• Status Closed
  • Percent Complete
  • Task Type Bugs
  • Category Music playback
  • Assigned To No-one
  • Operating System All players
  • Severity Low
  • Priority Very Low
  • Reported Version
  • Due in Version Undecided
  • Due Date Undecided
  • Votes
  • Private
Attached to Project: Rockbox
Opened by nls - 2006-12-27
Last edited by kugel. - 2009-01-25

FS#6479 - Compressed audio watermark calculation is wrong for high bitrate formats.

The compressed audio buffer watermark calculation does not take the bitrate of the audio into account. This makes the watermark too low for high bitrate formats such as flac and therefore can cause a skip in music playback when the buffer has to be refilled, especially if the disk is powered down wich makes the spin up time slightly longer.

Closed by  kugel.
2009-01-25 23:41
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

r19743 remade watermarks

Try increasing the "Anti-Skip Buffer" which increases the default watermark.

In reviewing the code, it appears that the watermark calculation does use the current track's bitrate. However, the watermark does not appear to be updated for each track. It looks like it gets set when the codec is loaded and when new tracks are loaded, but the calculation is based on the current track. I guess a solution would be to have the codec update the watermark for each new track and take that calculation out of the playback code.

Could this perhaps explain the reported cases where buffering never seems to stop with low bitrate files? Or is that a seperate problem where the audio buffer still isn't full after buffering the allowed 32 tracks..?

It definitely seems reasonable, since we set the anti-skip buffer in seconds, to have some kind of average bitrate for all files currently buffered which lets us update the watermark setting.


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