[MPlayer-dev-eng] ANNOUNCE: new audio filter layer in use

[Anders Johansson]

Hi,

> Hi,
> 
> The new af layer is not stable yet, so please test it I want to find
> the bugs. The code is auto-configuring so I think there will be quite a
> lot of issues before it gets stable. Also delay in the filters is not
> compensated for yet, I will add this soon.  This is however not a
> problem yet cause there are no filters that have a noticeable delay
> that can be enabled.
> 
> My plans for the audio filter layer are as follows:
> 
> 1. Add a -format hint to try to force the audio out to use a specific
>    format.  
> 
> 2. Add functionality to enable filters on the command-line (what should
>    the switch be called?). 
> 
> 3. Add compensation for delay caused by the filters.
> 
> 4. Add functionality to add filters during playback (remove already works).

All above is done.

The delay compensation is calculated through the function af_calc_delay()
and should be added to the delay caused by the sound-card. Question is
where should the function be called: in dec_audio.c or in mplyer.c? 

Also I have found a problem with how the af_stream is allocated: The
stream should be allocated per session not per file. If not the
control() calls will cause mplayer to crash. This must be fixed but I
am not sure how it will affect mencoder, and have therefore not
touched the code yet. af_init() can be called multiple times for the
same stream so all that needs to be changed is to allocate
sh_audio->afilter on startup, avoid reallocation and deallocate
on exit rather that on file end.

//Anders