Pops and clicks during playback when playing a 24/96 recording

[Kitlope]

Hi all thanks for Rockbox, this is wonderful firmware to run on my iRiver iHP -120. I have never really had a problem with the firmware for the last couple years using it (except in version 3 where sometimes [once or twice a month]) where the track would "hang" and sound like a CD Skip and stay stuck on about a .3 second part of a song until I turned off the player and booted it back up. Version 3.1 fixed that though since it hasn't happened since. Much appreciated!

My question now is to do with 24/96 Sound. I've got a vinyl rip of Boston - Boston (1976) that was remastered in 2006. I loaded it into the iRiver and when I went for a drive today I heard some weird glitches & pops at various intervals. At first I thought it was an inferior vinyl rip but playing it back on my home pc using Foobar2000 it hasn't made these types of noises. Clean as a whistle. So this led me to belive it was Rockbox and perhaps the downsampling involved (from what I read here it downs from 24/96 to 16/44 on iRivers).

Basicly, my question is has anybody else had this problem? Is it in fact the downsampling thats making these glitches occur? And was it fixed in this latest version 3.2?

Thanks for any help.

Kit

[saratoga]

The downsampler is of poor quality, but should not produce clicks (those are probably due to bad vinyl recording).  You can test this by resampling your files to 44.1kHz and replaying then in Rockbox.

[Kitlope]

Thanks for the speedy reply.

those are probably due to bad vinyl recording

That was my first guess too. But like I said in my post above I'm not getting any of these artifacts at all while listening to it on Foobar2000. I'm halfway through the album and its been nothing short of great, clean sound.

[saratoga]

Yes I read that the first time you said it.  Have you verified that its a problem with the resampler yet?

[Kitlope]

I'm going to have to guess that it is.

What I'll do is upgrade to 3.2 and see if it continues. And if it does I'll convert it from 24/96 to 16/44. No matter though, I have the same remastered album but in CD ripped into FLAC at 16/44.


edit: I converted the 24/96 FLAC into a WAV and according to the iRiver its playing at 4608 kBit. I'm going to assume though its still downsampling to the output of 16/44. However, the pops, clicks and glitches have now dissapeared.

Now, I'm a bit of a n00b when it comes to all this but would that be a Rockbox issue since the FLAC had issues and the WAV doesn't, regardless of output bit/sampling rate?

I am using Rockbox 3.1, my next step will be to upgrade to the latest version.

[dreamlayers]

I was able to reproduce this with a 44100 Hz 24 bit FLAC file.  I was unable to reproduce with a 44100 Hz 24 bit WAV file and a 96 KHz 16 bit FLAC file.  I made a bug report at:  http://www.rockbox.org/tracker/task/10111

Edit: A fix is now available.

[Kitlope]

Thanks for looking into this. I'm glad its simple bug and better yet that a fix has been found.

I looked around the flyspray site for more information but have no idea how to add this code into Rockbox to eliminate this bug. Could you send me in the right direction on how to do so?

Thanks again!


Kit

[dreamlayers]

All the information you need is available at:
http://www.rockbox.org/twiki/bin/view/Main/SimpleGuideToCompiling

Or, if you don't want to do that, I compiled a build with the fix:
http://drop.io/dreamlayers/asset/rockbox-20668m-h120-flac-rice2-zip
Edit: That build is obsolete.  The patch is in SVN. Get a current build instead.

[Kitlope]

It works! I can't thank you enough for this.

Just wondering, I used the build you compiled, is this Rockbox 3.2? In system info on the iRiver it doesn't say.


Thanks again.


Kitlope

[saratoga]

You can grab the version number during start up or under system > rockbox info.

But no, its not going to be 3.2.  People don't generally bother patching old builds. 

[dreamlayers]

Yeah, that was not 3.2.  The revision number (20668) is in the filename.

I've committed the patch in r20671.  You can simply get a current build now.  I'm deleting the H120 build I compiled earlier.

[Kitlope]

I did a Rockbox reinstall and have updated it. I played back the file in question and it works fine.

Once again, thanks for all this.



Kit