Soundcard

The soundcard section shows in the first line the selected soundcard and below the selected audio format. The most important number here is the sampling frequency. It determines the quality of the digital sound as it is produced from the sound card. If the sound is to be encoded at low bitrates a lower sample bitrate might be justified.

The number of bytes received from the sound card is shown next. This number is reset each time the sound card is reopened.

The blue progress bar indicates the buffer status. Every byte received from the soundcard is entered into a buffer before being send to the encoder. The encoding time varies depending on the difficulty to encode, the processor load, and other circumstances. If the encoder is too slow to keep up with the soundcard, the buffer will fill up and this will be reflected in the progress bar. Once the buffer is full, bytes arriving from the sound card can not be stored and are lost. This will result in an audible gap in the sound. In normal processing, this should never happen. If it does, you should upgrade to a faster processor or you have to reduce the processing requirements by lowering the samplerate and the encoding quality.

At the bottom there are a Play button and a Stop button.

• Pressing the Play button will start the soundcard and will cause a continuous stream of data to be send to the encoder.
• Pressing the Stop button will reset the soundcard and the arrival of new sound data will terminate immediately. Data that is still in the buffer will continue to flow to the encoder. The buffers are flushed only when the Play button is pressed again, while old sound data is still in the buffers.