Rockbox mail archiveSubject: Re: WAV Codec for Archos
Re: WAV Codec for Archos
From: Christoph Niedeggen <Niedeggen_at_gmx.net>
Date: Tue, 24 Jan 2006 23:31:11 +0100
> Patching the PCM codec into Rockbox for Archos is not not a trivial task. If
> done properly, it's an opportunity to renovate the playback+recording code,
> like keeping the bitswap away from the big buffer, a different concept for
> metadata of buffered files, a frame walker for mp3, trick modes, etc. I'd
> liked to have done that, but other priorities got in the way.
That's a pity! But does it really need to renovate the whole playback
and recording code and do the other things you mentioned?
As a start I would be completely happy if someone wrote a plugin for
WAV/PCM recording and a plugin (probably a viewer!?) for WAV/PCM playback!
> For full quality wav pumping, our poor CPU would be pretty busy with
Could you explain why the recorded data has to be bitswapped? Do the
most significant byte and the least significant byte have to be swapped
in order to get a proper WAV stream?
It would be perfectly alright as a start to just be able to write the
plain PCM data to disk (with the said plugin) and to do the post
processing (e.g. bit swapping and adding of a WAV header) later on the
PC. This would also prevent the Jukebox CPU from becoming too busy.
> Don't let your expectations fly too high about running codecs
> on it, too. The disk will be busy, too, having 8 MB helps.
Right. Having 8 MB means that the buffer has to be written to disk every
45 seconds when recording 44.1 kHz, stereo. But that should still be OK.
> I'm not worried about audio quality. When using S/PDIF, it's 1:1, as much as
> you can get.
I think that even recordings made via the Line-In might benefit from a
WAV/PCM recording if the analogue input level is high enough so that the
built-in amplifier does not have to be set to a high gain (thus
producing more noise.)
Received on 2006-01-24