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| ==== General Information about Alpha Manipulation ==== | | ==== General Information about Alpha Manipulation ==== |
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| In previous versions of Kdenlive (<17.04 ??) Alpha Manipulation effects always needed to be used in combination with a [[Special:myLanguage/Kdenlive/Manual/Transitions/Composite|composite transition]] or an [[Special:myLanguage/Kdenlive/Manual/Transitions/Affine|Affine transition]] . This is because Alpha Manipulation has to do with manipulating the so called "alpha-channel" of images and videos. The alpha channel is data that describes how two images are to be combined (or composited) into one. So you needed a composite (or affine) transition on the timeline to tell '''Kdenlive''' that you are compositing the videos from two different tracks into one image.
| | Alpha Manipulation, more commonly known as Chroma Key compositing is an effect that changes the background of the picture to a different background the editor may want. |
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| However, in version 17.04 of kdenlive an option was introduced that automatically composited two tracks that have Alpha channel data in them. You turn this feature on by selecting either [[Special:myLanguage/Kdenlive/Manual/Timeline/Editing#Track_Compositing_-_HighQuality|High Quality]] or or [[Special:myLanguage/Kdenlive/Manual/Timeline/Editing#Track_Compositing_-_Preview|Preview]] from the Compositing Option drop down found under the Project Bin. Select None from this drop down to turn this feature off.
| | More information can be found on the pages for the effects themselves: |
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| | [[File:Two tracks no transition.png|left]] || This image shows two video tracks with no transition.<br />The project monitor shows how the upper track takes precedence when no transition is in play.
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| | # [[Special:myLanguage/Kdenlive/Manual/Effects/Alpha manipulation/Blue Screen|Chroma Key ]] (for simple chroma key effects) |
| | [[File:Two tracks composite transition no alpha info.png|400px|left]] || This image shows two video tracks with a composite transition in place but with no alpha information to tell '''Kdenlive''' how to combine the images.<br />With a composite transition but no alpha info to describe how to composite the picture, the top track still takes precedence.
| | # [[Special:myLanguage/Kdenlive/Manual/Effects/Alpha manipulation/Color Selection|Farvevalg]] |
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| | [[File:Two tracks composite transition with alpha info.png|400px|left]] || Dette billede viser situationen med alfainformation tilføjet ved hjælp af blå skærm-metoden.<br />Blå skærm-effekten kendes også som "Color to alpha" [http://www.mltframework.org/bin/view/MLT/FilterFrei0r-bluescreen0r]; alt hvad blå skærm-effekten gør er, at sørge for at alfaværdien er 0 (dvs. gennemsigtig) dere hvor videoen er blå.<br />Nu, hvor vi har alfainformation kan vi se det andet billede der hvor alfakanalen siger, at billedet skal være gennemsigtigt.
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| Nå først du har nogle alfakanaldata kan du ændre indstillingerne for din [[Special:myLanguage/Kdenlive/Manual/Transitions/Composite|sammensatte overgang]] for at ændre, hvordan billederne kombineres. Se siden om [[Special:myLanguage/Kdenlive/Manual/Transitions/Composite|sammensatte overgange]] for detaljer.
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| Du kan også kombinere to videospor ved hjælp af overgangen [[Special:myLanguage/Kdenlive/Manual/Transitions/screen|screen]] (hvis en af dem er filmet på en sort baggrund).
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| ==== Tips til forhåndsvisning af alfamanipulationseffekter ====
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| Forhåndsvisningen i projektmonitoren kan blive meget mærkelig, hvis du markerer den sammensatte overgang eller video 1 i tidslinjen. (Rapporteret som fejl [http://www.kdenlive.org/mantis/view.php?id=2990 2990] og rettet i ver >= 0.9.5 af Kdenlive)
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| [[File:Weird preview look.png|400px|left]]
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| Sådan ser projektmonitoren ud, når du bare markerer den sammensate overgang i tidslinjen. Det er ikke sådan den renderede video kommer til at se ud. For at se, hvordan videoen vil blive renderet til skal du klikke på Video 1 og så på Video 2 i tidslinjen.
