Dazzle DVC100 as a sound device, driver subtlety

Questions about codecs, DVD playback, web plugins...
Forum rules
Before you post please read how to get help
Post Reply
chrisjengle
Level 1
Level 1
Posts: 2
Joined: Thu Feb 22, 2018 12:11 am

Dazzle DVC100 as a sound device, driver subtlety

Post by chrisjengle » Thu Feb 22, 2018 12:50 am

I have been floored by avconv and the avlib. It does, with more control, what I could not do in windows with the manufacturer's, now defunct, install cd (only eventually with third party lite-ware, and downloads); I have full color video playback on Linux from the getgo.

In trying to understand the common problem of no sound, I looked at this tutorial: viewtopic.php?t=123022

In my case, the Dazzle is visible as a sound device in sound preferences, but I do not see the meter flash when input is being sent. I can reference the device as an input in avconv, that I presumed from the only USB audio input, but there is no sound in playback or writing (there is also some alsa warning, but that probably has to do with my lack of avlib knowledge. The fact that I see no metering in sound preferences makes me think it's unrelated).

By the wording in the tutorial I'm not sure if an active capture program has to 'awaken'(?) the input for the meter to even show anything in sound preferences. I'm also not sure if forum member Ertain did anything special to activate the em28xx kernel module for the Dazzle, or if that can be assumed to be set because the device is visible.

This is all just beyond the scope of my comprehension of Linux, I could pull out my third-of-the-way-read book on drivers, and grab the script for listing active modules in use, but I'd hate to think I'd have to finish that entire 600 page book to solve this problem :)

If somebody knows the subtle link in the chain I'm missing (it could be very superficial, a newbie probelm) in getting to Ertain's results, that'd be very welcome.

much thanks.

Hoser Rob
Level 11
Level 11
Posts: 3831
Joined: Sat Dec 15, 2012 8:57 am

Re: Dazzle DVC100 as a sound device, driver subtlety

Post by Hoser Rob » Fri Feb 23, 2018 10:22 am

chrisjengle wrote:
Thu Feb 22, 2018 12:50 am
... there is also some alsa warning ...
If you want these sorts of problems sorted you need to be a lot more specific. What's the warning???

chrisjengle
Level 1
Level 1
Posts: 2
Joined: Thu Feb 22, 2018 12:11 am

Re: Dazzle DVC100 as a sound device, driver subtlety

Post by chrisjengle » Fri Feb 23, 2018 12:39 pm

For Hoser Rob (Yeah sorry; when a newb, sometimes specific text is a half-hour or more of command and browser history searching away) :

Code: Select all

[alsa @ 0x7bb4c0] ALSA buffer xrun
[alsa @ 0x7bb4c0] Thread message queue blocking; consider raising the thread_queue_size option (current value: 8) 
Update: Suddenly, after shutdown and boot, all is black and white!, haha. Oh well. I went back the Windows partition to see if using the NHC's Debut video capture (the lite-ware I spoke of) would reset a hardware switch. I haven't tried the other windows software for this purpose yet (like the manufacturer's dysfunctional 32bit capturer). So to add to any advice someone might have, is there any fiddling I should do to try to jostle the color back?

When I first tried a avconv capture with V4L2 it gave me a very narrow color image, 130px something to 140px something wide, with probably the normal height. When I removed avconv's -f video4linux2 option, then avconv guessed a better input format than what I got from simply specifying video4linux2, and that's how I got a beautiful high res image (720x480). The color was always present during that entire session though.


The grayed-out text above is off-topic (video color comes and goes as it pleases...) But back to SOUND:

I've got my video playback to work in Guvcview by entering command line arguments for the resolution and input (still no audio). Without this command Guvcview crashes before allowing you to change the parameters:

Code: Select all

guvcview --resolution=720x480 --format=NTSC --device=/dev/video1 --audio_device=2
There are some things to play with here in Guvcview's audio panel, but so far no luck. It calls audio_device=2 DVC100, so that's good. I also found the "line" capture device, as found in the first mentioned tutorial, in alsa-mixer by pressing f6 and selecting the "soundcard". I didn't know where the author had seen that first time around. Volume is set to max there... still not sure what it all means.

The volume was muted on first launch (of guvcview), but unchecking it did nothing.

Is Pulse involved here? (that's some kindof filter module hook-up thing?)... Should I try "PORTAUDIO" as the "Audio API"? ... I'm so close...

NCH Dash free home-edition was the only software capable of getting sound on Windows, it didn't show up as an audio input in Windows volume controls there.

What hardware voodoo did it know (?) ...

Post Reply

Return to “Sound, Multimedia, & Codecs”