smart-renderer produces shortdistortions with titles

[Sektionschef]

So it looks like Smart renderer, when rendering transitions, do this:
1, expands video proportions to width 720 px including a source video
2, then makes a transition of 720 px width
3, then restore default video width to 704 px

And thats the reason of distortions, in my opinion...

I assume there is an easier explaination:
If your video is 704X576 but you change project and output settings to 720X576 then smartrenderer will detect that the video and the project settings do not match and will automatically deactivate smartrendering.
And if smartrendering is deaktivated then no distortions will be seen.
Whether samrtrendering is enabled or disabled should be indicated by the rendering time. Do you get the same rendering time when changing the project and output settings to 720X576 is is the rendering much slower?

By the way, I remember in the past I made some tests using 720X576 mpeg2 files and also got the distortions. Therefore the problems seems to have nothing to do with the hor. size of 704 pixels.
On the other hand, only a view people have reported this problem so far and I think all of them encountered the problem with 720X576 mpeg2 files. Perhaps the Problem does NOT appear when using 720X480 NTSC files, but that's just a guess.

Regards
Sektionschef

[Black Lab]

Perhaps the Problem does NOT appear when using 720X480 NTSC files, but that's just a guess.

I work, almost exclusively, with 720x480 NTSC DV-AVI files and have NEVER had a problem with distortions around the transitions.

[Sektionschef]

I work, almost exclusively, with 720x480 NTSC DV-AVI files and have NEVER had a problem with distortions around the transitions.

Thanks for your answer!
The problem seems to appear only with MPEG2 files and when smartrendering is enabled.
Do you like to make a test for us , put a 720X480 NTSC mpeg2 file on the timeline(if you don't have one then just rip one from a DVD) and insert a transition inside.
Enable smartrendering and create a new mpeg2 file.
Does it have distortions?
Regards
Sektionschef

[etech6355]

Your trying to perform frame accurate editing on a video that's using a non-frame accurate codec. If your performing simple cuts/splicing and re-timestamping then the ulead smartrender will work correctly. Otherwise as you have experienced it's not going to get better.

Convert your video to DV-type1 and perform the editing, you will see a big differrence and you can use smart render with dv.avi because it's frame accurate.

Sometimes editing mpeg2 files can be hopeless. Depends how they were constructed, especially if they were created by a different encoder than the one performing the editing and re-encoding.

[Sektionschef]

many Thanks for your answer.

Your trying to perform frame accurate editing on a video that's using a non-frame accurate codec. If your performing simple cuts/splicing and re-timestamping then the ulead smartrender will work correctly. Otherwise as you have experienced it's not going to get better.

I do not understand this.
Smartrendering means that the software can detect what portions of the project do not need to be reencoded again and what portions must be encoded because they do not match to the settings of the output file.
If I would just do simple cuts/splicing then no smartrendering is required at all because always all portions do not need to be reencoded.
Therefore if a software promises that it supports smartrendering then I expect that it can handle such projects with different video portions.
For example, Womble Video Wizard handles this in an excellent way which confirms that VS11 is faulty here.

Convert your video to DV-type1 and perform the editing, you will see a big differrence and you can use smart render with dv.avi because it's frame accurate.

I do not understand this as well.
If the source material and the target format is mpeg2 why should one convert to DV-AVI???
The goal is the prevent reencoding to get max. video quality. Even if I convert to DV-Avi and then smartrender with DV-avi I finally must reencode back to mpeg2 which should be avoided.
So what's the sense behind this?

Sometimes editing mpeg2 files can be hopeless. Depends how they were constructed, especially if they were created by a different encoder than the one performing the editing and re-encoding.

So why doesn't Womble has any problems with the same files that produce the distortions with VS11? As long as the mpeg2 files follow the mpeg2 standard then VS11 should also have no problmes with them.

Again, in my opinion this is a terrible bug in all VS versions including VS11.
More and more mpeg2 camcorder(HDD,miniDVD,SDcard) appear on the market and I assume that more and more Ulead customers will run into this bug soon or later.

Regards
Sektionschef

[Trevor Andrew]

Hi

I work with Pal format and as Jeff said, I have had no problems with distortions.

I missed out on the sample video in your earlier posts, and have not seen the bad effects.(cannot seem to access the link)

By the way, why are you working with Ntsc files, I thought Austria was Pal???

[Sektionschef]

Hi

I work with Pal format and as Jeff said, I have had no problems with distortions.

I missed out on the sample video in your earlier posts, and have not seen the bad effects.(cannot seem to access the link)

By the way, why are you working with Ntsc files, I thought Austria was Pal???

Many Thanks for your answer, Trevor
I exclusively work with mpeg2 PAL files.
The idea was that perhaps the problem does not appear with NTSC files.
If you like then you can download this small test file:
http://members.chello.at/lorber1/test.mpg
Size is about 8MB.
It is PAL 704X576, 25fps, mpeg2 VBR max. Bitrate=9558kbps, mean bitrate=~9Mbps,16:9, audio is mpeg2, 48kHz sample rate,CBR 256kbps bitrate,stereo.
It comes directly out of my Panasonic Camcorder.
Just put it onto the timeline, insert a transition and do a smart render.
Regards
Sektionschef

[Trevor Andrew]

Hi

As the clip was only 7.5 seconds I inserted to timeline twice.
Added a ¡¥Barn Door 3D¡¦ rendered to same properties.

No problems, the original and the new file look the same.
Transition looks smooth.

I will try to get the file to you.

But haven¡¦t much time at the moment.

[Sektionschef]

Hi

As the clip was only 7.5 seconds I inserted to timeline twice.
Added a arn Door 3D?rendered to same properties.

