[mythtv-users] HVR-950q analog/NTSC capture has no sound

[James Miller]

MythTV 0.27 installed under Gentoo with ALSA-only sound configured, kernel 
3.18.25. Acquired a couple of these tuners (used) recently. Set up one of 
them, without any hitches whatsoever, to record ATSC: it's been working 
great. Decided to experiment with the other, hoping to capture some analog 
broadcasting from a DTA. Tried ffmpeg capture, viewing with mpv, vlc, and 
MythTV (set up as analog capture card under the latter) using various 
iterations of suspected audio hardware specification: I get no sound in 
any of those configurations--only video gets captured.

The clue that makes most sense to me as an explanation was found in the 
thread https://lists.gt.net/mythtv/users/450443 in a comment made by Devin 
('Bear in mind we're talking about the ALSA *capture* device built into 
the HVR-950q, not the sound card that you output to. You can run "arecord 
-l" to determine which capture device is the 950q'). Devin's suggestion to 
run arecord -l to find out the ALSA designation for the card's audio 
component results in no detection of any sort of sound device associated 
with either of the HVR-950q's attached to my system; only the onboard 
audio chip in my Liva X gets listed. Same results looking at 
/proc/asound/cards under alsamixer. So, if I'm understanding correctly 
what's at stake here, the analog sound hardware for this device is somehow 
not detected/configured on my system, so of course I cannot capture any 
sound to go along with the analog video I am able to capture from it.

Research indicates it is a fairly common problem that recording analog 
audio from this device fails. Someone at 
https://ubuntuforums.org/archive/index.php/t-1340117.htm (fairly old post) 
goes so far as to claim that OSS compatibility is required to get reliable 
analog audio from the HVR-950q. Other information I've encountered leads 
me to believe it should be possible to capture analog audio using ALSA.

Can anyone offer input on what sorts of additional steps I might take to 
try and get analog audio capture working on this device? It's beginning to 
look to me as though this will be a hardware issue I'll need to solve for 
this particular machine/distro. But any sort of leads any list member 
might offer that could get me started in the right direction will be 
appreciated.

Further background on the task: the apartment building in which I live 
supplies cable for now, though they may ditch it soon. In the wake of the 
switchover to copy-protected digital broadcasting in my area, I decided to 
borrow a DTA that has an analog F connector that outputs non-encrypted SD. 
The aim is to capture a particular cable program we watch with some 
regularity. To that end I set the DTA to output on channel 3 and tuned it 
to the desired station. The DTA outputs both sound and video when hooked 
directly to a TV. Under MythTV, I should be able to set the system to 
record from the analog capture device (one of the HVR-950q's) for a given 
period of time on certain days. Like I said above it seems mostly working 
apart from the lack of sound to go along with the analog video.

Other links: https://forums.gentoo.org/viewtopic-t-866117-start-0.html and 
the list thread entitled [mythtv-users] Analog cable on an HP KS523AA