Jim Henderson wrote:
> On Sat, 09 Feb 2008 16:47:22 +0100, Tor Olav Kristensen wrote:
> 
>> Jim Henderson wrote:
>>> On Fri, 08 Feb 2008 23:20:53 +0100, Tor Olav Kristensen wrote:
>>>
>>>> Jim Henderson wrote:
>>>> ...
>>>>> Actually, I was surprised that the Amazon downloadable Complete LOTR
>>>>> soundtracks are in MP3 format.  I don't *think* there's any DRM
>>>>> involved (which was really surprising).
>>>> But maybe they can tell who bought the mp3 file by looking at it...
>>>>
>>>> http://www.google.com/search?q=mp3+watermark+amazon
>>> I'm sure they probably can.  That's a bit different than DRM, though,
>>> which has the explicit stated goal of preventing people from
>>> "inappropriate use".  Watermarking allows them to act reactivley - and
>>> I believe is fairly easy to remove anyways...
>>>
>>> mplayer -ao pcm:file=temp.wav file.mp3 lame -h temp.wav
>>> file-without-watermark.mp3
>> Yes, but then you assume that the watermarking is done on the bit-level.
>>
>> What if they change the music somewhat in a way that will survive format
>> conversion ? (E.g. tiny changes in volume levels within a frequency
>> band, small phase shifts, changes in the dynamic range, added noise or a
>> combination of some of these.)
>>
>> There will only have to be minor changes to the sound, as they will only
>> have to encode something like e.g. 30 bits into more than 100s of sound
>> in 2 channels.
> 
> I'd think that the conversion back and forth would modify an attempt like 
> this enough.  Remember that mp3 encoding is lossy, not lossless.

Yes, I know. And to overcome that, just don't make the changes to the
sound THAT small.


> Of course, though, the best option is to not give the files away.

=)

-- 
Tor Olav
http://subcube.com

Post a reply to this message