FAQ

Product Features

1001. Can I connect through NAT/Router or a firewall?
1002. Is multicasting supported?
1003. What is the underlying API, used in the VCX library?
1004. Can I record from any of the input devices listed in the Windows audio control panel?
1005. Is it possible to use the VCX library on a web page?
1006. Do your VCX library supports MP3 format?

Technical Details

3001. My applications work fine from the VB IDE. However, in the compiled program no events are fired.
3002. Do you have more samples for your library?
3003. How could I receive a list of FormatTag property values?
3004. Why are lots of audio packets skipped when transferred through the network?
3005. The component could not be switched to a stereo mode.

Licensing

5001. What license do I need if I want to develop and distribute my application with VCX Library?
5002. I am a single developer, how much or which license do I need?

Generally our VCX library requires direct connection between two peers for streaming to be possible.
If your NAT/Firewall is configured properly, it should also be possible to connect through it. All you need to make sure is that NAT allows connection on specific UDP or TCP port to be made from local client (located behind the firewall) to remote server (located in the Internet).

Moreover, the server machine could also be located behind the NAT/Firewall, and client from Internet still can make a connection to it. Again, if NAT supports this and is configured properly.

No, only broadcast sockets are supported.

ACM and MME.

We have a component for recording live audio from any installed sound card in any supported format. All you have to do is to place the vcproxWaveInX component on a form, specify the pcm_XXX properties and activate it by setting active property to true.

If you wish to save recording in a WAV file, simply link the above component with our vcproxWaveRiffX component. You can refer to our WaveRec demo, located in "demos\c#\WaveRec\" folder of VCX installation for example.

Yes, we have an example of how you can integrate our VCX library into a web page. Please refer to the "demos\web\mgclient.html" HTML page for more details.

If your system have MP3 ACM codec installed, you can produce and playback WAV files with MP3 stream inside. It is also possible to stream directly in this format. Switch codec-dependent components into MP3 mode by setting their FormatTag = 85.

We are also planning to add support for third-party libraries such as Lame or BASS in future updates.

This is applicable for VB 6.0 and lower. VS.NET applications are not affected.

If you are using event handler for any of our components, please make sure that SyncEvents property is set to True for all components with event handlers.

You can find basic examples on the Samples page.

In addition, check the Solutions page for more samples.

You can find the full list of numbers in regmm.h file from Platform SDK, or in the MSDN Library. Please also note that only limited number of codecs listed there are usually installed on a system by default.

To see which codecs (with their numbers) are installed on your system try this program. Redirect the output to a file name to review the results:

acmEnum > codec.xml

Ensure that you have enough bandwidth for the quality you want to achieve or decrease the quality settings (PCM... properties values). Each codec has own compression ratio. For GSM codec (FormatTag = 49) the ratio is 1:10, for ADPCM (FormatTag = 2) it is 1:4. Uncompressed CD Quality stream requires a bandwidth of about 200 KB/sec. Also, you may try to increase the OverNum property value, which represents the buffer size. This makes sense in WAN that may group a number of packets before sending them out to the air, so receiving side should be prepared to receive all of them at once.

GSM codec which is used by default in our examples (FormatTag property is set to 49) do not support stereo streams, so you should try ADPCM or even MP3 codec instead.

You can develop with Developer or Enterprise license, but only Enterprise can be redistributed.

Enterprise license is for group of developers (up to 10).

Please refer to order page for more information about different licenses.

You only need a Developer version of VCX Library.