Audio Bug when Producing?

JamalG

Newbie Joined: Aug 23, 2018 15:37 Messages: 15 Offline

Solved by

Sep 10, 2018 02:51

Got another strange problem...

I've noticed that on some of my complex projects that the audio for select clips will get slightly distored at times. It sounds amplified or out of phase. The problem is noticable in the preview mode as well as the Produced output. The distortion is usually duriing a multiple layered audio segment and it seems to happen when the system gets over-taxed (low on memory maybe). I've come to realize that if I quit PD and then re-start, the problem will be gone (temporarily). This is a real pain as A) the problem hampers my preview mode and B) if I forget to re-start before selecting "Produce" the output is likely to be ruined.

Look at this waveform comparison:

(Ugh -- just realized I cannot upload a reference picture directly to this forum. Kinda lame.)

So... imagine... two waveforms which are distinctly different. Both are output from the same PD project w/o any changes to the project itself. The first was created when I noticed the problem and hit Produce, then the second was created after quitting and re-starting. Without any changes to the project, the audio output is not the same. It's as if a memory leak or other bug is affecting the Produce process for audio.

Known problem? Any ideas?

StevenG

Contributor Joined: Jan 14, 2014 14:04 Messages: 513 Offline

Sep 10, 2018 07:48

Are you monitoring your audio levels using the meters in the Audio Mixing Room? You need to keep the levels in the green. If your audio is peaking above zero or the meters show it as yellow or red, it is over-modulating.

Many people just assume that the levels of audio they hear when they play their timeline on their computer is a realistic representation of what the final audio will sound like. You really need to use the meters to check your audio levels!

If that's not it, consider the sources of your audio.

Is this music? Is it audio from the video itself? Is this narration recorded with a microphone? Each audio source can produce issues, depending on its specs.

JamalG

Newbie Joined: Aug 23, 2018 15:37 Messages: 15 Offline

Sep 10, 2018 14:11

Quote Are you monitoring your audio levels using the meters in the Audio Mixing Room? You need to keep the levels in the green. If your audio is peaking above zero or the meters show it as yellow or red, it is over-modulating.

Many people just assume that the levels of audio they hear when they play their timeline on their computer is a realistic representation of what the final audio will sound like. You really need to use the meters to check your audio levels!

If that's not it, consider the sources of your audio.

Is this music? Is it audio from the video itself? Is this narration recorded with a microphone? Each audio source can produce issues, depending on its specs.

Gotcha -- but I don't think that addresses my specific problem. Why would my output change from one render to the next without any changes to levels in the project? In other words.. I expect consistent audio output (bad or good) regardless of my current system load (or other variable).

StevenG

Contributor Joined: Jan 14, 2014 14:04 Messages: 513 Offline

Sep 11, 2018 08:13

There are so many things to consider, Jamal. Like the possibilities I suggested.

It also may be an old HD audio codec driver or even something in the media player you're using to play the file. But without more details from you, we can only take shots in the dark.

Can you post one of your videos to YouTube so we can hear the distortion ourselves?

This message was edited 1 time. Last update was at Sep 11. 2018 09:00

AVPlayVideo

Senior Contributor Location: Home Joined: Apr 06, 2016 19:03 Messages: 703 Offline

Sep 11, 2018 10:30

Quote There are so many things to consider, Jamal. Like the possibilities I suggested.

It also may be an old HD audio codec driver or even something in the media player you're using to play the file. But without more details from you, we can only take shots in the dark.

Can you post one of your videos to YouTube so we can hear the distortion ourselves?

It has already happened (rare) that I only produced the audio on 1st, then I added this new audio to the project.
For this I deactivated the video tracks and effects so as not to interfere with the audio.

I currently prefer instead to mute audio from a clip, unlink audio and video, and delete audio that I'm not going to use.

There was a problem with audio distortion that was fixed in an update, I do not remember whether for PD16 or earlier.

JamalG

Newbie Joined: Aug 23, 2018 15:37 Messages: 15 Offline

Sep 11, 2018 14:32

I appreciate the input, but let me re-iterate... this is a RENDERING issue (not playback, not source, not levels, etc). In fact, I almost think PD is ignoring the level settings for some clips when memory is low. The exact same project will output different results (after PD restart) which can be heard and "seen" by looking at the waveform.

Possibly related (or not), does anyone ever have the thumbnails in the media bin get all scrambled? (ie change to "Cyberlink" text or other non-related images.) This sometimes happens at about the same time I have problem with audio and to my mind is another indication that the program/system is over-taxed and I need to restart.

Sorry -- I don't have time right now to easily post reference files. Maybe later.

StevenG

Contributor Joined: Jan 14, 2014 14:04 Messages: 513 Offline

Sep 12, 2018 07:44

As we've said, we'll better be able to help you once we hear the problems you're describing.