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Input Demystification + (When is DMA Audio possible?)
PostPosted: Sun Jan 18, 2009 6:02 am Reply with quote
TrinitronX
 
Joined: 20 Dec 2008
Posts: 7




So far I've been unsuccessful to get my setup working the way I want.

I've been attempting to get my card working with both video input methods, using the double driver solution mentioned on various threads here. This means:

  • cx88_dvb for HDTV through Over the Air ATSC digital signal (RF Coax input).
  • v4l2_common for Standard-Def (SDTV) from my DirecTV box with following connections:

    • Either RCA composite or S-Video for the Analog Video signal
    • Red/White RCA->3.5mm jack cable going into the audio-in port of the 5500



I've tried connecting the loop cable on my card to line-in, however I get *really* bad crackly audio through this method (see link reference 1... (thanks buggy snd_hda_intel)). From reading threads about this in various places here, it seems this either may or may not be possible when using the analog input (see thread references 2->5).

However, I have had no such luck using "alsamixer -c 1" and setting the
5500's Conexant Cx8801 to capture (the Cx88 is card #1, my onboard ALC888 is card #0).

I think that this confusion is generated by people's interchangeable use of the words: analog, composite, s-video, etc...
Some threads say: Analog = v4l=possible to get audio from card (but what *input* are they using??)
Others say: With *certain* inputs --> not possible to get audio through DMA

As a budding electrical engineer, this is making me confused as to if it's possible to actually get audio through DMA when using the S-Video & analog audio jack on this card. In reality, here's how the input connections map to the words "Analog" or "Digital".

Due to the many terms and connectors used for A/V signals, this leads to a "BIG MESS":
Bolded connections are supported on the pcHDTV 5500

  • Analog:

    • Video

      • S-Video
      • RCA Composite (Yellow)
      • Analog RCA Component (Red, Green, Blue)
      • RF Coaxial (with Analog NTSC signal)
      • VGA

    • Audio

      • RCA Audio (Red/White)
      • RF Coaxial (with Analog NTSC signal)
      • 3.5mm stereo jack


  • Digital:

    • Video

      • RF Coaxial (with Digitally encoded high-def ATSC signal)
      • HDMI
      • DisplayPort
      • DVI
      • Digital RCA Component (Y'CbCr)

    • Audio

      • S/PDIF
      • HDMI
      • DisplayPort
      • TosLink (fiber optic)


  • "HD" Video supporting connectors:

    • HDMI

      • Output
      • Usually locked down by HDCP

    • DisplayPort

      • Not in wide adoption yet, standard still being worked on (competing w/HDMI)
      • Output or Input (can go from device->display or internally chip->chip)
      • Possibly locked down by HDCP or DPCP

    • DVI

      • Output
      • Possibly locked down by HDCP, though not usually (as of this writing)

    • RF Coax (with ATSC encoding)

      • Input
      • Locked down by the "Broadcast Flag", though some tuner cards choose to not follow this Wink

    • Digital RCA Component (Y'CbCr) (Output)

  • "SD" (standard-def) Video supporting connectors: All others


References:

  1. http://www.mail-archive.com/alsa-user@lists.sourceforge.net/msg24251.html (ALC888 line input cracklyness)
  2. http://pchdtv.com/forum/viewtopic.php?t=7145 (DMA audio possible?)
  3. http://pchdtv.com/forum/viewtopic.php?t=7096 (DMA audio possible?)
  4. http://pchdtv.com/forum/viewtopic.php?t=7031 (DMA audio not possible?)
  5. http://www.pchdtv.com/forum/viewtopic.php?t=1466 (DMA audio not possible?)
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Re: Input Demystification + (When is DMA Audio possible?)
PostPosted: Thu Jan 22, 2009 2:24 am Reply with quote
xyzzy
 
Joined: 12 Feb 2006
Posts: 225




TrinitronX wrote:

As a budding electrical engineer, this is making me confused as to if it's possible to actually get audio through DMA when using the S-Video & analog audio jack on this card.

It's not possible to record from the line in. The line in is just a pass-through to
the line-out. The 5500 can only record analog audio from the RF coax input using the tuner.
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PostPosted: Wed Jul 08, 2009 8:03 pm Reply with quote
mholtz
 
Joined: 07 Jul 2009
Posts: 2




Quote:
It's not possible to record from the line in. The line in is just a pass-through to
the line-out. The 5500 can only record analog audio from the RF coax input using the tuner.


xyzzy:

Can you confirm whether your statement about the 5500 also applies to the 3000? I ask because I am trying to setup my system in the same way. Is the audio input on the card able to be recorded? If not, then what is the point of using your eeprom update utility to enable the audio chip?
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PostPosted: Tue Jul 14, 2009 1:01 am Reply with quote
xyzzy
 
Joined: 12 Feb 2006
Posts: 225




The 3000 is the same as the 5500. You can use the audio function to record the audio from analog TV from the RF input. Which isn't all that useful now that the digital change over has happened.
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Input Demystification + (When is DMA Audio possible?)
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