Soundcard Dialog

The soundcard dialog is pretty simple. At the top, it allows the selection of one of the installed sound cards. Below, it offers a choice of some predefined sound formats. Currently, only sample frequencies of 11.025kHz, 22.05kHz, 44.1kHz, and 48kHz are offered, with 16Bit, stereo and mono. Formats not supported by the selected soundcard are not shown in the list.

The next line lets you set the maximum buffering in seconds. The default buffering is aimed at providing just enough buffering to ensure proper operation in case the encoder is fast enough to encode at the same speed as the soundcard is delivering the data. More buffering might be needed in case the processor load varies greatly or you use m3w for recording only. In a normal streaming application big buffers are typically not needed, since data is expected to move through the system quickly. But why is a buffer limit needed anyway? There is a hard buffer limit build into your computer: the maximum available main memory. Once this limit is reached, m3w will produce error messages. But this is may be not what you want, because it will require user interaction. The limit given here is a softer limit. When the limit is reached no new buffers will be allocated and sound data arriving from the sound card is simply ignored until buffer space becomes available again from the encoder. This is called a sound gap.