when the external mute switch is on the app has no sound. I use SimpleAudioEngine in my app to play sound effects.
How can I play sounds even if the mute switch is set to silent?
If you initialise with [CDAudioManager initAsynchronously:kAMM_PlayAndRecord]; the mute switch is overridden. This is as far as I know also the only way to get microphone input.
When I used [CDAudioManager initAsynchronously:kAMM_PlayAndRecord]; I was faced with a very low volume problem. Use [CDAudioManager initAsynchronously:kAMM_MediaPlayback]; instead and volume won't be affected.
This will also work in cocos2d-x (either with c++ or js) since that also uses cc.audioengine.
Related
I want to get sound level, so I can display it in my SDL application (the platform is Linux) when recording sound. How can I do that? I use FMOD API in my app, but for recording, I'm using SoX (forking and using exec() to set it up - probably this could be done better but I don't know how :( ). Should I use some function of SoX, FMOD API, or maybe directly access /dev/dsp to get sound data?
You can do recording in FMOD if you like. FMOD APIs such as System::recordStart and System::getRecordDriverInfo can be used. FMOD ships examples of recording which you can use as a basis for your solution.
Specifically for getting the sound level, if you wanted to do it as a runtime thing you could use Channel::getWaveData which will give you a snapshot of the current playing audio, for this you would need to play the recording data.
Or alternatively you could use Sound::lock / Sound::unlock to get access to the recording sound data if it isn't playing.
Once you have access to the sound data through either method you can read through the values to get sound level / peak information.
No, at the very least you should use the "safe" ALSA API. But you should consider using something higher up such as Gstreamer or PulseAudio.
In a c++ program run on Win7, is there a way to fake a mouse movement or something like that, just to keep the screen saver from starting and the system from going to sleep? I'm looking for the minimal approach and I prefer not to use .NET.
Thanks,
-nuun
Don't mess with the screensaver settings, use SetThreadExecutionState. This is the API for informing windows on the fact that your application is active:
Enables an application to inform the
system that it is in use, thereby
preventing the system from entering
sleep or turning off the display while
the application is running.
, and
Multimedia applications, such as video
players and presentation applications,
must use ES_DISPLAY_REQUIRED when they
display video for long periods of time
without user input
That's not a bad idea, any decent media player does it... Look for SystemParametersInfo(SPI_SETSCREENSAVEACTIVE ...) function in Win32 api, it should do the trick.
Before Windows starts screen-saver, it sends SC_SCREENSAVE notification in WM_SYSCOMMAND message to applications. If application wants to prevent screen-saver from starting, it should set "handled" flag to true and return zero during message processing. There is also SC_MONITORPOWER to prevent display from going to low power state.
https://learn.microsoft.com/en-us/windows/desktop/menurc/wm-syscommand
I am making a program in C++ for Windows XP that requires sound to be played so that any program that is currently recording the microphone can hear it, but it will not come out of the speakers. There seems to be no "real" way of doing it, but it is possible to go into "sndvol32 -R" and set the Wave out mix or similar as the current input device. Then you can turn the master volume to 0, play the sound, turn it back up, and reset the input device to the microphone. Is there a way of doing this transparently, or setting the current input device using functions, so that you dont have to see sndvol32 pop up?
Thanks
Doing this would require a complicated kernel-level driver.
Fortunately for you, someone has already done this (it's not free, but it's a fantastic program).
How can I completely disable the keyboard using c++ in windows? And by completely disable I mean so even Ctrl+Alt+Delete doesn't work. I did consider using a keyboard driver but I think you need to restart the computer after it is installed, but since I only need to disable it for a couple minutes that wouldn't really work.
This is not really possible.
WinLogon is designed as the one process that intercepts the Ctrl+Alt+Del key press, even when all other things hang or die.
This is the failsafe against malicious sessions, etc. So there is no obvious workaround.
Maybe a keyboard filter driver would make your request possible, but that is a real kernel-driver.
You can't disable Ctrl-Alt-Delete without removing the keyboard or replacing the keyboard driver, it generates a kernel level notification.
You could use BlockInput function. But it doesn't block CTRL + ALT + DEL.
You could install a keyboard hook and filter out the messages, but you might need to have your application as the top most window. Even then Ctrl+Alt+Del would not get filtered out.
