[opendtv] Re: re-encoding
- From: "Silvio Macedo" <s.macedo@xxxxxxxxxxxxxx>
- To: <opendtv@xxxxxxxxxxxxx>
- Date: Mon, 16 May 2005 14:15:48 +0100
If I'm not mistaken, BBC owns the rights on the MOLE - may be it
shares them with S&W?
And, if it was BBC Technology, now Siemens owns them :)=20
(some colleagues of mine, at INESC Porto, Portugal, worked on that).
The MOLE requires that the encoding decisions are registered somewhere
in the stream.
But at IBC last year, I saw someone else doing it "blindly", in the
context of re-encoding for satellite reception and distribution. I
mean, the system was looking into the unencoded video (presumed to
result from an MPEG-2 stream as well) and telling its own encoder to
align the GOP to make the I-frames coincide. They detected an
unencoded I-frame by image processing (don't know how they did it..
but if we try ourselves, we can; a computer can be made to do it more
or less too).=20
In this way, a big part of the degradation that happens when you use a
B or P frame to compress something that resulted from an I frame,
disappears or at least is alleviated. (and in principle, block
searching for P/B frames will also give better results).
This is done without any extra information, but obviously not as good
quality as with the MOLE.
Silvio
> -----Original Message-----
> From: opendtv-bounce@xxxxxxxxxxxxx=20
> [mailto:opendtv-bounce@xxxxxxxxxxxxx] On Behalf Of Martin Holmes
> Sent: 13 May 2005 23:55
> To: opendtv@xxxxxxxxxxxxx
> Subject: [opendtv] Re: re-encoding
>=20
>=20
> Thanks Mark for remembering,=20
>=20
> S&W call the process MOLE. SMPTE calls it 329M MPEG 2=20
> Recoding Data Set.
>=20
> Best, MH.
>=20
>=20
>=20
> -----Original Message-----
> From: opendtv-bounce@xxxxxxxxxxxxx=20
> [mailto:opendtv-bounce@xxxxxxxxxxxxx]
> On Behalf Of Mark Schubin
> Sent: Friday, May 13, 2005 6:32 PM
> To: opendtv@xxxxxxxxxxxxx
> Subject: [opendtv] Re: re-encoding
>=20
> Yes. There was a major project. I think Snell & Wilcox was=20
> in charge=20
> of one version; I think Sony had a different version.
>=20
> TTFN,
> Mark
>=20
>=20
> Doug McDonald wrote:
>=20
> >Has anybody designed, or tried to design, an MPEG
> >encoder that, knowing that it is receiving a signal
> >(be it digital or analog) that was previously MPEG
> >encoded (at the format sent to it), tries to replicate
> >the exact previous encoding, so that succeeding generations
> >will remain lossless (compared to the first encoded generation)?
> >
> >This would be a great boon to the consumer .... if it
> >will run on say a Pentium 4 or Pentium 5. Especially
> >thanks to a certain district court.
> >
> >Doug McDonald
> >
> >
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