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-   -   Audio problems - can't hear it but Audacity can record it (https://www.linuxquestions.org/questions/linux-newbie-8/audio-problems-cant-hear-it-but-audacity-can-record-it-819713/)

genogebot 07-13-2010 11:43 PM

Audio problems - can't hear it but Audacity can record it
 
I've installed a tv card but I can't hear the sound through my built-in CMedia soundcard when I watch tv with TVTime. The tv card's audio output is externally connected to my soundcard's line in input. In the 'Input' tab of the 'Sound Preferences' dialog, I can see the input level meter moving.

Audacity can record the tv sound, and I can hear it when I have the 'pass-through' option enabled, or when I play the recording.

I can play media files without a problem, and I can hear the system sounds.

But for some reason I can't get the tv sound to go through to the soundcard's output.

Obviously I've got the audio configured wrong, but I don't know what to do to fix it.

sntnlz 07-14-2010 04:21 PM

Try the simplest of solutions first. For some reason some sound mixers or volume control applets don't do a good job reporting all your in/out channels. For instance, if you're using the PulseAudio mixer to set the different volume levels, try running KMix and explore your options there. The channel may be muted but may not show in the first one, but may be reported in the other.

If this doesn't get you anywhere, post some technical details about your distro, desktop, and hardware so others can give you more advice.

genogebot 07-16-2010 09:15 AM

Ok I've installed every mixer I can find and none of them help. On the Pulse Audio Volume Control's 'Input Devices' I can see that the Line-In port level meter is reacting to the audio input, so it is clearly not an issue of the input being muted. Every device channel I can find is enabled but still no sound is coming through from the tv card.

Worse still, after messing around with the system for a whole day, I can now no longer even get Audacity to record the sound!

Aaargh! Why is this so difficult?!! I love the way linux's hardware detection has progressed in the last couple of years, but this is apparently one of the areas where there is a lot of room for improvement. I can't help but compare it to Windows - which I thought I'd left behind - where this is all automatic and effortless. The fact is I don't want to spend ages geeking around with obscure system settings - I just want the #$^%& thing to work.

jefro 07-16-2010 02:13 PM

Audacity has a menu choice transport. Select overdub or playthough.

genogebot 07-17-2010 02:08 AM

Quote:

Originally Posted by jefro (Post 4035621)
Audacity has a menu choice transport. Select overdub or playthough.

Yes I know:

Quote:

I can hear it when I have the 'pass-through' option enabled
Never mind, I've given up on this. I tried MythTV, but that was useless - it's setup program wouldn't run properly, repeatedly complaining about some SQL error, with useless dialog boxes containing the single word 'Cannot' and an 'Ok' button - a little internet research showed that this is a known bug, but unfortunately none of the supposed fixes worked. I'm glad it works for some people, but on my system it's a turd.

I did manage to get VLC to record some tv with sound, but the quality was rubbish.

I've wasted far too much time with this. It looks like I'll have to keep my Windows installation for a while longer.

Shadow_7 07-17-2010 09:56 AM

Are you wanting to watch? OR record? OR both?

Code:

ffmpeg -f oss -ac 1 -ar 48000 -i /dev/dsp \
      -f video4linux -s 640x480 -pix_fmt yuvj422p -i /dev/video0 \
      -acodec pcm_s16le -ac 2 \
      -f avi -vcodec mjpeg -qscale 1 -r 30000/1001 -y test.avi

Assuming that your capture device is present and you have access to it.

$ groups

$ ls -l /dev/dsp*

$ ls -l /dev/video*

You can do a jack_connect trick to bridge input to output on your audio device. Most time the video takes longer to decode / deliver so there's a latency there where audio arrives BEFORE video. There's a trick to add audio latency to match, but I don't recall it off hand. But an option. Depending on your soundcard you might have mixer settings to make that bridge in alsamixer. It is generally disabled because if input is a mic and output speakers in proximity of the mic you get feedback.

$ v4l-info
$ v4l-conf

$ v4lctl
(part of xawtv)

For the quick and dirty just run jackd and qjackctl to make the audio connections manually.

genogebot 07-19-2010 06:19 PM

Shadow 7: thanks for the detailed response. Unfortunately it demonstrates one of the shortcomings of Linux at present - the geeky rigmarole users have to go through to get things to work. Yes I can do it, but I just don't think I should have to.

