Restoration tips: Andrea’s Corollary to the Kush Gauge™

prologue: DON’T (always) TRUST COMPANIES!

Following many HDTV and internet broadcaster advices, a “studio quality” transmission for an H.264 1080p transmission could be achieved with a bitrate of a mere 6mbps; if we use the Kush Gauge formula, we can see that this is true only if the motion factor is lower than medium… for 16/9 sport material at 29.97fps, for example, a 17.4mbps bitrate is needed!

 

ANDREA’S COROLLARY TO THE KUSH GAUGE

To calculate video bitrate for a codec different from H.264, the Kush Gauge costant value should be changed accordingly to the codec used.

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Restoration tips: Kush Gauge™

KUSH GAUGE™ -> new Kush Gauge calculator

What is the Kush Gauge™?

It’s a rule of thumb to calculate the needed bitrate for H.264 encoded video; it was written by Kush Amerasinghe, a computer scientist. In this context, the word “gauge” means “a device used to make measurements

How does it work?

Quoting Kush’s document:

to estimate the optimal H.264 bit rate value that would give what is considered “good quality” results for a given video, you could multiply the target pixel count by the frame rate; then multiply the result by a factor of 1, 2 or 4, depending on its motion rank; and then multiply that result by 0.07 (the constant, Ed.) to get the bit rate in bps (divide that by 1,000 to get a kbps estimate or by 1,000,000 to get a Mbps estimate).

The Kush Gauge™ formula:

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Restoration tips: Overlap matching

OVERLAP MATCHING

What is the Overlap matching?

When two images of different sizes are used to improve the final result.

Could you be more specific?

Usually this is used when two different versions of the same movie are available at different aspect ratios.

Let’s say you want to restore a movie that is not available in high definition, and you want to upscale a DVD or a laserdisc capture. If you are lucky, an anamorphic DVD is available, so a theoretical 720×576 (PAL) or 720×480 (NTSC) max resolution could be achievable. But, if the original aspect ratio of the movie is 2.35:1, then you have only 720×432 (PAL) or 720×360 (NTSC). Well, enough resolution left to do a decent upscale. However, if the DVD is not anamorphically enhanced, actual resolution drops to 720×324 (PAL) or 720×252 (NTSC).

But what if the only (or the best) available low definition sources are analog? In this case, a 2.35:1 original resolution in laserdisc could be at maximum 576×324 (PAL) or 576×262 (NTSC), while VHS could be 328×324 (PAL) or 328×262 (NTSC)… pretty poor…

So, how it’s possible to improve the quality of such low resolution sources? Continue reading

Restoration tips: the Slice Technique™

Restoration tips: the “Slice technique”

THE SLICE TECHNIQUE™

What’s about this so-called “Slice Technique™”?

In few words: achieve the widest (highest) image possible adding a “slice” of another video clip.

Be more specific…

Well, sometimes there are two editions of the same movie, where one has more image on one side, while less on the other side, and vice versa. So I thought to use the missing “slice” of one joined together with all the other, to obtain the widest image possible. Indeed, it could be only (e.g.) 3% wider than any each version, but I much prefer a 100% wide image Vs a “mere” 97%… (^^,)

Of course, it’s quite difficult – sometimes impossible – to use this technique with every movie, because what must be taken in account are the dimensions (eventual image rotation, width and heigth of sources and chosen slice, eventual resizing and cropping, exact point of matching), colors (both versions should have the same color grading, or one should color match the other), video quality (grain, resolution/definition, different compression used in the sources, frame whobbling in a version not present in the other – in particular at the beginning and ending of a shot), etc.

In these examples, I used a vertical slice and two sources, Continue reading

hardware device as audio analog to digital converter (ADC)

My PC sound card is (still) the original integrated one; it’s a SigmaTel with the CXD9872RD chipset – not too bad to be an integrated sound card; plus, it has the ability to capture bit-perfect audio via the digital input – and that’s a VERY GOOD feature, when you must capture laserdisc PCM/AC3/DTS soundtracks.

However, the analog input/output, even if good, is not comparable with the best sound card around. The solution is simple: to buy a better sound card! Even if the solution is simple, I can’t afford the brand new sound card I’m dreaming of now, so I thougth about an alternative solution. Which one?

