Sound missing or dropping out

[Rowland]

I have been using Audacity for about 15 months now, and I find it a very competent program, most of the time.
During this time I have used it mainly for recording audio book chapters, and I have recorded several hundred chapters. Twice ( Only twice, but still, so far) it has happened that a file, after a first editing and saving (in AUP format), and one just very, very recently now, that when I start it up again to do the final adjustments before converting it to other formats I can see the audio waves on the screen, but the sound drops out on a more or lees regular basis. I.e. I hear the reading for a short period, then only silence, then the sound comes back, then it is gone again, and so on. I see no solution but to redo a chapter like that.
Anyone who can explain what has happened?
Once it has also happened that having read a chapter and having edited it, and prof listened to it, and finding that everything was OK, I exported it into Mp3 and uploaded it to "Librivox". Then the proof listener there said it was almost impossible to listen to, because there was a terrible noise all through the recording. So I went back to the original Audacity (AUP) file to make a new export. But !!! the original file was suddenly totally corrupted too. The only solution was to redo that chapter from the beginning.
I also see that others have had problems with crashes and difficulties finding the temp-files etc. That has happened for me too, and the recording doesn't have to be very long for it to happen. When it happens it always happens when I am to save the file. Five or six times out of three hundred recordings it has happened, but I have learned to puzzle the small (6 seconds) pieces together manually, just recently having found the recover program, so I haven't tried it yet. I actually hope I won't have to use it.
Rowland

[kozikowski]

AUP files are not sound files. They are supervisory files for Audacity Projects. Projects are enormously complex affairs, but the AUP file is plain text and you can open it up in NotePad and read it. Here's a picture of a simple one ...

http://kozco.com/tech/audacity/aup1.jpg

Use the magnifier tool to see it. It's mostly English words. Their job is to point to the rest of the files making up the Project, and there could be thousands of them depending on how long you were recording.

Audacity Projects, because of their complexity are easily damaged. It is strongly suggested that after a live capture you produce an actual WAV sound file through the Audacity export tools. This becomes your Capture Master sound file and you can make a copy of it and save it on another backup drive for safety.

Then you can edit that and export it to the other formats and services you need. Even if your computer catches fire, you can go back to your safety drive in the closet with your backup WAV files and keep going.

You can't move or copy AUP files.

I've been known to go through an entire live capture all the way to (simple) delivered product without making an AUP file.

You can get temporary Computer Insanity by either filling up your hard drive or not defragmenting your drive(s) properly. Audacity will not work into a highly fragmented hard drive.

Let me know if I hit it.

Koz

[Rowland]

Thanks a lot,

I can't say I am quite into this technical bit about Audacity yet. I used to work in a radio-studio, but there we used tape-splicers and tape.
Let's see if I have got it right. If I record and save in Audacity's native format, it isn't actually a sound-file? But still it produces sound.
WAW is a normal or common sound format, I know that, so I'll think about it and remember it in the future. And I do have a separate hard disk, where I put backups and special data. (And I have a couple of computers to play with too).
But I still would like to know how and why a file that was good when I "left it" can go corrupt the next. And my test-program said the hard disks weren't fragmentated at all.
Rowland

[kozikowski]

<<<but there we used tape-splicers and tape.>>>

Scotch 808? Wasn't there a low-noise version? Like 908 or something? Edit-All block, right? Somebody else made popular blocks.

I don't remember who made the razor blades.

<<<Let's see if I have got it right. If I record and save in Audacity's native format, it isn't actually a sound-file? But still it produces sound.>>>

Most of the time, yes. The Project is kept in its component form in order to be the most efficient and fast. If you're editing hour one of a two hour show, it's a complete waste of time and resources to load and run hour two -- or the whole show.

My silly analogy is somebody building a highway just in front of you and then taking it all up again as you pass. When you get to your destination in perfect order, you look back and it's fields and trees. No road.

So yes, it's not a sound file, but it plays sound. If you were to decide that a portion of your show needed reduced volume, all it would do is pin a little pink note on the AUP file that says, The next time the user plays this portion, reduce the volume, OK?" None of the original work or capture material is actually changed.

Obviously, this makes UNDO a snap. Just unpin the note, crumple it up and throw it in the bin. No more volume reduction next time you play the work.

The pink note and pin are actually commands and instructions inside the AUP file. That's XML (eXtensible Markup Language in case you couldn't sleep not knowing that.) And it's a recipe for how to make your show.

