What are Microsoft codecs?

[Antonio Olivares]

--- On Thu, 8/6/09, gilpel at altern.org <gilpel at altern.org> wrote:

> From: gilpel at altern.org <gilpel at altern.org>
> Subject: What are Microsoft codecs?
> To: fedora-list at redhat.com
> Date: Thursday, August 6, 2009, 5:50 PM
> What are Microsoft codecs? Is it more
> than an encapulation of MP4? What's
> the legal status of MP4? 

apparently still proprietary :(, Fedora policy is like GAYS IN THE MILITARY ===> DONT ASK DON'T TELL and DON'T BOTHER :)

no harm intended here, :)  

http://en.wikipedia.org/wiki/MP4

NOTE:  some m4a files are/were MP4 files.  See above link. 

> Once you have at hand the
> compression/decompression algorithms -- which must have
> been developed by
> mathematicians decades ago -- is there so much work
> involved in writing
> codecs? Has the reason they weren't developed before more
> to do than with
> the fact the CPUs weren't powerful enough to use them?

Mathematicians writing compression/decompression algorithms?  This is something I would be interested in :), I only see certain situations like for se playing a music file with mplayer I see a ratio depending on which bitrate a file was encoded in:

192 bitrate
==========================================================================
Opening audio decoder: [mp3lib] MPEG layer-2, layer-3
AUDIO: 44100 Hz, 2 ch, s16le, 192.0 kbit/13.61% (ratio: 24000->176400)
Selected audio codec: [mp3] afm: mp3lib (mp3lib MPEG layer-2, layer-3)
==========================================================================

128 bitrate
==========================================================================
Opening audio decoder: [mp3lib] MPEG layer-2, layer-3
AUDIO: 44100 Hz, 2 ch, s16le, 128.0 kbit/9.07% (ratio: 16000->176400)
Selected audio codec: [mp3] afm: mp3lib (mp3lib MPEG layer-2, layer-3)
==========================================================================

.... and so on :)  I see the ratio 13.61% vs 9.07% 


> 
> In other words, are codecs more than a marketing scheme,
> just as were the
> "codecs" for Word  and Excel documents? 'Cause, if you
> save a Word file to
> odt format, the size will shrink by about 75%. (I must
> admit I checked
> this with rtf vs odt, but I suppose it's at least as bad
> with doc format.)
> It seems the extra code's only purpose is to make
> decryption more
> difficult.

I somewhat agree with your accessment :), but might be some added extra xml/proprietary stuff added by Micro$oft, but who knows but that appears to be the case.  Saving a file with ODT extension vs DOC does save you a few BYTES :)  

> 
> Isn't this the same with MWV codecs?
> 
> 
> 
> 
> -- 

I will try a little bit to explain what I know/understand for all of this.  I also assume that MWV, you meant wmv :)

wma ---> Windows Media Audio
wmv ---> Windows Media Video
wav ---> Microsoft format also BTW

http://en.wikipedia.org/wiki/WAV
http://en.wikipedia.org/wiki/Windows_Media_Audio
http://en.wikipedia.org/wiki/WMV

Hope this helps in some way :)

Regards,

Antonio