Audio Configuration

Picolo U4 H.264 PCI-104 supports the following audio configurations:

The default audio configuration is 6-bit linear PCM 8 kHz.

Child elements of AudioEncoder root element

XML elements

Attributes

Content

Number of occurrences

Description

Verbose/VB
Concise/CS

Immediate

EMPTY

0/1

Syntax that the driver uses to generate this XML file. By default, the driver uses the verbose syntax.

Active/ACT
Idle/I

Immediate

EMPTY

0/1

Controls the audio encoder operation.

Volume/V

Immediate

PCDATA

0/1

Controls the volume. Value range: [25..275]. Default value: 100.

FormatG711ALAW/G711A
FormatG711ULAW/G711U
FormatLPCM16/LPCM16

 

EMPTY

0/1

Selects the audio format. The default format is G.711 A.

BufferSizeAuto/BSA

 

EMPTY

0/1

The buffer size is automatically determined by the driver. Its capacity corresponds to 160 milliseconds regardless the sampling rate. This is the default setting.

BufferSize/BS

 

PCDATA

0/1

Size, expressed in bytes, of one encoded audio buffer. Default value: 0.(*)

BufferCount/BC

 

PCDATA

0/1

Number of encoded audio buffers. Default value: 3.

BufferOffset/BO

 

PCDATA

0/1

Address offset of the first data. Default value: 0.

(*) The buffer is filled with at most 160 millisecond of data regardless the sampling rate.

Child elements of FormatLPCM16 element

XML elements

Attributes

Content

Number of occurrences

Description

SamplingRate8KHz/K8
SamplingRate16KHz/K16
SamplingRate22.05KHz/K22.05
SamplingRate44.1KHz/K44.1
SamplingRate48KHz/K48

 

EMPTY

0/1

Audio sampling rate. (*)

The default sampling rate is 8 kHz.

(*) Each audio source can be configured individually. However, the following restriction applies: The audio sampling frequencies of all the audio sources of a board must belong to one frequency groups. There are two groups:

XML File Example

<root>/audio/source*/config.xml – Read operation – Verbose mode

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE AudioEncoder SYSTEM "config.dtd">
<AudioEncoder version="1.0">
    <Verbose Immediate="true"/>
    <Idle Immediate="true"/>
    <Volume Immediate="true">100</Volume>
    <FormatLPCM16><SamplingRate8KHz/></FormatLPCM16>
    <BufferSizeAuto/>
    <BufferCount>3</BufferCount>
    <BufferOffset>0</BufferOffset>
</AudioEncoder>