I am using Codename One to record the microphone input and play it back to the connected earphones.
First of all if I record audio from mic to a file, and play it back when the recording is over, it works as expected. That's why based on this 2014 question I implemented 2 periodic tasks (timer and timertask), as long as 2 files : one for recording, one for playing. I set the periodic tasks period to values between 100 ms and some seconds, but the result was awful on the Android device. Indeed there were random gaps, it was not smooth at all, nor understandable.
I assume the overhead of writing to a file every period is too high and consequently is causing that behaviour. So using proper high-level Codename One methods does not seem the way to go.
Then in the same question from 2014, the requester is suggesting to create an inputstream from the recording Media and use it as input for the playing Media. However the method MediaManager.createMediaRecorderStream() does not seem to be available anymore. I tried to use the file used to record audio as InputStream for the playing Media through fs.openInputStream(recFilepath) but it did not output any sound nor error on the device.
So my question is whether or not I can achieve my goal with bare Codename One or do I have to use the native interface ? Moreover Shai (in the 2014 above mentioned question) wrote that the second approach with MediaManager.createMediaRecorderStream() might work on some platforms : is the android platform among these, or only iOS platform was aimed at ?
Any help appreciated and sorry for not posting code since I cleared it as soon as an attempt did not appear to work. So I really messed up with my code which now is not doing anything I targetted initially.
Cheers,
As far as I recall Android back in the day didn't support input stream for media and later only allowed capturing input directly as uncompressed WAV which makes full duplex usage impractical. This might have changed since as I recall they did some overhaul of their media libraries.
I'm not sure if this is exposed in our higher level code. Besides using native interfaces you can also help us improve Codename One by forking and hacking it e.g. this is the relevant code in the Android project:
https://github.com/codenameone/CodenameOne/blob/master/Ports/Android/src/com/codename1/impl/android/AndroidImplementation.java#L2804-L2858
This is a contribution guide to Codename One, it covers running in the simulator but that's a good start: https://www.codenameone.com/blog/how-to-use-the-codename-one-sources.html
You can test your changes on an Android device with instructions here: https://www.codenameone.com/blog/debug-a-codename-one-app-on-an-android-device.html
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I am very new at this and trying to get an understanding of this. I have read a lot on the DroneKit-Python site trying to figure out how exactly am I able to communicate with it.
Drone I am currently using is Iris+
I have looked more and there are software that already provide this, but I want to be able to control it plus more.
I want to set waypoints, tell it to then fly give the way points and keep going to them. Also, to be able to arm itself, which is in the example, and override the safety mechanism.
Here is the basic of what I am trying to use it for. Have it fly up at a certain time. Go to the waypoints 1,2,3,1,etc.. Then after X amount of time or on low battery go back to launch point and land.
I have found plenty of code that provides what i need to do, though I don't know if it will work and more importantly I don't even know how to start programming for this. Maybe I have the wrong approach in doing this?
I kind of want this to be a light API, so that in the future I can make a simple UI on my phone and insert some coordinates to give it ways points and that is it. I know there is software out there already that does it, but I want to remove the need for touching the drone. I want it to start and end autonomously.
If anyone could help provide some info that much would be greatly appreciated.
Assuming you have no companion computer (Iris+ does not by default), you are OK with running a ground station app (you won't be out of range to send commands to "end mission on time expiry") and that driving the behaviour from your phone is important, I would be looking at DroneKit Android.
Some notes:
You're going to have to touch the drone at some point to attach the
batteries.
You can arm the device from dronekit
You can override the safety mechanism from a script. I hope you have
a lot of money to pay for the new drones you're going to have to buy when they crash and all the litigation from damaged people and property (in other words "don't do it".
The default behaviour is to return the device to launch (RTL) on low battery. This is convigurable
Setting a time is more "problematic". You can have a timer in a script that then sends return-to-launch but the script needs to be connected to the UAV. This means that either you have to be running in a connected ground station (which might potentially be out of range) or on a companion computer.
Iris+ does not have a companion computer. You have to install one or connect from a Ground Control Station.
DroneKit-Python runs on Linux, MacOSX or Windows. You can't just run it on an ordinary phone, though you could find some other mechanism to send messages/scripts to it running on a companion Computer.
DroneKit Android runs on Android. We do have a planned iOS version too. In theory these could run on a companion computer, but in practice currently these are only used as ground stations.
I asked this question in the Raspberry PI section, so please forgive me for posting this here again. Its just there doesn't seem to be as active as this section of the forum. So, onto my question...
I have an idea and I'm working on it right now. I just wanted to see what the community's thought was on using a screensaver as digital signage. Every tutorial I've read shows someone using chromium in kiosk mode, and while that's fine and works well for some uses, it doesn't work for what I need. I have successfully completed a chromium kiosk, and it was cool. But the signage that I need to create now, has to work without internet. I've thought about installing LAMP locally on the PI, and still using chromium. I still may have to if this idea doesn't pan out. All I need from the signage is a Title Message in the top center, and a message body underneath it, with roughly 300-400 character limit. My idea is to write a screensaver module, in C, that will work with a screensaver such as xscreensaver. The module would need to be able to load messages from a directory on the pi. Then for my clients to update their signage text, I would write a simple client that sent commands as well as the text via SSH to the pi. I want to know what other people think about this. Is it a good idea? Bad idea? Should I "waste" my time doing something like this?
