Ability to record a single channel and adjust volume on the CA input

Description

In many audio configurations, the input is a mono source, and may be connected to only one channel of a stereo input or USB audio source. In these cases it is best to only record the channel with a signal (e.g. the left channel).

It is also useful to be able to adjust the volume level up or down at source (i.e. on the CA), to compensate for different microphone and audio hardware configurations.

The attached patch from Adam MacKenzie implements both of these. A new audio producer, ALSAMONOSRC, allows selection of one channel from a stereo source. A new configuration parameter, volume, implements the gstreamer volume element and allows volume adjustment from 0 to 10 (1= 100%, so 0.5 = 50%, 4 = 400%).

UCT has deployed and tested this on a 1.3.x production CA. Here is a sample configuration for a USB audio source (Behringer UCA222 external soundcard) with a left-channel input, volume-adjusted to 4x.

capture.device.Audio.codec=flacenc
capture.device.Audio.flavor=presenter/source
capture.device.Audio.outputfile=audio.flac
capture.device.Audio.type=ALSAMONOSRC
capture.device.Audio.src=hw:1
capture.device.Audio.channel=1
capture.device.Audio.volume=4.0

Steps to reproduce

None

Status

Assignee

Greg Logan

Reporter

Stephen Marquard

Criticality

None

Tags (folksonomy)

None

Components

Fix versions

Affects versions

1.3

Priority

Configure