Recording problem

[steve]

As you can see from these screenshots, we are looking at a massive increase in severe drop-outs.


What we don't know is why, and why after 2 minutes.

annemarie said "The original audio is still on and works fine -- so it's not a source issue." so the issue is happening when recording into Audacity.

waveform.png (117.05 KiB) Viewed 750 times

I'll put a small piece of chocolate on Windows update kicking in.

[kozikowski]

<<<annemarie said "The original audio is still on and works fine -- so it's not a source issue." >>>

If she's listening to it on the CamCorder, then she's right. The camcorder is continuing to send a line level audio signal into the laptop. That's one thing we tell people doing tape dubs. Did the original tape playback fail, or the the capture downstream turn to mud.

Maybe she'll drop back in and tell us more accurately what's exactly she's listening to and how. I'm still going with the signal not making it past the sound card/device. Most microphone connections don't take kindly to massive overload like that.

<<<issue is happening when recording into Audacity.>>>

Maybe.

Since the Windows Sound Recorder will only handle 60 seconds, play a loud tape and only start recording 1:30 into the performance.

<<<a massive increase in severe drop-outs.>>>

I can hear my English teacher insisting that should be "drops-out."

Not only that, but they're periodic. If you switch to the dB view, you can also see that the waveform degenerates into several levels instead of being the smooth waveform we expect with undistorted audio. I swear that's what happens when the digitizing levels start failing.

Koz

[annemarie]

Very strange, I posted a reply yesterday and it seems to have disappeared. Then again we had a snowstrom and all connections went down....

I was saying that
1. I have used the line-in feed with other sources (both music and speech audio-cassettes hooked up from their audio out to laptop) and it worked fine.
2. I have used another software - DC Millenium -- to try and extract audio from my videocassette and that worked but the sound quality was not good.
3. I think that maybe my new virus protector has to be shut down...and I will try that next.
4. I will try another software and hope for better results.

The issue was that I thought that going directly from source to an audio file would give me better results than going from source through TV to DVD rather than DVD to audio (which is what I ended up doing).

Any other suggestions? Maybe for another software?

By the way, my cut out seems to be less than 2 min....maybe about 30 secs.

Thanks
Anne-Marie

[steve]

1. I have used the line-in feed with other sources (both music and speech audio-cassettes hooked up from their audio out to laptop) and it worked fine.

So the hardware works ok.

2. I have used another software - DC Millenium -- to try and extract audio from my videocassette and that worked but the sound quality was not good.

So the videocassette works, but the sound quality is not great. I can tell from the "good" part of your sound clip that the sound quality is poor - you're not going to make it sound wonderful, even with Audacity, but it should be good enough to hear what is being said.

3. I think that maybe my new virus protector has to be shut down...and I will try that next.

Shutting down your antivirus is a very good idea (also shut down your internet so as not to leave your computer vulnerable - best to be on the safe side). If your "new virus protector" is AVG7, then I'm surprised that it's causing a problem, unless it starts doing a scheduled scan. If it starts scanning your system, then you can be certain that recording without drop-outs will be impossible.

For future reference, could you post exactly what your anti-virus program is, and if disabling it solves the problem.

I am using AVG 7.5.503 FREE and I have no problem. I only have the anti-virus installed - not the anti-spyware, or the internet security suite.

4. I will try another software and hope for better results.

For completely free audio editing software, I think Audacity is the best there is - the more I use it and the more I get to know it, the more I like it. If the problem is being caused by an anti-virus program scanning your hard drive, you will almost certainly get the same problem with other software. With audio recording, the data has to be written to disk pretty quick, and that can't happen if the disk is being heavily used by another application.

I thought that going directly from source to an audio file would give me better results than going from source through TV to DVD rather than DVD to audio

If you mean, as the alternative, going from source to a DVD recorder, then ripping the audio from the DVD - that should give very good results (depending on the quality of the source material, which in this case is not that great). DVD recorders usually have half decent audio in, and half decent A/D converters (in some cases they can be very good indeed) and ripping the audio from the DVD should be very close to perfect.

Recording directly from the source into your computer should also be very good, as long as you have a decent quality sound card. If your sound card only has a "mic in" and no "line in", then the quality will not be so good.

Any other suggestions? Maybe for another software?

I think that shutting down the anti-virus will fix it.

I'd recommend sticking with Audacity for a while (assuming we've fixed the problem) - get to know it, get to love it. (btw, I'm not in any way connected to the Audacity project, I'm just an enthusiastic user).

By the way, my cut out seems to be less than 2 min....maybe about 30 secs.

You've not said if you've tried this more than once, and if the "cut out" happens at the same place each time. In the event that switching off your anti-virus does not cure the problem, this information could be important.

Good luck.

[kozikowski]

<<<With audio recording, the data has to be written to disk pretty quick, and that can't happen if the disk is being heavily used by another application.>>>

That's not what happens. Audio recording or capture creates new files and the virus software insists on inspecting each file as it's being created to "protect you." This can slow the system down to the point where you get dropouts or crashes--but usually not distortion like this.

Sometimes you can defeat the real time inspection but leave the software running for manual system scans.

Koz

[steve]

That's not what happens. Audio recording or capture creates new files and the virus software insists on inspecting each file as it's being created to "protect you."

I was talking specifically about AVG anti-virus, and the difference between when it does it's background monitoring, and when it scans the hard drive(s).

During normal background monitoring, AVG will "keep an eye on" new files, but it does so very efficiently and there is NO problem caused in Audacity from this (even on an old Pentium I ). On the other hand, if AVG is doing a scan (which by default are scheduled once per day), it makes considerably more demands on the processor, memory and the drives.

AVG will also, by default, update once per day from the internet. When this happens, cpu usage shoots up, and will cause major problems.

My main machine is a Pentium II 500, and I have AVG set to update on first switch on in the day - that gets it out of the way. I only scan manually and have the scheduled scan turned off so that it does not start a scan at an inconvenient time (such as when I'm recording). I also have AVG running in the background at all times, monitoring my system, and there is no problem whatsoever - it uses a total of about 1MB of ram, and less than 1% cpu (shows as 00 in the task manager).

[alatham]

Actually, it is possible to record an arbitrary amount of time in Windows Sound Recorder (and I completely agree that it's an excellent test for hardware).

Open up Windows Sound Recorder, click record and then stop after a few seconds. The program should tell you the length of the file off to the right. Now, if you click Effects -> Decrease Speed, this length will double. Do this until the length is long enough for your purposes, in this case about 150 seconds or so. Now, click rewind and you can record over the entire length of the file (it will stop automatically at the end, I think).

We've seen this issue with sound cards suddenly recording poorly after some amount of time, but I still haven't seen a very good explanation of why. The first time we had a guy with this issue, he was using a Creative Audigy card and eventually just replaced it and the problem went away. Sometimes it crops up when people are using the Mic In input with a Line Level signal, however I don't think that's happening here. I suspect the extra current heats up the components too much, but that really seems like a long shot to me (being an EE, I should know these things).

I'm with Koz here. Unless Windows Sound Recorder is able to record perfectly, I suspect the sound card hardware of being faulty. By the way, what model sound card is it? Also, who wrote the drivers, someone competent or the computer manufacturer?