Archives | November 2009

I've personally been very happy with the blog. Have you? Traffic and posts are rising and it's a useful mechanism that allows the folk here at KernelLabs to communicate with you. The blog is also a mechanism that enables you to comment on the specific issues we're raising. We like your feedback. The blog is about news, announcements and basic communication. For a long time we've considered opening up a dedicated forum to better focus the discussion and pick up where the blog falls short. Actually, a forum with many sub-forums for specific drivers, products and applications. This would channel...

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So way back at the end of September, just after the Plumbers Conference 2009 I mentioned on the blog that we were taking another look at the HVR1800 raw audio and VBI support. Well it took a little longer than expected but yesterday we posted a cx23885-audio tree that contains two sets of important changes. 1. It adds support for ALSA audio, applications that understand ALSA can now stream raw analog audio as well as raw analog video. (Remember that TVTime itself does NOT support ALSA directly. See Below). If you're into recording TV audio then you'll be happy about this. 2. It adds support...

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My last few months have mainly been spent working on various analog-related projects. As a result, I often need to test various tuners with analog. I typically use the stock tvtime that ships with Ubuntu for this testing. Over the last year or so, a number of problems have become blindingly apparent with tvtime. Here's a brief list of the things bugging me (in no particular order): Lack of audio support for modern tuners - many tuners deliver audio on an ALSA device, and tvtime has no ability to stream this audio. As a result, people end up with running sox or arecord/aplay in a separate...

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At KernelLabs, one of the questions we receive often has to do with choosng a tuner for use under Linux. Sometimes it's from end users looking to buy a single tuner for their home theatre PC, sometimes it's from resellers, and sometimes it's from embedded customers looking to deploy thousands of units. And in most cases, whoever asks has some difficulty appreciating why our initial answer is almost universally "Well, that depends...". The goal of this post is to provide some insight into the factors that effect the decision making process, and why it's not as easy as "Oh, just buy Product XYZ". When...

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With the HVR-1600 ALSA stuff completed and being validated, I switched over to wrapping up the outstanding em28xx VBI support for PAL. Since I do not have access to a teletext signal here in the United States, I have taken a two-phase approach to adding the support. Phase 1 involves local validation using a well-defined PAL signal source that contains VBI. Fortunately, Andy Walls was very helpful in mailing me a CD a couple of months ago with some MPEG samples that include such info, and that can be used in conjunction with an old Hauppauge PVR-350 that has "TV out" functionality: (Click...

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There is now a tree that users are welcome to test which provides an ALSA interface for the HVR-1600: http://kernellabs.com/hg/~dheitmueller/hvr-1600-alsa-2 As was the case with the ClearQAM improvements, we have ONELAN Limited to thank for sponsoring this work. One thing that is interesting: as a result of wanting to do some testing, I noticed that neither tvtime nor mplayer really work gracefully with the HVR-1600. Both applications only support raw video streaming via MMAP, and the cx18 driver only supports the read() interface. Also, neither support the HM12 colorspace that is specific...

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... So for some reason network traffic to the web server stalled yesterday around 2pm. Thanks to everyone who emailed to raise the issue. The server is back up now, around 9.30am Sunday (Yes - clearly, as you're able to read this). We also have an intermittent disk issue that I've been monitoring for the last few days. I plan to take the server down on Tuesday 24th between 9am and 6pm for analysis and repair.

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A couple of weeks ago, I mentioned that the ATI TV Wonder 600 was available on woot.com for a very reasonable price. Some people bought the device, and had some questions on making it work with MythTV. Here are a couple of notes that resulted. First off, make sure you install the firmware. Instructions can be found here: http://linuxtv.org/wiki/index.php/ATI/AMD_TV_Wonder_HD_600_USB#Firmware If you have a kernel later than 2.6.27, then you do *not* need to install the latest v4l-dvb code. Once you get the firmware installed and reboot, you may need to change the MythTV "Video Scan"...

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Just a heads up to those who were kind enough to try out my testing tree for the HVR-1600 ClearQAM performance improvements: the fixes were merged into the mainline on Friday. So at some point you should stop using my private tree and switch back to the mainline v4l-dvb tree at: http://linuxtv.org/hg/v4l-dvb My tree will be removed from the KernelLabs HG repository towards the end of the week to prevent people from accidentally using it when they should be using the mainline code.

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I spent some time this weekend dealing with various users of the "DVICO Dual Digital 4" who were seeing that zl10353 regression I have fixed on four other boards so far. I can say some choice words about the person who submitted the patch that caused the breakage, or the person who blindly accepted it upstream without considering the implications for all the other products, but there isn't much value in pointing fingers at this point. I just don't have the time/energy to go through and fix *all* the effected products, so I have to deal with them as people report the problem. The big project...

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