Mono Clips [SOLVED]

[jt49]

It seems that PTE 10.5 reduces the volume of mono clips by about 3 db. I did not notice this effect in 10.0 and 9.0.

[Igor]

Hi,

Please send me 1-2 sample videos.

[denisb]

Hi

in 9 or 10 the mono was put on left and right canal unchanged the overall volume was multiply by 2

in 10.5 the mono is put on left and right canal with overall volume same as mono.

Denis

[jt49]

I do not agree. The two attached clips run at the same volume (~ -6 db) in Audacity, foobar2000, Windows Media Player, VLC, PTE 9, PTE 10. In all these cases: For the mono clip, the mono channel is played on both stereo outputs (no factor of 2). All the players above do it as it should be. PTE 10.5 reduces the output of the mono clip to a volume of ~ -9 db (it should not be like this).

 

440Hz_Mono.wav440Hz_Stereo.wav

[denisb]

I don't talk about the amplitude of the signal, but the loudness of the music.

If you measure the loudness of the 440Hz_mono you will find -9.8 LUFS.

If you measure the loudness of the 440Hz_stereo you will find -6.8 LUFS.

But I agree, the normal behaviour is PTE 9 or 10 and not PTE 10.5

Denis

[jt49]

I think that we do not talk about loudness in the sense of EBU R 128, but just about the specification what PTE's stereo output should be when the input is a mono track. And it should be the same as for a stereo input whose channels both coincide with the mono input. 

I often make mono recordings with a microphone. With PTE 10.5 most of my old projects do not run correctly, the voice-over is too low.

[Igor]

Thanks, I confirm both problems.

[Igor]

Indeed, it's interesting problem which doesn't have a simple solution. The same situation was discussed on another forum:

"Why does ffmpeg's conversion from mono to stereo lower the volume?"

https://sound.stackexchange.com/questions/42709/why-does-ffmpegs-conversion-from-mono-to-stereo-lower-the-volume

Quote

It seems that FFmpeg attempts to respect a common pan law (when routing a centered mono track to a stereo track, lower the mono signal by - 3 dB on each channel of the stereo track). The goal is that the perceived loudness remains coherent.

We do the same in PTE 10.5. 

I checked various video players. Almost all players keep the same loudness for mono audio. And I found that an old MPC-HC version reduces loudness as PTE 10.5.

What you think?

[jkb]

Hi Igor, we are having a 'Sound in AV' meeting at Wilmslow on Friday.
We will be trying out different microphones, both mono & stereo and putting the sound files into PTE.

This is an interesting problem & we will try it out to see exactly what happens. with different mics & different versions of PTE
Also using Audacity, Audition etc.

Jill

 

[jt49]

Working with VLC: I converted my mono clip from above (440Hz_Mono.wav) with VLC to a stereo clip. The result: VLC just copied the given mono channel into both channels of the resulting stereo clip.

Working with Audacity: How does Audacity mix a mono track into a stereo track? Here is the result: Audacity mixed the mono channel into both channels of the stereo track, and it did it without reducing by 3 db. Here is an example (see image below):
- Track 1 is mono
- Track 2 is stereo, it is just silence (amplitude=0)
- Track 3 contains the mix of Track 1 and Track 2. Both of its channels contain the original mono channel of Track 1

 

Would we really like that PTE had a mixing behavior that is different from the famous audio editor?

Would we like to lose compatibility to all former versions of PTE?

Would we like it if PTE would play certain tracks different from VLC, foobar2000, WMP and others?

 

 

 

 

[denisb]

Jt49  "Would we like to lose compatibility to all former versions of PTE?"

No

[Igor]

Thanks for your opinions. We'll try to make it as in earlier versions.

P.S. I moved my reply to this topic, wrongly posted in another thread.

[Igor]

On 11/7/2021 at 1:24 PM, jt49 said:

It seems that PTE 10.5 reduces the volume of mono clips by about 3 db. I did not notice this effect in 10.0 and 9.0.

We fixed this issue today. I'll publish a new Beta tomorrow.

[jt49]

I like it 

[Igor]

On 11/7/2021 at 1:24 PM, jt49 said:

It seems that PTE 10.5 reduces the volume of mono clips by about 3 db. I did not notice this effect in 10.0 and 9.0.

Try a new version 10.5.6 Beta:

https://files.wnsoft.com/test/pteavstudio-setup.exe

Note, that you need to manually clear the cache of waveforms, or rename a WAV file to update old waveforms.

[jt49]

I've made a short test, showing the return to the behavior of mono clips that we had with former versions. That's fine.

[Igor]

Fine. Please check other projects other audio clips to make sure that everything works correctly.

I also discovered that some videos from smartphones (iPhone) are recorded with mono sound. So this change will affect these video clips, too.