[ogg-dev] Min and max cutoff frequency

[Benjamin Schwartz]

On Fri, Mar 22, 2013 at 8:42 AM, Fernando Alberto Marengo Rodriguez <
fmarengorodriguez at yahoo.com.ar> wrote:

> Dear Benjamin,
>
> > What is your motivation for constructing this hardware?  Is your goal
> to learn/teach from the experience, or are you trying to build something
> that you cannot buy?
>
> Yes, I am interested in learning how Ogg Vorbis works, and what its
> performance is in audio players in comparison with MP3 and AAC players. It
> is said that Ogg encoded files have higher quality than MP3 encoded files.
> It would be interested to verify that in hardware, not just in audio player
> software.
>

I don't quite see why this is interesting.  A correctly functioning Ogg
Vorbis decoder, whether made of silicon or C or javascript, will produce
the same output from the same file.  I suppose that "correctly functioning"
and "the same output" are subtle concepts, so it could be interesting to
verify the correctness of different implementation.


> We have been investigating about Flac, but for the time being we know
> little about Ogg Vorbis. Could you please tell me which Ogg audio player
> hardware is available in the market?
>

"player hardware" is a very difficult concept.  Every Android phone is an
Ogg Vorbis audio player; to most users that qualifies as "Ogg audio player
hardware".  However, it sounds like you are interested in lower-cost,
lower-power solutions.  We maintained a list of low-power Vorbis decoders
at http://wiki.xiph.org/Vorbis_Hardware .  Calling these "hardware
decoders" is problematic.  There is a spectrum from firmware running on
general-purpose CPUs, to DSPs (perhaps with some Vorbis-specific
additions), to complete silicon decoder logic with a microcontroller CPU
for dispatch.  From the manufacturer-supplied documentation, it is not
always possible to tell where on this spectrum each product stands.

--Ben



>
>
> Thank you very much and best regards,
> Fernando
>
>   ------------------------------
> *De:* Benjamin Schwartz <benjamin.m.schwartz at gmail.com>
> *Para:* Fernando Alberto Marengo Rodriguez <fmarengorodriguez at yahoo.com.ar>
>
> *CC:* Monty Montgomery <monty at xiph.org>; Silvia Pfeiffer <
> silvia at silvia-pfeiffer.de>; "ogg-dev at xiph.org" <ogg-dev at xiph.org>; Sergio
> Castells <canistells77 at hotmail.com>; Lisandro Conde <
> lisfconde at yahoo.com.ar>; Muro Gustavo <gmuro at fceia.unr.edu.ar>
> *Enviado:* viernes, 22 de marzo de 2013 0:30
>
> *Asunto:* Re: [ogg-dev] Min and max cutoff frequency
>
> On Thu, Mar 21, 2013 at 9:54 AM, Fernando Alberto Marengo Rodriguez <
> fmarengorodriguez at yahoo.com.ar> wrote:
>
> I am asking this because we are studying the OGG Vorbis format and its
> applications. We are very interested in constructing an audio player
> hardware, based on DSP or DSPic, and the audio files are stored in an SD
> card.
>
>
> What is your motivation for constructing this hardware?  Is your goal to
> learn/teach from the experience, or are you trying to build something that
> you cannot buy?
>
> --Ben
>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.xiph.org/pipermail/ogg-dev/attachments/20130323/fe10358e/attachment.htm