Crashing Audacity

[LoZio]

I'm using 1.3.4 on Vista X64 (Dell D830 with 4 Gb RAM).
I found a way to crash Audacity. Here are the steps to reproduce:
1) Open a file (mine is 33 Mins)
2) Select a part of the file (about 3 min)
3) Crop to selection
4) Select a part of the remaing audio
5) Crop to selection
6) Make the stereo track a mono track
7) Normalize (0 dB)
8) Play. When you click play Audacity crashes.

I don't know if all the steps are necessary, but they are surely to crash Audacity (and loose my work, several times )
Hope it helps, and keep going on this good job!

[steve]

6) Make the stereo track a mono track

There is a known bug that causes Audacity to crash after using "Stereo to Mono" (hopefully to be fixed in v.1.4).

The work around is to amplify by -6dB (minus six), then split the stereo track using "Split Stereo Track" in the drop down menu in the tracks information box, then using the same menu, set each track to mono and mix the two tracks together ("Quick Mix" in 1.2.x, or "Mix and Render" in v.1.3.x)

If both left and right channels are identical (it started off as a mono recording), the work around is even easier - simply split the track as described above, then delete one of them and set the remaining track to mono.

[LoZio]

6) Make the stereo track a mono track

There is a known bug that causes Audacity to crash after using "Stereo to Mono" (hopefully to be fixed in v.1.4).

The work around is to amplify by -6dB (minus six), then split the stereo track using "Split Stereo Track" in the drop down menu in the tracks information box, then using the same menu, set each track to mono and mix the two tracks together ("Quick Mix" in 1.2.x, or "Mix and Render" in v.1.3.x)

If both left and right channels are identical (it started off as a mono recording), the work around is even easier - simply split the track as described above, then delete one of them and set the remaining track to mono.

Many thanks. Just a question: if it is a known bug, and it crashes the program loosing the data in it, why it should be fixed in 1.4.x since we're with 1.2 stable and 1.3 beta? Not kidding, real question.
Bye

[steve]

why it should be fixed in 1.4.x since we're with 1.2 stable and 1.3 beta? Not kidding, real question.

The next stable release of Audacity will be 1.4 and it is based on the (almost stable) current 1.3 beta version.

[breezewave]

I have a worse experience.
I have incorrect mono tracks from splitting single stereo track.
It sounds all right, but when I use Hex Workshop to see the binaries, the intensity values (maybe 1 %) aren't the same as stereo track.

1.2.6 stable is fine, but it occurs with 1.3.4beta.
And I have changed preference -> quality -> sampling rate and format to 48K/16bit, the same as my input.
My steps is:
1. drag file to audacity
2. split stereo track
3. close track of splitted right channel
4. mono
5. file -> export

So, is it a bug or my wrong manipulation?
I guess maybe the problem comes from a resampling that should not happen?

Thanks a lot.

[steve]

My steps is:
1. drag file to audacity
2. split stereo track
3. close track of splitted right channel
4. mono
5. file -> export

I presume that your initial track was a 2 track mono recording (both channels identical)
For a true stereo track, the slightly longer method of mixing left and right should be used.

I've noticed that if I work in 16 bit, there are some tiny discrepancies, but they are in the order of -70dB, so it's not usually noticeable. Using 24 bit does not work on my machine (seems to be a common problem), but at 32 bit (float) it is "bang on" (bit perfect).

[breezewave]

Yes, my initial track has two identical channels from a mono mic.
The discrepancies are really not noticeable, but this might result difficulties in debugging.

Oops, I don't want to mix, and nor do my steps.
If mixing, I believe maybe some algorithms are used due to psycho-perceptual things.
but I don't understand why a demux of simple stream copying have discrepancies.

1. change preference to 32bit
2. split
3. save or set sample rate to 16bit then save

1. preference of 16bit
2. set sample rate to 32bit
3. split
4. save or set sample rate to 16bit then save

Finally, I got 4 different files.
It seems a stable version is more stable.

Thanks a lot.

[steve]

There will always be some slight "errors" when ever you convert from one bit depth to another due to "quantisation" errors. The audible effect of quantisation can be minimised by using "dithering" (which Audacity does by default).

You can read more about quantisation errors and dithering here: http://www.pcrecording.com/dither.htm

[breezewave]

My steps is:
1. drag file to audacity
2. split stereo track
3. close track of splitted right channel
4. mono
5. file -> export

I've noticed that if I work in 16 bit, there are some tiny discrepancies, but they are in the order of -70dB, so it's not usually noticeable. Using 24 bit does not work on my machine (seems to be a common problem), but at 32 bit (float) it is "bang on" (bit perfect).

Did you mean that at 32 bit, I can get the bit perfect splitted one channel?
But at that time, I can't find out how.

Yes, I know what dithering is and what for.
But my input, output and edit->preferences are all the same sampling rate.
Theoretically, no dithering is needed, and I didn't think of it.
Anyway, after I turned dithering off, i got what I want and know what happened.

Thanks again.

[steve]

But my input, output and edit->preferences are all the same sampling rate.Theoretically, no dithering is needed, and I didn't think of it.

I've not checked it out, but I think that Audacity may use 32bit internally. If I remember, I'll do some tests to check that later.