[VideoBrick] capture HDMI video and audio at multiple resolutions

[ottingerg]

[VideoBrick] capture HDMI video and audio at multiple resolutions

More technical details at Link to bug in the

Brief explanation

VideoBrick is an ongoing OSHW project aiming to provide an HDMI-Input interface to a small SBC called Olimex LIME/LIME2 (which is a OSHW project itself). It is designed as a daughter board (shield) containing an HDMI-Receiver IC (analog ADV7611). It converts the HDMI to a parallel signal, which can be captured via the CSI Interface of the SOC. Connecting a HDMI Receiver to a CSI Interface is a bit unusual. But tests on the alpha prototype have shown that this is a feasible approach. The desired outcome of this project is to provide a OSHW, low-cost, standalone single-channel HDMI capture devices, running a complete Linux-Stack.

Expected results

• stable HDMI-Capture (video and audio) using the V4L2 API
• working Linux V4L2 driver module supporting multiple input resolutions

Detailed Explanation

VideoBrick hardware prototypes (Rev. Alpha4) are produced and software development already started in 2014 (but paused early 2015). We have prototype hardware and POC code that verfies our assumption that our choosen HDMI-Receiver IC with parallel output can be connected to the parallel CSI interface. The software currently is not stable, doesn't support multiple resolutions and is lacking audio support and because of its scetchy nature needs a complete rewrite. Nevertheless the electrical signal-chain for video input is thus tested. Work on the audio signal chain has not started yet and troubleshooting on the hardware level can be expected.

The task of getting video/audio capture can be subdivided:

• prototype and/or troubleshooting audio input support
• designing or borrowing a test enviroment for multiple HDMI-Input resolution/formats
• implementing/modifying a Linux V4L2 kernelmodule (support for ADV7611 and the Allwinner CSI Interface are already available)

Further reading

• VideoBrick Dev Blog
• Olimex LIME/LIME2

Knowledge Prerequisites

• Linux, C, Shell
• Understanding of V4L2, HDMI (EDID), I2S
• Electrical Engineering Troubleshooting
• Linux Kernel Driver programming

Contacts

• Mailing list: [email protected]