"Broken" files with Project Settings.

[PuzZLeR]

Hello again,

Has anyone noticed this or had the same problem with MPEG-2 (or other) files?

Before I begin, this is NOT a complaint about out-of-sync video. I am referring to a segmentation in VS's output. I'll explain.

When I make my edits, cuts, etc. with VideoStudio, to save as much source quality as possible I use "Create Video File"->"Same as Project Settings", name and save (while I have Smart Render enabled).

What happens is strange. When using this resultant file in another app I get out of sync errors. I also get "broken" encodes when I then compress to H.264 or use another app to deinterlace (since I hate VS's deinterlacing "frame based"). Even some playback apps recognize that it's "broken".

When I mean "broken", I mean that where there were cuts and transitions from VideoStudio I get sync problems and skip-errors there with other apps. It's as if there's some sort of "seam" or "segmentation" that VS left behind in the file it just finished editing. I personally think that VS didn't complete its work with "time stamps" and such.

The only way I know around this problem is to just create a .VSP file out of the project and use "Batch Convert" and encode to MPEG-2 that way. Doing a complete re-encode solves the "broken" video problem and completes the file.

But it's a two-fold disadvantage because it takes longer to encode, which wouldn't be so bad if it wasn't for the other worse disadvantage - it diminishes the source quality. No matter what bitrate, you do lose quality re-encoding again to MPEG-2 as we all know. I even notice it too - the new encoded video has a definite "softer" touch with several finer details lost.

So how do I correct this? I don't want to re-encode. It's not the extra time that bothers me, but the quality loss hurts.

I've tried apps like ProjectX. It does detect the "seams" but what it does is remove the segmentations and the resulting file is one that "skips".

Any ideas?

Thanks so much for your consultation in advance.

[heinz-oz]

Mpeg2 is essentially a packaging compression codec, meant to be for viewing/archiving, not editing. The files are heavily compressed using a lossy compression algorithm. Only I frames contain the full image detail while subsequent P and B frames only contain the bits which have changed since the last I frame. Cutting at any frame other than an I frame is bound to lose vital data. putting transitions in between these clips is going to compound the problem.

[PuzZLeR]

Greetings Heinz-Oz and thank you for your reply.

Your explanation certainly makes sense as to why this is happening. It seems that only re-encoding would "readjust" the B-frames, P-frames, I-frames, GOPs, timestamps, etc. to solve this problem.

However, I was hoping there was some solution through muxing/demuxing or MPEG repair, etc.

Is there?

Thanks in advance all. I would rather re-encode as a last resort.

[heinz-oz]

There might well be but I am not the right person to answer that. I don't edit mpeg2 as a rule.

Hopefully someone more experienced with this is going to come to your aid.

[lancecarr]

Hi Puzzler,
the bottom line on this is that VS is a "reasonable" MPEG2 editor and is probably good enough in its output to create a perfectly good MPEG file for the purpose of creating a DVD or watching on a computer.
Yes I am sure the MPEGs it puts out have all sorts of little errors however these are not really important for playback, which is what VS is designed to create.
If you import the file structure from any DVD cam or Hard disc cam and load it into a program like DVD Remake you would be horrified at the number of errors that are contained within the file structure! All sorts of IFO errors and VOB errors.
However for the purposes of either playback or importing from the disc those errors are fine and most software will work around them.

In your case you are taking the MPEGs and editing in a "reasonable" MPEG2 editor then outputting to another MPEG2 THEN wanting to further compress that into, as you say, the H.264 codec and have trouble...of course!

If MPEG2's are the way you are going to go and you want perfect output for the purpose of further compression or conversion then you would probably be better served by a purpose built MPEG2 editor like Womble.

Remember, VS is a "jack of all trades and master of none!"

[PuzZLeR]

Thanks once more for your input my friends.

@Heinz-Oz:
Nevertheless, you got me on the right track, at least in thinking that is. I'm now looking into maybe DV and lossless encodes, but it's a different science and new learning curve for me. But I do agree that MPEG-2 in general has its shortcomings. Although heavily supported, it's not the best video format.

@Lancecarr:
Greetings. You do make an excellent point. VS can do lots, but that doesn't mean it's the best at everything. From an Average Joe Consumer's point of view, VS is a sending from Heaven. It is really, no sarcasm. It's a great package.

But if you want to do more complex tasks, and need "perfect" MPEG-2 for example, or other advanced video projects like even H.264, you will be deprived.

Sadly, you're correct.

And to comment on what you said, not to bash VS but as input, VS is NOT the best MPEG-2 encoder. It's "good", but not the best.

I've compared encodes with VS and others (won't mention), and although VS does get the job done, it falls short in quality. Not much, but for example I notice that in one clip, one man wearing a white jacket with light gray stripes came out nice with another MPEG-2 encoder, but VS's output showed him wearing a plain white jacket. The stripes were lost, even when I encoded it with 8000kbps at DvD rez, which should have been enough... and this was from VS edits as well!

So that's why I don't want to re-encode or render my material with VS. I do value the quality.

I will look into Womble, but the truth is that I do love VS's functionality and hate to move somewhere else as of yet.

I did try frameserving as a solution, but for some reason, I still can't get the best quality out of it feeding frames to the "other" encoder. For some reason, the "other" encoder gives excellent quality only when I feed it the MPEG-2 content and full file from VS's Smart Render, but the "broken" parts come out with glithes and sync issues - exactly where I made VS cuts, joins and transistions.

Oh well...

Looking into remuxing and MPEG repair again too.

And if I find a good solution for VS users I will definitely revive this thread.

Thanks for your feedback and anybody else's. Great forum, great community.