Alias Issue and relink problems

[Derek Ruddock]

Hi again from the newboy.
I followed advise and tried using the Movie Wizard to creat a slide show.
Quite impressive, but I dcided to carry out further edits in the VSE as I wanted to play with the pan and zooms.
This worked OK but the results on playback on a TV showed alias pattern noise to very visble levels in some pan and zoom shots.
As the original jpegs had a default sharpen applied in Picasa prior to import, I thought this might be the "edginess" that the patterened inteference was caused by. I copied an original jpg file (just for saftey sake) I then edited that original and saved the edit.
When I reloaded the VSP file the program moaned that the file of that image did not exist (even though it is still there!) Is there some other attribute it is wanting to be unchange?
The issue then got deeper. The program gave me the option to relink, but any attempt to do this resulted in the Video Studio Pro crashing, sending error reports and closing. I tried several times without success.
Renaming the old copy allowed reload OK.
Delboy

[Ron P.]

Did you perhaps use Progressive JPEG as the format for your image? Progressive JPEGs are interlaced, and regular JPEGs are one full frame. VS handles regular single frame JPEGs much better than the Progressive.

[Clevo]

I hope I read you right...

Any slight change to the picture will result in it's bits & byts to change too...even the metadata has changed to a different creation date so quite rightly VS see's it as a different file.

To remedy the situation is to instead of re-linking. add the new updated still in the library.

Add the new picture to an overlay track from the library, we're just putting this there as a holder.

Click on the old still you are about to replace. We want to simply work out it's exact duration in seconds & frames (00:00:06:12 as an example, this means 6 seconds and 12 frames)

With the new picture in the overlay track we can now adjust its duration to match exactly.

Now that all that needs doing is to drop the new picture over the old one in the timeline, it should keep any transitions...but you will have to play with its pan & zoom

[Derek Ruddock]

Thanks for the replies.
First I am not sure of the jpeg format. My camera states jpeg exif 2.2, but as yet I have not identified the true specv of this (it's a Canon SX1 IS).
The batch process was carried out in Picasa, very simple but fast, but I am not sure what the file format it saves in is, whether it merely copies the original file format I dont know.
I have as yet to rework my video to leave out the enhancing carried out prior to import. I will make a shorter version this time for a trial. I can still not understand why some scenes have alias artifacts whilst similarly zoomed and panned images do not suffer any artifacts.
As to the re-link, I can imagine that the process is locked into original file info such as a check sum or something, for video this is clearly important, for images less so but it would be a legacy protocol that would commonly be used. I can see noe it is only suitable for relinking lost files, not changing the content even if the change is subtle.
Thanks again for your thoughts
Delboy

[jbarchuk]

The batch process was carried out in Picasa, very simple but fast, but I am not sure what the file format it saves in is, whether it merely copies the original file format I dont know.

From what little experience I had with Picasa (and abandoned because of this fact) it stomped *horribly* on compression. See if there are more settings about that.

Simply glancing at file sizes of various versions/copies revelas all about compression levels.

As the original jpegs had a default sharpen applied in Picasa prior to import, I thought this might be the "edginess" that the patterened inteference was caused by.

Your observation was correct. The 'definition' of sharpen is 'find lengths of pixels with contrast (read: edges), and increase the contrast -along- those lengths.' Along those lengths meaning for a few pixels on either side of the lengths. Depth of sharpening is how many pixels on either side of the edge to modify, plus level of of contrast adjustment. I say lengths of pixels rather than lines because line generally means straight and the lengths aren't necessarily straight but can be curves too.

I copied an original jpg file (just for saftey sake) I then edited that original and saved the edit.

Meaning you loaded a jpeg, edited it, and saved it as a jpeg? *That* will cause further degredation. Even at 100% quality - 0 compression there is still always some loss. Better: first convert jpeg to tiff or png and then edit at will, and use -that- in the vid. Well, just an opinion, and circumstances/requirements vary, but any compression or loss of quality is *always* to be extremely avoided.

Even at the camera level jpeg is never 'original' as such. The camera itself compresses too.

Have a day!

Jim
jb@jbarchuk.com

[Ron P.]

Just to add to Jim's great advice...

Most image editing applications have the option of using a proprietary working file format for editing. Picasa does not, so any editing is done to the original, and thus degrades it.

For example Corel PhotoImpact uses UFO, PaintShop Pro Photo uses PSP, Photo-Paint uses CPT. These are working formats, provided so editing can be done to images, without losing quality. Once your editing is completed, you can then save as or export to one of the many common formats.

I developed a workflow some time ago, and it has become second nature now. Whenever I want to edit my photos, the first thing done in my program is to create a working image, be it PI, PSP, or CPP. This is done not only to maintain quality, but also to guard against corrupting my source image should something go wrong.

[sjj1805]

Picasa is great for showing off your albums on line. I would not use it though as an editor.