Hopefully not making this too vague... but I have been dealing with a lot of image scaling and manipulating with an app I'm working on and wanted to know:
Is it possible/feasible to warp images using java code and if so, is it possible? I have read up on JAI but can't seem to grasp it very well. Is there any form of built in implementation that would work with Android 2.3 or higher?
Any tutorials or examples that someone may have come across would be a great help as I have been researching for a while and can't seem to gain any ground.
End goal: to be able to warp an image (point to point by pixels) in multiple places and then saving the bitmap. This would be processed behind the scenes and show the user the end result.
do you have an example of the kind of warping that you want to do? It's certainly feasible but you'll probably end up doing pixel-by-pixel manipulation to generate the warped image.
there is a previous discussion here:
android image processing tutorial?
Related
I want to remove background color of video in exoplayer or make it transparent i.e if video background color is red then make it transparent and view behind exoplayer must be visible.
Note : I don't want to make changes in Exoplayer background only remove video background which is playing in ExoPlayer
I have made lots of search in google but unfortunate did't got right answer, Please let me know its possible or not and its possible using any other way please direct me.
Thanks in Advance
Exoplayer is not really designed to modify a video file like this while displaying it.
Given that the background may change from frame to frame, I suspect you may find it hard to find any solution that will be able to do this quickly enough on any regular Android device, as there will likely be quite a bit of video processing involved.
If your background is static, like the room behind the speaker in a Zoom or similar conference call, then it may be a bit easier and you could look at OpenCV background substitution techniques:
https://opencv24-python-tutorials.readthedocs.io/en/latest/py_tutorials/py_video/py_bg_subtraction/py_bg_subtraction.html
Most of the examples will be in Python so you will have to explore support in Android OpenCV, which is usually a subset and can be a little tricky to set up (check Q&A on SO for this). Android OpenCV also still uses Eclipse rather than Studio in the documentation at the time of writing, which is something to be aware of.
If you have the luxury of removing the background on the server side before you stream the video to the Android device then things will be easier and you should be able to find up to date example using Python and the OpenCV techniques linked above.
If you use case is a 'Greenscreen' background example, then ffmpeg can also provide you filters to change the background as you wish, including making it transparent. The documentation is here: https://ffmpeg.org/ffmpeg-filters.html#toc-chromakey
It includes an example to change the green screen to transparent in an image (png image in this example):
ffmpeg -i input.png -vf chromakey=green out.png
Since I got no answer and not much feedback on this question: Android Flutter Analyze Audio Waveform
and found nothing online about what I'm looking for, I'll simply ask a broader question, since a comment on that answer told me to use native code and use a platform channel to connect it to flutter but when I asked some clarifications I got nothing.
So my question is If I can do operations in Java (which has been around since a much longer time, and thus has a way bigger documentation), and then use the outcome in Flutter.
More precisely, could I do these things in Java and Flutter:
1) Analyse Audio waveform and find peak points in specific frequencies, and use the timestamp to display them in flutter;
Edit 1:
What Are Peak Points?
This Is the waveform of different frequencies ranges (The Orange one is bass (80-255Hz)), and the Points circled in black are Peak Points. I should analyze the audio specter of a song and Find the peak points in certain frequencies. Then When I Find the Peaks I need to save the timestamps, for example, 16 seconds in and so on.
2) Edit 2:
I need to Edit some photos in a video, like a video collage, for which each frame of a 30 or 60fps video is an image.
3) Edit 3:
I need to add basic frame specific effects to the video, for example a blur that will change frame to frame, or a glare.
4) Adding Music to that video and save it to an mp4 or avi or any format.
5) Edit 4: Most Important thing, I don't want to this all in real time, but more like an After Effect like Render process, in which all the frames are rendered together. The Only thing that would be nice is a sort of progress bar telling the user that the Render is at frame, for example, 200 of 300, but I don't want to display any of the frames or the video, just to render it in background and then save it to an mp4 video that can be viewed after.
As You can see it's a difficult process to do in a language to which you hardly find a tutorial on how to play music due to its early state. But Uis and some other things in flutter are way easier to do and Flutter is also Multi-Platform. So I prefer to stick to Flutter language.