No problems, the original and the new file look the same.
Transition looks smooth.

I will try to get the file to you.

But haven much time at the moment.

Thanks for taking the time to evaluate the problem, Trevor
The distortions do not appear with every cut(see history of this thread) but you could do the following procedure to get them:
-put http://members.chello.at/lorber1/test.mpg onto the timeline at 00:00:00:00
-cut the clip at 03:20 in 2 parts using the scissor
-insert a "fade to black" transition with a duration of 1 seconds at that cut position
-smartrender to a new mpeg file, it will have a distortion at the end of the transition.
-render again but disable smartrendering: no distortions can be seen
I did the same now and you can see the distortion in
http://members.chello.at/lorber1/test1.mpg
Please let me know your results
Regards
Sektionschef

[Trevor Andrew]

Ok

I have been able to produce the distortions using Fade to Black

I will agree disabling smart render (click options and un-check smart render) when using fade to black produces a good video.

Try

Cut at 03.20
Add black colour at 1 sec
Add 2 x-fade transition at 12 frames
The smart rendered file looks ok.

Smart render works for most video.

What your asking is how good is Smart Render.

You have found a glitch in fade to black, I use ¡¥colour¡¦ black and X-fade

Disabling smart render has cured quality problems in the past.
At least all frames are rendered, but it takes longer to render.

It¡¦s a trade off between smart render or full quality, most times smart render wins.

[Sektionschef]

Thanks again for evaluating my problem, Trevor.
Unfortunately the problem also exists with crossfade transitions and with titles(others not tested yet).
Do the same procedure as above:
Instead of fade-to black use a crossfade transition
Distortions will appear at the end of the transition.
Then
put test.mpg onto the timeline at 00:00:00:00 but do not cut it.
put a title of 1s at 03:20(until 04:20)
If you smartrender this project then you will see the distortions right at the end of the title.
So this isn't just a small bug with fade to black transitions.
This terrible bug appears with other transitions and titles as well.
For me VS11 is useless because the smartrenderer is so faulty.
Would be nice if someone could confirm this.
Regards
Sektionschef

[Jerry Jones]

I can confirm the problem here.

The "distortion" is not easy to notice here, however.

You have to really look hard to see it.

This appears to be a limitation of smart long GOP MPEG-2 editing in Corel (formerly Ulead) software.

Other editors force you to transcode using an intermediate codec, then edit, then output.

But that consumes a lot of time and hard disk space.

I wonder if Apple's Final Cut Pro suffers from this problem.

Apple Final Cut Pro can smart render HDV.

I wonder if they've figured out how to make perfect edits on I, P, and B frames.

You say Womble doesn't suffer from this problem.

Why not use Womble, then?

Corel should devote resources to fix this.

Jerry Jones
http://www.jonesgroup.net

[Jerry Jones]

I've done some more experiments.

I started with files recorded by a Panasonic VDR-M30 DVD disc camcorder.

Their properties:

* NTSC drop frame (29.97 fps)
* MPEG files
* 24 bits, 704 x 480, 29.97 fps
* Upper Field First
* (DVD-NTSC), 4:3
* Video data rate: Variable (Max. 8800 kbps)
* Audio data rate: 256 kbps

I re-encoded my source clip to an I-frame only MPEG-2 file using a bit rate of 15,000 kbps.

Then I inserted the high bit rate clip back into the timeline and added titles.

Then I rendered out the final file using a bit rate of 9800 kbps, which is the highest rate supported by DVDs.

The distortions no longer appear after the titles.

Yes, there's more rendering and there's a need for plenty of hard disk space.

But it stops the distortions.

Jerry Jones
http://www.jonesgroup.net

[Sektionschef]

I've done some more experiments.

I started with files recorded by a Panasonic VDR-M30 DVD disc camcorder.

Their properties:

* NTSC drop frame (29.97 fps)
* MPEG files
* 24 bits, 704 x 480, 29.97 fps
* Upper Field First
* (DVD-NTSC), 4:3
* Video data rate: Variable (Max. 8800 kbps)
* Audio data rate: 256 kbps

I re-encoded my source clip to an I-frame only MPEG-2 file using a bit rate of 15,000 kbps.

Then I inserted the high bit rate clip back into the timeline and added titles.

Then I rendered out the final file using a bit rate of 9800 kbps, which is the highest rate supported by DVDs.

The distortions no longer appear after the titles.

Yes, there's more rendering and there's a need for plenty of hard disk space.

But it stops the distortions.

Jerry Jones
http://www.jonesgroup.net

Many Thanks for your post, Jerry
At least you could confirm that the problem also appears with NTSC mpeg2 files.
Doesn't reencoding to I-frame-only mpeg2 already results in quality loss??? If so then you should get the same result if you just disable smartrendering instead of rendering 2 twice.
A "true" workaround to avoid the distortions but keep best quality is describled in the history of this thread.
By moving the cut borders to an I-frame location let the distortions disappear. Unfortunately this results in a lot of manual work...
I am still surprised how few people have run into this problem so far(or at least have reported it). In my opinion this is a very serious bug that makes editing of mpeg2 files useless!
Regards
Sektionschef

[Trevor Andrew]

Hi Sektionschef
.

I am still surprised how few people have run into this problem so far(or at least have reported it). In my opinion this is a very serious bug that makes editing of mpeg2 files useless!

A lot of users are working with Dv-Avi then converting once to create Mpeg, this would literally disable Smart Render as every frame would be rendered.

I make side shows from still images. But always render to Dv-Avi first.
This allows me to save back to Mini-Dv tape, The Avi being rendered again to Mpeg for burning