On Windows, all I have to do is start the tv app, change to the desired channel, and click the 'Record' button. When a linux distro can do it that simply it'll be worth considering. For now I'll stick to a dual-boot with my old XP that does the job effortlessly.

Shadow_7 07-19-2010 09:35 PM

But, that assumes that the 15 day trial period didn't end. Or you paid money for the OS / application to do that. And other, I could have had a case of beer and a bucket of chicken (or run windows).

Although I agree, it shouldn't be this techy to use an OS. But patches are welcomed.

Shadow_7 07-19-2010 09:45 PM

Or to put it more plainly. You expected to run a different OS, that you're not familiar with. And not have to "learn" anything? At some point you had to learn to press START to "SHUTDOWN". At some point you had to learn to run "netsh" to change your MTU. At some point you had to learn to right mouse click and select Run as Administrator. Yes it's different. Of course it's different. You expected different?

genogebot 07-20-2010 01:44 AM

Quote:

Originally Posted by Shadow_7 (Post 4038895)
Or to put it more plainly. You expected to run a different OS, that you're not familiar with. And not have to "learn" anything? At some point you had to learn to press START to "SHUTDOWN". At some point you had to learn to run "netsh" to change your MTU. At some point you had to learn to right mouse click and select Run as Administrator. Yes it's different. Of course it's different. You expected different?

'Different' is fine. I'm happy to learn new things. As I said, I can do this stuff - I've been using various operating systems since the CP/M days - this is the way it was back in Windows 3.1. But I also expect a modern OS to be less geeky - user-friendliness is about the system being sophisticated enough to let the users do what they want without making them jump through hoops. I am sure some of the Linux distros will eventually get there, and for many things they already are there, but this is an example of a situation in which they're not quite at that point yet. And like many people, I am prepared to pay for a software licence if that saves me the time I'd waste messing about with a system that doesn't do what I want. It isn't right or wrong, just my personal choice.

Shadow_7 07-20-2010 10:57 AM

Agreed, it'd be nice if more distros packaged packages like MythTV. It'd also be nice if alsa was more plug and play and otherwise self configuring. It'd be nice if X didn't require odd .conf's that vary depending on your cards manufacturer. Although I'm not quite willing to give up that conf for a system that just doesn't work. Or requires $30 after $30 patch work software to keep running and running well. Or a $2,500 development suite to make it do what you want it to do.

Not that I'm against windows, but if you have to install and maintain five different versions of windows on five different machines just to use your old printer, scanner, modem, or whatever device that's no longer supported by a manufacturer or the latest windows. That's gets pretty old quick. Granted that if you have all new stuff, with no legacy things laying around, windows probably is the better option. At least you know it should work there and can return it for a refund that day if it doesn't. As I look at all of the eWaste programs and wonder how much of that is windows fault? It doesn't work with my current version of windows, circular file...

genogebot 07-20-2010 05:42 PM

Ok, it seems at least part of the problem is a long-standing bug in TVTime - I've found references to it going back several years. The right and left arrow keys are used to display and control the sound volume in TVTime, but for some reason it's stuck on zero and won't change.

genogebot 07-21-2010 04:44 PM

Quote:

Originally Posted by Shadow_7 (Post 4039597)
Although I'm not quite willing to give up that conf for a system that just doesn't work.

In relation to my tv card, linux just doesn't work.

Quote:

Originally Posted by Shadow_7 (Post 4039597)
Or requires $30 after $30 patch work software to keep running and running well. Or a $2,500 development suite to make it do what you want it to do.

I've never had to pay for a patch in over 30 years of computer use. Nor have I ever needed to buy a development suite. Have you? Really?

Quote:

Originally Posted by Shadow_7 (Post 4039597)
... if you have to install and maintain five different versions of windows on five different machines just to use your old printer, scanner, modem, or whatever device that's no longer supported by a manufacturer or the latest windows.

Again, this has never been an issue for me. 'Five different versions of windows' - please! I doubt if anyone has ever done that.

Quote:

Originally Posted by Shadow_7 (Post 4039597)
Not that I'm against windows, but ...

Sorry, but I think you are. Your statements are clearly exaggerated. I don't think Windows is great, but I don't think linux is great. They're either useful tools or they're not, and an emotional attachment to an operating system does not contribute to a rational analysis of their respective usefulness. In fact I think this sort of fandom creates unrealistic expectations in the minds of new linux users, who end up disappointed when the reality does not match the hype, and consequently decide linux is rubbish, and that linux users cannot be taken seriously.


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