More > Media Center 14 (Development Ended)
loud "POP" sound when playing FLAC files
JimH:
How was the file created?
Alex B:
Here's what I found.
First I opened the file with a hex editor and checked for incorrect tags. The file has only valid FLAC tags at the beginning of the file. I couldn't see anything that looks like ID3 or some other tags at the end of the file.
Then tested the file with the verifier that is included in the official FLAC package (http://downloads.sourceforge.net/flac/flac-1.2.1b.exe). The file verified OK.
I decoded the file with a few different programs (the official "flac.exe", MC15, Sony Sound Forge Pro and foobar2000). All four produced an exactly identical wave form.
All four produced also the "loud pop" that you described. It consists of 55 apparently erratically stored audio samples at the very end of the audio track in both channels. 55 samples is just a bit more than one millisecond at the 44.1 kHz sample rate.
I have never tried WavPad, but perhaps it doesn't play the last few samples for some reason.
Here is a zoomed-in screenshot from Sony Sound Forge Pro:
I have no idea what could have created such a glitch. Since the file seems to be valid I can only assume that the same "pop" existed already in the wave form that was encoded to FLAC.
That kind of problem is easy to fix with a wave editor. If WavPad doesn't show the problem samples, you can use the Media Editor that is included with MC. You can either trim the file or make the offending samples silent.
duclosa:
--- Quote from: JimH on May 11, 2010, 09:53:18 pm ---On our wiki, there is an article about "DAC Settings". Please try it.
--- End quote ---
.
Nah. It's the interaction of the files and MC14-15. The sames files play OK in 3 other programs. Nothing to do with the DAC. MP3 and WAV files are OK in MC12-15 with the same setup.
Alain.
JimH:
--- Quote from: duclosa on May 12, 2010, 06:51:41 pm ---Nah. It's the interaction of the files and MC14-15. The sames files play OK in 3 other programs. Nothing to do with the DAC. MP3 and WAV files are OK in MC12-15 with the same setup.
--- End quote ---
It's worth a try. USB DAC's seem to all be a little different.
duclosa:
--- Quote from: Alex B on May 12, 2010, 06:06:59 pm ---Here's what I found.
First I opened the file with a hex editor and checked for incorrect tags. The file has only valid FLAC tags at the beginning of the file. I couldn't see anything that looks like ID3 or some other tags at the end of the file.
Then tested the file with the verifier that is included in the official FLAC package (http://downloads.sourceforge.net/flac/flac-1.2.1b.exe). The file verified OK.
I decoded the file with a few different programs (the official "flac.exe", MC15, Sony Sound Forge Pro and foobar2000). All four produced an exactly identical wave form.
All four produced also the "loud pop" that you described. It consists of 55 apparently erratically stored audio samples at the very end of the audio track in both channels. 55 samples is just a bit more than one millisecond at the 44.1 kHz sample rate.
I have never tried WavPad, but perhaps it doesn't play the last few samples for some reason.
Here is a zoomed-in screenshot from Sony Sound Forge Pro:
I have no idea what could have created such a glitch. Since the file seems to be valid I can only assume that the same "pop" existed already in the wave form that was encoded to FLAC.
That kind of problem is easy to fix with a wave editor. If WavPad doesn't show the problem samples, you can use the Media Editor that is included with MC. You can either trim the file or make the offending samples silent.
--- End quote ---
Hello again, Alex.
Thanks for the info.
I believe the files were created with an ealier (pre12) of MC.
If the problem is in the files, as you so convicingly demonstrated, then why does MC12 plays them correctly? I do not really feel like manually editing about 5k files... Is there a workaround? Or am I stuck with MC12 for ever???
Funny thing is all of the files have the same behavior. I'll look into SoundForge to see if it's all the same random bits that are added...
Alain.
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