[vlc] [Videolan-devel] strange parasites in frequency sweeping (was on videolan-devel)

[Elie Roux]

Rafaël Carré a écrit :
> On Thu, 2008-03-20 at 22:48 +0100, Elie Roux wrote:
>   
>> Hello,
>>
>> to test some headphones I wanted to hear the response of the headphones 
>> according to the frequency. To do so, I took this frequency sweep :
>>
>> http://norgz.info/download/sweep.flac
>>
>> As you will hear, with VLC, there are very strange and annoying parasite 
>> frequencies when it goes to high frequencies. This does not come from 
>> the flac : you can try it with mplayer or by burning it on a CD, you 
>> won't have those parasites. My version of vlc is the last debian/sid 
>> version :
>>     
>> VLC media player 0.8.6e Janus (interface wxWidgets)
>>     
>
> Try an unstable build from http://nightlies.videolan.org
>   

Same result.

>> I have a few questions about these parasites :
>>
>> The main question is : Is it a bug or a feature ?
>>     
>
> Does it reproduce at fixed timestamps ?


It are parasites frequencies that appear only in high frequencies. They 
appear between 6s and 13s...

>> If it is a feature I would be very interested in the precise reason of 
>> these parasites, it looks like a sample problem, but I can't really 
>> understand. I also think it would be interesting to have an option in 
>> vlc to get the exact sound it is sensed to play, even if it takes more 
>> processor ressources.
>>
>> A lot of other softwares do not pass the test of this sweep, for example 
>> : gstreamer, mpg321... the only software that does it right is mplayer.
>>     
>
> mplayer doesn't play the file, while gstreamer plays it well for me.


It is sad that your mplayer (maybe you should bugreport ?) does not play 
it, because it is the only player that works well for me... gstreamer 
(like vlc) plays it, but adds parasites, we hear the sweep, and other 
strange frequencies...

>
> Please use vlc at videolan.org in the future this is a more appropriate
> mailing list.
>
> videolan-devel@ is reserved for ECP students afaik

Done.

By the way, http://www.videolan.org/support/lists.html does not work to
subscribe to this list, I had to subscribe through
http://mailman.videolan.org/listinfo/vlc

Thank you in advance,
-- 
Elie Roux