Re: cx18: "missing audio" for analog recordings

[Darren Blaber <dmbtech@gmail.com>]

Andy Walls wrote:
> On Sat, 2010-04-10 at 23:21 -0400, Mark Lord wrote:
>   
>> On 10/04/10 06:54 PM, Andy Walls wrote:
>>     
>>> Hmmm.  Darren's having problems (loss of video/black screen) with my
>>> patches under my cx18-audio repo, but I'm not quite convinced he doesn't
>>> have some other PCI bus problem either.
>>>
>>> Anyway, my plan now is this:
>>>
>>> 1. on cx18-av-core.c:input_change()
>>> 	a. set register 0x808 for audio autodetection
>>> 	b. restart the format detection loop
>>> 	c. set or reset a 1.5 second timeout
>>>
>>> 2. after the timer expires, if no audio standard was detected,
>>> 	a. force the audio standard by programming register 0x808
>>> 		(e.g. BTSC for NTSC-M)
>>> 	b. restart the format detection loop so the micrcontroller will
>>> 		do the unmute when it detects audio
>>>
>>> Darren is in NTSC-M/BTSC land.  What TV standard are you dealing with?
>>>       
>> ..
>>
>> I'm in Canada, using the tuner for over-the-air NTSC broadcasts.
>>     
>
>
> Try this:
>
> 	http://linuxtv.org/hg/~awalls/cx18-audio2
>
> this waits 1.5 seconds after an input/channel change to see if the audio
> standard micrcontroller can detect the standard.  If it can't, the
> driver tells it to try a fallback detection.  Right now, only the NTSC-M
> fallback detection is set to force a mode (i.e. BTSC), all the others
> "fall back" to their same auto-detection.
>
> Some annoyances with the fallback to a forced audio standard, mode, and
> format:
>
> 1. Static gets unmuted on stations with no signal. :(
>
> 2. I can't seem to force mode "MONO2 (LANGUAGE B)".  I'm guessing the
> microcontroller keeps setting it back down to "MONO1 (LANGUAGE A/Mono L
> +R channel for BTSC, EIAJ, A2)"  Feel free to experiment with the LSB of
> the fallback setting magic number (0x1101) in
> cx18-av-core.c:input_change().
>
>
> Regards,
> Andy
>
>   
So far, it seems fine, no black screens, and audio seems to be fine.