[Kdenlive-devel] --disable-mmx for MLT and other options for ffmpeg

[Dan Dennedy]

On Tue, Jan 11, 2011 at 6:28 AM, Simon Eugster <simon.eu at gmail.com> wrote:
> I've been working on the «Installing from source» articles, set up a
> fresh Ubuntu 10.10 64bit in VirtualBox and gone through the whole
> installation process.
> Most of it at least. I cannot compile ffmpeg with x264. Therefore I

The problem is that ffmpeg head typically requires a newer version of
x264 than what is packaged.

> couldn't test MLT and kdenlive :P

I have a script extracted from the old kdenlive build wizard that
automates much of this including building x264 and libvpx from source
as well. I will look into adding that here somewhere.

> http://kdenlive.org/user-manual/downloading-and-installing-kdenlive/installing-source
>
> Comments welcome. Please improve if something is missing/bad/whatever.
> Especially regarding the ffmpeg flags; I have no idea whether they are
> good now.

--enable-postproc : mlt does not yet use libpostproc
--enable-x11grab : needed or auto-detected? not used by mlt or kdenlive anyways

The more dependencies on external libs increases the risk of failure.
Therefore, the following are irrelevant for most users:
--enable-libxvid
--enable-libgsm
--enable-libdc1394
--enable-libschroedinger
--enable-libopencore-amrnb
--enable-libopencore-amrwb

libfaac is still fairly interesting thereby necessitating the
--enable-nonfree. However, we should probably mention that is optional
along with --enable-libvorbis and --enable-libtheora.

> And thanks for the earlier answers which I understand now.
>
> Simon
>
> 2010/9/1 Dan Dennedy <dan at dennedy.org>:
>> On Wed, Sep 1, 2010 at 1:27 AM, Simon A. Eugster <simon.eu at gmail.com> wrote:
>>> Some weeks ago I read something about MMX being supported on 64bit as well
>>> (but unrelated to MLT, so I skipped most of the text). Now I tried to
>>> compile MLT without the --disable-mmx flag, and it seems to work here (I
>>> don't know what MMX depends on; Using kernel 2.6.34, gcc 4.4.5).
>>
>> Of course. The configure system got better, but not the documentation.
>>
>>> And about ffmpeg options listed here:
>>> <http://kdenlive.org/user-manual/downloading-and-installing-kdenlive/installing-source/installing-ffmpeg>
>>> What is the use of these?
>>> --disable-decoder=libdirac
>>> --disable-encoder=libschroedinger
>>
>> Arbitrary choices from the author of that page as far as I am concerned.
>>
>>> And does something speak pro/contra these?
>>> --enable-libspeex (speech codec) [1]
>>
>> Only if the libs and headers are available, but I find speex usage in
>> editing/post to be rather obscure, even for the FOSS amateur and
>> hobbyist. Personally, I would not recommend this option to be
>> conservative and not require the additional step of installing the
>> dependency.
>>
>>> --enable-libvpx (should speed up h264 decoding) [2]
>>
>> Wrong, has nothing to do with H.264. It is required for WebM encoding.
>> decoding WebM VP8 can be done with either libvpx or now it is native
>> in ffmpeg, and the native is faster. I think you have to explicitly
>> choose to decode with libvpx if the lib is enabled for encoding, but I
>> have to confirm that. It is probably a good thing to recommend this
>> option and advocate WebM, but the page should make it clear that this
>> is optional and has this external library dependency.
>>
>>> Just wondering :)
>>> Simon
>>>
>>> [1] http://www.speex.org/
>>> [2]
>>> http://www.slashcam.de/news/single/Libvpx-optimiert-VP8-Dekoder-8524.html
>>> (German)
>>
>> --
>> +-DRD-+