[MPlayer-dev-eng] Resampling

[Arpi]

Hi,

> I have managed to get the down-sampling to run - it is not funny at
> all. It will have to reside in a separate function (can not be mixed
> with the up-sampling since the circular queue management is completely
> different and it also needs pre-filtering of the incoming data). I
> will create an example or add it directly to mplayer once the current
> version is added to mplayer. That way my code will be consistent with
> mplayers buffer management - and no one will need to re write it. Is
> that ok with you?
yes. please send me the code, i'll integrate to mplayer and you can continue
development there.

i have to change it a bit, because mplayer's playback design:
1. ask soundcard how many samples can be played immediately, with no
   blocking (buffer space) -> N
2. decode at least N samples
3. send N samples to the soundcard

I think the best place for your code would be dec_audio.c.
but it will cause timing problems - should be workarounded.

> In the meantime I will focus on optimising the filter parameters. I
> think I have found a way to minimise the quantisation error by using
> a type of genetic algorithm to tweak the filter parameters (really fun
> stuff).
> 
> By the way would it be interesting to add other sound features to
> mplayer? I could do stuff like synthetic 4-6 channel stereo (synthesise
> the missing channels from available data) or perhaps effects (room
> expansion, pitch shifting (for karaoke), church effect etc)? Just an
> idea.

I'm interested.

What about slower/faster playback with constant pitch?
Would be usefull for 24<->25 or maybe 30<->25 fps conversion.


A'rpi / Astral & ESP-team

--
mailto:arpi at thot.banki.hu
http://esp-team.scene.hu