• Status Closed
  • Percent Complete
  • Task Type Bugs
  • Category Music playback
  • Assigned To No-one
  • Operating System Archos Recorder
  • 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 ersau - 2008-11-12
Last edited by jdgordon - 2008-12-09

FS#9543 - buffer underflow

when listening music with high rate encoding (often VBR) the buffer in the view audio thread decrease until zero and the disk startup to fill it just before it reach zero. So the music cut the time of spining.
I notice too that the bitrate is not corrrectly reported (32kb in place of 224. The original archos firmware has not this bug but report a bad time duration which decrease like in fast forward instead to have steps by seconds. I have reproduced this bug on an older release of Rockbox.
I don’t know how the stack is managed, i suppose by a calc about the bitrate. If this, it would be an idea to check the speed of decrease. the time of spin up of the HD and to adapt the algorithm to anticipate the underflow.
I had this bug with one of the first release of rockbox when i have tried to change the hard disk. The new one was a 7200 rpm and was too long to start so i keep my old 20GO.
You can too put a parameter to force the buffer to refill below a certain %

A great work notwhistanding :)

Size: 7,35 MB (15% of original, 6 to 1 compression)
Original Size: 46,1 MB Length: 4 minutes 34 seconds
Channels: 2 (stereo)
Sample Rate: 44,1 KHz;
Sample Size: 16 bit
Bit Rate: 224 kbps
Encoder: LAME3.97U
Encoder Settings: Variable Bit Rate 224 kbps
Audio Quality: Very High (Lossy)
Play Count:
Last Played:
Channel Mapping: Left, Right
File: 09 Morrò, ma prima in grazia (Un ballo)
Type: Winamp media file [.mp3]

I think i have encoded this with dbpoweramp with lame encoder

Closed by  jdgordon
2008-12-09 10:18
Reason for closing:  Not a Bug
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

details in the comments

Project Manager

The buffering system uses the bitrate to calculate the watermark. Your files don’t have a VBR header, which contains the information needed to calculate the average bitrate.

You can fix the files with the “vbrfix” plugin. Navigate to the file, hold Play to bring up the context menu, then select “Open with” and then select “vbrfix” from the list of plugins.


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