Technical info on 16:9 MPEG-2 files (1 Viewer)

[John_Berger]

Quote:

So, what would the purpose be for these? Just possible compatibility for future use?

 

[Wayne Bundrick]

So, what would the purpose be for these? Just possible compatibility for future use?

HDTV is 16:9 but it also has square pixels. I suppose either "1" or "3" could be used for that. The HDTV standards documents show that both are valid, which means HDTV decoders need to know how to handle both. And 1:1 could be used for nonstandard resolutions which are neither 4:3 nor 16:9.

The 2.21:1 aspect ratio could be nifty for putting the "anamorphic squeeze" on HDTV resolutions in the same way that 720x480 which was originally intended for 4:3 is made to do 16:9. But 2.21:1 isn't included in any HDTV standard. Just for kicks I gave it a try with PowerDVD and it just reverted to 4:3 mode.

 

[John_Berger]

Exactly. Just a little checkbox that says "I don't care what my sequence header tells you, I'm supposed to be 16:9." Like I said, Sonic Solutions is just way too inflexible.

That also doesn't say very much about the various video editing packages, like Media Studio Pro or Adobe Premiere, who still don't offer 16:9 flags. (Then again Premiere can't even handle MPEG-2.)
Looks like I'm going to have to pull my Perl for Dummies book out and dust it off.

 

[Jeff Kleist]

(Then again Premiere can't even handle MPEG-2.)

Premiere is meant to be a full-frame NLE package, ULead Media Studio is aimed at the amature. Since MPEG does not contain all of the frames, it works totally differently than Premiere is designed to.

Remember, maybe 1 in 6 frames actually exist in an MPEG file. There are 3rd party plugins to let Premiere read MPEG, but I have yet to find something that really works well.

 

[John_Berger]

There are 3rd party plugins to let Premiere read MPEG, but I have yet to find something that really works well.

That explains some things. Since I don't work with AVIs **shudder** I couldn't get into Premiere.
I really like Media Studio Pro 6.5. I handles MPEG-2 files natively through Ligos without the need for plug-ins.
It does have its quirks, such as it's not too pleased if you mix and match source MPEG-2 files of different bit rates, and it definitely prefers WAV audio as opposed to MPx audio, but when you learn to identify and get around the quirks, it's fantastic. I'm really pleased with it.
If you're having problems with MPEG-2, you should give MSP a shot.
I don't work for them. Really. Just basing it on what I've done so far.

 

[Wayne Bundrick]

I don't do MPEG until I'm done editing. I capture and edit in DV format.

 

[John_Berger]

I don't do MPEG until I'm done editing. I capture and edit in DV format.

You know, I've tried that and I've found it to be so bad to work with. I've actually had far, far better quality capturing 720x480 MPEG-2 at a nice high bit rate (usually 10,000 video, 224 audio) than raw DV AVI files. Between the blockiness and the enormous file sizes of DV AVI, I gave up and went back to capturing in 720x480 over the S-Video connection on my DV camcorder. I'm much happier doing it that way.

Maybe it's my capture software or something. Are you using a Mac or PC? From what I understand DV on PCs generally use the Microsoft DV drivers, so I'd be surprised if you don't get the same kinds of DV glitches that I do.

 

[Jeff Kleist]

You're using MS' DV codec and cheap hardware. That's your problem

If you use a good Pinnacle or Canopus product your DV will look fantastic. The file sizes are huge for a reason. MPEG is not a format meant to be used in serious editing, while AVI is. Ask any pro, they don't go MPEG until the final step

 

[John_Berger]

Of course it's cheap. This is just a hobby. Then again, that doesn't explain my 16:9 TV. Hmmmmm.....

Ask any pro, they don't go MPEG until the final step

Well, I'm not a pro, so I'm not going to worry about it. At this stage, I'm a-just havin' fun!

 

[Fredrik L]

Marty:
Great explanation on 16x9! But I must ask this, cause I just cant get this part:

If there are only so and so many pixels, say 720*480, to draw a picture, and these pixles are arranged in a 4:3 aspect ratio, then how can you just pull these apart into a wider image without quality loss? I can't get a grip on how using three sets of pixel-sizes can solve this, since I guess each pixel - whatever its size - holds the same picture information, say the color red. If one red pixel is used and arranged for drawing one pixel area of an apple in a non proportional (say, vertically squashed) image, then if the pixel is unsquashed, what will happen is that the pixel will get wider, BUT it will still display the same color, right?

