recording SKIPS a bit every 6 seconds

[zangly]

i'm a relative newb when it comes to audacity, and how sound works on the computer in general, so please forgive my poor technical-speak.

i usually avoid betas like the plague, but i really needed the timer recording feature to record a radio show while i was out. i fiddled with the settings and did some test recording, all seemed to be good. i set everything up, left home, and came back. (actually i noticed that in the 'audacity smart record progress window' the printed remaining time was jumping around all over the place, going from 8h to 7h and everywhere in between. (it should have been around 7 hours) but i didn't think much of it.)

when i came back, several hours after the recording should have been done, that window was still going. the 'audacity timer record' was also still open behind it, and the main audacity window behind that. and it was still recording, on its 5th hour! i'm pretty sure it wasn't a mistake on my part. i double checked my start and end time, and the duration was set as 2 hours.

weird thing is, that i set the recording to go from 9am-11am, and got home around 5pm. so the recording should have been starting its 9th hour, right?

i didn't know what to do, so clicked 'cancel' on the 'audacity smart record progress window' (which btw, said there was still about 2 hours left before the recording was to start), but nothing happened. eventually, i terminated audacity with task manager, knowing there was a built-in recovery feature. i restarted audacity and was able to recover my project, and saved it.

i started to play it back. the sound quality was fab, except that the recording seemed to skip/jump once in a while. as i paid closer attention i realized it happened every 6 seconds. the jumps seem to be pretty significant, i'd guess at least 1-2 seconds long. i read that audacity writes to the disk every 6-12 seconds (http://audacityteam.org/wiki/index.php? ... 12_seconds), but i don't think the problem is that my soundcard is picking up noise from the hard drive, because...

i opened a new project, and tried recording again, this time just for 20 seconds. i played it back, no problems, no jumps. thinking that maybe it's the timer recording that's screwing it up, i did a test timer recording of 1 minute. again, no problems.

so, what happened?

----- further thoughts
seeing that my recording was about 5h30m when it should have been around 8h, i lost 2h30min of sound. uh, so... it only recorded about 2/3 successfully?

5.5h = 330m = 19800s
2.5h = 160m = 9600s
19800s/6s = 3300 jumps
9600s/3300jumps = 2.91s/jump

so each jump was around 3 seconds. is that right..?

hmm... any help is appreciated! thanks in advance!

----- edit

my mistake, when i came back it wasn't the same window. before i left the window was: 'audacity smart record - waiting to start.'

i'm trying this again tonight. hope it somehow fixes itself!

[waxcylinder]

zangly,

Actually the current beta of Audacity seems fairly stable.

But you're right that that interface for timer recording is a little flaky in that it leaves the timer record dialog boxes open long after the recording has terminated.

But it does seem to work consistently for me, recording exactly the times I set it to record. You need to be careful setting it up as the set-up dialog box can be a little twitchy - it can be easy to set the wrong date or time - so I always check very carefully.

Hmm... deliberately crashing Audacity and relying on the Recovery utility in the Beta - seems like a high risk strategy to me, glad that it worked for you though - and good to know that the Recovery worked so well. For future reference in that situation note that you should be able to take back control of Audacity even while the time record period is open - clicking on the Stop seems to work ok - and then you can save the project and/or Export to WAV in the normal way.

Now the bits I can't help with:

Why 5.5 hours rather than 8? Have you run out of disk space? Or maybe you have run into an Audacity/Windows limitation. Maybe someone else can offer insights about this. I do remember seeong some postings a while ago about maximum lenght of recordings - try the Search function on the forum.

The six second skips: can't help with this either - it doesn't happen on my setup (FMtuner=>external USB soundcard Edirol UA-1EX=>indows PC XP-HE-SP2=>Audacity 1.3.3 at 44.1kHz/32-bit). But once again it does ring a few bells about other earlier postings with similar problems.

If it is your hard disk writing that is causing the problem - be aware that you can configure Audacity to do all its work in main memory - but for 8 hours you will need an awful lot of RAM ....

Hope someone else tunes in to this thread who can address these two points.

WC

[steve]

Depending on what you were recording, you may get some clues as to what was going on, for example if recording from the radio, can you find out what time your recording actually started?

Do you have a screen saver or does your computer go to sleep? I guess this could have an impact - I'm not at my best when I've just woken up, and computers are often the same.

Does your system clock run OK? Try checking the accuracy of the clock by leaving the computer switched off for a couple of days, then boot up without an internet connection and check that the clock is correct.

Make sure that you do not have Audacity set to record only to RAM "Edit > Preferences > Directories > Audio cache"

There's probably loads of other things that could affect long, timer recordings, including the usual suspects (low memory, high background activity, anti-virus programs, low disk space, high disk fragmentation...)

