Audio Capture

[News Groups]

Hi, I would like to be able to capture the audio coming in through the Line
In port on my soundcard, using VB.net 2008 Express. I know there are
prebuilt
things that can do this but I would like to build my own!. I've searched the
web but cannot find anything that helps me to get my head around what I need
to do. The reason for all of this is that I can receive data signals from my
radio (i.e. taxi dispatch) and I will push this in through the sound card
and
then decode the data with software. This has been done and is available in
various languages but I've not seen it in VB.
Please format any replies in simple terms and also any examples would be
better in VB and not C!
Thanks
Nigel.

 

[kimiraikkonen]

Hi, I would like to be able to capture the audio coming in through the Line
In port on my soundcard, using VB.net 2008 Express. I know there are
prebuilt
things that can do this but I would like to build my own!. I've searched the
web but cannot find anything that helps me to get my head around what I need
to do. The reason for all of this is that I can receive data signals from my
radio (i.e. taxi dispatch) and I will push this in through the sound card
and
then decode the data with software. This has been done and is available in
various languages but I've not seen it in VB.
Please format any replies in simple terms and also any examples would be
better in VB and not C!
Thanks
Nigel.

I also wonder audio / video capturing classes, but it seems in .net
2.0 or newer frameworks do not provide that kind of classes natively.
3rd party COM libraries might be needed.

It would be great if there was a line-in input and real-time mp3
encoding recording capable library for that purpose. I know Windows
built-in sound recorder is bad for recordings over 60 seconds with
only PCM support.

 

[Guest]

I also wonder audio / video capturing classes, but it seems in .net
2.0 or newer frameworks do not provide that kind of classes natively.
3rd party COM libraries might be needed.

Managed DirectX does provide recording capabilities from what I recall. Or
you can use a library called BASS.

 

[RobinS]

(e-mail address removed):


Managed DirectX does provide recording capabilities from what I recall. Or
you can use a library called BASS.

You're right. My company is using DirectX to record from the microphone
input and do sound editing.

To do mp3 encoding, you have to have a LAME encoder. DirectX records to .wav
format. Note that the LAME encoder is free for a consumer, but if you
package it inside your product and sell your software, you have to pay
license fees.

RobinS.
GoldMail, Inc.

 

[kimiraikkonen]

You're right. My company is using DirectX to record from the microphone
input and do sound editing.

To do mp3 encoding, you have to have a LAME encoder. DirectX records to .wav
format. Note that the LAME encoder is free for a consumer, but if you
package it inside your product and sell your software, you have to pay
license fees.

But as you know LAME does not provide a wrapper for VB.NET, it has a
unmanaged dll as lame_enc.dll written in C++. Callling it under VB.NET
might be frustrating, the easiest wrapper to understand might be
lame.exe as being comman-line shell program.

 

[Herfried K. Wagner [MVP]]

Hi, I would like to be able to capture the audio coming in through the
Line
In port on my soundcard, using VB.net 2008 Express. I know there are
prebuilt
things that can do this but I would like to build my own!. I've searched
the
web but cannot find anything that helps me to get my head around what I
need
to do. The reason for all of this is that I can receive data signals from
my
radio (i.e. taxi dispatch) and I will push this in through the sound card
and
then decode the data with software. This has been done and is available in
various languages but I've not seen it in VB.

Solution using MCI:

<URL:http://google.com/groups?selm=#[email protected]>

 

[kimiraikkonen]

Solution using MCI:

<URL:http://google.com/groups?selm=#[email protected]>

If you record in CD quality (44100 freq, 16bit sampling, 2 channels) a
random distortion and corruption is occured in some parts of recorded
wave file with this MCI code. No problem with Windows's built-in Sound
Recorder with this settings on same system. Also using 8bit instead of
16bit sampling helps to get rid of this sound corruption problem for
files recorded using MCI.

 

[RobinS]

But as you know LAME does not provide a wrapper for VB.NET, it has a
unmanaged dll as lame_enc.dll written in C++. Callling it under VB.NET
might be frustrating, the easiest wrapper to understand might be
lame.exe as being comman-line shell program.

Yes, you're right. This, and the licensing issue, is why we send the sound
file up in wav format, and convert it to mp3 on the server.

RobinS.
GoldMail, Inc.