Joe Bleasdale Posted May 12, 2012 Share Posted May 12, 2012 I know what Alpha channels are and how media servers deal with them, but actually creating content isn't my thing. Usually I have content people give me stuff for the servers on whatever show but I have built up a little library of stuff from Internet sources etc and I have some JPGs I want to easily convert to PNG then add an Alpha channel to them. I know Photshop and After Effects can do this but I don't want to pay out money if I can avoid it! Anybody know of some freeware or cheap software that can do this, preferably with an easy interface too! Any ideas people? Thanks. Link to comment Share on other sites More sharing options...
mark_s Posted May 12, 2012 Share Posted May 12, 2012 GIMP - open-source image editor along the same lines as Photoshop. Just as powerful, although if content isn't your thing (like me), it may take a bit of fiddling to work out how to do what you want to do. But there are plenty of resources out there if you get stuck. Link to comment Share on other sites More sharing options...
Joe Bleasdale Posted May 12, 2012 Author Share Posted May 12, 2012 Great ill take a look. Forgot to mention I'm looking for something to run on Mac... I have dual booted windows but only for 3 very specific program's, I'm trying to keep from using the windows partition too much. Does GIMP work on Mac? Thanks for the quick reply too! Link to comment Share on other sites More sharing options...
Dj Dunc Posted May 12, 2012 Share Posted May 12, 2012 Yes GIMP does work natively on a mac. Linux too I believe. The website is gimp.org if I remember correctly. There are plenty of tutorials and plugins available for GIMP around the web, and its very much an up to date piece of software. Link to comment Share on other sites More sharing options...
Joe Bleasdale Posted May 12, 2012 Author Share Posted May 12, 2012 Fantastic! Thanks for the quick advice guys, I'll get learning that today :) Link to comment Share on other sites More sharing options...
indyld Posted May 12, 2012 Share Posted May 12, 2012 The difficulty, particularly with movies, is how you create the Alpha after the fact. Obviously as the JPEGs don't have an Alpha initially, then with a still image you have to create one. Ok, so that's all good if it's just a regular shaped ident or similar and GIMP will knock this up. With movies, if the thing stays still on screen it helps but then you are still into Photoshop On Wheels (Sorry, After Effects) territory. Creating Alpha stuff from vector bits and bobs, outputs from CGI software etc. is easy enough. It's the hardcore creation of anything more than the simplest of Alphas based on a raster still or moving image is the time consuming bit. Link to comment Share on other sites More sharing options...
sleepytom Posted May 14, 2012 Share Posted May 14, 2012 Adding alpha is somewhat misleading.. you should think in terms of removing stuff to create transparency. Google "Background removal" Link to comment Share on other sites More sharing options...
indyld Posted May 14, 2012 Share Posted May 14, 2012 Adding alpha is somewhat misleading.. you should think in terms of removing stuff to create transparency. Google "Background removal" Well, that's an argument on semantics of the usage. Creation of an alpha channel, where none previously exists in a plain ol' raster format is still adding. Just because the resulting channel ends up being used to calculate transparencies, doesn't change that. The alpha itself may be used for Z-depth information instead, though granted possibly not in Joe's media server application. If all you want to do is remove background with your alpha, knock yourself out. It still needs to be created and can be time consuming, especially in a frame situation. Link to comment Share on other sites More sharing options...
sleepytom Posted May 15, 2012 Share Posted May 15, 2012 It may be semantics but it changes the usefulness of a google search significantly; "adding alpha channel" brings up few useful results where as "background removal" brings many tutorials for adding an alpha channel. The point being that few media servers will deal with additional alpha channels to do anything useful. They are expecting 32bit RGBA images such as 32bit PNG - given that the OP explicitly stated this is in his post it seems a little silly to have to get into the semantics of this. But if you want to get silly about it there are various image formats (eg PSD, openEXR) which can contain multiple alpha channels which will not be any use in the mediaserver application the OP speaks of. More over the use of additional channels to represent Z depth or whatever is different to Alpha - Alpha always referes to opacity, other channels such as specular, diffuse, normals, Z depth etc are not strictly speaking alpha channels. All of which is pointlessly off topic. Link to comment Share on other sites More sharing options...
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