<title>DVB Audio Device</title>
<para>The DVB audio device controls the MPEG2 audio decoder of the DVB hardware. It
can be accessed through <emphasis role="tt">/dev/dvb/adapter0/audio0</emphasis>. Data types and and
ioctl definitions can be accessed by including <emphasis role="tt">linux/dvb/video.h</emphasis> in your
application.
</para>
<para>Please note that some DVB cards don’t have their own MPEG decoder, which results in
the omission of the audio and video device.
</para>
<section id="audio_data_types">
<title>Audio Data Types</title>
<para>This section describes the structures, data types and defines used when talking to the
audio device.
</para>
<section id="audio_stream_source_t">
<title>audio_stream_source_t</title>
<para>The audio stream source is set through the AUDIO_SELECT_SOURCE call and can take
the following values, depending on whether we are replaying from an internal (demux) or
external (user write) source.
</para>
<programlisting>
typedef enum {
AUDIO_SOURCE_DEMUX,
AUDIO_SOURCE_MEMORY
} audio_stream_source_t;
</programlisting>
<para>AUDIO_SOURCE_DEMUX selects the demultiplexer (fed either by the frontend or the
DVR device) as the source of the video stream. If AUDIO_SOURCE_MEMORY
is selected the stream