asvravi at gmail
Aug 9, 2009, 10:34 AM
Post #33 of 33
Andy Walls wrote:
Re: Fwd: [UNKNOWN IVTV CARD] (cx23416) AverMedia M113-C
[In reply to]
Ravi, Please test the latest patch at http://linuxtv.org/hg/~awalls/ivtv"]http://linuxtv.org/hg/~awalls/ivtv it adds a secondary set of user controls for manipulating the WM8739 audio controls via v4l2-ctl. You will see controls named "secondary_volume", "secondary_mute", etc. Hans, If these control settings are usable for Ravi, can you please comment on the patch. It was the simplest way I could think of to effect the change in a very generic way, that should work for any ivtv card. But looking at it, I get the sense it could possibly be improved.
Ravi, I'm going to leave the cx25840 module alone for now. I really don't have time to chase problems with changing the VCO operation and it wasn't needed to get your card working (AFAICT). My pull reuqest only include the changes needed for you card (so far) and the PARTSNIC tuner. So what's left? You said you had some noisy/weak audio right? I'll try to add the v4l2-dbg support to the wm8739 module sometime this weekend. I'm essentially going to mimic the implementation in the cs5345 module. That way, you'll be able to experiment with wm8739 settings. Regards, Andy Hi Andy, Thanks. Yes, the VCO change was not needed for me to use my card. About the audio, it is not too bad, but it could be made much better if the gain in WM8739 is increased. Currently it does not seem to be using the full scale range of the ADC, and besides, there is attenuation on the board too, so the final output is pretty low. Increasing the WM8739 volume should help to boost the SNR a lot. I can experiment with the settings once you add the WM8739 support.
The other issue I am seeing is the Composite input quality which I mentioned sometime back. There are jagged edges in red/yellow and sometimes white edges. Moving text is very jagged too. I think it may have something to do with the internal de-interlacing in the card, but I have no clue. I plan to try some register settings tomorrow. The S-Video input does not seem to have this problem and gives crystal clear picture. I don't have any thought on this at the moment. Life got busy recently. Regards, Andy
I returned from my travel, and could test the latest patch today. I could see and control the secondary volume successfully. It was best at full setting (65535) with minimal noise/hiss and no distortion had yet set in with a standard line input source.
The issue of choppy audio is still there maybe because this patch still has the VCO changes. One thing I observed, this choppiness is present only in mplayer and vlc, it is smooth in MythTV. However MythTV does report buffer underrun errors on the mythfrontend stdout every once in a while, although that does not seem to affect its actual sound output noticeably. The 82a264ea2784 patch audio was just fine even in mplayer and vlc, and no buffer underrun reports in MythTV.
As for the video artifacts, I played around with the comb filter settings, but could not find any settings that made it better .