"ASIOHost.dll"

Announcing the availability of a new DLL for developers of professional *ASIO audio applications...

ASIOHost.dll vers. 2.00

*ASIO is a trademark of Steinberg Media Technologies GmbH

Contact me for licensing details.

This DLL was developed for the professional reproduction of audio in applications such as automation of radio broadcasting or any application where mission critical audio is to be played via a professional sound card with an ASIO driver. It is the engine behind the one of leading applications in this area in Brazil, InfoAudio, and is now available for licensing. It was developed in C++ and assembler, and you can access it from any Windows application. The current version supports sound cards with an internal format of 32 bit samples, such as M-Audio's Delta, or 16 bits like Digigram's VX222v2. It also supports 24 bit sound cards and some 20 bit cards. Save yourself the time of developing an ASIO interface and instead concentrate on the features of your application.

Features...

The DLL provides an interface much like Microsoft's DirectSound for quick and easy integration.

Provides mixing for an arbitrary number of virtual stereo channels. The virtual channels of your application are mixed in hardware by the sound card. Where the number of virtual channels of your application exceeds the number of channel pairs on the sound card, a Hybrid Mixer automatically mixes your channels down to a number that fits into the sound card's buffers, permitting you to layer your sound as you like.

Alternatively, you can direct output to a desired channel or channels, starting and stopping them individually or with sample accurate synchronization. For an example of this, try the ASIO MultiChannel Player.

Capable of mixing together audio at ¹ different sample rates, whether stereo or mono, streaming or fully contained within a single buffer.

Provides full attenuation capability i.e.: volume control, allowing you to do fade in, fade out, etc.

Provides for high resolution, real-time monitoring of signal levels, allowing you to display VU meters, etc.

Provides for buffer notifications, just like DirectSound.

All buffer attenuation, mixing, and loading done in highly optimized assembler language for maximum efficiency, leaving plenty of CPU headroom for your application to do intensive chores such as mp3 decoding.

Test signal generator built right into the DLL.

Functions provided...

The following list is only one variation of several possible configurations. For example, there are variations that permit your application to receive a list of devices available in a combo box, or a list of channels available in a list box, or to direct output to a desired channel. Your version of the DLL will be tailored to your particular needs. Documentation and sample code will be provided to show how easy it is to employ this DLL. You will be provided with support during development, as well as maintenance after. In over two years of operation in mission critical applications (radio broadcasting) the DLL was found to be robust, reliable and free of defects.

bool __cdecl ASIOOpenDriver(void);
void __cdecl ASIOCloseDriver(void);
bool __cdecl ASIOSystemInit(HWND hwndMain, int maxBuffers);
LPAUDIOBUFFER __cdecl ASIOCreateSoundBuffer(LPBUFDESC lpBufDesc);
void __cdecl ASIOReleaseSoundBuffer(LPAUDIOBUFFER lpAudioBuffer);
bool __cdecl ASIOSetSampleRate(DWORD dwSampleRate);
DWORD __cdecl ASIOGetSampleRate(void);
extern HANDLE __cdecl ASIOGetVUMeterEventHandle(void);
extern DWORD __cdecl ASIOGetCurPeakAmplitudes(void);
extern bool __cdecl ASIOStartPlay(void);
extern void __cdecl ASIOStopPlay(void);
void __cdecl ASIOGenerateSineWav(double frequency, double seconds, DWORD antenuationDBs);
void __cdecl ASIOGenerateSweepWav(double freqStart, double freqEnd, double seconds, DWORD antenuationDBs);

Once you get a pointer to a virtual sound buffer via a call to ASIOCreateSoundBuffer(), you have the ability to call the following member functions on the sound buffer object:

bool GetAudioPosition(LPDWORD pdwCurrentPlayCursor);
bool SetAudioPosition(DWORD dwNewPosition);
void SetNotify(LPPOSITIONNOTIFY NotifyInfo);
void CancelNotify(void);
void SetAntenuation(DWORD Antenuation);
bool Lock(DWORD dwOffset, DWORD dwBytes, LPVOID* ppvAudioPtr1, LPDWORD pdwAudioBytes1, LPVOID* ppvAudioPtr2, LPDWORD pdwAudioBytes2, DWORD dwFlags);
void Unlock(void);
bool Play(bool bLoopFlag);
void Stop(void);
bool IsPlaying(void);
void ProgramFade(DWORD dwFinalLevel, DWORD dwDuration);
DWORD GetPrimaryBufSizeBytes(void);
DWORD GetPrimaryBufferSampleSize(void);

Ask me about... my libraries that supply and manage multiple audio streams, parsing audio files and feeding the data to the driver interface, whether ASIO, DirectX, or Windows multimedia system wave format. Ask as well about my innovative mp3 file parser that loads these files in milliseconds and permits fast and agile seeking for decoding via your ²mp3 codec. For a demonstration of the capabilities of my libraries mentioned here, try the (prerelease version of) MultiStream Player.

1 Capable of mixing audio at the principle sample rate (Example: music from CDs or mp3s at 44,100 samples per second) along with audio at half the principle rate (Example: voice-overs at 22050 samples per second.)

2 *Note - I do not provide a mp3 decoder. For experimentation, there are several open source codecs available, but for commerical software, my mp3 parser would only be useful to a client who has purchased a license for an mp3 decoder. See the discussion on mp3 "Licensing and patent issues" on Wikipedia's MP3 page.