Quality Judging tool?

[barry_w2]

I am trying out a variety of editing, transcoding and encoding operations with the aim of getting the best quality.

Unfortunately my eye isn't very good for judging these things and however careful you are it is difficult not to allow any bias to creep in.

Therefore my question is is there any tool that you can run files through that give you a quality rating eg 0.9234 or 0.345 where 0 is can't register at all and 1 is perfect or something similar.

I tend to believe a number much more than my eyes!

My guess is there either aren't any of these or there are several.

The files I will be wanting to judge are DVD files (Video_TS).

[Bjs]

This can only be done by the person generating the file's ... though some software out there is complete and utter crap at it as well .

Bitrate's dont really give you a clue as to the final quality but here are some hint's that might give you an idea from my encoding's over the past .

For dvd :

Encode file's using quenc or other encoder ...

My preferance to encoding in "all" dvd , svcd and vcd supported format's is bbmpeg , the only one that allow's all these output's .

Example would be xvid avi , at 720x576 , video bitrate at 2500 ... this encode's well through bbmpeg , and would be the standard minimum I would aim for .

The quality is brilliant ... anything below this start's to show problem's .

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Then you start dealing with all those other codec's ... and different bitrate's ... anything below what my xvid is in the above example will have picture artifact issue's , as seen in playback .

If below my example , consider conversion to either vcd or a suitable avi container (mpeg4 / xvid + mp3) , and purchase an mpeg4 certified player ... divx certified is the same thing ...

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I have been told my non-compliant vcd's look brilliant compared to pirated dvd's converted to vcd's ... something I dont recommend .

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I have even been capturing my screen , while using various program's for dvd tutorial's , and people now ask how the ? , I manage to keep the font's so clear ... it's simple when you know how and what program's to use ... and all are free .

[jagabo]

MSU has a tool:

http://www.compression.ru/video/quality_measure/video_measurement_tool_en.html

I don't know how useful it is.

[bendixG15]

Some time ago, I made the quest to seek out
a quality test tool...Came up empty and quit .

You are just going to have to believe your own eyes
and equipment....

I came to the conclusion that most people outside of the "tech circle" really are not interested in quality.
As long as they can see and hear it, then thats just fine. Oh yes, it has to be cheap too.

Good Luck....

[edDV]

How would you want to judge quality if not from your eyes?

Quality for what? XP scandisk will say yes indeed it is a file. Nero will say it can be burnt. A DVD player will decide if it can be played.

There are thousands of ways to make a Video_TS directory for DVDR. Is that the quality spec?

Are we to assume you are looking for the minimal acceptable DVD that will play? Or are you looking to submit the contract for encoding the latest Hollywood film?

Let us know your process and we will offer advice.

[manono]

Hi-

Are we to assume you are looking for the minimal acceptable DVD that will play?

I assume he wants a way to measure the difference from the DVD source.

PSNR and SSIM are perhaps the best known. The one to which jagabo linked seems to support them both.

[barry_w2]

OK here are the full details.

I collect various TV shows and sports events.

I have worked out I can fit roughly 2 hrs 15 mins on a DVD-R at SP.

The problem comes for things that are longer eg a soccer match or 4 x 50 minute episodes.

I want them all to fit on the DVD-R.

As I intend to do a lot of this and I have only just switched over from video it seems worthwhile spending a bit of time getting it to as high a quality standard as possible.

I am very keen on the Womble editor partly because it says it only encodes the frame or two before and after the edit so the quality of the overall recording is not reduced. Secondly I have done various experiemnts with splitting some action with horses jumping a fence, ball in air etc and when you join it together you cannot tell the point that was split and rejoined.

Now originally I thought the obvious thing to do was use the Panasonic Flexible record mode. So I have my recording I tell my Panasonic to use the full disk with it then I am getting the best possible quality.

Then I did some experiments to see exactly how much you could fit on a DVD-R and much to my surprise found out you could actually fit 2 hrs 15 mins or so. This meant that my Pan was being very inefficient as it was wasting approx 12% of the disk as it was geared to fitting 2 hours at SP and wasting the remaining 0.7GB.

So I am trying to evaluate the best method for dealing with those things that are between 2 hrs 15 mins and say 4 hours.

I have the following options:

1. Panasonic FR mode.

2. Panasonic FR mode spread over 2 disks to get the benefit of the extra 2 hrs 15 mins.

3. Womble - encoding.

4. DVD Shrink.

1. Probably doesn't give me very good quality.

2. Is extremely fiddly.

3. This takes forever - 10 hours on reduced image size and 20 hours for normal!

4. Complicated process as I have to go to Womble to edit then to VTS Fix (for some reason my files aren't acceptable to DVD Shrink once they get over 40 mins) then to DVD Shrink.


I don't mind doing each of these various things once to compare but I am the sort of guy who much prefers to see a number as opposed to a person's opinion - particularly my own!

I hope this gives full details of what I am trying to do.

What would please me no end is for a couple of people to make a judgement (one of which would be me) then run them each through a routine and find the order is pretty much the same. Then I would be very happy that the option that is chosen is the best one as opposed to someone's particular whim that day!

Dealing with so many variables is very difficult. For Womble encoding as an example I have established that for a 3 hour file I need to use a bitrate of roughly 3348 if I use the reduced image size. My guess is for the normal image size it would be about 3100. I have no idea which of these 2 combinations is better or why there are these options. I am also puzzled that this is the 2nd tool out of 2 (the other one was Tempgenc) which tells you the settings you have chosen will fit on a DVD-R and then when you have waited your 20 hours or whatever it doesn't and in some cases isn't even close. I am learning but it is a painful process!

[Bjs]

Those clip's then that wont fit ... we need some info as to what they really are , as in stored format , length , and the the size (width vs height) , not forgeting the true bitrate of the video stream .

Use gspot , and load each file , and hit render .

Write down :

Video width + Height
Video bitrate
Video codec (assumed)

Audio attibute's
Format , mp3 , lpcm or
Frequency , 44.1hz , 48hz
Bitrate , channel's

Play length
Size of file

Of course if they are mpeg's , use vdub , and go to file , file information , and you will get the same thing's .

Form here it might be a little easier to give some other idea's as to how to help .

I can fit 8 hour's worth on a dvd , at reasonable quality using a few well know freeware tool's .

This though is pal video (mpeg2 , 325x288 , 25fps) + Ac3 (48000hz , 16bit , stereo) + subs (english) ... just finishing of my horror dvd for the camp trip next week ... there be no sleep that weekend .

Thankfully I dont do this with dl media ... got too have sleep sometime .

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Just finished another 45 title dvd ... encode video , strip audio , encode to ac3 , author each with ifoedit , create menu background's , author basic dvd with dvdauthorgui , pgcedit to import dvdauthorgui project , then import all 45 title's , edit nav command's for menu's , title's and menu button's ... and burn .

Only take's 14 hour's ... normally associated with dual pass encoding for quality .

[A_51]

My friend you should trust more on your self. If what you are doing is for you there is no better judge. If it’s for someone else, then ask someone you trust their opinion.
Nobody should rely on a program to tell them what is good for them because that is subjective to each and every one of us, even if you applied a set of standards as guides to what should be a quality end product