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Audio: Speakers with animated pitch cause clicks in rendered animations, crashes or huge filesizes in rendered audio
Closed, ResolvedPublic

Description

(Please add "Audio" to project tags. I find myself unable to do anything but delete existing project tags.)
System Information
OS: Windows 7 640but, GPU: GTX 580
also
OS: Windows 8.1 64-bit, GPU: FeForce CT 735M

Blender Version
Broken: As recently as BuildBot 2.71 5e3e095 to as early as official 2.65a, at least.

Short description of error
A rendered animation containing a speaker with pitch keyframed to go from very low to very high rapidly can usually (but not always, this makes tracking down the causes difficult!) contain a loud, inappropriate click during the transition from low to high pitch.

Attempting to render only the audio (to a .FLAC file) can cause Blender to crash before finishing, producing an incomplete audio file, cut off right before where the click would be, or it can continue, in which case it includes the click and produces a .flac file many, many times larger than it needs to be.

Exact steps for others to reproduce the error
Render the animation in this file:


When I do, I get this:

Render the audio in the file. When I do, I get a 1.2 GB file, which, when saved in Audacity, is only 294 KB.

Notes
I have not been able to find any setting (in file export type, in audio device settings, etc.) that reliably gets rid of the clicks. The only method to do so seems to be "avoid rapid increases in pitch." Also note that while my file is at 60 fps, I have observed clicks at 24 fps, as well.
I cannot guarantee that only rapid increases in pitch cause clicks, but I have observed no other situation that does.

Pardon any errors in format or etiquette, phabricator has eaten my bug report twice now and I'm just trying to get it out!

Event Timeline

Tom Benedett (moak) claimed this task.
Tom Benedett (moak) removed Tom Benedett (moak) as the assignee of this task.
Tom Benedett (moak) raised the priority of this task from to 90.
Tom Benedett (moak) updated the task description. (Show Details)
Tom Benedett (moak) edited a custom field.
Sergey Sharybin (sergey) lowered the priority of this task from 90 to Normal.Jul 21 2014, 11:55 AM
Joerg Mueller (nexyon) changed the task status from Unknown Status to Resolved.Jul 21 2014, 2:30 PM

I fixed the crash in r31e1a31feed3adbfba85ed319447fc13e9b454ee

The click comes from the sudden change of the frequency/pitch by a factor of 100 within a frame. If you want to get rid of it, you have to set the accuracy to 1 during audio export.