In my mind this generates a picture with more easily visible pixels=perception of image of lesser quality.

Am I way off?

 

[Ken Chan]

Yes, the pixels change shape and still display the same color. But the only way you'd notice the difference in quality is if you actually saw the "original" squashed image -- but you never do.

Also, stretching in one axis can also be considered squashing in another, so without some frame of reference, you can't really say that the picture is being pulled apart.

//Ken

 

[Aaron_Brez]

John,
Am I reading right? Are you saying Ulead Media Studio can't encode MPEG-2 with the 16x9 flag set? Because I've done it a number of times (MSP 6.0); it works just fine, and once the flag was set, DVD Workshop imported it without gagging and the resultant .iso image ran as 16x9 (I'll be honest and say I don't have a DVD burner, so I haven't tried that final step).
There was some kind of cryptic .INI file alteration to perform in order to get a "secret" Advance [sic] menu button to pop up, and one of the selections was aspect ratio: 4x3 or 16x9.
Ah, here it is (Thank Witek and Google!):
In article ,
Witold Matus wrote:
>Aaron,
>
>Here is how I do it.
>
>1. Find the file ulead32.ini , and open it in a text editor. Find the
>section “[VIODRIVER]”, and add the line “Advance=1” (without the quotes).
>The next time you fire up MSP6 or 6.5 and look at the Compression tab for
>MPEG export options, you’ll see a new button, Advanced. Inside, you’ll find
>options for MPEG-1, MPEG-2, Motion Properties, Aspect Ratio, Sequence and so
>on.
>
>2. Edit and encode your 16x9 material using 16x9 setting in Advanced
>options. Note your exact settings for video and audio. I use 6000/variable
>for video and 224/48 for audio. You can go 9800/variable like
>http://www.superbitdvd.com but with DV based material that would be waste. I
>think.
>
>3. Import all your material into DWS. Create chapter points and menus and
>hit finish/make disc/customize. Make sure settings here match your encoder
>settings exactly. Using Prassi PrimoDVD 2.0 smoke your AUDIO_TS and VIDEO_TS
>folders to DVD-RW. (It might be time to raid the fridge now)
>
>4. Start PowerDVD and enjoy your work. Do not use Media Player as it is
>unaware of ARF (aspect ratio flag)

 

[Fredrik L]

Ken (and Marty):
What is the squashed image im seeing in 4:3 before I switch to 16x9 then? Is it not the "original" 4:3 image?

Is the 4:3 squashed picture perhaps displaying only a hypothetical preview of the 16x9 real thing? Maybe it is actually so that a 16x9 image per definition only can exist in its proper quality on a 16x9 ratio?

I've read that if you want to shoot true 16x9 material on a DV-camera, the camera has to use a CCD with those pixel proportions=a wider CCD than 4:3. So in that sense, is it true that the CCD has more pixels on its width than on its height in the ratio of 16x9? OR, is so that the this 16x9 CCD actually doesnt fit more pixles proportionally than is appropriate for the standard NTSC DV of 720*480, except the pixel information is saved in the wider 16x9 pixel shape?

I'm just trying to get my mind to understand this. If there are any major, fundamental technical misconceptions in my answers, I beg you to correct me. And, if you can and have the time and patience, try to clarify/go into detail even more to explain this matter. I would appreciate it deeply.

 

[John_Berger]

Am I reading right? Are you saying Ulead Media Studio can't encode MPEG-2 with the 16x9 flag set? Because I've done it a number of times (MSP 6.0); it works just fine, and once the flag was set, DVD Workshop imported it without gagging and the resultant .iso image ran as 16x9 (I'll be honest and say I don't have a DVD burner, so I haven't tried that final step).

WHAT!?!SON-OF-A-BI**H!!
Even Ulead's own tech support people say that 16:9 is not implemented and is currently a tentative function for MSP 7.0!!
Excuse me while I climb the walls now.

Okay, I'm better.
I will DEFINITELY work on this over the weekend! I'll be very pissed and elated at the same time if this works. Considering that it works with 6.0, I can't imagine that it wouldn't with 6.5.
If worse comes to worst, I still can fire up a Perl script to change the flag like I had been planning on doing, but if that INI change is all that is needed, Ulead will not like the e-mail that they're going to get from me.
Thanks for the info!

