On May 5, 2009, at 4:02 AM, IOhannes m zmoelnig wrote:
hi.
sorry for the overcryptic mail...
Hans-Christoph Steiner wrote:
working on getting readanysf~ compiling nicely. Now that leads
me to wonder: how about getting Gem on Mac OS X to use gavl and
gmerlin-avdecoder? I think it'll have much better codec support
than Quicktime.
how not to?
I don't understand.
Gem uses configure to detect which libraries are available on the
build system. at least it does so on the autobuild machines.
since the configury is usually greedy, it will take conscious effort
to disable a certain feature (e.g. the use of gavl/gmerlin once it
is detected)
which complications do you expect?
of course the above is not entirely true (there are a few hacks in
the configury to avoid groups of libraries which are known to cause
problems: e.g. ImageMagick will automatically disable libtiff).
there might as well be special hacks that disable the use of the
more modular "new" (though quite aged by now) approach of film-
loading.
i know that there _are_ such special hacks, i just don't know
whether they effect the film-business (without looking at the code)
For Pd-extended, we should not rely on automatic detection, since it
is really a packaging question. When packaging, the standard practice
from what I've seen is to disable all automatic detection and
explicitly tell configure what it should be finding. For example,
this is what we did in the Fink package for gmerlin-decoder:
./configure --prefix=/sw --disable-gmerlin --enable-libavcodec --
enable-libpostproc --enable-libswscale --enable-libavformat --enable-
theora --enable-speex --disable-mjpegtools --enable-vorbis --disable-
libmpeg2 --enable-libtiff --enable-openjpeg --disable-samba --enable-
libpng --enable-faad2 --enable-dvdread --enable-flac --enable-musepack
--enable-mad --enable-liba52 --enable-libdca --enable-libcdio --
disable-win32 --with-avcodec=%p --with-avformat=%p --with-vorbis=%p --
with-faad2-prefix=%p
So ffmpeg, gavl, and gmerlin-decoder are now installed on all the Mac
OS X build machines, so I think it would be good to give a similar
treatment to the Gem options for Mac. Any suggestions? You could just
commit them directly, its in packages/Makefile.
Hmm, I don't really know enough to say. August and I have been
working quite a bit on getting this whole thing building in Fink
and now MinGW. I think then Gem, Gridflow, PDP, etc. can all use
this single framework for AV IO on all platforms, or at least GNU/
Linux and Mac OS X.
which is great (esp. as Gem should already be there :-))
Check out all of the codec libs that are included.
obviously these is exactly not the point of having a plugin-
architecture...
I don't understand. not?
that was the unneccessary harsh part of my mail.
however, let me explain:
plugins (as used e.g. by gmerlin) are used to create a flexible
bridge between two "applications"; if the code-base of appA changes,
then appB does not need to know anything about this change; if appA
is totally unavailable, most functionality of appB will be untouched
(e.g. Gem can be seen as a bridge between openGL and Pd; openGL
doesn't know nor care which Pd version we have; nor the other way
round; it's part of Gem's task to track any incompatible changes in
either of them; if openGL is entirely missing on a system, this
doesn't affect Pd as a whole; it will make Gem unusable, but you can
still play nicely with Pd)
this is even more true with decoder-plugins: if the Sorenson2000
codec is missing on my system, i still might be able to decode
motion jpeg videos; my application should continue to work even
without any plugins installed. if i need a special codec not
installed on my system, my task should be to install the missing
codec and not to update my application. (now , that's an important
statement here)
obviously, to make a platform to work with in a reasonable way, an
application might choose to ship with some plugins. (and i think
that is your point here)
what i mainly wanted to oppose with my rant was, that by embracing
gmerlin/gavl in the way it is done know (that is: fully including
the source into PdX), you are giving away to good things about it.
in one of my former mails i have written: "the ffmpeg-nightmare is
delegated to a single-point: gavl".
by including the sources of gavl/gmerlin, the near impossible task
of tracking changes of ffmpeg is back with us: whenever ffmpeg
changes sufficiently (that is: each other week), gmerlin will have
to adopt. then we will have to import the new gavl sources, in order
to support the new ffmpeg version.
otoh, having a stable API in gavl/gmerlin enables us to just link
against gmerlinj/gavl "once", and ship (with) "a" decoder-plugin for
ffmpeg, and once this is outdated, the decoder-plugin could be
updated, rather than the entire PdX. and less dependencies to wait
for.
all in all, my point about plugins is that they are plugins, thus
externally loadable and updateable pieces. the sole idea of plugins
lies within this externality. (else we could just statically link
everything in)
i guess your point about pugins is, that they are totally useless
unless you have them. (else we could talk about black holes and
whatelse, with an equal impact on Pd)
like always, we are both right.
On Mac OS X, the ffmpeg, gavl, gmerlin, etc. stuff is all shipped as
dylibs in Pd-extended.app/Contents/lib, just like VLC does it. OSX is
crippled as compared to Debian with package management, so this turns
out to be the best way to manage this stuff. If you want, you could
swap out those dylibs with newer versions for the 'plugin'-ability.
Windows is a about the same, so the idea with the Pd-extended
installer is that it installs the DLLs for the codecs.
The tricky question for now is on Debian/Ubuntu. gmerlin-decoder is
not in Debian or Ubuntu.
.hc
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