CX Capture App

EXPERIMENTAL!! ALPHA PHASE!!

A Linux GUI capture application for Connexant cx2338[0/1/2/3] and cx25800 based cards.

GUI Layout

Dependencys

• GNU Radio Companion

Ensure your GNU Radio Installation is 3.10.5.0 (Python 3.10.6) or newer.

• CXADC

Notes

You will need to install GNU Radio Companion for this to work, and any depndencies it needs.

You will need a version of the cxadc driver that supports center_offset value (Current release has this)

Use the center_offset value to correct for non-centered singals.

The scale of the graph is +127 to -127, the 100 notations on the amplitude axis do not represent 100%.

Installation

You'll need to have granted yourself read access to /class/cxadc0

Read/write access to the cxadc sysfs parameters (be in admin group).

CXADC Locations /sys/class/cxadc & /dev/cxadc0

Usage

Open via phython in terminal ./cx_capture_app

Open via GNU Radio Companion in GUI cx_capture_app.grc

Features

• Capture Start/Stop

• Set Capture File Path

• Gain Level Adjust

• Amplitude Messurement

Limitations:

• 16 bit mode is not supported.

• Auto adjustment of level not support (like how cxlvlcavdd does for CAV LaserDiscs). As such, probably not best solution for CAV discs.

• Can't change vmux from within the program (this would require further updates to cxadc driver to allow real time vmux change).

• vmux changes won't be recognized while the program is running.

Modify & Update

You can edit the .GRC file in GNU Radio and then preview with F5 and to export to a working python script press F6

Demos

YouTube

Notes & Warnings

Still very experimental.

Not sure if this is the best way to develop a capture app for cxadc, it's just what i could get done quickly.

I also haven't tested A/B capturing with this and straight cat /dev/cxadc0.