I am trying to use Apple's RecordAudioToFile and MyRecorder examples. The first example runs well and the file is recorded but I can't hear any sound. And the second example, when I press the Start button, it does nothing. I'm using a Mac Mini to record.
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I tried to record a video with Camtasia Recorder, but got this error:
Camtasia (Windows): We're Sorry! There Was a Problem with Your Recording File
The file has no audio or video. How do I fix this?
The problem is usually with the sound device.
Unplug every recording device except the one you're using. So if you have a studio mic AND another mic (such as a webcam), unplug the other one.
Go to the Camtasia settings and change the recording format. PCM works but another may work for you as well.
Close an reopen Camtasia. Make sure the right recording device is selected. It should work now.
I created a small OSX app that takes a picture on the webcam every hour. However, as soon as the first webcam picture is taken, the app gets listed in the dreaded "Apps using significant energy" list under the MacBook battery menu. It then remains in this list until the app is closed.
However, when examined in Xcode, it is clear the app only consumes energy for the brief second that the photo is taken, as seen here:
Is there any way to tell OSX to re-audit energy usage? Or could I silently quit and restart my app after each photo to "clear its record"? How else can I get rid of this false bad-rap from the OS?
EDIT: Further research shows that simply accessing the camera is does not automatically put an app on this list. Apple's own Photo Booth app, for example, does not get listed even when it is filming video. I've edited the title and question to be more explicit about finding what it is that triggers this warning.
I'm using the popular ImageSnap code for taking the picture. The same issue happened with both the original and the new Mavericks-specific version.
If I use my in-ear headphones with my macbook pro it takes me a few minutes until they are fitting perfectly (due to the foam bits on the headphones) :)
My idea is to use internal macbook pro microphone to be able talk to somebody coming to my desk without having to remove the headphones every time. So kind of an 'intercom' thing which can be enabled by hitting a hotkey.
First thought was to use applescript which could be easily used for pausing iTunes, but I could not find information about how I could forward the microphone output to my headphones.
Next try was to check Xcode for writing a Cocoa App. By starting with an example provided by Apple I think it would be achievable for me to extend it to fit my needs.
So my question is:
Do you have a better idea/approach to solve my problem?
I'm looking for writing virtual camera drivers. Does anybody has idea?
Any book that would be helpful or any link.
Adding more details:
I have developed a device driver which saves the image to disk and the display uses the device driver to display the image. The performance does not seem good.
The fns. that I have used are:
//to capture
GetDesktopWindow()
CreateCompatibleBitmap()
Save()
//to display
WM_MOUSEMOVE
giving a call to capture and display every time
but the display is not continuous and appears only after window goes out of focus and comes in focus again
Should I use some other technique to record or display images, what will give fruitful results, please help.
Thanks,
-mitesh
What do you mean by virtual camera driver?
It is possible to write a virtual capture device using DirectShow. Such a virtual capture device can then be used by applications such as skype, etc. If that suffices for your needs, you can download vcam from http://tmhare.mvps.org/downloads.htm under the "Capture Source Filter" link.
Edit:
In order to use that capture device in the link I posted you need to download the Windows SDK. The Windows SDK has a tool called "GraphEdit" If you search online, I'm sure you can find a quick GraphEdit tutorial. Basically GraphEdit allows you to construct a multimedia pipeline by connecting a bunch of filters. (This is what happens in the background for instance when you play a movie on your computer. ) This could be something like
web cam -> renderer
or
file source -> some decoder -> renderer
and would result in you seeing the video captured by the web cam or the content of the file. The example download shows how you can construct a virtual capture device i.e. it looks like media is coming from a 'real' capture device, but actually you can generate any video you want if you adapt the code to your specific means i.e. take a screengrab and output that. Applications like skype can pick up you virtual capture device if it is registered correctly.
The easiest way to find out if this is sufficient for your needs is to download the capture source filter, register it with the regsvr32 command, and then to use GraphEdit to insert the capture source into a graph, connect the source to a video renderer and hit the play button. A lot of the above mentioned concepts/keywords might seem new to you, but you can do some reading on each topic, and perhaps this will give you a point to get started.
Edit 2:
Is the capture source filter approach not sufficient for your requirements?
1) AFAIR you stated in your (now deleted) answer that you would like to take a screen grab, and use that as a virtual camera device for use in applications such as skype.
If that is all you require, you do NOT have to write a device driver. DirectShow can do that perfectly well by means of the capture source filter. You would then need to
learn some basic DirectShow
modify the source code of the capture filter to take screen grabs etc.
As far as books are concerned to write device driver to accomplish the same, I have no idea. The point I'm trying to make, is that you need to determine whether you actually need to write a device driver or whether simply modifying the open source capture filter is sufficient.
I am developing an application which access my audio input device and record audio from my microphone.
Here when i am pressing START button it have to record audio from microphone and have to stop recording when pressing STOP button.
My device is Lynx-AES16 and i got driver from there site.
In windows i am accessing the machine(Lynx) by using direct-show SDK(Graph edit).
Is there any similar tool like direct-show is available. I checked with AUAudio and IOkit but didnt understood that much.
Can anyone provide some sample or some useful links. Apple link is not good for a starter
Look at the CoreAudio sample code at developer.apple.com. There is plenty of useful code there.
In particular look at the RecordAudioToFile example.