Thanks in advance.
I am already using a rPi as digital signage, just over a year. I am using two different setups:
version 1 uses Raspian loading xdesktop and qiv image viewer to cycle images stored on the Pi itself, synchronized with a remote server. The problem I found was power and SD stability, when the power fails, which it will do no matter what, just when... The Sd card can become corrupt due to all the writing that Raspian does all the time. Certainly does not really need to write to SD.
version 2 uses a RO-filesystem and a command line image tool. Uses the same process to show images from local, and sync with server. But power fail causes no ill effects.
I am not using screensaver to display images, that seemed redundant to me, and unnecessary to wait for the SS to start just to display the images.
Some of the images are created using imagemagik, which is nicely dynamic where needed.
I'm running into problems on the WP7 with MediaElement downloading a 128kbps mp3 stream from a web service for a music player app that i'm working on. The file downloads correctly when the wp7 is on a wifi connection, but downloading sometimes stops when off of wifi. The problem is that i'm not getting any errors or exceptions when the downloading fails and the MediaElement state is "playing". MediaElement runs right past the downloaded portion of the stream and acts like it is playing, but there is nothing to play since the download stopped. I can somewhat replicate this issue based upon my location and using the 3g instead of wifi, so i believe it is due to a low connection. I don't believe any code needs to be shown in this instance, but i try to post something. I want to know if I have any control over this? Are there any other events I could use to detect when the download has failed? Is there another way I could download a mp3 stream that is more reliable and play it? Is there another player/component I should try?
Thanks in advance
You could always use MediaStreamSource to try to handle the download and implement streaming, to some extent. It is a more "painful" way of doing this since you will have to work with an extra media layer, but it pays off by improving playback stability.
Here is a starter example by Tim Heuer. Take a look specifically at how he takes advantage of a custom implementation of MediaStreamSource. Here is a more complex sample.
If streaming is not a requirement, you could download the file (and store it in the Isolated Storage) and then play from there.
I have a C program that runs a scientific simulation and displays a visualisation in an OpenGL window. I want to make this visualisation into a video, which will eventually go on YouTube.
Question: What's the best way to make a video from a C / OpenGL program?
The way I've done it in the past is to use a screen capture program, but this is very labour-intensive (have to start/stop the screen capture program, save the video file, etc...). It seems like there should be a way to automate the process of making a video from within the C program. Then I can leave it running overnight and have 20 videos to look through in the morning, and choose the best one to put on YouTube.
YouTube recommend "MPEG4 (Divx, Xvid) format at 640x480 resolution".
I'm using GLUT 3.7.6_3, if that makes a difference. I can change windowing system if there's a good reason.
I'm running Windows (XP), so would prefer answers that work on Windows, but Linux answers are ok too. I can use Linux if it's not possible to do the video stuff easily on Windows. I have a friend who makes a .png image for each frame of the video and then stitches them together using "mencoder" on Linux.
you can use the glReadPixels function (see example)
But if the stuff you are trying to display is made of simple objects (i.e. spheres, rods, etc..), I would "export" each frame into a POV-ray files, render these, and then make a video out of these pictures. you will reach a much higher quality like that.
Use a 3rd party application like FRAPS to do the job for you.
Fraps can capture audio and video up
to 2560x1600 with custom frame rates
from 1 to 120 frames per second!
All movies are recorded in outstanding
quality.
They have video samples on the site. They seem good.
EDIT:
You could execute a tool to record the screen from your C application by calling it like system("C:\screen_recorder_app.exe -params"). Check camstudio, it has a command line version.
i am developing a video player i silverlight
i wanna something to prevent recording or screen capturing
i thought about hacking the windows APIs and stop my program from running if there was any of those capturing software asking the user to close it first but i donno how to do this
is there another solution ??!!!!
It's simple not possible. If you try it, you're only going to annoy people.
Even 'hacking the windows API' would not work, since the OS itself could be run inside a VM.
I hate to be a downer, but task is impossible to fully accomplish.
If you were somehow able to hook the keyboard (from a silverlight app no-less) I would certainly hope that whatever AV the user is running would throw up some red flags.
Also what if the user doesn't use the standard (alt)+prtscr? A third-party tool might use a different key-combo. Also, I've written a screen-grabber with the GDI+ API, and there's no way to disable something that low-level.
What about attached capture-cards? What if your app is running in a VM or over remote-desktop?
If you are that deeply concerned about protection your HD content, watermark it, or make the user pay for it first.
All-in-all, as soon as your content's data enters your user's computer, they can duplicate it.
You could go about using a key hook system, stopping the user pressing the print screen key on the keyboard, that would be a start. There aren't many systems which stop users from print screening video specifically. You might want to try just watermarking your video instead? At least then people know that the video was originally sourced from you.
The solution is not to allow your application to run on a computer, but instead target a device such as a phone. Computers will always allow some kind of screen capture and video capture but this is much harder and less likely to be tackled if you restrict to only playing on certain devices.
How badly do you need this? There are many ways to defeat screen capture protection: for instance, aiming a video recorder at the computer screen (or looping output to a TV with a capture card, etc. etc. etc.)
Go for a commercial solution if you really really need this: don't have any experience with those myself, however.