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| [[File:Two tracks composite transition with alpha info.png|400px|left]] Sådan kommer forhåndsvisningen til at se ud, når du også markerer Video 2 i tidslinjen. Det er sådan den renderede file kommer til at se ud
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| ==== Effekter i kategorien alfamanipulation ====
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| # [[Special:myLanguage/Kdenlive/Manual/Effects/Alpha manipulation/Alpha gradient|Alfagradient]] | | # [[Special:myLanguage/Kdenlive/Manual/Effects/Alpha manipulation/Alpha gradient|Alfagradient]] |
| # [[Special:myLanguage/Kdenlive/Manual/Effects/Alpha manipulation/Alpha operations|Alfa-operationer]] | | # [[Special:myLanguage/Kdenlive/Manual/Effects/Alpha manipulation/Alpha operations|Alfa-operationer]] |
| # [[Special:myLanguage/Kdenlive/Manual/Effects/Alpha manipulation/Alpha shapes|Alfaformer]] | | # [[Special:myLanguage/Kdenlive/Manual/Effects/Alpha manipulation/Alpha shapes|Alfaformer]] |
| # [[Special:myLanguage/Kdenlive/Manual/Effects/Alpha manipulation/Blue Screen|Chroma Key ]] (formerly Blue Screen) | | # [[Special:myLanguage/Kdenlive/Manual/Effects/Alpha manipulation/Blue Screen|Chroma Key ] |
| # [[Special:myLanguage/Kdenlive/Manual/Effects/Alpha manipulation/Color Selection|Farvevalg]] | | # [[Special:myLanguage/Kdenlive/Manual/Effects/Alpha manipulation/Color Selection|Color Selection]] |
| # [[Special:myLanguage/Kdenlive/Manual/Effects/Alpha manipulation/Mask0Mate|Rectangular Alpha mask]] (Formerly Mask0Mate) | | # [[Special:myLanguage/Kdenlive/Manual/Effects/Alpha manipulation/Mask0Mate|Rectangular Alpha mask]] |
| # [[Special:myLanguage/Kdenlive/Manual/Effects/Alpha manipulation/Rotoscoping|Rotoscoping]] | | # [[Special:myLanguage/Kdenlive/Manual/Effects/Alpha manipulation/Rotoscoping|Rotoscoping]] |
| # [[Special:myLanguage/Kdenlive/Manual/Effects/Misc/keysplillm0pup|keys Spill Mop Up]] | | # [[Special:myLanguage/Kdenlive/Manual/Effects/Misc/keysplillm0pup|Key Spill Mop Up]] |
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| ==== Baggrundsmateriale om compositing ==== | | ==== Baggrundsmateriale om compositing ==== |
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| {{Prevnext2 | | {{Prevnext2 |
| | prevpage=Special:MyLanguage/Kdenlive/Manual/Effects| nextpage=Special:MyLanguage/Kdenlive/Manual/Effects/Audio
| | | nextpage=Special:MyLanguage/Kdenlive/Manual/Effects/Analysis_and_Data |
| | prevtext=Effekter | nexttext=Lyd
| | | nexttext=Analysis and Data |
| | index=Special:MyLanguage/Kdenlive/Manual | indextext=Indholdsfortegnelse | | | index=Special:MyLanguage/Kdenlive/Manual/Effects#Effects_Categories| indextext=Effects_Categories |
| }} | | }} |
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| [[Category:Kdenlive/da]] | | [[Category:Kdenlive/da]] |
Effekter - alfamanipulation
General Information about Alpha Manipulation
Alpha Manipulation, more commonly known as Chroma Key compositing is an effect that changes the background of the picture to a different background the editor may want.
More information can be found on the pages for the effects themselves:
- Chroma Key (for simple chroma key effects)
- Farvevalg
- Alfagradient
- Alfa-operationer
- Alfaformer
- [[Special:myLanguage/Kdenlive/Manual/Effects/Alpha manipulation/Blue Screen|Chroma Key ]
- Color Selection
- Rectangular Alpha mask
- Rotoscoping
- Key Spill Mop Up
Baggrundsmateriale om compositing
For noget baggrundsinformation (på engelsk) er Wikipediaartiklen alpha compositing nyttig. Se også Porter, Thomas; Tom Duff (1984). "Compositing Digital Images". Computer Graphics 18 (3): p253–259 1984 pdf
