Okay .... I found ONE solution for my problem, but I think this is not the sense of the corel videostudio pro x4 software. Also with this solution there is one problem left that really annoys me.
I´ve read, i.e. if you´re rendering a videoclip with the method "same as first videoclip" usually the software shouldn´t change everything on a non-touched original video, but it really does changes some slight things. Why ? Nobody knows. You can proof this by adding an original clip into the timeline without using any fx, filters, texts, etc. and rendering it "same as first videoclip" .
Then do compare both clips via MediInfo and you will see those slight differences. Smaller bitrate, smaller filesize. BUT if you compare both clips concerning picture quality in Media Players, you cannot see anything that changes as long as you have NOT used filters, fx, text, picture in picture etc.
So any change to the original file by filters, fx,transfers, etc. results in a worse picture rendering quality. If you have read my problem above, I also mentioned the video seems to stutter or have a lower framerate if an effect appears, a text or the use of a videofilter.
So I can give you the solution, to avoid this stuttering, but you will see the video itself has an even more worse rendering qualty. Just compare the two pictures below....
SOLUTION AVOID STUTTERING :
My original *.m2ts files are 1080/25i files from a Sony HDR-CX 130:
Start a project with the setings 1080/25 frames interlaced upper field first.
The solution is to render all your original clips without use of a filter, effect texts, etc. etc. - just put your original files into the timeline and add, change or cut NOTHING !!! But for the output process do NOT use "same as first video", select a pattern Corel Videostudio offers you ... i.e. BluRay-Disc 1920x1080i
Render this file ... it doesn´t matter if smart render is on or off, it doesn´t matter if smart proxy is enabled or not, it doesn't matter if hardware acceleration is used or not, so use the fast process you can choose.
Now work with this NEW rendered video file, keep up all the settings in the project or start a new project with the same settings. Now you can add effects, filters, texts, transfers between two clips, picture in picture and all the other things, that Corel Videostudio includes. Then if you wanna output use THE SAME output format as before. You will see, there are no more stutters or lower framerates in that new rendered video.
So it seems, Videostudio ProX4 can handle and work way better with a clip, when it was rendered before once in the programm itself. So you got smooth videoclips without stuttering, bit you have one issue left: The picture quality isn´t as good as the original Clips. Take a look at my comparison between the picture from the original clip and the picture from the rendered clip .... artefactsm fragments and bad colours - especially you can see those in fast movements and high detailed pictures wich is very sad.
Here are the comparison pictures !
Screenshot of the original video-file:http://www.4shared.com/photo/3JlWHolv/f ... furl=d1url
Screenshot of the rendered video-file - setting: BluRay 1920x1080ihttp://www.4shared.com/photo/kuuR0a65/f ... furl=d1url
SO if anyone can help me out to find a solution to keed the original video quality, I really would be happy ...