Salt, flour, eggs, whipping cream....

That whole production only becomes one single, stand-alone sound file at Export. WAV files are uncompressed and undamaged and represent the identical quality that your Project was. They're big. Sometimes very big. I have produced two and three hour shows that went into the Giga Byte range.

MP3 files and other compressed formats are much smaller and easier on the computer, but almost all compressors damage the sound in order to get that efficiency. WAV is a production format, MP3 is a delivery format.

So, if you have a Project and it has pieces and fragments missing, then something on your computer caused one or more of the tiny pieces of your project to be misplaced or destroyed. Without the backup WAV file, the show may be gone.

This can happen when you start filling up your hard drive and the system and Audacity become marginally unstable and slow. I noticed you carefully avoided telling me how full the drive was. Actual numbers are good. My drive is 150 GB and I'm only using 40 BG. Beyond 90% full and Bad Things can happen.

Koz

[kozikowski]

Just a note. This can also happen if you try to move a Project or "clean up" and accidentally destroy some of the pieces of the show. It's easy to do. This problem reduces Obsessive-Compulsives to jelly. They clean up and organize all their files after a live capture and there goes the show. The AUP file always points at the same directories and folders. If you move, rename, or delete anything on your machine, there could be trouble.

Koz

[Rowland]

Thanks again,
I think I have got a bit better understanding of how the program actually works, and I will try to take precautions next time.
To answer your question about the hard-drive. The partition on which I have the recorded files is 108 GB and just now 57 GB is used. The harddisks (3 at the moment) are defragmentated automatically every week, and in between, if my tune-up program thinks it necessary.

As far as I know. The file that has made trouble just now, is, or was, about 16-18 minutes long. After a first editing, cutting out mistakes or long pauses ( i.e. things like having had to start a sentence or paragraph several times because of mistakes in reading), and saving it at frequent intervals, and at the end, I now got back to it to do the last clean ups (this is the way I have done it so many times already), like coughs, heavy breathing, etc, and then I found that parts of the sound is/was missing at irregular intervals. As I have read a few more chapters from the same book after this one, and they are all stored in the same folder, I checked some of them, and they seem to be quite OK.

One learns by mistakes.

Rowland

[kozikowski]

<<<The partition on which I have the recorded files is 108 GB>>>

That raucous sound is the alarm bell sounding. Never capture to a partitioned drive. You do not "magically" get three drives out of one when you partition. You get three apparent drives each with one third or less the speed of one. Speed is a big deal when you do anything live, video or audio. If the drive is off servicing partition three at the same time you're trying to capture to partition two, then you lose on Sports Call. There's only one actuator inside the drive and it can't be in two (or more) places at the same time.

Audio (and video) doesn't wait. If the drive isn't there and ready, the data is lost.

Another really messy thing that happens with partitioned drives is group failure. If the platters or spindle goes down on a partitioned drive, D:, E:, F:, and G: all hit the dirt at the same time. Everything on all the partitions. History.

The ideal system has two physical drives; one smaller fast one for the operating system and programs, and the other larger one for the data and shows. The truly compulsive will have a third portable drive with the backup capture master WAV files on it.

Unless your performances aren't that valuable.

Koz

[steve]

The harddisks (3 at the moment) are defragmentated automatically every week, and in between, if my tune-up program thinks it necessary.

Just make sure that your tune up program does not think that defragmenting is necessary while you are recording. A well behaved tune up program should not do that, but if it did it would be very likely to cause problems. Personally I would disable it while working with audio.

[Rowland]

That was interesting! I haven't thought about the question of partitions really.
I don't know why, but it seems to be very common when you by a new computer today, like a high spec lap top, that there are two partitions on the drive. (Even a small Net book computer with a hard-drive has two partitions.) I don't really like that, but I haven't done anything about it on this one yet. I'll put the files on the (larger) separate drive instead then. And I will also look into the defragmentation thing. I noticed last night that Vista automatically wants to defrag once a week, and that at a time when I am often recording. So I'll change that. The tune-up does its work at other times, but I'll check that too to be more on the safe side.
Rowland

[kozikowski]

I've seen partitioned drives on new machines where one small partition carries system restore and backup information. They usually try to hide this partition so the casual user doesn't try to damage any of this information or data by accident.

That kind of thing is probably OK because the backup partition isn't actively managed.

I'm still not particularly happy about it.

Koz