If you’ve ever had to poke at a DVB driver under Linux, you’ll notice that the configuration for the demodulator and tuner refer to an “IF”. For example, with the xc5000 driver, there is a mandatory parameter called “if_khz” which has to be provided when the driver is initialized. What is an IF, and what… Read More
Tutorial
USB power analysis
Been doing some HVR-950q debugging for the last couple of weeks. Finally getting around to cleanup on some existing patches that haven’t gotten upstream, as well as investigating some new reliability problems. Out of concern that one of my problems might be power related, I dug up some hardware I hacked together about four years… Read More
Michigan Users Group Talk
Last night I gave a talk about LinuxTV at the local Michigan!/usr/group. The slides can be found here: Slides for Michigan Users Group (PDF) The talk went quite well, and it’s always good to hear some feedback from the community as to what issues they are encountering (e.g. MythTV configuration, finding device firmware, debugging issues,… Read More
Em28xx video quality
I’m sure you have all seen the following on a channel in the middle of the night. It’s a set of colorbars. [lightbox title=”Em28xx video quality” href=”../../blog/wp-content/uploads/2010/01/tvtime-output-085940-PM-300×200.png”][/lightbox] The above colorbars were taken using KernelLabs’ analog generator, in conjunction with an em28xx based device. I had been bothered about the general picture quality on the em28xx… Read More
How Tuners Work…
For this blog post, I figured I would introduce you to the basics of tuner design. The goal is to give a high level overview of how these products are built, so you can better understand what is required to work on LinuxTV drivers. We’ll also introduce the key concepts and terminology so that when… Read More
HVR-1600 Performance and Reverse Engineering
Haven’t had much time to update the blog lately. All week I’ve been quietly grinding away at two basic issues: PAL VBI support for the em28xx chip, and identifying/addressing the HVR-1600 performance problem. I often get questions from users along the lines of “how do you make boards work?”. Reverse engineering is a bit of… Read More