[vdr] Re: AC3 over DVB-s is possible - Part2

[Wolfgang Fiesel <fie@iis.fhg.de>]

Stefan Huelswitt wrote:

> On 19 Feb 2002 Wolfgang Fiesel <fie@iis.fhg.de> wrote:
>
> > as I promised last week,
> > now AC-3 over Digital Output (SPDIF) for DVB-S is reality (recordings
> > and DVD playback).
>
> Very good!! This is great work!! Thanks.
>
> It works fine with DVD and recordings here. CPU load is around
> 3-4% on my Celeron/400. Only drawback is, that before switching
> to DD there is a small audio glitch. By this may be because the
> DD-receiver needs some frames to detect the wrapped ac3 data.
> All trickmodes are working flawlessly here, too.
>

That's right. During the switch process of the DD receiver there is always
a small audio glitch. The reason is that I wrapped the first available AC-3
frame from the recording at once into the IEC 60... format to signalize DD.
But the receiver expects still raw PCM and interpretes this data as pur
audio. (->sound noisy)

Simple solution.
Before I send the first real AC-3 data stream, I wrapped one or more
(depends how long is the receiver open for PCM) zero PCM bursts into the
IEC 60... format to force the receiver to switch into DD mode. On this way
there is no real audio data anymore to misinterprete and the receiver will
be quit.
That's all

I'll do this modification this evening. Please be patient.

Wolfi


>
> I had some problems to apply the patch to my MP3-enabled version
> and for this I supply a upgrade patch against MP3 version 0.36 on
> my homepage:
> http://www.muempf.de/down/vdr-0.99-mp3-0.36-ac3.diff.gz
>
> --
> Stefan Huelswitt
> huels@iname.com  | http://home.pages.de/~nathan

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Dipl.-Ing. Wolfgang Fiesel                   EMAIL: fie@iis.fhg.de
Group Manager Audio Systems 2
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