Rockbox General > Rockbox General Discussion

Sluggish when filling buffer

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PHK Brasil:
♪

--- Quote from: Llorean on December 30, 2006, 03:17:36 PM ---No, what you've shown me is that your evidence is that Apple spends less time buffering, not

that they fill the same amount of the buffer. Their firmware is several megabytes, and

evidence suggests that all of it is in RAM at once, which means they have much less RAM

available for audio buffer, and so could reasonably take less time to fill.
--- End quote ---

iPod 5G 30gb = 32MB total RAM
iPod 5G 60gb = 64MB total RAM (Hmmm...at least 32MB for audio buffer)

Both uses same firmware. So, iPod 5G 60gb has at least 32MB extra for audio buffer + the same ammount of MBs of 30gb's model audio buffer.
Is much more ammount of audio buffer than Rockbox (only 32MB).

Time to fill the audio buffer:

-Apple OS takes around 7 seconds while PLAYING

-Rockbox takes 12s to fill 32MB audio buffer (PAUSED, no EQs or Crossfeed)

-Rockbox takes 50s to fill 32MB audio buffer (PLAYING, no EQs or Crossfeed)

-Rockbox takes 75s to fill 32MB audio buffer (PLAYING, Crossfeed ON)

Just a quick comparison, but it depends of bitrates, audio format, etc, while playing and filling buffer.

Thanks.
♪

soap:
But LLorean's basic question was "how often does Apple firmware rebuffer?"  I don't think he ever disputed that Apple FW appears to spend less time buffering.  
This can be tested quite simply by creating a playlist of high-bitrate music that is playable on both AppleFW and Rockbox, starting the playlist in one firmware, measuring how long the hard drive spins, then measuring how long until the drive spins again.  Repeat with firmware #2.  Preferably done with a playlist longer than the buffer of your player, for we know Rockbox will refill the buffer, even if you create a playlist of only one song.

nls:
IIUC the portalplayer processors have dma that can be used for reading from the disk and should be a lot faster than what rockbox does now, and that is probably used in the OF. This combined with the fact that the cpu is generally rather busy in rockbox on portalplayer based DAP's makes buffering slow.

Llorean:
As Soap said, I never denied that Rockbox likely buffers more slowly. What I'd like to establish is *how much* more slowly. :)

Sentertainment:
I'm quite sure rockbox has a larger buffer too....it seems to be buffering 2-4 tracks ahead on my iPod.

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