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.
Thanks for the help,
Rick
On 3/9/2020 4:05 PM, Ted Park wrote:
Hi,
I have a sine wave audio test file generated with Matlab in FLAC and also WAV
formats which load into several audio applications at full scale amplitude
(16-bit sine wave peaks at +32767 and -32767). The other applications play
this file at maximum full scale amplitude yet FFPLAY plays the file at 3dB down
from maximum amplitude. Converting the file with FFMPEG to other formats
results in an identical amplitude file which is full scale also. Other programs
play this file at maximum amplitude but FFPLAY again is at -3dB from full
scale. Is there a command that I need to issue to FFPLAY to make it play at
the native volume?
Here is my command:
C:\ffmpeg\bin\ffplay -volume 100 Sine_65s_997Hz@FS_44.1k_16b_int16.flac
The sine wave FLAC file is 1.7MB and I can provide that if that would be useful.
Odd thing here is that I have tried several song files, and even live audio
streams in FFPLAY, and they play at the correct full scale amplitude.
Where are you measuring the level to be 3dB lower than normal? You might have a
mono file that is being panned left and right each at half power, which is
sqrt(/ about -3dB gain. So to get a 0dB total, you see the 3dB attenuation per
channel. Does this sound plausible?
Regards,
Ted Park
_______________________________________________
ffmpeg-user mailing list
[email protected]
https://ffmpeg.org/mailman/listinfo/ffmpeg-user
To unsubscribe, visit link above, or email
[email protected] with subject "unsubscribe".
_______________________________________________
ffmpeg-user mailing list
[email protected]
https://ffmpeg.org/mailman/listinfo/ffmpeg-user
To unsubscribe, visit link above, or email
[email protected] with subject "unsubscribe".
