Bug Report Audio artifacts when streaming or recording Super Mario World

B

BeeKaaaay

New Member
Hi.

I have encountered what looks like a bug in the AAC encoder that ships with OBS (libfaac?). The bug manifests as crackling/hissing/popping. It is prevalent inside Ghost Houses in Super Mario World. Something about the Ghost House music triggers it. Example: https://www.twitch.tv/beekaaaay/v/102364208?t=22m25s (a few seconds in).

Note that I am recording/streaming using an emulator. I have tried several (Snes9x, BizHawk, Higan) with a variety of audio settings (drivers, buffer sizes, sample rates, stereo vs. mono), but the problem persists. I have found two workarounds:

#1. Setting the audio bitrate in OBS to at least 224kbps. 192kbps or lower produces the audio artifacts. So, maybe it's a bug in the AAC encoder when encoding at 192kbps or lower? Unfortunately, 160kbps is the maximum AAC bitrate allowed on Twitch, so this workaround cannot be used for streaming on Twitch.

#2. Installing CoreAudio as per https://obsproject.com/forum/resources/obs-studio-enable-coreaudio-aac-encoder-windows.220/. CoreAudio does not have this problem.

I can readily reproduce the problem by playing a Ghost House in Super Mario World and recording it. Is there something I should try? Do you need any more information?
 

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You're having this issue. I suspect the issue is related to the Media Foundation AAC Encoder, as I explain in that thread.

Does the issue also occur at 64 kbps? How about 96 kbps? Can you reproduce it using 32-bit OBS Studio?
 
The problem does not occur at 32 and 64kbps, but does occur at 96, 128, and 160kbps, and stops at higher bitrates. It happens both in 32- and 64-bit OBS Studio.
 
The behavior with respect to the different bitrates is exactly as I expected. The information that it happens in 32-bit OBS Studio contradicts the information from @smite. I'm fairly convinced the culprit is Microsoft Media Foundation, though I don't know why exactly why it's happening. Installing CoreAudio will likely solve your issue.
 
I Followed the guide but i am still getting clipping issues I dont know what is further causing it even going down to a 32 bit version of OBS as it was the only version that would show that it was functioning.

Should I look into Ducking??
 
This thread is about an encoding bug causing specific audio artifacting in the encoded output. Not about any actual audio chain issues.

Clipping is a result of a part of the audio chain having an audio waveform above the maximum amplitude. Ducking will not help -- lower your input volume/gain.
 
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