Error on sliding time scale/pitch shift - SOLVED

[mdubin]

Steve:

I zipped the WAV file in question and the size of the zip is 95,019 KB. Here is the link:

http://www.sendspace.com/file/3tqe6r

Thank you.

mdubin

[PGA]

No problem found when applying the 12% values using Audacity 2.0.1 running under Windows 7 Home Premium SP1 64-bit

[mdubin]

PGA:

Did you apply 12% or -12%?

I applied a 12% reduction (-12%).

Anyway, I reinstalled 2.0.1, got the error and did a screen print. Here is the link:

http://www.sendspace.com/file/qroia6

mdubin

[steve]

http://www.sendspace.com/file/qroia6

Ah ha - you have Quality set to 16 bit. I've not tried that (I always work in 32-bit float as that is "native" to Audacity and avoids unnecessary conversions).
I'll try 16 bit and see if that makes any difference.

[PGA]

I'm out of town until Thursday mid-morning. I'll try at 16bit when I get back.

[mdubin]

PGA and Steve:

I have had the quality set to 16 bit for a long time. I always work with WAV or FLAC. All my edited tracks in Audacity are eventually burned to CD-R. I wanted the quality to match that of PCM.

When I first started using Audacity, I kept the default of 32 bit float. But I was getting some additional noise in my output which was not present in the source files. So I then found out about the quality settings and changed to 16 bit. Everything had been fine since then. If I am mistaken in regard to 32 bit float vs. 16 bit, please enlighten me.

Note that all my source files are either WAV ripped from CD or MP3 downloads which I convert to WAV or FLAC. I do not do any of my own recording.

EDIT: I changed the quality to 32 bit float and did the same -12% speed reduction on that track. It did not error out. Maybe that explains things for 2.0.1 but how come I never got any erroring out in prior versions using 16 bit? I need to be fully enlightened on using 32 bit float and how that would affect the sound quality on resulting WAVS or FLACS burned to CD-R.

mdubin

[steve]

I've repeated your steps as closely as possible on Windows XP SP3 about 20 times with your original file and about 20 times with other files in Audacity 2.0.1 and about the same in Audacity 2.0.0. This took a long time as my XP machine is very old and slow (processing time about 15 minutes for that file).

I've repeated the steps about the same number of times on my (main) Linux machine about the same number of times.
I've also tested (countless times) generated test signals on the Linux machine with both the 2.0.0 and 2.0.1 versions with a full range of alternative settings.

The most noticeable differences are:

• 2.0.1 is a little slower than 2.0.0 when "Dynamic Transient Sharpening" is disabled, and a lot faster than when "Dynamic Transient Sharpening" is enabled.
• 2.0.0 with transient sharpening enabled gives slightly better sound quality with "Dynamic Transient Sharpening" enabled compared to "Dynamic Transient Sharpening" disabled.
• 2.0.1 does not have a "Dynamic Transient Sharpening" control.
• The sound quality of 2.0.1 is significantly (audibly and measurably) better that 2.0.0, with or without "Dynamic Transient Sharpening".
• If part of a track is selected rather than the entire track, 2.0.0 produces a very noticeable glitch at the start that is like a 0.03 second "fade in". 2.0.1 produces a seamless transition between the unprocessed audio before the selection and the processed audio. There is very minor (and unavoidable) glitch at the end of the selection with both versions.
• I have had 1 failure (crash) which was with the file that you provided, on XP SP3 with Audacity 2.0.1

What conclusions would you draw?

[steve]

I've moved the post about Quality settings here: http://forum.audacityteam.org/viewtopic ... 46&t=66589

[mdubin]

Quote: I have had 1 failure (crash) which was with the file that you provided, on XP SP3 with Audacity 2.0.1.

It happened again with 32 bit float. "An unhandled win32 exception occured in audacity.exe[2992]

This was with a different shorter WAV file.

I must go back to 2.0.0 for peace of mind

mdubin

[steve]

At least we know that the 16-bit aspect is probably irrelevant.
It's a shame because the newer version gives definitely better quality. If you find any more information that you think may be relevant, please let us know, but as the only way that I've been able to reproduce a crash is by flogging my poor old XP machine relentlessly for hours on end I don't think there's a lot more that I can do other than log the case. I'll post if I hear any more. Releases seem to be scheduled for about a 3 month cycle, so let's hope that you find sliding time scale/pitch shift more stable in 2.0.2. Thanks for investigating this with me.