AVI source unkown, looking for tools to determine specs.

[pcexpress-guy]

I have a source MPG file, but I am uncertain of what exactly it is. (I wonder if it is interlaced, non-interlaced, etc.. )

The orginal came from a demuxed DVD, but the orginal DVD source may have actually been from VHS source which i suppose is interlaced.

I may be confused, but is it true the DVD source (and now my demuxed video file) could be interlaced? Is there a tool, which will tell me all the specs of my video?

Thanks!

[Sifaga]

try gspot

[BJ_M]

gspot will not tell you anything on a mpeg file you are asking ..


bitrate viewer will though ...

no mater what it will prob. show as interlaced if its ntsc ...

it may of been film rate with pulldown , but its interaced as far as bitrate viewer is concerned..

[pcexpress-guy]

so chances are I need to set TMPGEnc encoder to interlaced mode for the source. (even though the MPG came from a DVD.)

I think I am confused... what is interlaced and what does it have to do with progressive? I think I know, but the brain just crashed and the reset switch is broken. :O

[BJ_M]

what exactly are you trying to do ?

[pcexpress-guy]

Thanks!

I have this source file, which is I am not sure what variety it is i.e. interlaced, non-interlaced, or anything else. I just have the file. It is mpg2 though.

What I am trying to do is encode it using TMPGEnc plus, but I am uncertain to the settings for the source within this TMPGEnc dialog box, because I do NOT know what it is, I have exactly.

Thanks again!

[BJ_M]

use the wizard instead , or use bitrate viewer ..

[junkmalle]

could be interlaced? Is there a tool, which will tell me all the specs of my video?

Yes, they're called eyeballs. Just find a high motion scene and view a still frame. If you see something like this:



it's interlaced.

If the MPG file is less than 480 lines high it's probably non interlaced. For example 352x240 will not be interlaced, 720x480 might be.

[pcexpress-guy]

I can't get gspot to tell me if the file is interlaced or not. (is there a trick? or where do I look?) also I look for the eye method, and I can not find any high speed action in the video to see the interlaced. This method is inconclusive at best. Is there a trick for this?

any ideas here would be great!

Thanks to folks for the help!

[BJ_M]

here is one trick https://www.videohelp.com/forum/viewtopic.php?p=862923#862923 (the one where it points out not to use gspot and what to use)


and here is another good trick to use here right along the same vein https://www.videohelp.com/tools?tool=167#comments

[pcexpress-guy]

man your funny.

I must have mis that part in your post. It is a great post, glad you sent me the link

Thanks Again!

[junkmalle]

pc,

I can not find any high speed action in the video to see the interlaced.

You don't really need high speed action. Anything moving, or the camera panning or zooming, will make interlace obvious. High speed just makes it much more obvious. Even small movements will show interlace artifacts. It sounds like you haven't seen any interlace lines at all.

This method is inconclusive at best.

That may be true. But all other methods are inconclusive too. The file could contain material that was interlaced but encoded improperly -- so it could look interlaced but not be. Or the file may contain no visual evidence of interlace because it's from a progressive scan source, but it could still be two interlaced fields.

[junkmalle]

Oh, I forgot to mention one thing. Many programs will perform some sort of deinterlacing for display on the computer screen -- because interlace looks so ugly on a progressive display. You'll need to use a program that lets you see the full image 1-for-1 (ie each pixel in the MPG file becomes one pixel on the screen). I find that WMP and Realplayer work for this purpose when they are set to 100% or "full size" display. TMPGENC's Preview function at "original size" works too.

[BJ_M]

virtualdubMOD is also excellent for this as you can also step frame by frame and detect pulldown pattern ..

[pcexpress-guy]

ok I am afraid to ask what is pull-down pattern? link?

by the way, the bitrate viewer says I have an interlaced video. Is it safe to say I have interlaced video or should I cross-check this with something else as suggested?

Thanks again!

[BJ_M]

well then its interlaced ...

pulldown is added to film format mpeg files (24 frames per sec) to change them to 29.97 frames per sec (ntsc) by repeated certain fields .. its ussually a 3:2 pattern but also can be 2:3:3:2 or other patterns ..

funny -- we seemed to have forgot pulldown in our glossary

[junkmalle]

pc,

What I am trying to do is encode it using TMPGEnc plus, but I am uncertain to the settings for the source within this TMPGEnc dialog box, because I do NOT know what it is, I have exactly.

Why don't you do some experiements: Use TMPGENC's "source range" option to mark off a scene with some motion. Then convert that small section with each possible setting. Then examine the final results to see which setting worked best.

As BM_M said, pulldown pattern refers to the way 24 fps film is transfered to 60 field/sec video. To make 24 fit into 60 each frame of the film is displayed an average of 2.5 times. Half the frames are displayed for two fields and half are displayed for 3 fields. The end result is that some frames (pair of fields) from the NTSC video come from a single frame of the original film, whereas some video frames are a mixture of two film frames.

For example, take 8 film frames at 24 fps:

.....film: 1 2 3 4 5 6 7 8

record half of them for two fields the other half for three fields:

.....vid fields: 11222334445566677888

Now break them up into pairs to make video frames

.....vid frames: 11 22 23 34 44 55 66 67 78 88

As you can see, the first video frame consists of two fields from the same film frame. So does the second video frame. But the third video frame consists of a field from film frame 2 and film frame 3. And the fourth video frame is half film frame 3 and half film frame 4. In the end, 2 out of every 5 video frames contain parts of two different film frames.

The pulldown pattern refers to the pattern of full vs. half frame fields.

This doesn't matter when you watch on TV because you don't see both fields at the same time -- by the time the second field is displayed the first has faded away. It does matter on the computer because you see both fields at the same time.

Keep in mind that the reason interlace is a problem, and hard to fix, is because video cameras don't capture full frames and then split them into two separate fields (actually some can now, my camcorder has a 30 frame/sec progressive mode). They capture fields one at a time. That means 1/60 of a second has transpired between the first and second fields of a frame. Anything that moved during that 1/60 of a second will be in a different place. Again, it doesn't matter on a TV because by the time the second field is displayed the first one has faded away. But when you capture as frames you see both fields at the same time on the computer screen.

Since you have TMPGENC take a look at its "inverse telecine" feature. Press "Settings" at the bottom of the main window. Select the "Advanced" tab. Double click on the "Inverse Telecine" line about half way down the dialog box. The program will give you a window with 5 thumbnails of pairs of fields at the top, and a big 1:1 display of one of the frames at the bottom. You can scroll through the film to examine different parts.

If your MPEG file was originally from film, and is still interlaced, you will see that 2 of every 5 frames shows artifacts like in the image I sent earlier.

If the original source was video, and is still interlaced, you will see artifacts in every frame. Well, not EVERY frame -- if nothing moved between the two fields you won't see any artifacts.

If you don't see any artifacts, then your MPEG file has already been deinterlaced somehow.

[BJ_M]

another thing to rememeber is that interlacing is a good thing IF the source was shot on video AND you are playing it back on a normal TV ..

de-interlacing in those cases will make the picture worse because you are removing info
..