. But the ARC150/125 seems to have such setting. Has anyone ever played with these and who likes to share his experience?
Any other manufacturers worth looking?
Thanks!

[latreche34]

Usually changing the aspect ratio involves transcoding the video, Did you try the capture software? Some of them have such option.

[jnielsen]

Quote:

Originally Posted by Präsi

I’d like to see the 4:3 sources pillar-boxed in a 16:9

I do not really understand the devices you describe. However on a capture you could use Avisynth and add wide black borders and resize to some 16:9 resolution

If you capture in 720x576:
Crop(8,4,-8,-12) # crop overscan left, top, right, bottom
AddBorders(128,8,128,8) # left, top, right, bottom
spline36resize(1280x720) # resize to 16:9 square pixels

This will also make the movie square pixels meaning it can be played on all computers, smarts tv´s and Youtube with the correct aspect ratio. The letterbox movies you could simply crop more in top and bottom (and only add 8 at the sides)

[jwillis84]

The device your looking for with the controls you seek is called a Digital Scaler. They take analog in and produce digital output, or HDTV output.

The reason you don't see a lot of discussion here about them is they are usually used for 'Presentation' on a Projection system, and also include many additional features you didn't mention for things like Keystone correction and Custom Aspect Ratio adjustment. They are commonly used in Universities, Boardrooms and Churches. Correcting aspect ratio or changing it arbitrarily is not something commonly done with Broadcast signals, or the signals recovered from VHS.

Kramer and Extron made them too, you will have to search through old versions of their websites to find any useful reference to their analog features. Their current websites only discuss product and features regarding their digital to digital scaling and transcoding products.

Sometimes they go by the name (or umbrella term) of "Digital Switchers" because they "switched" between sources, and since different sources could have different aspect ratios, they had to be "corrected" or "customized" to fit the target "Presentation" system. (Not all) switchers included advanced "Scaling" features however, only the more expensive and comprehensive models.. which is why you need to research their features on an archived websites spec page or sales page.. scaling was lumped into the fine print, or discussed as an "additional feature".

[Präsi]

Hello all,
back after 4 years.
Thanks for the input. I guess I should have made it clearer from the start, that I'm not using a non-linear editing process (i.e., using a computer and software) but an old school linear process, i.e., actual hardware processors. I like it better this way.
No, I don’t need a scaler. The output is still SD, just the aspect ration is changed. (I do own a scaler from Analog Way and I know the difference in application, thank you.) Nevertheless, some scaling happens inside the ARC, and it must use some of the methods that are employed in products named scalers.
In the meantime, I got a BrightEye 94. According to its makers, it does recognize the 2:2 and 2:3 cadence of PAL and NTSC film sources. That is, it creates an internal progressive frame from the correct two fields that stem from the same scanned film frame. IMHO, this is a prerequisite for properly converting a letterboxed movie (from VHS or LD) to 16:9 full frame. It would be counterproductive to scale fields individually. The downside of the BrightEye is that is not a 19” unit, it uses a noisy fan, some operations require a computer hooked up to it, it doesn’t offer seamless scaling, and the handling of embedded sound seems to be faulty with my unit.
I still like to meet users of the Snell & Wilcox ARC 20 20
S&W don’t really explain how they handle film/video cadence in PAL or NTSC in the user manual. But I’m certain this company has given it a lot of thought. Anyone who has working experience with it?
Thanks,
Präsi

[Eric-Jan]

Why even bother converting ? you only loose quality, you bake into the material, on the playback side there are better options, also quality wise and you don't bake in any degradation.

[Präsi]

Quote:

Originally Posted by Eric-Jan

Why even bother converting ? you only loose quality, you bake into the material, on the playback side there are better options, also quality wise and you don't bake in any degradation.

