Audio Mixer: Technical Specs

Audio Mixer DirectShow specs.

Audio mixer is a standard DirectShow filter.

Number of input pins >= 1 (new pin will be added after connection of all free input pins).

Number of output pins >= 1 (new pin will be added after connection of all free output pins).

Input/output media type: MEDIATYPE_Audio, MEDIASUBTYPE_PCM, FORMAT_WaveFormatEx.

Parameters of format:

WAVEFORMATEX: wFormatTag=WAVE_FORMAT_PCM

WAVEFORMATEX: nSamplesPerSec, wBitsPerSample: the same for all inputs/outputs.

WAVEFORMATEX: nChannels: 1 or 2 (mono or stereo). Can be different for different input/output pins.

Each input channel can be mixed with second channel of the same pin (for stereo inputs) or with any channel of another input pin (or several input pins). Input channels can be switched on another output pin in play time also (without graph stop).

Notes:

• All input frequencies should be identical (resampling not implemented in current version).

• After start of graph the media type of output pins cannot be changed (mono to stereo and vice versa).

The filter will have a COM interface and property page for set/get parameters of mixing (Input/channel -> Output/channel).