[Mp4-tech] MPEG-4 compression

[Boris Felts]

Thanks for your precisions Alexandros.
  To answer Serge's questions:
- The version of Envivio Encoding Station (2.1) released at that time
was using MPEG-4 part 2, more exactly it supported ASP level 5.
- There has been few more releases of the product, still based on the
syntax and constraints of ASP. The current version is 2.5 and the
quality has improved since 2.1. Also, the quality of the encoded results
highly depends on the set of prefilters, encoding parameters and
postfilters used for the considered job. This may require some
optimization.
- You will find some other proprietary or standard codecs which can do a
better job for a particular target. MPEG-4 part 2 enables a fairly large
amount of applications and the decoder syntax has been frozen for a
while. Conformance insures compatible and backward compatible products,
but may prevent from the latest technological advancement additions.
- MPEG-4 part 10 is now part of our products, and shows significant
quality improvement over other legacy or proprietary codecs. It is
probably the best codec available. You will find (hopefully!) many
MPEG-4 part 10 implementations, but you need to be attentive to the
different profiles supported and the constraints respected by each
encoder to assess their quality.
Best Regards
Boris Felts
Envivio.
> -----Original Message-----
> From: mp4-tech-bounces lists.mpegif.org [mailto:mp4-tech-
> bounces lists.mpegif.org] On Behalf Of Tourapis Alexandros
> Sent: Tuesday, October 28, 2023 12:03 PM
> To: Serge GEDEON
> Cc: mp4-tech lists.mpegif.org; Gary Sullivan; sunx
> Subject: RE: [Mp4-tech] MPEG-4 compression
> 
> According to the system's specifications seen here :
> 
> http://www.visiblelight.com/mall/products/envivio/docs/ees.pdf
> 
> this coding station only supports Advanced Simple Profile MPEG-4, and
does
> not claim support for MPEG-4 part 10. It is claimed that both
realnetworks
> and microsoft codecs (which were developed after MPEG-4 part 2) are
> considerably better than this profile (but not better than MPEG-4 part
10).
> 
> Alexis
> 
> 
> -----Original Message-----
> From: Gary Sullivan [mailto:garysull windows.microsoft.com]
> Sent: Tuesday, October 28, 2023 2:19 PM
> To: sunx; Serge GEDEON
> Cc: bfelts envivio.com; mp4-tech lists.mpegif.org
> Subject: RE: [Mp4-tech] MPEG-4 compression
> 
> 
> One thing to keep in mind is that standards do not specify how to
encode
> video -- only how to encode it.  There is a great deal of freedom
> provided in the standards that allows encoding designs of vastly
> differing quality.  You should never look at the quality decoded from
> some particular implementation of an encoder using a particular
standard
> and assume that this quality is the only quality (or the best quality)
> that is possible to obtain when using that standard.  You should
> definitely not expect the quality produced by all products to be the
> same.  Not only is there freedom allowed in the design of
pre-processors
> and encoders but there is also freedom allowed in post-processing and
> display aspects after decoding.
> 
> Another aspect implicit in Sunx's response is that there are a number
of
> different syntaxes that fall under the term "MPEG-4 video".  There are
> somewhere around 20 profiles in MPEG-4 part 2 and three profiles in
> MPEG-4 part 10.  For ordinary camera-view video, the most efficient
> syntax design currently in MPEG-4 is in the Main profile of MPEG-4
part
> 10 (a.k.a. AVC a.k.a. ITU-T H.264).  Serge did not specify which
profile
> was implemented in that Envivio product.
> 
> And of course the RealNetworks codec that Serge referred to is not
even
> constrained by conformance to any standard.  The quality it produces
is
> constrained only by the product's implementation resources, the
> expertise of its designers, and the deadlines of its design project.
> 
> Best Regards,
> 
> -Gary Sullivan
> 
> +> -----Original Message-----
> +> From: mp4-tech-bounces lists.mpegif.org
> +> [mailto:mp4-tech-bounces lists.mpegif.org] On Behalf Of sunx
> +> Sent: Tuesday, October 28, 2023 8:35 AM
> +> To: Serge GEDEON
> +> Cc: bfelts envivio.com; mp4-tech lists.mpegif.org
> +> Subject: Re: [Mp4-tech] MPEG-4 compression
> +>
> +>
> +>
> +>
> +> On Tue, 28 Oct 2003, Serge GEDEON wrote:
> +>
> +> > Dear All,
> +> >
> +> > I am currently comparing different compression solutions
> +> for streaming pedagogical multimedia contents over the Internet.
> +> >
> +> > But with the software I am using (Envivio coding station
> +> 2.1) to encode MPEG-4 content,
> +> > I can't reach the same quality with the same bitrate as
> +> with Real 9. Real 9 compression is better, the thing that I
> +> find a bit odd.
> +> >
> +> > Could anyone help me in this? did anyone do such a
> +> comparison? may it be the soft that I am using? could anyone
> +> advise me with another soft?
> +> > or may it be the parameters that I am using, I ve tryed
> +> aproximatly all the combinations possible!!!
> +> >
> +>
> +> I believe one major reason that MPEG-4 is better than MPEG-2
> +> is that it
> +> has better motion compensated coding, which is especially
> +> true in H.264.
> +> My suggestion is that maybe you need to tune those paramters
> +> of control
> +> PVOP and BVOP coding carefully. Real format is modified from
> +> MPEG-2 (?),
> +> so MPEG-4 should at least achieve the comparative performance in
most
> +> cases.
> +>
> +> >
> +> > Thanks in advance,
> +> > Serge GEDEON
> +> > Ph.D. Student
> +> > Paul Sabatier University - Toulouse, France
> +>
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> +>
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