[MPlayer-dev-eng] [PATCH] Audio plugin to reverse L&R channelsof stereo

[Anders Johansson]

Hi,

Your plugin should sheck what kind of format the audiodata strem has
during init(), and report error messages if it is not supported. The
most comon format is AFMT_S16_LE, the second most comon is AFMT_U8.
It is enough to make the plugin work for AFMT_S16_LE. I guess you
should ignore mono streams. and swap L/R for 2 and 4 channel ones. 5
and 6 channel streams should have the 4 first swapped pairwise and the
two last unchanged, i.e: 

1 ch: ignore print information message but don't stop.
2 ch: tmp=R; R=L; L=tmp
4 ch: tmp=LR; RF=LF; LF=tmp; tmp=RR; RR=LR; LR=tmp;
5 ch: tmp=LR; RF=LF; LF=tmp; tmp=RR; RR=LR; LR=tmp; ignore 5 channel
6 ch: tmp=LR; RF=LF; LF=tmp; tmp=RR; RR=LR; LR=tmp; ignore 5 and 6 channel

Good luck,
//Anders


> ----- Original Message -----
> From: "Felix Buenemann" <atmosfear at users.sourceforge.net>
> To: <mplayer-dev-eng at mplayer.dev.hu>
> Sent: Saturday, March 23, 2002 4:43 PM
> Subject: Re: [MPlayer-dev-eng] [PATCH] Audio plugin to reverse L&R
> channelsof stereo
> 
>  >From what I've seen, your plugin doesn't check for number of channels
> > (and maybe also samplesize), so you should probably add some case to
> > support at least mono and probably also multichannel sound (4/6
> > channels).
> 
> Hi Atmos,
> 
> thanks for your reply. I only check for AFMT_S16_LE, which is what most
> movies I have are using. I guess AFMT_S16_BE, AFMT_U16_LE and AFMT_U16_BE
> could be done in the same manner, but I have no idea how to handle AC3 and
> mono (what good is this plugin to mono anyway?). Most of the other mplayer
> plugins I saw did just like me (or I did like them, to be precise), so I've
> no idea how to make this better. I'd love to improve it though, so I'd
> appreciate it if you can give me some hints.
> 
> Regards,
> Joro
> 
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> MPlayer-dev-eng at mplayerhq.hu
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-- 
______________________________________________________________________
Anders Johansson    Room 314,113  Australian Telecommunications .-_|\
Visiting Research Associate       Research Institute (ATRI)    /     \
telephone:  +61 8 9266 3268       Curtin Uni of Technology     P_.-._/
e-mail: ajh at atri.curtin.edu.au            Bentley WA, 6102.         o
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