xc2028 sound carrier detection

xc2028 sound carrier detection

[Aleksandr V. Piskunov]

Is xc2028 tuner able to autodetect/handle different sound carrier standards
without being spoon-fed precise input system information using module param
or ioctl?

Got an ivtv board here (AverTV MCE 116) with xc2028 and cx25843.

When I specify a generic standard using 'v4l2-ctl -s pal', xc2028 loads
firmware specific to PAL-BG, so if there is an PAL-DK or PAL-I signal on RF
input... nice picture but no sound. Setting a more precise standard like
'v4l2-ctl -s pal-dk' fixes the issue, but other PAL-BG or PAL-I channels
loose sound.

Bttv board with a tin-can tuner sitting on the same RF source autodetects
PAL-BG, PAL-DK and PAL-I without any manual intervention.

So any voodoo tricks to get the autodetection running?

Re: xc2028 sound carrier detection

[Aleksandr V. Piskunov]

On Mon, Sep 21, 2009 at 09:52:38PM -0300, Mauro Carvalho Chehab wrote:
> Em Tue, 22 Sep 2009 01:37:51 +0300
> "Aleksandr V. Piskunov" <aleksandr.v.piskunov@gmail.com> escreveu:
> 
> > Is xc2028 tuner able to autodetect/handle different sound carrier standards
> > without being spoon-fed precise input system information using module param
> > or ioctl?
> > 
> > Got an ivtv board here (AverTV MCE 116) with xc2028 and cx25843.
> > 
> > When I specify a generic standard using 'v4l2-ctl -s pal', xc2028 loads
> > firmware specific to PAL-BG, so if there is an PAL-DK or PAL-I signal on RF
> > input... nice picture but no sound. Setting a more precise standard like
> > 'v4l2-ctl -s pal-dk' fixes the issue, but other PAL-BG or PAL-I channels
> > loose sound.
> > 
> > Bttv board with a tin-can tuner sitting on the same RF source autodetects
> > PAL-BG, PAL-DK and PAL-I without any manual intervention.
> > 
> > So any voodoo tricks to get the autodetection running?
> 
> No, sorry. It requires specific and different firmwares based on your video
> standard. I suspect that it is due to some firmware limiting size, since newer
> products from Xceive, like xc5000 don't have such troubles, but this is just my
> guess.

Mmm, tested that tuner under windows, it autodetects all 3 sound carrier sub-
standards instantly: PAL-BG, PAL-DK, PAL-I.

In order to test, I connected ancient Panasonic VCR that has a built-in tuner
and can output video to RF-OUT on fixed frequency using PAL standard. Sound
carrier frequency can be choosen using hardware switch BG, DK or I.

So under windows: tuner produces clear audio in BG, DK and I, hardware switch
can be toggled on fly, audio never stops, only a few miliseconds of static on
switch.

Under linux: audio only works if driver is set to use specific audio carrier
sub-standard AND same is selected on PVR. (not to mention extremely unreliable
PAL-DK detection by cx25843, only works 50% of times, but thats another issue)

Either a more generic firmware exists can be uploaded on xc2028.. or several
can be uploaded at once. Any xc2028 gurus out there?

Re: xc2028 sound carrier detection

[Devin Heitmueller]

On Wed, Sep 23, 2009 at 3:28 PM, Aleksandr V. Piskunov
<aleksandr.v.piskunov@gmail.com> wrote:
> Mmm, tested that tuner under windows, it autodetects all 3 sound carrier sub-
> standards instantly: PAL-BG, PAL-DK, PAL-I.
>
> In order to test, I connected ancient Panasonic VCR that has a built-in tuner
> and can output video to RF-OUT on fixed frequency using PAL standard. Sound
> carrier frequency can be choosen using hardware switch BG, DK or I.
>
> So under windows: tuner produces clear audio in BG, DK and I, hardware switch
> can be toggled on fly, audio never stops, only a few miliseconds of static on
> switch.
>
> Under linux: audio only works if driver is set to use specific audio carrier
> sub-standard AND same is selected on PVR. (not to mention extremely unreliable
> PAL-DK detection by cx25843, only works 50% of times, but thats another issue)
>
> Either a more generic firmware exists can be uploaded on xc2028.. or several
> can be uploaded at once. Any xc2028 gurus out there?

It's possible that perhaps the Windows driver is relying on the
cx25843 standard detection and then using that to load the appropriate
firmware on the 3028.

I can confirm though Mauro's assertion that the 3028 does use
different firmware depending on the selected audio standard.  You
might want to try to get a capture of the device under Windows and see
what firmware gets loaded.

Devin

-- 
Devin J. Heitmueller - Kernel Labs
http://www.kernellabs.com

Re: xc2028 sound carrier detection

[Aleksandr V. Piskunov]

On Wed, Sep 23, 2009 at 05:27:56PM -0400, Devin Heitmueller wrote:
> On Wed, Sep 23, 2009 at 3:28 PM, Aleksandr V. Piskunov
> <aleksandr.v.piskunov@gmail.com> wrote:
> > Mmm, tested that tuner under windows, it autodetects all 3 sound carrier sub-
> > standards instantly: PAL-BG, PAL-DK, PAL-I.
> >
> > In order to test, I connected ancient Panasonic VCR that has a built-in tuner
> > and can output video to RF-OUT on fixed frequency using PAL standard. Sound
> > carrier frequency can be choosen using hardware switch BG, DK or I.
> >
> > So under windows: tuner produces clear audio in BG, DK and I, hardware switch
> > can be toggled on fly, audio never stops, only a few miliseconds of static on
> > switch.
> >
> > Under linux: audio only works if driver is set to use specific audio carrier
> > sub-standard AND same is selected on PVR. (not to mention extremely unreliable
> > PAL-DK detection by cx25843, only works 50% of times, but thats another issue)
> >
> > Either a more generic firmware exists can be uploaded on xc2028.. or several
> > can be uploaded at once. Any xc2028 gurus out there?
> 
> It's possible that perhaps the Windows driver is relying on the
> cx25843 standard detection and then using that to load the appropriate
> firmware on the 3028.
> 
> I can confirm though Mauro's assertion that the 3028 does use
> different firmware depending on the selected audio standard.  You
> might want to try to get a capture of the device under Windows and see
> what firmware gets loaded.

Ok, done a little research, here are results:

1) Best suitable xc2028 firmware for PAL audio is the one that gets chosen 
for PAL-I, to be more precise its
"Firmware 69, type: SCODE FW  MONO HAS IF (0x60008000), IF = 6.00 MHz"
With this firmware loaded, tuner seems to pass everything from +5.5 MHz to
+6.5Mhz straight to cx25843, resulting automatic detection of BG, I and DK audio.
Instant detection on source change, instant playback, same as under windows.
Would be great if more people would try "v4l2-ctl -s pal-i" and give feedback,
especially for stereo sources.

2) Extremely unreliable detection of DK was caused by cx25843 trying to guess
if 6.5MHz carrier is system DK or system L, special register was set to autodetection
which failed half of the times. Will send a patch in a separate mail.