--- On Thu, 8/6/09, gilpel@xxxxxxxxxx <gilpel@xxxxxxxxxx> wrote: > From: gilpel@xxxxxxxxxx <gilpel@xxxxxxxxxx> > Subject: What are Microsoft codecs? > To: fedora-list@xxxxxxxxxx > 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 -- fedora-list mailing list fedora-list@xxxxxxxxxx To unsubscribe: https://www.redhat.com/mailman/listinfo/fedora-list Guidelines: http://fedoraproject.org/wiki/Communicate/MailingListGuidelines
