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Topic: Clips on decoded mpc files (Read 4241 times) previous topic - next topic
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Clips on decoded mpc files

I'm trying mpc and after compress an album with standard and extreme preset and xlevel and then I decoded to wav just to compare with the original wav amd the files decoded are clipped. Now I decrease the wav file for 1 db (Normalize -1 dB) and the wav decoded was a -0,2 dB) for almost files that I encoded. The originals wav files of the album (Santana - Shaman) that I encoded are between -0,2 to 0 dB.
Questions:
1º) What's wrong?
2º) Shoud I try some scalefacor to compress with mpc?
3º) It's this normal with mpc? Just as mp3 aps
4º) any suggestions?
MPC: --quality 10 --xlevel (v. 1.15s) (archive/transcoding)
MP3:  LAME 3.96.1 --preset standard (daily listening/portable)

Clips on decoded mpc files

Reply #1 –
 What version of decoder you are using?  [Download mppdec 1.93j]
Clipping?
yes,  but at bitrate below 100 kbit/s!!!???

Edit : MPC is already well tuned and it's quite ok to use only "--quality" & "--xlevel"


Musepack.org recommend using "--insane --minSMR 0" over "--xtreme"

  http://www.musepack.org/

Check this:

  http://www.hydrogenaudio.org/forums/index....=ST&f=11&t=1927


I'm not sure about this................
Information provided by me might be wrong

Clips on decoded mpc files

Reply #2 –
This is a well known problem with all lossy encoding schemes. You should try replaygain, which comes together with mppdec. It will analyze your files and put some extra info about the levels in the file header, so that upon playback you can choose to play it without any clipping. Then the volume of this track will be lower than on the original, but without the extra clipping. Instead you could turn up the volumeknob on your amplifier to compensate for this.

A second alternative would be to try the foobar2000 player which uses softer clipping than the hard clipping you would hear in other players. This will probably be much less audible. But the best solution would be a combination of replaygain and the foobar2k player.

Clips on decoded mpc files

Reply #3 –
Quote
Musepack.org recommend using "--insane --minSMR 0" over "--xtreme"

Totally outdated. This comes from a time where "--insane" didn't use any lowpassing.

Clips on decoded mpc files

Reply #4 –
Quote
What version of decoder you are using?  [Download mppdec 1.93j]
Clipping?
yes,   but at bitrate below 100 kbit/s!!!???

I'm using mppdec 1.93 and the wav decoded from the mpc files are clipped, 180 to 220 kb/s (bitrate), I'm using --quality 6/7 --level
MPC: --quality 10 --xlevel (v. 1.15s) (archive/transcoding)
MP3:  LAME 3.96.1 --preset standard (daily listening/portable)

Clips on decoded mpc files

Reply #5 –
Quote
This is a well known problem with all lossy encoding schemes. You should try replaygain, which comes together with mppdec. It will analyze your files and put some extra info about the levels in the file header, so that upon playback you can choose to play it without any clipping. Then the volume of this track will be lower than on the original, but without the extra clipping. Instead you could turn up the volumeknob on your amplifier to compensate for this.

Replaygain lows the levels to much, the wavs resulting are -9 dB and the audio cd resulting is very quieter. I'm burn the mpc files to audio cd, with no clips and the same loudness that the original cd. I can't hear the clips anyway, I'm just to see it in the wav editor (sound forge)
MPC: --quality 10 --xlevel (v. 1.15s) (archive/transcoding)
MP3:  LAME 3.96.1 --preset standard (daily listening/portable)

Clips on decoded mpc files

Reply #6 –
Quote
A second alternative would be to try the foobar2000 player which uses softer clipping than the hard clipping you would hear in other players. This will probably be much less audible. But the best solution would be a combination of replaygain and the foobar2k player.

I can't use foobar2000 becouse I'm using win98 in my computer
MPC: --quality 10 --xlevel (v. 1.15s) (archive/transcoding)
MP3:  LAME 3.96.1 --preset standard (daily listening/portable)

Clips on decoded mpc files

Reply #7 –
B) Anyway, I find a solution, I will low the levels of the wav files by 1dB before encode to mpc. The wav decoded resulting is about -0.1 to -0.3 dB. 

NOTE: yes, I know folks, my english sucks, it's horrible, I'm sorry but I'm from Argentina, I'm just started to learn to speak english but I speak spanish perfectly!!! 
MPC: --quality 10 --xlevel (v. 1.15s) (archive/transcoding)
MP3:  LAME 3.96.1 --preset standard (daily listening/portable)

Clips on decoded mpc files

Reply #8 –
Quote
Anyway, I find a solution, I will low the levels of the wav files by 1dB before encode to mpc.


Mhhh... you shouldn't really do that. That still doesn't guarantee that your files won't clip when encoded to MPC.

I think you should be able to prevent the clipping by selecting "ReplayGain Off | ClipProtect title/album based" in the MPC Winamp plugin, or by using --gain 0 --prev (for title based ClipProtect) or --gain 1 --prev (for album based ClipProtect) with MPPDEC.

I still find it hard to understand why 89dB average volume is "too quiet"...

Clips on decoded mpc files

Reply #10 –
is there a command in mppdec that will apply the calculated scale automagicaly if clipping is found (without any additional questions that is)?
PANIC: CPU 1: Cache Error (unrecoverable - dcache data) Eframe = 0x90000000208cf3b8
NOTICE - cpu 0 didn't dump TLB, may be hung

Clips on decoded mpc files

Reply #11 –
You mean, apply the replaygain as soon as clipping is found? I don't think so (if that's what you really meant) - it wouldn't really make any sense as far as I'm concerned.

But there is --gain 0/1 --prev (as mentioned above) which will enable only the clipping protection, meaning that all files should be scaled down just below the point at which they would clip.

Clips on decoded mpc files

Reply #12 –
i didnt meant that, and i dont understand the --gain 0/1 --prev thingy, i guess that would work only when rg is calculated for the file?

what iam looking for is a --scale thingy, but sort of --autoscale    (there is no rg info)
PANIC: CPU 1: Cache Error (unrecoverable - dcache data) Eframe = 0x90000000208cf3b8
NOTICE - cpu 0 didn't dump TLB, may be hung
 

Clips on decoded mpc files

Reply #13 –
Quote
i didnt meant that, and i dont understand the --gain 0/1 --prev thingy, i guess that would work only when rg is calculated for the file?

Yes. It's the same as enabling ClipProtect (title/album based) in the Winamp plugin.


Quote
what iam looking for is a --scale thingy, but sort of --autoscale    (there is no rg info)


Hmm... anybody want to write a MAD decoder for MPC?