The MPEG myth

[TDK1044]

This is meant as a friendly observation regarding some MPEG2 posts in this forum. Much has been written in this forum about MPEG2. I've edited with MPEG 2 in Video Studio 7, 8, 9 and now 10, and I have yet to experience a problem with either a corrupt MPEG2 file or the much talked about quality loss. If you know what you're doing within a project, and you only perform one render of your captured MPEG2 files within video studio prior to the burn to DVD, the end result is totally fine and perfectly in sync. I think some people who were looking for solutions to various problems in this forum simply blamed MPEG2 because MPEG2 was there to blame. The statement often seen and repeated here that "MPEG2 is for viewing but not editing" is utter nonsense in my experience. Yes, we can all go into a detailed MPEG 2 compression discussion and the technicalities involved with it, but the end result of our projects in the vast majority of cases are not being judged by video engineers with vector scopes and wave form monitors, but by friends, family members or colleagues. The tests that I have run suggest very little difference between capturing and editing using MPEG or AVI. The real point is that while you can make a technical case for AVI over MPEG at capture, MPEG 2 is not the monster it is made out to be, it's simply the biggest patsy since Lee Harvey Oswald.

[jchunter]

TDK,
I completaly agree. I also have captured and edited mpeg2 since VS7. The tests that I have run show no difference in picture quality between DV and Mpeg2.

If anything can reduce picture quality, it is transcoding from one compression algorithm to another because information that is discarded in the first compression MAY be useful in the second recompression. IMO, the best rule of thumb is to preserve the original encoded format wherever possible. In the case of DV, one transcoding is required prior to burning the video to DVD. But if the video is originally encoded in DVD compliant mpeg2, as in Vinman's Sony SR90, best results will be achieved by preserving that format all the way to the DVD burn.

I think that the origins of mpeg demonization date back to when editing mpeg 2 was as flakey and troublesome as editing the more highly compressed Mpeg4. Divx, H.264 formats are, today. I hope to see improvements in Video Studio that will permit these formats to be easily edited in the future.

[sjj1805]

Terry.

This has had a very big airing already and I have repeatedly stated
"Just because you walk on a tightrope doesn't mean you are going to fall off"

Please view:
http://phpbb.ulead.com.tw/EN/viewtopic. ... 5788#55788
In particular please read
http://phpbb.ulead.com.tw/EN/viewtopic. ... 5015#55015

We are all adults here and no one is going to tell another user 'You must do it this way' what we hope to achive on this forum is users pooling the results of their experiences so that our members can make informed judgements based upon those experiences.

If you wish to capture in MPEG - fine go ahead and do so.
If you wish to edit MPEG files - again fine go ahead and do so.
If you wish to author a DVD from a VideoStudio project file - fine go ahead and so so.
If you wish to burn your DVD at your burners maximum speed - fine go ahead and so so.

You may find that for you everything went according to plan and you are now the proud owner of a small Steven Spielberg style masterpiece.

However do you now feel happy telling everyone else
There is no need to follow all the advice given out on this forum, I ignored it and had no problems so don't listen to them.

Are you then going to re-imburse the countless number of angry members who then took that advice and ended up wasting hours of valuable free time creating their latest masterpiece only to have to throw the DVD disc into the dustbin because it failed to work?

[TDK1044]

Your point is well made, Steve. The problem is that people take as verbatim statements that are made on forums like this, and they then pass those statements on as if they are facts. The statement "MPEG2 is for viewing, not editing" has been repeated here by a lot of people who have read that statement posted by a user on the forum, and they now use it as a factual statement to inform others. It's like a digital version of 'Chinese whispers'. I'm sure that some people have had genuine issues with MPEG compression, and many others haven't but think that they have. For the record, I think this forum does a superb job in many ways, and a handful of people like yourself, Steve, have provided much needed help to many people who otherwise would have torn their hair out. You've certainly helped me out on many occassions. I just think we should all preface more with "in my experience...." rather than making statements which may be interpreted by some as being factual rather than opinion.

[sjj1805]

Terry
Well put and I agree with your statement.

[jchunter]

Steve,
There is nothing "tightropish" about editing mpeg. I would prefer to discuss this topic factually.

Editing video, in general, is complicated and not for the faint of heart. But there are many paths through this maze. Whatever workflow people adopt HAS to be based on a well disciplined management of video properties. It also has to be structured to facilitate debugging, when things go wrong.

There are many possible sources of error and finding out which one is the root cause is difficult. I am sure that you appreciate the logical fallacy of declaring "A" to be the cause of "B" just because it happens to have occurred before "B." Yet, I have observed, all too often, that when a user reports a problem, some of us immediately blame mpeg - rather than focusing on the correct execution of the mpeg workflow.

For example, the evidence that you cite, above, assigns blame for the VS8 OOS problem to mpeg - even though there have been many counterexamples of DV users who experienced the same problem.

The Recommended Procedure has always recognized two different workflows (Mpeg and DV) and that is the way it should remain. Both workflows disserve respect regardless of our personal preferences.

[skier-hughes]

and so the debate will go on........ neither party will agree

[Trevor Andrew]

Hi

I have a digital camera like most of us capture in Dv-Avi.
The data recorded on my camera is Dv-Avi and capturing is a simple process of copying the data to my pc via firewire.
Results are great, then edit and render once to create a file (mpeg) for burning. Fine!

If I were to capture analogue, a VHS connected ‘composite’ needs re-coding to whatever format I choose. Mpeg or Avi

But be aware Avi and Dv-Avi are really a different breed. One needs re-coding one is copied.

Connect analogue and the data needs coding during transfer / capture.

I see no reason why I should not capture to Mpeg using the settings that are compatible for burning my dvd.

Capture to Dvd—Create Vide File—same as first clip—render is quick.

Capture to Avi—Create Vide File to DVD Mpeg 2—render is as long as it takes.

I have worked with Mpeg with little or no problems, but again from analogue capture.

Give me a digital camera and I will use Dv-Avi

The main problem is understanding the video properties.
Whats the difference between an Mpeg template and say Pal-Dvd???????
If you don’t know then you may have problems.

Trevor

[sjj1805]

[skier-hughes]

[Black Lab]

I can't tell, is that can open?

[Ron P.]

I can't tell, is that can open?

I think if you look close, you can see where the can opener sliced the lid

Ron P.

[RussB]

and so the debate will go on........ neither party will agree

<P>
I agree.

[TDK1044]

Please lock this post. Good opinions expressed.

[daniel]

I see no reason why I should not capture to Mpeg using the settings that are compatible for burning my dvd.

Capture to Dvd—Create Vide File—same as first clip—render is quick.

Capture to Avi—Create Vide File to DVD Mpeg 2—render is as long as it takes.

Without forgetting of course that on-the-fly MPEG encoding with personal computers will never get you the MPEG quality you can achieve when you computer spends the whole night encoding your finished project.
It all depends on the "difficulty" of the compression. Some parts will be markedly different after 1/10th of a second encoding or slow-paced 100% quality for the same scene change for instance.

It also depends if you need to cut or edit your movie in the middle of a GOP sequence, forcing re-encodings.

It also depends if you know beforehand what length your project could be, so you don't need to change bitrate after acquisition...

Steve is right, this is a danger area, not a sure death path.
Steve may be wrong; this is not a can o' worms, but a snakepit with Pandora's box open inside. Heeding Murphy's law call.