• Status Closed
  • Percent Complete
  • Task Type Bugs
  • Category Codecs
  • Assigned To No-one
  • Operating System SW-codec
  • Severity Low
  • Priority Very Low
  • Reported Version Daily build (which?)
  • Due in Version Undecided
  • Due Date Undecided
  • Votes
  • Private
Attached to Project: Rockbox
Opened by dreamlayers - 2009-04-09
Last edited by dreamlayers - 2009-04-10

FS#10111 - Pops and clicks when playing 24 bit FLAC files

When playing 24 bit FLAC files I can hear some pops. For example, a 27 second 44100 Hz 24 bit FLAC file encoded by flac-1.2.1 has about 5 pops of varying intensity. They are always at the same positions. There are no pops when Winamp plays the same FLAC file or when Rockbox plays a 44100 Hz 24 bit WAV version of the same sound.

This is on my 5G 30GB iPod running r20636. The problem was first reported on 24/96 FLAC file on an iRiver iHP -120 by Kitlope at:

Closed by  dreamlayers
2009-04-10 02:16
Reason for closing:  Fixed
Additional comments about closing:   Warning: Undefined array key "typography" in /home/rockbox/flyspray/plugins/dokuwiki/inc/parserutils.php on line 371 Warning: Undefined array key "camelcase" in /home/rockbox/flyspray/plugins/dokuwiki/inc/parserutils.php on line 407

Fixed in r20671

The Rockbox FLAC decoder comes from ffmpeg. Here is a thread about this issue in ffmpeg: According to that post the problem is due to improper decoding of RICE2 entropy coding.

This was fixed in ffmpeg r15334 by michael: Then the fix was fixed in ffmpeg r15338 by michael: Finally, another fix was applied to that line in ffmpeg r17550 by mru: The last fix is irrelevant because MIN_CACHE_BITS is 25 and Rockbox doesn’t have A32_BITSTREAM_READER. I still think including the last fix is a good thing, in case the ARM-optimized A32_BITSTREAM_READER is added in the future. Here is a patch with the final form of the fix. This code is also used in the Shorten (SHN) codec.

Unfortunately, I haven’t taken the time to understand this code. All I can say is that it makes the pops go away and it is the only change in get_ur_golomb_jpegls() in ffmpeg-0.5.


Available keyboard shortcuts


Task Details

Task Editing