[MPlayer-dev-eng] Re: Make dvd-compatible mpeg's and keyint (gop size)

[Matthias Wieser]

Am Donnerstag, 29. September 2005 13:40 schrieb byavl:
> Oded Shimon wrote:
> > On Thu, Sep 29, 2005 at 03:12:09PM +0600, byavl wrote:
> >>What exactly ? mpeg-4 has smart defaults, but what dvd ?
>
> [...]
>
> > It's not bullshit, it's still a completely valid mpeg-2 stream, it's
> > just not a valid _DVD_ stream, because the DVD specification is VERY
> > (studpidly) strict, the values requested by the standard increase
> > bitrate and lower quality A LOT, so making them default, when using
> > MEncoder is usually for making high quality low bitrate MPEG-4
> > streams, not DVD, is just not sensible!!
>
> Stop! Here is not clear for me. Would you to say if bitrate is big
> quality is a less ? I sure it is not. A small mpeg-4 movie has degraded
> picture then original big DVD! Where is true ?
> Or is it meants that dvd compliants default is not suitable for mpeg4 ?

Decreasing(!) quality:
Mpeg4 -> DIVX4 compliant mpeg4  -> mpeg2  -> DVD compliant mpeg2


> > MEncoder is a command line tool, it's purpose is not to be friendly,
> > but to be powerful. If a (l)user wants to create a compliant DVD, he
> > should check the documentation (see DOCS/HTML, there's a COMPLETE
> > guide there about DVD compliance, including command line examples) to
> > do it right, or use a smart frontend which already does the settings
> > for him...
>
> Here was to mention of 'user'. What is your opinion about who is a
> 'user' ? Is it specialist or just regular linux man ?

A user is someone who wants to use mencoder. A user should be able to read 
the HTML documentation or download a GUI frontend. An advanced user may 
additionally read the mplayer man page.

> > MEncoder was originally an MPEG-4 creater, creating valid DVD streams
> > is a VERY recent new feature in MEncoder, and it's even a hack...
> > And, well, the default has to be picked for SOME direction, it being
> > towards MPEG-4 makes more sense as it is more popular to use MEncoder
> > for MPEG-4 than for DVD.
>
> Really ? And what is better in mpeg4 stuff?

Quality at a given bitrate.

> My advice is to take more efforts to mpeg technology.

You wrote: "By the way I'm programmer in linux[...]" so you know what to 
do. ;-)