On Sat, Nov 22, 2008 at 10:00 AM, Andy Walls <[EMAIL PROTECTED]> wrote:
> On Fri, 2008-11-21 at 15:28 +0200, Dmitry Podyachev wrote: > > is any tools for it ? or is it possible to use some API from v4l for it > > (I do not see any way - may be via some gpio ?)? > > > 1. The strategy may be to check the AGC level after the AGC settles > > > after tuning to a channel or switching to a baseband input. If the > > > level is up near the top of the AGC's range, maybe +9 dB out of the +12 > > > dB max (0x36 or 0x37 in register 0x488) then turn on the +12 dB > > > amplifier for the input to get more dynamic range out of the final > stage > > > of the amplifier. > > > > > > > > 2. Maybe you could also, after changing the channel and letting the AGC > > > settle, record the AGC value for that channel or input and then put the > > > AGC in a manual mode > > > > yes, but how? how write something manual to AGC register ? write c-code > > or other way exist ? > > > > > Look at the definitions on page 5-92 and 5-93 of > > http://dl.ivtvdriver.org/datasheets/video/cx25840.pdf > > And the experiment using v4l2-dbg as root: > > # v4l2-dbg -d /dev/video0 -R type=host,min=0x2c40488,max=0x2c4048f > ioctl: VIDIOC_DBG_G_REGISTER > > 00 04 08 0C 10 14 18 > 1C > 02c40480: f825ea1c 001020dc > > > Note when using the HVR-1600's built in NTSC tuner, tuned to an over the > air broadcast signal, VGA gain on my card is at 0x1c right now which > corresponds to 0.875 or -1.16 dB: close to the middle of it's range. The > Digital AGC, which comes after the VGA, has adjusted it's fine gain to > 0x5ea. > > > What gain is your card's VGA set at when video comes from the source > with which you have problems? > > Andy, I am trying to record from SVIDEO 1, something I did not think to mention. $ v4l2-ctl --get-input Video input : 1 (S-Video 1) $ v4l2-ctl --get-tuner Tuner: Capabilities : 62.5 kHz multi-standard stereo lang1 lang2 Frequency range : 44.0 MHz - 958.0 MHz Signal strength : 99% Current audio mode : lang1 Available subchannels: mono Here is the output: $ sudo v4l2-dbg -d /dev/video0 -R type=host,min=0x2c40488,max=0x2c4048f ioctl: VIDIOC_DBG_G_REGISTER 00 04 08 0C 10 14 18 1C 02c40480: f825451d 001020dc I am quite suprised how great the system requirements are for this card. When I first tried to boot the computer it wouldn't boot, I had to raise vmalloc to 192M it's currently consuming about 120M+/-. The card worked well in my dual core amd64 but I will need an IR Blaster in order to migrate everything to that machine. Thanks for all of the energy you're putting into this... I really do appreciate this. Al
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