AC3 through SPDIF and mga_vid video output

Stéphane Borel stef at
Mon May 7 20:54:39 CEST 2001

On Mon, May 07, 2001 at 08:21:20PM +0200, German Gomez Garcia wrote:
> 	Hello,
>  After updating CVS I'm really impressed with current status of VLC, it DVD
> support is outstanding, but I've found that ac3_spdif doesn't work (skip
> and chop sound continuously)

I don't have such a big problem; it isn't synchronized yet so it can go
to fast sometimes but I experienced only a few blanks.

>  and that mga_vid video output plugin is just
> sketched. Is anybody working on it? I would like to help. One question, is
> really necessary to have a new ac3_spdif? 

It was just a choice since the ac3_dec was being worked on and I didn't
want to experience cvs conflicts; but I don't think it make any
difference. On the other hand we must have a special output.

> it's quite easy to reuse
> ac3_decode module but change it so it doesn't decode, only parse and
> syncronize and then 'patch' the output buffer to convert it to an iec958
> compliant stream, at least I made that in mplayer and it works perfectly

I'll have to look at your code since i don't understand how we can
synchronize digital data inside the player; I thought the right way to
do was to send time stamps to the hardware decoder.

> (you have also to make the dsp plugin aware that it is in spdif mode so it
> disable dsp buffering and write in blocks of size 4096). All this is for
> SBLive, the only card, AFAIK, that currently support AC3 through SPDIF.

Hum, I'm currently using 6144 bytes blocks; maybe that's a problem with
your card ; I'll try to investigate further.


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