It’s possible to use an external device as ADC (Analog Digital Converter); Continue reading

AviSynth and VirtualDub – speed improvement

Recently my old video card die… it is (was) a GeForce GTL 7600 (a custom made version by Sony, the same specs of a GT 7600, but a bit slower and with a very good pipe cooling system). It was the default video card in my Sony HTPC PC – a VGX-XL202 – and I never thought to replace it because, even if it was slow and old and with only 256MB, it was capable to play Blu-ray without stuttering (with some codecs and setting tweaks) and because AviSynth and VirtualDub use only CPU for their processing…

Or, at least, it was what I thought!

Just today I replaced it with a brand new Sapphire (AMD) Radeon HD 5450; a low profile 1GB DDR3 “honest” video card. I chose to buy this because I need a video card ASAP, it’s cheap and, as I have other two PCs, I’ll buy a better one later when I’ll upgrade another CPU.

Well, as I was working onto one of my project the day the card died, I promptly re-run the conversion, and I noted one thing: conversion speed is improved, A LOT! Now it runs at about double speed!

So, it seems that AviSynth and/or VirtualDub DO USE GPU power too, or the old GPU simply slowed down the CPU speed?

If it’s true that GPU power is important for conversion speed as the CPU, my next upgrade (CPU from Core 2 Duo E6300 1.86GHz to Core 2 Quad Q6700 2.67GHz, and GPU from GeForce GTL 7600 256MB to AMD Radeon HD7750 1/2GB) will improve speed up to 2.5x/3x thanks only to CPU; how much the video card will improve speed is to be discovered…

If someone had some similar experience, please post here… if only I knew this, I would have replaced my old video card before… years before!

PaNup™: or, how to upscale PAL + NTSC capture and live (quite) happy…

Today I was thinkering with the “pyramid” LD capture, and, when I was looking for the files, I encountered an old test script for upscaling, abandoned two years ago. Idea was good, so I managed to improve it – as now I have more knowledge than at that time – and results are quite good.

The idea is simple: take two captures of the same content, one PAL, one NTSC, then merge them to “squeeze” every bit of details from it… everyone knows that a PAL capture has 576 horizontal lines, while NTSC has 480… now, when a movie was transferred to video, usually original resolution was higher than that (not all the times, but often); so, the PAL and NTSC “received” different lines of image… see the next image (obviously intentionally exagerated…):


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Laserdisc PCM to low compressed AC3

I know, I know, laserdisc PCM soundtracks should be left “as is” (when possible, because they must be converted at least to 48KHz to be BD/DVD/AVCHD compliant), but I did my projects with several soundtracks in different languages, and I guess I could spare a little bit of disc space compressing them, and leave video more space. You know, adding four PCM soundtracks could “eat” something like 9/10GB disc space, and leave only 15GB to video in a BD-25…

As there are wonderful LD AC3 5.1 discrete soundtracks (and they are all 384kbps), I think a PCM 2.0 could be compressed with little or no artifacts at 640kbps (for BD/AVCHD) or 448kbps (for DVD) – or even less. I thought also to use DTS, but to achieve a similar quality I should compress at higher bitrates, and AC3 decoder are a little more spread than DTS ones.

Ideally, it could be converted to DTS-HD MA or Dolby TrueHD, but I know no software (free and/or open source) that could do that, and these kind of decoders are less spread than AC3 and DTS…

Opinions?

Color IQ test

…or, try to put colors in the right sequence, and discover if you have problem recognizing colors (or if your display should be optimized):

http://www.xritephoto.com/ph_toolframe.aspx?action=coloriq

My score is 0, and this is the best possible score… so, my display should be optimized enough to let me see colors in the right way, and I’m not that old as I thought (at least, not about color vision)…

Now, i’m fully qualified to do any color grading project… (^^,)

Take a look, do your test (five minutes to complete) and post your score here!

Restoration, Preservation, Fan Edit – definitions

I’m into this hobby (movie restoration) for two years now, and still not got a complete, final, ultimate definitions of what Restorations, Preservations, Fan Edits (and so on) are, according to everyone… I tried to write down them here, based on what I have understood in this time, what are my personal thought, what other members think about them, and also on the FAQ of this forum and fanedits.com.

Obviously someone will agree with some or all definition completely, someone will agree partially, and others will strongly disagree… and it’s the meaning of this post: trying to find a common thought about WHAT precisely we are doing here!
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