Edit 5:
I took a look at Qt and JUCE, and found out that Qt seems a valid alternative but it seems for what understood more like a "closed" system, I mean, for example I looked the multimedia library but for what I've understood, you can do basic stuff, for example play a video, but not collage frames and save it. (Don't know if I explained myself well). JUCE On the other side, looks better but it seems more for PC audio VST than for mobile applications including video rendering. And another thing is that these two are not free and open source like Flutter is.
Then There is Kivy, which could and could not be the best, because it is a Python port for Mobile Devices and I have a lot of experience with Python And I think it's one of the easier language to learn, but on the other side, it hasn't got that much UI power. and as you mentioned there could be problem using libraries on Android.
You stated I could use C++ or Java With Flutter, but with C++ you told that it's a difficult process. So My question turned out to be Could I write the process in java with a Normal Android Application And Then in some way use the functions in a Flutter App?
Edit 6:
I found a possivle alternative:
Kha (http://kha.tech/). But again found nothing on how to use it with Flutter. Could it be a good Idea?
I'm asking more of a confirmation on if I could use Java or any other language to do what I need in a Flutter Application. And If yes if it's complicated or not that much. (I'm a beginner sorta). But Some tutorial or links to kickstart the code would be helpful aswell!
Flutter at this time is great for building UIs but as you've mentioned, it doesn't have a lot of power or compatibility with libraries yet. A good part of the reason for that is that it doesn't have easy integration with c++, but I won't get into that now.
What you're asking is most likely possible but it's not going to be simple at all to do. First, it sounds like you're wanting to pull particular frames from a video, and display them - that's going to be an additional complication. And don't forget that on a mobile device you have somewhat limited processing power - things will have to be very asynchronous which can actually cause problems for flutter unless you're careful.
As to your points:
This is a very general ask. I'd advise looking up android audio processing libraries. I'm almost sure it's possible, but SO questions are not meant for asking advise on which framework to use. Try https://softwarerecs.stackexchange.com/.
Once again, fairly general and a bit unclear about what you're asking... Try sofwarerecs. I assume you're wanting to take several frames and make them into a video?
Some of those effects (i.e. zoom) you could definitely do with flutter using a Transform. But that would just be while playing in flutter rather then adding to the video files themselves. To do that, you'll have to use the video library in android/java code.
Once again, the video library should do this.
This should also be part of the video library.
I do know of one audio/video library off the top of my head called Processing that may do what you need, but not for sure. It does have an android sdk though. OpenCV would be another but only for video/image processing and I haven't used it directly with Java so I'm not sure how easy it is to use.
For how you'd actually go about implementing this along with flutter... you're going to need to use Platform Channels. I mentioned them in the comment to your other answer but figured you could look that up yourself. The documentation does do a much better job of explaining how that works and how to set it up than I can. But the TLDR is that essentially, what they allow you to do is to send serialized data from native code (java/kotlin/swift etc) to flutter code (dart) and vice-versa, which gets translated into similar data structures in the target language. You can set up various 'channels' upon which the data flows, and within those channels set up 'methods' which get called at either end, or simply send events back and forth.
The complication I mentioned at the beginning is that sending images back and forth across the channels between flutter and dart isn't all that optimal. You most likely won't get a smooth 24/30/60fps of images being sent from java to dart, and it might slow down the rest of the flutter ui significantly. So what you'll want to use for the actual viewport is instead a Texture, which simply displays data from the android side. You'll have to figure out how to write to a texture from android yourself, but there's lots of information available for that. Controls, the visualization of the audio, etc can be done directly in flutter with data that is retrieved from native.
What you'll have is essentially a remote control written in dart/flutter, which sends various commands to a audio/video processing library & wrapper code in Java.
If all that sounds complicated, that's because it is. And as much as flutter is very nice to build UIs in, I have doubts as to whether it's going to be worth the extra complications if you're only targeting android.
