I've been loitering around ScummVM for a while, but only just got my hands on a nice spangly new LOOX N560. I'm very much looking forward to trying the new SVN build on it
I have one question (at the moment, that is): all my games (that allow it) are compressed with vorbis audio. Would I get better performance on a device like my loox if i re-compressed with mp3? I.e., do they have any sort of hardware decompression for mp3 that they lack for vorbis?
I haven't done measurements on the libraries as used by Scummvm, so other people may know more exactly than me, but I have some previous experiences with MP3 and Ogg decompression on ARMs.
Ogg decoding using Tremolo (an ARM optimised version of the Tremors lib) takes at least 50% more processing power than MP3 decoding (using an ARM optimised decoder).
Assuming that the C compiled versions of the libs exhibit similar relative performance, then yes, using MP3 files would probably get you better performance.
BUT... I wouldn't go recompressing stuff from Ogg -> MP3 willy nilly. Not only will you lose quality, your device has a 624MHz processor, which should be perfectly capable of coping with Ogg data - my 400MHz device copes just fine I think.
I am 99% sure that no form of hardware decompression is used for either MP3 or Vorbis as part of this port.
I am sure Knakos or someone that knows more will correct me if I'm wrong with any of this.
robinwatts wrote:BUT... I wouldn't go recompressing stuff from Ogg -> MP3 willy nilly. Not only will you lose quality[..]
as far a s I know you can't re-compress datafiles (i.e. everything apart from cd-audio) from one compressed format to another anyway since the compression tools can only cope with the original datafiles
robinwatts wrote:Ogg decoding using Tremolo (an ARM optimised version of the Tremors lib) takes at least 50% more processing power than MP3 decoding (using an ARM optimised decoder).
Yep, it is my impression too that MP3 decoding is less demanding than ogg.
robinwatts wrote:I am 99% sure that no form of hardware decompression is used for either MP3 or Vorbis as part of this port.
AFAIK the libraries feature no device specific accelerations.
robinwatts wrote:
BUT... I wouldn't go recompressing stuff from Ogg -> MP3 willy nilly. Not only will you lose quality, your device has a 624MHz processor, which should be perfectly capable of coping with Ogg data - my 400MHz device copes just fine I think.
Haven't even got an SD card yet, so haven't tried it I was guessing it would work fine for the 320x200 games, I was wondering more about ones like bs1&2 & comi: with a 640x480 screen they should display full res, but I guess it might be quite demanding. I'll let you know how I get on.
I was guessing it would work fine for the 320x200 games, I was wondering more about ones like bs1&2 & comi: with a 640x480 screen they should display full res, but I guess it might be quite demanding. I'll let you know how I get on.
