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it-it:9.0:techniques:alpha [2014/03/16 11:11] carbat01 |
it-it:9.0:techniques:alpha [2022/12/18 11:20] |
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- | ======Usare video con canale alfa====== | ||
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- | Video con canale alfa e PicturesToExe | ||
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- | ==== Spiegazione ==== | ||
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- | Cominciamo con una spiegazione di cosa sia un video con canale alfa è, e di cosa sia possibile fare con video o effetti video che utilizzano questa tecnologia. Poiché la maggior parte degli utenti conosce i file GIF e PNG con trasparenza, | ||
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- | ==== Tecniche ==== | ||
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- | Usando queste tecniche, è possibile produrre effetti come movimento di testo tridimensionale, | ||
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- | ==== Video RGBA avi con canale alfa ==== | ||
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- | Nell' | ||
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- | I video RGBA avi di terze parti sono stati inseriti direttamente in PicturesToExe sui livelli sopra l' | ||
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- | ==== Video MOV o Flash FLV con canale alfa ==== | ||
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- | L' | ||
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- | The alpha matte is a pure black and white duplicate of the alpha channel video. The areas of transparency in the embedded alpha channel are black in the alpha matte and the subject areas are pure white. So when the alpha matte is used with PicturesToExe as a video mask and the video itself is placed inside the mask container, the result is functionally identical to using an RGBA avi video. The areas of transparency in the embedded alpha channel video become transparent so that whatever lies in the layer beneath shows through in these transparent areas while the opaque portions of the alpha channel video play on top. | ||
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- | In the example below, the alpha matte for the plant in the foreground with flowers was used as the video mask. The color video was placed inside the mask container and this ensemble resides on the layer above the fall scene still image background. In this specific case, the alpha matte was not available from the source and was created by importing the original color MOV format video with embedded alpha channel into the freeware version of VideoPad Video Editor and adjusting the brightness, contrast and gamma values to render a black background with pure white plant and flowers. This is quick and easy to do. This was then output in avi format. The original MOV with embedded alpha channel was also output as an avi and each of these were converted with the PicturesToExe video conversion feature to render the video elements used in this example. The original MOV video with embedded alpha channel was over 700 megabytes in size for the ten second run time duration. After conversion with PicturesToExe with absolutely zero loss in quality, the entire video including the rather high definition background still image is about 64 megabytes! | ||
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- | ==== Esempi in Youtube ==== | ||
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