Not really related to the answer but rather some friendly advice:
There is one other thing I'll mention - I don't know your level of proficiency with programming and with different languages, but video/audio processing and such are generally not done in java but rather in actual native code (i.e. c/c++). As such, there are actually two levels of abstraction you're going to have to be dealing with here (to some degree as it will probably be abstracted somewhat or a lot depending on the library you're using) - c/c++ to java and java to dart.
You may want to cut out the middlemen and work more directly with native - in that case I'd recommend at least taking a look at Qt or JUCE as they may be more suitable than flutter for your particular use case. There's also Kivy (uses python) which may work well as there's a ton of image/video/audio processing libraries for Python somehow... although they may not all work on android and still have the c++ => python translation to some degree. You'll have to look into licensing etc though - Qt has a broad enough OS licence for most android apps, but JUCE you'd have to pay for unless you're doing open source. I'd have to recommend Qt slightly more than the others as it actually has native decoding of video frames etc, although you'd probably want to incorporate OpenCV or something for the more complicated effects you are talking about. But it would probably be on the same level of complicated as simply writing in java code, but with a slightly different UI style & easier integration with c++ libraries.
I'm trying to develop a sort of AR for BlackBerry devices. Trying to achieve the best compatibility for old devices, if it's possible I would like to make it for BlackBerry OS 5 / 6.
Due to lack of hardware performance, I'm not trying to show a real-time solution on screen. Right now I just want to recognize some symbol that the camera see, at the moment the symbol is recognized I want to capture a photo of the current view.
After that, I want to crop part of the captured photo and compare it with a imagery and determine if it matches some image.
I'm quite advanced on researching the alternatives, for the image comparing step, I know there are two common techniques histogram and keypoints. I'm almost decided to use histogram method, but I'm worried about the colors captured by the camera could be a little different from which ones I got in the database (due to light sources, colors, etc.)
Any ideas of which is the best method to achieve what I'm trying to do?
Thanks!
I get this problem:
The type java.awt.image.RenderedImage cannot be resolved. It is indirectly referenced from required .class files
I know it means that there is no reference to it in my build-path and I heard that java.awt.image is not in the Android SDK. So I am trying to figure out how to work around it.
This is my code:
Bitmap image = (Bitmap)data.getExtras().get("data");
String text = new OCR().recognizeEverything(image);
Obviously you can see that I am trying to use a OCR library. If it is impossible to get around this then can anyone show me a reference to maybe a "how to make an OCR program" or something along those lines. I pretty much have NO experience with images.
Thanks!
If your OCR library uses java.awt classes internally, you can't use it on Android. Porting it to use Android classes instead is likely to be non-trivial, especially if you have no experience. This library is being actively developed, and is reported to work on Android (I haven't personally used it). You might want to give it a try. Also, searching helps too: this is a fairly frequent question on SO, you might get some other ideas from previous answers.
We are developing pure java OCR library here:
http://sourceforge.net/projects/javaocr/
At the moment, there is some image processing stuff, invariant moment based recognition
and high performance binarisation. There are also demos schowcasing complete roundtrip for android ( gathering samples, performing recognizer training, performing reconigtion )
I already published 2 appluications based on it:
http://www.pribluda.de/android/charger/
http://www.pribluda.de/android/ocrcall/
i want to use a function for image recognition
i dont want to make an algorithm.
please suggest me a function where i could compare two images and tell whether these images belong to the same object.
please help me!.
Arbitrary image recognition is something that computers can't yet do (even for supercomputers). However, Google Goggles comes close, being able to recognize a wide range of objects. Read its limitations, and see if it suits your purpose.
Yes. There are definitely ways to do this but they all depend on what you are trying to do. If you are more specific about what you want to compare then it will be easier to give a more thorough answer.
There are some excellent libraries out there but it will require some effort on your part to learn and understand how to use them and how to use them on the iPhone.
The most famous algorithms so assist in finding images inside other images are called SIFT and SURF. Unfortunately both are patented and cannot be used commercially in an application.
Consider using OpenCV for most of your image operations.
Or you could use OpenFrameworks (google has tagged it as a phishing site for some reason, im sure theyll fix that soon)
You might also consider VXL which has started to become more popular.
Good luck!