DVD Authoring from MPEG-2 with no quality degrade?

[SeanG]

I've compared authored .VOB's of a reference MPEG-2 (a ~3.5Mbps DVB recording) from DVD-Lab, TMPGENC DVD author, and IFOedit; and all three induce precisely the same amount of video noise from the original DVB MPEG-2....

I eliminate variables in playback by playing both the original MPEG and the converted .VOB's from my PC to my TV (not my PC's monitor) - both with the same program; and the same amount of distortion on the same video frames (all of the frames, of course; but some make the noise more obvious) is apparent.

Are there some settings in any of these authoring programs that I can exploit to eliminate this distortion? Of course, the video noise is slight; but it is obvious... basically it's the same sort of MPEG video compression effect apparent on any DVB broadcast, but just exagerated... Do you know what I mean?

[ZippyP.]

The authoring does not change the video itself. It merely takes the mpeg video, multiplexes it with the sound and then creates the menus and DVD file structure. If you want to change the look of the video then you need to re-encode it.

[SeanG]

Well, evidence from my eyes leads me to disagree with you on that. The video is infact changed. The quality is slightly degraded.

Of course, I don't want to reduce the quality, so I avoid reencoding throughout the entire process... till authoring, then I'm not sure what's happening; but the authored video quality is degraded - playing from my PC to TV, or authored DVD in an external DVD player to TV.

[gshelley61]

Not sure what you are seeing as far as the quality degradation described. Authoring .mpg files to VOB without re-encoding simply multiplexes the existing .m2v and audio file and creates the DVD files, maybe with chapter points and/or a menu and all, but does not actually alter the original video file in any way (other than cutting out or joining, which still doesn't require re-encoding and would not lower the quality).

[SeanG]

On the degradation effect: have a look at a DVB stream - MPEG2 - and see the way it fades colors, like a sunset - colors not continuously fading from one shade to the next (as you'd expect on a commercial DVD), but changing abruptly from one shade an obviously different one... Well, that effect is basically blurred somewhat on the authored MPEG-->VOB, so that the lines separating one shade from the next aren't as smooth as before "authoring to DVD"...

But more importantly:
The "blocky," video effect is exagerated as well - where you'll see a large pixel grouping *abruptly* change shade every 10 frames or so instead of more continuously (maybe every three frames) on a regular DVB stream... Have a closer look; it's there.

[lordsmurf]

I think you're imagining it ... or viewing results on different displays/players (or just different conditions in general). Authoring alone doesn't do what you describe, not possible.

[gshelley61]

It sure sounds like you are re-encoding somewhere along the way... or like lordsmurf said it is in your imagination, or different conditions and/or displays, etc. Authoring alone simply does not alter .mpg video.

[overloaded_ide]

As others have said and I agree also, you should have the exact same video after authoring as you used for the source, only the file names have changed and it's been broken into smaller chunks of files instead of one giant sized file basically. The is no changed to the actual data unless you are re-encodeing somewhere. So there is no change to quality either, unless you re-encoded.

Think of it as playing a dvd from your burner, then playing the same disk from a plain DVD drive. Same thing either way right. Changing drives doesn't change the disk, and just plain authoring doesn't change video quality either.

If there is a noticeable difference then something else did it.

[FulciLives]

I think something is being missed here.

Yes it is true that a "proper" DVD authoring program does not do any re-encoding or change to the video.

HOWEVER ...

There are DVD Authoring programs that will re-encode any video you import into it even if that video is MPEG-2 DVD spec.

So to the person that is seeing a difference ... what DVD Authoring program are you using?

Some I know of that will re-encode include Ulead Movie Factory and NeoDVD ... I'm sure there are others.

- John "FulciLives" Coleman

[overloaded_ide]

I think something is being missed here.

I agree, I think you missed something

He said to begin with

I've compared authored .VOB's of a reference MPEG-2 (a ~3.5Mbps DVB recording) from DVD-Lab, TMPGENC DVD author, and IFOedit; and all three induce precisely the same amount of video noise from the original DVB MPEG-2....

I use Tmpgenc DVD Author all the time for many things, I never saw it re-encode any of my DVD compliant files. I only tested DVD-LAB a couple times and don't rember for certian, but I think it did not re-encode either.
Darned trial ran out before I had time to test DVD-lab much, got busy soon as I installed it, like the day after, next time I opened it I got a time expired type message. Rats, it looked interesting too though I never saw enough of it to know if I wanted to buy it.

Anyway, maybe your on to something, maybe the missing key here is DVD compliant files?? Perhaps his are not and then the programs are trying to re-encode, though I don't think Tmpgenc encodes does it??

[DereX888]

Any *DVD authoring* software should NOT dare to do any reencoding of standard-complaint files. If it does - it is piece of crap that should be avoided.

SeanG - what exactly you mean, what kind of DVB noise had been introduced during authoring process? In short: VOBs are like containers, therefore they contain inside exactly same video MPEG stream as you fed it to your dvd authoring software, nothing more or less. It is impossible for any 'noise' to be added in this process, unless - as ppl before me have said - unless your authoring software is not really an authoring software, but some kind of authoring-encoding-reencoding-transcoding combo.
I.e. TMPGEnc DVD Author doesn not do any encoding or transcoding on video streams at all, it merely checks are they compliant with dvd-video standard and either rejects or approves them. If you really got some noise added it is most likely comes from bad software player.
BTW - I dont trust any software PC players, as we all know theyre all not even half-real standalone substitutes. Ive seen PowerDVD, WinDVd, and bunch of other greatly 'enhancing' the picture when playing DVD or just VOBs of off hard drive. Its all bullshit with all the software dvd players. The only one I ever seen to come close to the real standalone player was RealMagic Hollywood Plus, but even this one couldn't i.e. read subtitles on CVD or SVCD (perhaps its successor can - xcard or whatever its called?).

I'd suggest to proper burn them to a DVD-R/RWs and then play them from standalone player on TV, compare each other, and see is there really any added noise on them.

[SeanG]

overloaded_ide: I think you've hit it...

See, these DVB files are a "non-compliant" (with DVD) resolution - 544x480; not 704x480 or 720x480...
TMPGEnc flags this as an unacceptable error; so, I've used DVDpatcher to circumvent this...

Could that cause the observed increase in video "distortion"?

Also, it's warned (by TMPG) that the GOP is "too long"; and I haven't bothered to "fix" the GOP's in the MPEG's I've authored (and compared, each found to be equally, slightly degraded) with these three programs.

Could that be the trouble?

[SeanG]

Well, it turns out that there's no problem at all.

(After reading other topics on this, I found The quality reduction is the result of my external DVD player (Panasonic) translating the 544x480 resolution of the DVB MPEG's to display to TV! Not a GOP problem, though TDA - and only TDA - says that the GOP's are too long.

I compared playback from my *DVD player* to TV, and my DVD-RW through ProgDVB & my Nexus-S DVB card to TV - the PC played it just as it should be - no quality reduction apparent relative to the originally viewed, broadcast DVB stream. So **** it. I'll settle there, rather that bother re-encoding - and probably lost more quality that gained by "better" resolution.