Preserving quality of lines through 'saves' and 'loads'

I am new to 'Xara', although the process I am about to describe, is well-proven with another brand of software. However, I have never been satisified, due to the amount of pixellation on the margins of lines, and with Xara, I am looking for an improvement.

Basically, I am using graphics programmes to animate lines onto a 'live' video background. I do that by preparing a blank green mask, and tracing, by means of a slightly lighter line, (which is still rendered invisible by the following 'chroma' process in video-editing), as a guide. The actual tracing out of route followed, and so-on is onto the green 'blank', in preparation for the usual 'green-screen' process, to follow in my video editing stage. The principle is well proven and produces authentic animation over a background which proceeds as normal video. (It is also possible over a still photograph). The raster used subsequently, is the AVCHD standard of 1920 x 1080, the animation is of clusters of from three to five frames per 'exposure' and the whole thing is rendered in mpg2 into a continuous video-clip, from which time it becomes 'video'.

However, each frame is required to be 'saved'. When I first tried 'Xara' I was chuffed that the most recent extensions to my ever-lengthening lines were so 'sharp', and that encouraged me to use a line of only 4 pixels width, but when the resulting animation
frames were recalled for storage in preparation for the animation-proper, the lines had developed the usual pixellated 'steps-and-stairs' and pixels on both margins of the lines were in a no-man's land, being half-and-half green and a muddy half-white, (white being the line I have standarised on, for technical reasons of minimal 'bleeding' etc).

What I wish to preserve, is the crisp whiteness of the lines, and the finely pixellated line-margins I began with. I can, for example, broaden the line, but if I broaden it beyond 8px, or so, I am right 'back' where I was with 'the other graphics-programme'. I can, of course, double the size of the raster to 3840 x 2160, (and do, on occasions for static one-off shots), but there are excellent resource-hogging reasons, why I do not wish to do so for sequences of up-to 200 frames, at-a-time.

Am, I missing something somewhere, using a 'wrong' procedure, or simply asking too much of the software? I would be extremely grateful for the input of anyone who might be able to point me in the right-direction.

Ian Smith
Dunedin, New Zealand.

Welcome to TalkGraphics Ian

How are you saving these lines? It sounds as if you are exporting them as bitmaps in which case the lines transition from scalable and vector lines to bitmap images which are made up of pixels.

If there is a possibility to export your lines as SWF (Flash) then the vector quality of the lines can be maintained.

If you have to export the lines as bitmaps, then what is the resolution of the lines?

Xara anti-aliases lines on export to bitmap, but a bitmap is made of pixels and the anti-aliasing is still pixels but blended (anti-aliased) to the background color of the page or rectangle over which the image is exported.

the reason a line in xara looks so sharp is that the xara screen rendering automatically anti aliases it to the editor background [in high quality views]

once you export this, that anti aliasing is fixed and likley this is messing up your chroma - hence the 'muddy green-white'

the best way round this IMO is not to use chroma at all but to use video editing that supports full transparency - maybe in combination with vector swf as Gary suggested, but I appreciate this may not be an option for you

it is actually possible to export from xara without the anti aliasing but then you are back to high resolution, in order to avoid the visible 'steps' that are the inevitable consequence of rectangular pixels

Gary and 'Handrawn',

Thanks for the prompt replies. The lines were exported in bmp format, (I may have mentioned that), and at 96 DPI. I need only to be pointed only in the most fruitful direction in which to follow-it-up, and I am quite capable of taking it from there with the contents of the manual to help me. In connection with video, I am used to manuals of 200 plus pages of content to wade-through and creating my own music as well causes me to consult several whopping manuals in connection with that niche of my activity too.

The outcomes can be excellent, and I am looking forward to compositing various logos, etc in connection with my video-production setup which is known as 'Back-to-the-Drawing-Board', is in High Definition, (as of last August), and has been in 16:9 since the mid-nineteen-seventies and the days of film and anamorphic lenses. Anway, thanks for your helpful suggestions, I will follow them up.

Ian Smith
Dunedin, New Zealand.

Is the pixelation at the white-on-green step, or earlier? One thing you can play with is seeing if you can use a two-color export rather than a true-color. The following is png, but a 1:1 output of 96dpi example showing how the true color becomes muddy and the 2 color becomes much crisper. But close examination shows the true stair-stepping occurring on the two-color version.

Another tack you can try is copying the lines multiple times on top of themselves, either selecting them and Ctrl-K for cloning, or placing them on their own layer and duplicating it several times. The anti-aliasing routines will see the duplicates and make the output lines much sharper, but some pixelation will still occur.

Thanks David, something else for me to follow-up on. I have read the 'Xara' manual from approximately p400 several times, and I think I have a solution which may be worth trying, that is, to 'export' in the video 'AVI' format, after doing the animation in the 'Xara' animation setup. AVI, in video is particularly useful, since there are numbers of image-manipulation programmes which work in that format, and several more based upon a scripting-language, called 'avisynth'. If that doesn't bear fruit, I shall try the SWF format for export. For some of my simpler animations (they are generally small items in the corners of the screen), the 'flash-based' techniques might be quite OK. Most of the major items, such as animation over live screen-action, are full-screen though.

I do have another 'device' which I use, and it is highly effective, especially since pixellation doesn't matter. I use a hand-held GPS to keep track of where I 'am', when in unfamiliar territory. Now, the LCD screen of a GPS never 'shows-up' in a photograph, or movie, because it has low contrast and is usually so dark in relation to its surroundings, that the video process will not treat the contrast-range kindly. So, based upon a photograph of my 'GPS', a Garmin 'Oregon 400' I have created a 'graphic', which consists essentially, of a frontal view of the GPS, with the screen replaced by a blank 'chroma-green' window. Although the screen contents
are not usable, the equivalent portion of the map in my computer, into which all 'routes' are downloaded upon my return home comes-across perfectly well. It is simply, then a matter of finding the portion of the map, appropriate to where I have been,
cropping it to size, and fitting it (apparently) into the vacant 'window' of the GPS. By duplicating that map, 'x-number' of times and
animating onto it the route taken on-the-day, frame by frame, the 'GPS' graphic may 'show' in the bottom left-hand corner of the screen, in concert with the 'live-action' taking place, if I have patience enough. The screen on my GPS is 'high' and narrow, but I actually have three views of it, the full-frontal 'upright' version, a version rotated 90 deg. to the left, and one rotated 90deg. to the right. That takes care of those routes which should, properly, travel across the screen width-wise, instead of 'up-and-down' and having two versions of the graphic which orienate, 'across-screen' makes an allowance for routes of travel 'left-to-right' and vice-versa. There's always more than one way, of skinning a cat!

Ian Smith
Dunedin, New Zealand

perhaps you could show us an example video - i would love to help but i confess i have absolutely no idea what you are talking about