 

[Aaron_Brez]

Well, I don't know what to say re: Ulead tech support people. The fact that you have to go through such a manual rigamarole to get this to work implies that it's either a an unsupported feature, it's buggy, or Ligos forced them to disable it for some reason.

Let me tell you what you don't get: you don't get a pretty, 16:9 aspect ration preview window, or a 16:9 aspect ratio source window; all of your edits have to take place on stretched-looking 4:3 frames. However, if you can get beyond that (and I can), you've got what you're looking for.

I also got it to work in TMPGEnc, as well, although it's been almost a year since I tried the experiment so I don't remember how I did it-- I do know I had to mess with a configuration file to modify some defaults.

 

[Ken Chan]

I've read that if you want to shoot true 16x9 material on a DV-camera, the camera has to use a CCD with those pixel proportions=a wider CCD than 4:3

There may be a practical reason why that is the case, but in theory, you could do what they do for film: use a lens to squeeze/stretch the wider image so it fits on the CCD. If we had a whiteboard, this would be easier
The CCD has 720x480 elements. They are arranged in a grid so that they are 4:3. Note that 720x480 is actually 3:2, so the elements are not in a square grid, they are closer horizontally than vertically. For filming 4:3, the undistorted optical image comes through the lens and strikes the CCD and is recorded.
For 16:9, you could use an additional lens just before the CCD that squeezes/stretches that wider picture onto the same 4:3 CCD.
I say "sqeezes/stretches" because it depends on how the 16:9 mode works on this hypothetical DV camera. If it actually shows more content on the sides, then it would squeeze horizontally. If it crops the top and bottom, it would stretch vertically. But in either case, the full resolution of the CCD (and therefore the DV frame) would be used. ("Fake" 16:9 modes simply mask off pixels on the top and bottom.)
Those light-sensitive elements on the CCD are just like the pixels on the DVD frame. They take the image, 16:9 or 4:3, and divide it into a grid that's 720x480. Either way, the pixels are not square.
//Ken

 

[John_Berger]

The fact that you have to go through such a manual rigamarole to get this to work implies that it's either a an unsupported feature, it's buggy, or Ligos forced them to disable it for some reason.

I don't care if it's unsupported as long as it works. And if it doesn't work, I can still run it through a quick Perl or shell script to switch the repeating 4:3 flags to 16:9 flags. I can't imagine that Ligos stopped them because this is a flag that is built into the MPEG design and is NOT any kind of proprietary Ligos code.

Of course, that doesn't forgive the people at Sonic who could have just as easily added an option to convert the flag to 16:9 when re-muxing the DVD.

I can deal with the stretched-looking 4:3 frame while working on the video files, as long as I'm sure that the final result when the disc gets popped into the DVD player is the result that I want.

 

[John_Berger]

If it actually shows more content on the sides, then it would squeeze horizontally. If it crops the top and bottom, it would stretch vertically.

The main gripe that I have with supposed "widescreen" 16:9 functions on DV camcorders is that they actually crop the top and bottom then stretch the image vertically to simulate 16:9. I checked the 16:9 function of at least three different top manufacturers, and all of them were "fake" 16:9. Bastards.
I actually have a Sony 8mm camcorder that does true 16:9 widescreen (more image on the sides), but being 8mm the picture quality is nowhere near as good as DV.

 

[John_Berger]

on.

I'll be damned! There it is! YAHOOOOOO!!!!
The file was different with mine. It was the msp.ini fies that was embedded in Cocuments and SettingsAll UsersApplication DataUlead SystemsUlead Media StudioPro6.5 . I'm guessing the directory location is because of Windows 2000, but the file is most likely a new MSP design.
But there it was, plain as day. You know, is it so difficult to either mention this sh*t or at least be honest about it when someone asks?! I'll be writing that snotgram tomorrow. There is no reason why this information should be hidden away, particularly when it was available on a previous version as well!
Well, at least MSP can handle MPEG-2 without the need for an unstable plug-in! {coughPremierecough}
Thanks a bazillion, Aaron!

 

[Aaron_Brez]

Glad it worked out for you!

Inspired, I cought a DVD-R burner this weekend (since it was a Pioneer A04 which was $300 after rebate, I was pleased). Worked like a charm, although none of the (ancient) DVD players in my house will play DVD-RW.

DVD-R worked great, though. Got some bizarre combing artifacts when played back on a regular TV, but that's for another thread...