[FFmpeg-user] FFPLAY plays some audio files at their native amplitude while others are playing 3dB down in amplitude

Mark Filipak markfilipak.windows+ffmpeg at gmail.com
Tue Mar 10 04:00:35 EET 2020

On 03/09/2020 09:51 PM, Rick Keniuk wrote:
> You found it Ted...  FFPLAY interprets a mono (single channel WAV) file 
> to be played at -3dB from full scale while the other programs set the 
> mono file at full scale on both stereo channels. I simply modified my 
> Matlab code to generate a stereo file with identical channels (from the 
> original single channel data) and that fixed it.  I guess they are 
> "power dividing" the single channel signal.  I don't think I agree with 
> FFPLAY's interpretation of the amplitude of a single channel WAV file 
> but that is what is happening.  Maybe there is a configuration to fix 
> this effect.

You know, Rick, if you think about it, what ffplay does is actually 
pretty smart -- sound pressure level of dual-mono == sound pressure 
level of single channel).

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