I am looking for a way to offer a live videostream through a website, but with the idea that certain area's on the videostream are either blurred or pixelated. Because this will be for a competition based setup, it is important that the manipulation is done on the server side and not on the client side. Can anyone recommend me what the best practice is on this, because i have been playing around with ffmpeg but haven't made any progress so far.
What you want to do is called a convolution with a gaussian filter.
Doing this for only a small region would be pretty fast, so you should still be able to achieve good framerates.
Here's a page with a bunch of examples.
Some previous questions on SO:
How do I blur an image?
Fastest Gaussian blur implementation
Related
I am trying to make a game where you have multiple levels where you have to figure out a way to where a certain color should go through pipes that are displayed on the screen. The pipes look like (it all should be better, but just as a reference). So basically there should be an animation of color going down these pipes (different color for different pipe). Now, I can make a gif and use that as my animation, but it's just too large (aprox. 5MB, which isn't a lot, but if you put dozens of levels, it tends to add up).What would be a solution that would be the most efficient?
Well I would first recommend you to go with Unity for Game Development.
If not then check out cocos2d or any other frameworks.
Secondly, if you want to animate things using the native code, then play around with draw() functions (as suggested by #Wakeman) of the Canvas.
Now coming to your question, if your game does not involve continuous user interaction and you are thinking of GIFs as a solution then I would recommend using Lottie library.
You can create beautiful animations in Adobe After Effects and import those (json files) in Android without hurting much memory, plus would get high resolution output.
Have you tried using the drawRect() or drawCircle()? You only need coordinations of the starting point, the turning points, and the ending point. Draw it with a recursive function with delay, and it should look good.
It would be better to construct your levels as tilemap. Every segment of pipe can be coded by number and drawn as bitmap (Sprite) that depends on its state (empty, 1/4, 1/3, 1/2 or full). Similar principles works for engines like Unity/Cocos 2D or your own renderer. This way of building your levels would be hundred times lighter in size than full screen animation and used multiple times for different levels.
I built a simple OCR to detect text. I now need to identify and segment the text from the source image. I used the Canny edge detector to get something like this.
http://i.imgur.com/at4YTb2.png
Sorry, I don't have enough reputation to post images.
I can't figure out a way to separate the text part. I have read,
http://www.math.tau.ac.il/~turkel/imagepapers/text_detection.pdf which is using the Stroke Width Transform
ROBUST TEXT DETECTION IN NATURAL IMAGES WITH EDGE-ENHANCED MAXIMALLY STABLE EXTREMAL REGIONS
The algorithms described are probably the best answers but are very difficult to implement in Java. Moreover, in my use cases the text would be prominent much like above. The above algorithms seem like overkill. I would be grateful if anyone can suggest any alternative to solve this problem. Thanks!
I've got this BufferedImage object that's guaranteed to contain only one color. I'm using it to display a sample image to show size, shape & hardness of a brush in a painting tool. I've tried several different blur implementations for hardness... the latest, that seems to work fairly well is this Stack Filter written by Romain Guy.
I've got 2 problems.
Faster on 1 channel than 4?: None of the blur filters I've tried seem to be quite fast enough... I realize this question has been asked before (and I'm not quite ready to try pulling in FFTW from C), but I'm wondering if there's a way to perform the blur using ONLY the alpha channel bits? The image only contains one color, so none of the other bits will change across points anyway and my thought is that this would cut the number of calculations for the blur to about 25% of the whole blur operation and I figure that's likely to result in a noticeable improvement in performance? I've not been able to find any information about this being tried via web search.
Eliminating the Dark Halo: Every time I try a different blur algorithm I end up having to rewrite it to get rid of the dark shadow around the shape caused by blurring in "black" from colorless pixels where nothing has been painted in yet. I've read about this and I'm using (as far as I know) INT_ARGB_PRE image types, which I remember reading as a solution to this problem. Am I missing something in that solution? Do I need to preformat the image in some way to make it interpret all the empty pixels as white instead of black?
Thanks!
You may find this interesting:
http://www.jhlabs.com/ip/blurring.html
The dark halo issue is discussed, all source code is available as as far as I can recall, it only uses standard Java SE stuff.
I need to draw some execution sequences for some real time systems scheduled using rate monotonic algorithm. The drawing has to be done using Java and it has to be very basic.
Do you a very simple way to do this drawing? Simpler than Graphics2D?
Thanks a lot!
The diagram I want to be as simple or even simpler as this one:
I would suggest you to try with Processing, which is able to do such things with Java in zero time.. home page here.
You can easily embed a Processing frame inside your app, but remember that they are based on AWT so they are heavy weight and don't like being overlayed (for example in a JInternalFrame)
By the way what you seem to want to draw is a Gantt chart right?
You can try with JFreeChart too (see demo here), it's quite customizable and works fine.. homepage here
I have recently been developing a sim game in java, as many of my questions show, and it's come a long way! Graphically, it is somewhat lacking, and at current I'm using shapes for items, people, rooms etc.
I was looking at other similar projects, and noticed that one was using OpenGL. I have been reading CokeAndCode "space invaders 103 - refactoring and OpenGL", and I still don't know if it is something I need in my game or not.
Here is a video that I used for a previous question, but it still shows basically what I have so far (http://www.screenjelly.com/watch/Bd7d7pObyFo), although I have done a lot of refactoring and re coding over the last few weeks, but graphically, nothing has changed. As I understand it, I'm currently using java2D to do this.
I really don't know how I should continue graphically with this game. This is my first project I have done outside of learning for my own enjoyment, and so I'm still rather new to this.
Thanks in advance!
This could turn into a long subjective conversation quickly but I want to state the fact that you don't need openGL. Your application doesn't need to be the best looking one out there. Nethack still attracts people and between you and me : the graphics sucks.
Do you want to learn about 2D and 3D graphics and textures and so on ? Then try stuff... best way to learn. Then you can add this to your resume.
There are a lot of tutorial to do your first steps in OpenGL or some other graphic library. You can even try Qt Jambi. But once you start, you're in for a ride ;)
According to this, it's still largely possible to implement a working graphical game in Java2D with decent performance, as long as you make sure not to do a certain number of bad things.
It might help you to check and see how your approach is, compared to this.
I have no idea how far along Java has come with OpenGL support, so were I in your place I would probably just see how much refactoring of the Java2D code I could do, and figure out what to do from there.
Hope this helps, at least a bit.
One good side of using opengl (even for 2D graphics) is that you will get (if properly done) hardware graphics acceleration for your scenes.
Also, you can use orthogonal projection and keep one of the axis (Z) as zero to do your 2D graphics. It will be easy if you want to add a 3D effect (like lightning or something) if you use OpenGL.
However it all depends on how much you want to improve the graphics, since adding OpenGL might make things a little more complicated than plain Java2D.
How to continue graphically: use textures, more interesting animations (implement a simple physics engine and/or collision detection, that always looks nice).
When you go 3d (for example using opengl) you can add lighting effects to the equation, that usually does a lot to the aesthetics of the whole. For example if the moving circle was a sphere with a nice texture (marble or something), then you could make it really role over the board, and you could specify diffuse and specular reflection values to vary the lighting like for example here.
Camera movement can also beef up the graphics.