You will need to do some tests to try and narrow it down - it may even have just been a one-off problem.

[Gale Andrews]

Re deliberately crashing Audacity, it's safe for an advanced user that's prepared (if recovery fails) to manually recover all the .au files from the temp.file and batch rename them to be in strict alphanumeric order within creation date. I gather though that when the timer progress dialogue stays after recording, you can still File > Save Project. I'd like it to have an option to save to a project with a predefined path after recording.

When the dialogue stays up, the timings are usually nonsense, and what actually happens unstudied, so we shouldn't assume that it's either skipping every three seconds, or stopping and starting recording every three seconds. Have you tried both 1.3.4 though (assuming Zangly is not on a Mac)? We did some work just before releasing 1.3.4 that should have helped some timing issues.

The "hold recorded data in memory" preference is actually a misnomer, as it writes imported files and changed project files to RAM as well, and can cause crashes if you import large files or projects.

I think we'd concede that 1.3.x may be more finnicky recording on some systems than 1.2.x, but we don't know exactly why. I had pops and dropouts on a USB turntable recording with 1.3.4 recently, but suspect it was a USB bandwidth problem and simply cannot reproduce it now. A user and a developer are currently both getting clicks recording with 1.3.4 but not with 1.2.6. Dropouts are often caused by the writing of the .au files not leaving enough system resources to carry on recording at the same time. The clicks we're encountering at the moment look like small amounts of data being overwritten.


Gale

[kozikowski]

This is the Windows forum, isn't it? When was the last time you defragged your hard drives? a heavily used Windows computer will have all sorts of disk access speed problems because of chunks and fragments of files sprayed all over the place.

When was the last time you did a comprehensive virus check? By that I mean the one where you have to stop using your machine, not the one that runs "in the background." If a virus check is convenient, it can't be doing a really good job.

Do you do your production work with the machine connected to the internet? Stop that. In fact, close everything else that's running while you work. Windows 2000 lets you Ctrl-Alt-Del to get to the task list and see everything that's running on your machine. Things like Canon Printer Advertisement, LiTronics Network Warning System, NVidia Video Color Manager, Virus-R-Us Scanner, Palm Pilot Sync Facility (that you forgot you had), etc.

There is a rule of thumb at work that if that list goes over one scroll-down page, you're due for burning the machine down, hosing it off, and starting over. People are shocked--literally--when they see how much faster and more efficient their old PC is without all those barnacles on the hull.

Koz

[rickbking]

I get drop outs and static like rubbing a fingernail on a washboard for a second.

This happened with 1.2.6 and now with 1.3.8. With 1.2.6 it took about 10 minutes of recording for it to be clear that there was a problem (I suspect that samples were lost all along the way but weren't enough to be easily noticeable). Coincidentally, 10 minutes is about 100Mb of data. With 1.3.8 the problems start within the first few minutes and I get less of the washboard static and more drop-outs and clicks.

I'm recording off an Edirol UA-25 through USB with the most recent driver.

It is true I have other things like a disc drive attached on USB, and a bunch of stuff running internally, like photofun studio. However, I just installed 1.3.8. It's been a while since I did some recording, and when I was using 1.2.6 I tried turning everything off, disconnecting everything, turning off anti-virus, etc., and all that changed was that it seemed the washboard static started at about 13 minutes. So it did make a difference, but nothing significant.

I've also defragged recently.

What is disturbing is that I can record just fine with CDEX. No dropouts, washboard static, etc. And I've been doing that all along with all the software, disc drives, antivirus, etc. running. So it seems to be strictly an Audacity problem.

[waxcylinder]

It is true I have other things like a disc drive attached on USB, and a bunch of stuff running internally, like photofun studio.

Capturing digital audio is quite demanding on a computer. Other applications running can sometimes give this symptom (particularly other heavy use applications like image management) - even virus checking s/w can sometimes cause these little interrupts.

Also I hope that you are not trying to capture direct to the extrenal USB dis are you? That is not recommended - a USB disk is unlikely to be fasty enough to keep up with digital audio capture.

WC

[rickbking]

As often happens, giving up and asking for help caused me to rethink and look at my problem in a new way. I recalled that Roland recommends connecting the Edirol after booting up, and that otherwise the driver might not work properly. Upon doing that, suddenly there are NO PROBLEMS with Audacity that I can see right now. I've always had a problem with noise when recording and that seems to be gone, and there are no problems with the recording levels either.

I don't understand what it could be about Audacity that would have caused problems that didn't show up when recording with CDEX, though.

BTW, I understand the main issues with USB and was recording directly to my local C: drive.

I hope my problems have been solved.

Thanks for the response.