[FFmpeg-user] ffmpeg4android and missing math functions

[C E Macfarlane]

There are similar problems compiling FFMPEG on MIPS/UCLibc

See:
https://ffmpeg.org/pipermail/ffmpeg-user/2014-August/023120.html

I have now got the same errors by two completely different methods ...
	1)	Compiling with the native GCC on the target device
	2)	Compiling with a cross-toolchain
... and have come to the conclusion that the problem is fundamental to
FFMPEG, in that it somehow is not configured correctly for UCLibc (despite
the title of my original thread, I now think that most probably MIPS is
irrelevant, and the problem is really UCLibc.

Regards, Charles Macfarlane
www.macfh.co.uk/CEMH.html

>     -----Original Message-----
>     From: ffmpeg-user-bounces at ffmpeg.org
>     [mailto:ffmpeg-user-bounces at ffmpeg.org]On Behalf Of ????? ???????
>     Sent: 28 October 2014 17:54
>     To: ffmpeg-user at ffmpeg.org
>     Subject: [FFmpeg-user] ffmpeg4android and missing math functions
>
>
>     This thread came to my attention today:
>
>     http://ffmpeg.org/pipermail/ffmpeg-user/2014-July/022377.html
>
>     Although the problem is solved, I want to point to the root
>     cause, which I
>     reported long time ago, here:
>
>     https://code.google.com/p/android/issues/detail?id=38423
>
>     Because Android build system is so different than "regular"
>     ./configure;
>     make; it introduces all kinds of ugly porting problems, which may be
>     resolved only by all kind of ugly hacks (which You may see in
>     ffmpeg4android makefiles), especially when You step away from default
>     architecture.
>
>     So, there is libc in NDK which You can download from android homepage,
>     there is libc in NDK which is embedded in android source code
>     tree, and
>     there is bionic, Android's version of libc. And the problem
>     is - although
>     highly compatible, THEY ARE NOT THE SAME. Same may apply for other
>     libraries. configure/make is not aware of bionic, or any other library
>     present in Android source code tree, it is aware of libc and libraries
>     installed in NDK sysroot (which is minimal), and in the end
>     Your software
>     needs to be linked and run against bionic, and libraries in
>     Android source
>     code tree. This is a source of horrendous problems when trying to port
>     something to Android. E.g. in order to enable libx264, the
>     library needs to
>     be installed in NDK sysroot, so it may be found during
>     configure phase, but
>     in order to use Android build system to build FFmpeg with
>     libx264 enabled,
>     libx264 needs to be ported, compiled, and its binaries in
>     out/target/product/.../wherever folder.
>
>     The horror increases when You involve C++.
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