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Clipping on certain tracks

  • 24 September 2021
  • 13 replies
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Userlevel 1

I have noticed that certain tracks are clipping on Deezer HiFi. I have emailed Deezer about this before and they first gave me the standard copy-paste responses and then refused to acknowledge the issue.

I reckon that the issue isn’t necessarily Deezer, but could also be caused by labels or artists not properly mastering their tracks.

I have Downloaded some problematic tracks directly from Deezer to demonstrate the issue, so there’s absolutely no chance that the Deezer application or my device is at fault here.

Some tracks where the clipping is obvious:

I hypothesize that Deezer is carelessly converting tracks supplied in formats with floating point samples to formats with fixed point samples, without properly limiting or attenuating them. What contradicts this hypothesis though, is the fact that the clipping doesn’t always occur at the 0dB point, but sometimes a bit under it. This would lead me to believe that it’s the mastering engineer’s fault.

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Best answer by Zipdox 4 October 2021, 13:23

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13 replies

Userlevel 1

I made some changes to the script and put it in in the GitLab repo.

Change:

  • Error handling: if an error is encountered the score will be -1
  • The output is now one song per line, score and filename separated by a tab (thus can be read as CSV file)
  • Added script to print all tracks and their clip scores, not just clipping ones
Userlevel 7
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Thanks for the script @Zipdox I’ve sent it to the music team devs too :)

Userlevel 1

I have also written a little bash script to automatically scan files

#!/bin/sh
for file in *.flac; do
clipvalue=$(./clipdetect 3 3 "$file")
if [ $(echo "$clipvalue >= 0.5" | bc ) -eq 1 ]
then
echo $file
echo $clipvalue
fi
done

A few songs I caught with this:

  • Baha Men - Who Let The Dogs Out.flac
    • 0.934460
  • Coolio, L.V - Gangsta's Paradise.flac
    • 1.417202
  • Dusty Springfield - I Only Want to Be with You.flac
    • 1.326108
  • Earth, Wind & Fire - December (Based on "September").flac
    • 2.582442
  • Foo Fighters - Learn to Fly.flac
    • 2.416830
  • Hank Levy - Whiplash.flac
    • 1.131244
  • Smash Mouth - I'm A Believer.flac
    • 6.147865
  • TLC - Waterfalls.flac
    • 0.919380
Userlevel 7
Badge +4

@Zipdox I have passed the feedback and mentioned the program you developed to our music team (I can’t guaranteed if they will be using it though)
Thanks for sharing :nerd:

Userlevel 2
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I wonder then if its the Android App that did it? It sounds awful. 

Userlevel 1

I checked the track with both my algorithm and manually and it doesn’t seem to be clipping.

Userlevel 2
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Hi! Is there any work done on this? Even quiet songs from  Katie Melua have clipping and distorted sounds in the base tones.

 

This is not HiFi

 

 

Edit: Enabling Normalise Audio in the settings helps a little, only because on this track it atenuates the volume. 

Userlevel 1

I reworked the algorithm to give a per mille score of clipping samples. Now a reasonable score would be under 2‰. Holiday is 8.8‰ and Tokyo is 5.2‰.

Userlevel 1

Oh so I had my suspicions about Tell Me Bout It, because the YouTube versions also kinda sounds like it’s clipping, and the peaks don’t look perfectly flat either. Anyway, I wrote a program to detect clipping. And using this I was able to determine that the Caramella Girls tracks were in fact clipping quite badly. Holiday was by far the worst, getting a score of a whopping 16 compared to 10 for Tokyo, which is also quite bad.

https://gitlab.com/zipdox/clipdetect

If you could send this to programmers at Deezer who know C, they can probably automate it to scan large numbers of tracks.

Userlevel 2
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I've noticed this too, but thought it might be due to Bluetooth or something. The above result can indeed be because of several conversions without care for settings. 

Userlevel 7
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We really appreciate your help :nerd:

 

Userlevel 1

Hi @Zipdox I have reported this to our music team.
Can you please confirm how often does this happens? Do you have more examples?
Thanks :)

Well it’s a song-specific issue. If I’d have to guess the issue is more common in electronically produced music, like EDM, but that isn’t to say it doesn’t occur in other genres. I might write a program to detect clipping in tracks in a way that can be automated.

Userlevel 7
Badge +4

Hi @Zipdox I have reported this to our music team.
Can you please confirm how often does this happens? Do you have more examples?
Thanks :)

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