Hi, I explained my motivation for authoring to 16:9 DVD in the original post. The obvious ergonomic advantage to the end user is already a sufficient reason to perform ARC in advance, IMHO. Didn’t Disney issue Fantasia on a pillar-boxed DVD? Are they misled?
Nevertheless, please elaborate on your argument as I seem to be missing a point. You seem to have your own observations & research, pls share. Are you suggesting that playing back a letterboxed movie from a VCR on a pixel-based display device will show superior results when using the displays "zoom" function over using a dedicated ARC?
How in your opinion does a dedicated ARC processor degrade the picture per se? And what choice does one have, anyway?
When pillarboxing, there is no vertical conversion at all. Resampling the lines horizontally is not going to lead to a loss of horizontal resolution if you consider the 440 lines of even the best analog consumer systems.
Removing letterboxing is a different animal. Regardless of whether done with a dedicated ARC device, or a so-called scaler or with a display’s internal circuitry, the result will depend on the ability to differentiate between film and video source, then identifying the cadence in the former case, and creating an intermediate frame. With a film source this would be from two fields of the same film frame. With a video source an artificial frame needs to be created from the interlaced fields through temporal-spatial filtering and interpolation. Bobbing would result in terrible artefacts as would stretching fields individually. Finally, the calculated full frame needs to be chopped into interlaced video. In case of film to NTSC, 2:3 pullup must be applied. The signal can then be recorded or just displayed. (I grant you that using a display’s internal scaler will avoid a second conversion in the digital domain from SD to HD or whatever.)
An unique advantage of using an external dedicated ARC processor is its uncompressed SDI output. One maintains complete freedom in terms of distribution infrastructure (“cables”), recording or further processing. Yes, at the end of the day SD-SDI must be converted to the display’s native resolution, so the process starts over gain. At least, the input is best it can be.
Anyway, I've obtained a S&W ARC 2020 from a seller nearby (costing me two cases of cold ones) and will share my experience you all. That will include a comparison with the zoom function of our Panasonic TH-42PF20.
Cheers!

[latreche34]

These were famous in the 2000's, They are rare now and often expensive especially the rackmount ones, The suggested method is to capture the content as they are in lossless AVI, De-interlace then fix the frame geometry by either cropping and/or upscaling or just assigning an AR flag in the final playback format, say h.264. You won't get much help about stand alone scalers and processors, This forum is mainly about capturing and preserving video.

[Präsi]

Quote:

Originally Posted by latreche34

The suggested method is to capture the content as they are in lossless AVI, De-interlace then fix the frame geometry by either cropping and/or upscaling or just assigning an AR flag in the final playback format, say h.264.

Thanks for the advise. I don't hate computers and I use a very capable computer to edit my digitally shot videos. I know that there are some costly hardware-based capturing devices for analog video out there. Let's just say I trust my non-linear system better. Besides, the output from my chain is either SDI or IEEE1394 so I could easily "record" the result to a computer.

Be that as it may, I did test the Snell & Wilcox ARC2020 today, using letterboxed PAL LaserDiscs (Starship Troopers and Schlafes Bruder). The results of the S&W are clearly superior to the internal "Zoom 1" function of the Panasonic professional PDP. Much smoother edges and slightly sharper image. (If anyone is interested in the signal chain, I'll post it here.) I’ll make NTSC comparisons using the US edition of Starship Troopers, soon.

Cheers!

[latreche34]

Almost any Snell & Wilcox or equivalent pro device I know have the ability to change or add an AR flag that a device downstream can recognize, However most of people who capture analog video do want to de-interlace, crop/mask the unwanted overscan, and encode to a final format. If those steps are not important to you that's fine but the rest of us want to perform them, so a hardware based solution cannot work, or if it works it it will be all performed in the analog domain, or in the digital domain but in real time which affects the quality since the processing has to be fast enough to keep up with real time frame streaming.

[lordsmurf]

I wouldn't state "you won't get much help here", as that's not true. But sometimes the proper answer isn't to just blindly give the desired answer by the question asker.

Messing with AR prior to capture, in a capture workflow, makes a mess, lowers video quality. Even those broadcast appliances had to make sacrifices in image quality, as realtime was required. These days, there is rarely legitimate need for realtime, as the software now is better quality, and runs near/at/above realtime.

[Eric-Jan]

You could ask Doug Johnson, he has a website and a Youtube channel he is an expert at live productions
Search for: Doug Johnson Productions