Here's SetWindowsHookEx on MSDN
Example of Hooking the Keyboard
Ok, here goes several random suggestions. I don't have a definitite answer, but here's where I would start:
1) SetupDiRemoveDevice is probably the API you want to call. Although to call it, you'll need to make a lot of other device enumeration calls. Enumerate your HID and USB devices and find the keyboard. Start by looking for the VID/PID of the actual device for starters.
2) Delete the drivers kdbclass.sys and kbdhid.sys. You'll be fighting Windows system file to do this. I have no idea if this will work, but sounds interesting and simple.
3) Write a USB filter driver. Your driver will need to know (or be passed) the vid/pid of the device to filter on, but it might work.
This is NOT a question on plain old boring customization; I actually want to create an program, you know, with source code, etc...
I'm thinking about programming my own media centre interface, and I figured it'd look better if I coded my own splash screen for when the OS is loading.
Note: The media centre interface will be run in X, but this question is regarding what will happen before the X server loads.
Simply, I'd like to make a splash screen application to hide the linux kernel boot messages. Is there a way I can program some animation in to this like some sort of animated progress bar for example? I assume that I won't be able to code any 2D/3D graphics (as that'd require X to be running, right?), so how would I go about generating that?
I'd prefer to do this in C++, but C is also an option.
Note: I'm not looking to use any existing "themes" or anything like that, just interested in the programming side of things.
Update:
Some suggestions have been to use standard images (.bmp, .jpeg, etc), I am not interested in loading images in to an existing application. But obviously I may want to load images in to the boot screen application that I will make.
I'm not tied to a Linux distro, so this can be for anything, although Debian or a Debian-based distro would be nice.
I like the suggestion about loading the X server early and running a loading screen from there, however is there not a more direct approach? Surely you can make a program which hides the boot messages and shows a custom program? Obviously this would be very low level programming, but that's what I'm looking for...
Also, I'm not interested in altering the boot loader (LILO, GRUB, etc).
Update 2:
So far good suggestions have been looking at the source code for applications like splashy and fbsplash. Can anyone better this suggestion?
For the graphical output you can use the Linux framebuffer, for application development you can use gtk which support rendering directly to the framebuffer GtkFB.
For the video and such you can use mplayer which also support rendering to the framebuffer.
For the initialization you have to look around the system used, debian uses a sysv init style initialization http://www.debian-administration.org/articles/212, ubuntu uses upstart.
I'd look into splashy source code. But you will need to code in C.
If you have the skills, you can implement a software based 3D engine (like in the good old days). A simple rotating cube shouldn't be very hard to code and there are tons of tutorials.
The downside is that you will increase the boot time, something not very pleasant in a media center.
Here's the thing: there is a library/kernel patch, fbsplash, that has already been written to do exactly what it sounds like you want to do. It will display an image in place of the normal boot messages, and it can also incorporate a progress bar. When you're trying to do something for which a well-established open-source implementation already exists, there's really no better way to learn how to do it yourself than to look at the source code.
Even if you're looking for something more complicated (say if you want to create some fancier animation than a progress bar), you might be able to start with fbsplash and modify it to suit your needs.
There are several ways you could do this. You could have the X server load very early, and just write a program to display the splash screen. You could also use the framebuffer device. If you are using Intel hardware, or are willing to use the OSS AMD drivers, or Nouveau for Nvidia, you could use kernel mode setting. For this, I would look at Fedora's Plymouth. You could just write a Plymouth plugin to display your splash screen.
The splash screen is simply an image (.bmp, .jpg, etc.) and can be loaded by the boot loader. Since you haven't specified the distribution you're using, look into LILO, grub, or whichever one is appropriate. Check the /boot directory for clues that will direct your search.
If all you want to do is have a nice clean boot sequence with your own splash and absolutely no boot messaging you can do the following:
First, silence grub, boot messaging, and console cursor:
GRUB_CMDLINE_LINUX_DEFAULT = quiet fastboot splash vt.cur_default=1 loglevel=0
GRUB_TIMEOUT = 0
This will very quickly and silently (fade to black) bring you to your login screen, where you can place a splash. Your distro may show it's own splash briefly, which you can change if you like.
This yeilds a professional clean boot sequence, without all the usual linux warts and wrinkles. (Like OSX and Windows).
I personally use Ubunutu with LXDE, and have a clean splashy boot in under 3 seconds, even on older hardware.