How can I get FFmpeg to locate installed libraries when --sysroot is pointing to another directory?

问题

I've been going at this, literally for days. I'm trying to build FFmpeg with libmp3lame for use in an Android application. The build script sets a --sysroot flag that points to the Android NDK directory necessary to build these libraries in a way that Android can use them.

The problem comes when I add the flag to --enable-libmp3lame; I get ERROR: libmp3lame >= 3.98.3 not found during the build start up. I know that LAME, and it's libraries are installed, because I can just run ./configure --enable-libmp3lame manually and the configuration launches without a hitch, and shows that libmp3lame is enabled for this build. However, building like this will simply not work for what I need it for, since I need the Android NDK to do some work.

I've tracked the problem down to the fact that this build script is declaring the sysroot, and through some research, I've tried adding -Luser/include, -L/user/includeto the extra cflags, and ldflags (which I've read is the default search location for gcc). I've tried several other things as well, but I'm confident that someone out here can help with this specific problem. This entire build script is as follows:

Extra info:

Build OS: Ubuntu 11.10
FFmpeg Ver: Latest from git
LAME Ver: 3.9.x
Android NDK: r7

build.sh

#!/bin/bash

if [ "$NDK" = "" ]; then
    echo NDK variable not set, assuming ${HOME}/android-ndk
    export NDK=${HOME}/android-ndk
fi

SYSROOT=$NDK/platforms/android-3/arch-arm
# Expand the prebuilt/* path into the correct one
TOOLCHAIN=`echo $NDK/toolchains/arm-linux-androideabi-4.4.3/prebuilt/*-x86`
export PATH=$TOOLCHAIN/bin:$PATH

rm -rf build/ffmpeg
mkdir -p build/ffmpeg
cd ffmpeg

# Don't build any neon version for now
for version in armv5te armv7a; do

        DEST=../build/ffmpeg
        FLAGS="--target-os=linux --cross-prefix=arm-linux-androideabi- --arch=arm"
        FLAGS="$FLAGS --sysroot=$SYSROOT"
        FLAGS="$FLAGS --soname-prefix=/data/data/net.smartnotes/lib/"
        FLAGS="$FLAGS --enable-shared --disable-symver"
        FLAGS="$FLAGS --enable-small --optimization-flags=-O2"
        FLAGS="$FLAGS --disable-everything --enable-protocol=file"
        FLAGS="$FLAGS --enable-libmp3lame --enable-encoder=nellymoser"

        case "$version" in
                neon)
                    EXTRA_CFLAGS="-march=armv7-a -mfloat-abi=softfp -mfpu=neon"
                    EXTRA_LDFLAGS="-Wl,--fix-cortex-a8"
                    # Runtime choosing neon vs non-neon requires
                    # renamed files
                    ABI="armeabi-v7a"
                    ;;
                armv7a)
                    # I have tried many things here.
                    EXTRA_CFLAGS="-march=armv7-a -mfloat-abi=softfp"
                    EXTRA_LDFLAGS=""
                    ABI="armeabi-v7a"
                    ;;
                *)
                    # I have tried many things here.
                    EXTRA_CFLAGS="-Luser/include"
                    EXTRA_LDFLAGS=""
                    ABI="armeabi"
                    ;;
        esac
        DEST="$DEST/$ABI"
        FLAGS="$FLAGS --prefix=$DEST"

        mkdir -p $DEST
        echo $FLAGS --extra-cflags="$EXTRA_CFLAGS" --extra-ldflags="$EXTRA_LDFLAGS" > $DEST/info.txt
        ./configure $FLAGS --extra-cflags="$EXTRA_CFLAGS" --extra-ldflags="$EXTRA_LDFLAGS" | tee $DEST/configuration.txt
        [ $PIPESTATUS == 0 ] || exit 1
        make clean
        make -j4 || exit 1
        make install || exit 1

done

回答1:

Instead of changing the include paths, why don't you try copying all the libmp3lame files that were created by 'make install' to the relevant directory where the script will look for them. Insert ECHO statements to find out what exactly the PATH/CFLAGS/LDFLAGS are at the point where you get the error, and copy the files there so it does find them.

回答2:

I saw you were using the project located at http://bambuser.com/opensource

I had the same problem and resolved like this:

compile lame for android using https://github.com/intervigilium/liblame

this is a small diff between the original build.sh from "bambuser.com" and the one I used:

3c3,6
<  export NDK=${HOME}/downloads/android-ndk # r8d
---
> if [ "$NDK" = "" ]; then
>     echo NDK variable not set, assuming ${HOME}/android-ndk
>     export NDK=${HOME}/android-ndk
> fi
15,16c18
< #for version in armv5te armv7a; do
<  for version in         armv7a; do
---
> for version in armv5te armv7a; do
24c26
<     FLAGS="$FLAGS --disable-everything --enable-libmp3lame"
---
>     FLAGS="$FLAGS --disable-everything"

from "intervigilium" project copy the folder liblame/jni/lame to PATH_TO_NDK/platforms/android-3/arch-arm/usr/include
from "intervigilium" project copy liblame/libs/armeabi-v7a/liblame.so to PATH_TO_NDK/platforms/android-3/arch-arm/usr/libs and RENAME it in libmp3lame.so.
finally run build.sh.

you should be fine:

install prefix            ../build/ffmpeg/armeabi-v7a
source path               /home/samuele/downloads/ffmpeg/ffmpeg-android/ffmpeg
C compiler                arm-linux-androideabi-gcc
ARCH                      arm (generic)
big-endian                no
runtime cpu detection     no
ARMv5TE enabled           yes
ARMv6 enabled             yes
ARMv6T2 enabled           yes
ARM VFP enabled           yes
IWMMXT enabled            no
NEON enabled              no
debug symbols             yes
strip symbols             yes
optimizations             small
static                    yes
shared                    yes
postprocessing support    no
new filter support        yes
network support           yes
threading support         pthreads
SDL support               no
Sun medialib support      no
AVISynth enabled          no
frei0r enabled            no
libdc1394 support         no
libdirac enabled          no
libfaac enabled           no
libgsm enabled            no
**libmp3lame enabled        yes**
libnut enabled            no
libopencore-amrnb support no
libopencore-amrwb support no
libopencv support         no
libopenjpeg enabled       no
librtmp enabled           no
libschroedinger enabled   no
libspeex enabled          no
libtheora enabled         no
libvorbis enabled         no
libvpx enabled            no
libx264 enabled           no
libxavs enabled           no
libxvid enabled           no
zlib enabled              no
bzlib enabled             no

Enabled decoders:

Enabled encoders:
mpeg2video      nellymoser

Enabled hwaccels:

Enabled parsers:

Enabled demuxers:

Enabled muxers:

Enabled protocols:

Enabled filters:
buffer

Enabled bsfs:

Enabled indevs:

Enabled outdevs:

License: LGPL version 2.1 or later
Creating config.mak and config.h...
libavutil/avconfig.h is unchanged

Be aware, I still need to test the resulting FFmpeg build. To say the truth, now I have to learn how to use it in my App... ;)

EDIT: I tried removing --disable-everything and it builds OK the same, with a lot of encoders, decoders etc, but increasing to ~40MB for the build dir.

来源：https://stackoverflow.com/questions/9123846/how-can-i-get-ffmpeg-to-locate-installed-libraries-when-sysroot-is-pointing-to

标签

gcc

build

ffmpeg

android-ndk