MP3 files lack data

[PeterK]

I have just started using Audacity (1.3.13-beta, Mac OS X 10.6.8) to digitise LPs, and no problems with first few LPs. But some hitches with latest project. At first "export multiple" would not work at all and offered no explanation. I discovered I was at fault for using a non-acceptable character in label names ("/"). Maybe some help/guidance could be built in for the future, or have I missed something? After sorting that problem I managed to create an MP3 file for each track as usual, but two of these files contain virtually no data (4k and 12k respectively). I have checked that all tracks are unmuted in the project file. Might the problem be connected with the "mix and render" function which I use - perhaps erroneously - to get everything on to one track when the A and B sides of a source LP have finished up on separate tracks?

[Gale Andrews]

I have just started using Audacity (1.3.13-beta, Mac OS X 10.6.8) to digitise LPs, and no problems with first few LPs. But some hitches with latest project. At first "export multiple" would not work at all and offered no explanation. I discovered I was at fault for using a non-acceptable character in label names ("/"). Maybe some help/guidance could be built in for the future, or have I missed something?

It's a known bug for which there will be a release note in 1.3.14 if we haven't fixed it by then.

After sorting that problem I managed to create an MP3 file for each track as usual, but two of these files contain virtually no data (4k and 12k respectively). I have checked that all tracks are unmuted in the project file. Might the problem be connected with the "mix and render" function which I use - perhaps erroneously - to get everything on to one track when the A and B sides of a source LP have finished up on separate tracks?

You can use the blue Pause button to keep the recording on one track while changing LP sides.

I assume you realise you that with Mix and Render you may have to time shift the track for the second side to start after the end of the first track, otherwise the tracks would play simultaneously.

There are a number of scenarios where Export Multiple could produce minimal files - usually because there is no audio data for the label. This is another bug to be release noted in 1.3.14. If you cannot cure your issue, can you post a screenshot of the affected area of the track from which the two minimal files are exported?


Gale

[kozikowski]

If you drag-select one of the missing songs from the timeline, do you still get damage if you Export Selection?

Describe how you're capturing the second side of the record. I would be using Record Pause, flip the record, and resume capturing. What did you do?

Did you use Silence Finder to determine the gaps between songs? Are you actually missing songs?

Koz

[PeterK]

Thanks Gale and Koz. I tried to reply but the reply disappeared. Apologies if this duplicates.

The screenshot shows the two problem tracks, which happen to be consecutive, along with a bit of each of the tracks on either side, both of which are ok.
Koz, I should have thought of "export selection" for myself, except I haven't begun to work out yet what the various options do. That worked fine. Previously I had exported an album of 16 tracks into 16 MP3 files. According to onscreen indications, everything worked fine. But two of the MP3 files turned out to contain no audio data. By exporting those tracks as selections I was able to overwrite the defunct files successfully, and all 16 tracks now show up and play ok from a cd I've just burnt.

I realise I need to get smarter at turning LPs over. I usually do try to pause the recording without stopping it, but sometimes the button doesn't depress at the first attempt and I finish up hitting "stop". I then go back to the end of the A-side recording and hit "record" again for the B side. It carries on consecutively on the timeline, but on a new track.

Anyway, the job is done, for which many thanks, but obviously I'm doing something wrong, or the program is. Maybe the screenshot will help you pinpoint what.

[billw58]

Look at the label "Banjo Signal". There are two labels there, very close together. This is the source of the tiny exported file. Delete one of the labels (and similarly there is probably a double-label elsewhere) and you should be fine.

-- Bill

[PeterK]

Thanks Bill. That was exactly it.

[Gale Andrews]

I'm not sure if that was two label close together (in that case you would get your intended audio with an extra miniscule file), or a minuscule region label (probably you dragged it slightly with the arrow handles, in which case you will get a miniscule file instead of the intended one).

A good way to check if you have a miniscule region label is to click in the label. If you have two pointing arrows on the Timeline:

minimal region label

miniscule region label.png (1.42 KiB) Viewed 1447 times

rather than one, then you have a region label.



Gale

[PeterK]

Regional labels is indeed what I had Gale, though I didn't realise what they were. I had been pulling apart the labels by their arrows without realising, when I was intending simply to move them. They're a bit small for my eyesight, and zooming doesn't enlarge them.

Thanks again for all the help. The program's now doing a wonderful job, and not a penny spent!

[Gale Andrews]

The central circle in the label is what you grab hold of to move the label. It should change to white when you are hovered over it.

There is no reason you can't use region labels to mark the selections to export if it's less fiddly. Export Multiple still works if all labels are region labels. Region labels let you decide how much (if any) of the gaps between the tracks you want to export.




Gale

[PeterK]

Thanks. I'll do some experimenting.