I am looking for a command line tool to use in my bash script that converts a jpg image to a png one.
Thx!
edit: to be clear, the platform the script runs on is iOS. So I am looking for a binary that's compiled for the ARM plaform.
Since you mentioned iOS, I assume you are using Mac OSX. If so, you can install ImageMagick via Homebrew or MacPorts and use the following command in your script
convert my_image.jpg my_image.png
ImageMagick is a powerful tool for manipulating all sorts of images. Check out the documentation if you wish to go a bit more advanced
Related
I'm using this gem right now:
Do i need to install FFMPEG like i did for uploading images (imagemagick)?
If I do, i can't seem to figure out how to install FFMPEG since I'm using Nitrous.io, which is a cloud based IDE.
I found out how to install Image magick from a line of code on nitrous.io, but i see nothing for FFMPEG.
So far I have tried googling quite a lot for an alternative encoder that's compatible with nitrous.
Depends on the system you are running and the configuration you need. if on MacOS i suggest using Homebrew.
https://ffmpeg.org/download.html
I want to cross compile opencv with ffmpeg for arm.
I have cross compiled ffmpeg, how do I configure cmake to see the ffmpeg?
Edit: I am cross compiling for AR Drone 2.0. I use toolchain under platform/linux.
The answer to your specific problem is to use cmake-gui which provides you a visual interface to ease the process of setting up variables, like your ffmpeg package location.
However I have 2 recommendations:
Download the most updated toolchain.
DO NOT USE THIS GUIDE. Use instead the toolchain that you find in the package in sources\platforms\android\android.toolchain.cmake: read inside, you'll find the correct instructions at the beginning of the file.
Another optional recommendation: use ninja as build system, much faster.
I was successful in cross compiling OpenCV with ffmpeg for AR Drone's ARM processor by writing my own toolchain file where I explicitly set all the linker, pkg_config and compiler paths to relevant directories containing the cross-compiled stuff.
I have written a blog post detailing the entire process here:
How to Cross-Compile OpenCV with FFmpeg for AR Drone (ARM Processor).
I want to use and learn JavaCV.
• So, I read some articles about how to set up JavaCV development environment in Window 7. At first they download and install OpenCV and adding some directory paths to System Variable, After that ,they extract javacv-0.7-bin.zip and javacv-0.7-cppjars.zip packages to somewhere(probably C:) and add some .jar files to their projects.
My Question : Do I need to install OpenCV for developing in JavaCV? because I wrote some JavaCV programs and my JavaCV programs compile and run properly (without installing OpenCV).
According to a javacv developer, the answer is NO. It comes bundled. Source: javacv issue 406 on GitHub.
Simple question: can I build OpenCV on Angstrom (BeagleBoard) without downloading it as part of the toolchain ? meaning by downloading the code of the Unix version and building it
(of course, the build process itself would have to be done via the toolchain, but do I have to download the OpenCV as part of the toolchain rather than later, as separated files) ?
You can download OpenCV source code and use the toolchain to compile it. You might have to do some patching yourself, but you wouldn't be first to succeed.
I have a problem trying to get a webcam in OpenCV 2.3 to work with Cygwin. I have a Windows 7 64-bit system and I use Notepad++ and cygwin compilers to do my C++ programming. I have seen other posts with similar problems:
Getting Webcam to work in OpenCV
Can't access webcam with OpenCV
I first tried installing OpenCV via the Cygwin Ports. This is rather easy to install, but alas I run into the webcam problem (always returns false when trying to find a device). I have also attempted to build OpenCV and install manually using the command line flavor of CMake. I tried adding the HAVE_VIDEOINPUT and HAVE_DSHOW flags, but no dice. All my programs compile nicely and I have all the functionality of OpenCV aside for this webcam thing.
Has anyone successfully built OpenCV 2.3 on Cygwin with webcam working?
It is unlikely that cygwin build of OpenCV will be able to access a webcam. At least it is not possible without hacking OpenCV cmake scripts. Under cygwin OpenCV build always follows the UNIX branch and videoinput/directshow is excluded from build.