第一步,制作独立交叉编译链,我使用ndkr9制作的, 使用API 9平台,gcc4.6
进入ndk目录,执行

$ ./build/tools/make-standalone-toolchain.sh --platform=android-9 --install-dir=/home/aliang/arm-linux-androideabi

第二部,修改x264的configure

libpthread=""
if [ "$thread" = "auto" ]; then
    thread="no"
    case $SYS in
        BEOS)
            thread="beos"
            define HAVE_BEOSTHREAD
            ;;
        WINDOWS)
            if cc_check pthread.h -lpthread "pthread_create(0,0,0,0);" ; then
                thread="posix"
                libpthread="-lpthread"
            elif cc_check pthread.h -lpthreadGC2 "pthread_create(0,0,0,0);" ; then
                thread="posix"
                libpthread="-lpthreadGC2"
            elif cc_check pthread.h "-lpthreadGC2 -lwsock32 -DPTW32_STATIC_LIB" "pthread_create(0,0,0,0);" ; then
                thread="posix"
                libpthread="-lpthreadGC2 -lwsock32"
                define PTW32_STATIC_LIB
            elif cc_check pthread.h "-lpthreadGC2 -lws2_32 -DPTW32_STATIC_LIB" "pthread_create(0,0,0,0);" ; then
                thread="posix"
                libpthread="-lpthreadGC2 -lws2_32"
                define PTW32_STATIC_LIB
            else
                # default to native threading if pthread-win32 is unavailable
                thread="win32"
            fi
            ;;
        QNX)
            cc_check pthread.h -lc && thread="posix" && libpthread="-lc"
            ;;
        *)
            cc_check pthread.h -lc && thread="posix" && libpthread="-lc"
            ;;
    esac
fi

改为红色行的内容,因为android的ndk虽然有pthread.h,但是没有libpthread.a,集成到libc.a里了

第三步,定位到制作的独立编译链的头文件目录 /home/aliang/arm-linux-androideabi/sysroot/usr/include/
使用这个sched.h替换原有的sched.h文件

ok
./configure –host=arm-linux-androideabi –cross-prefix=arm-linux-androideabi-
可以看到,已经支持多线程了

platform:      ARM
system:        LINUX
cli:           yes
libx264:       internal
shared:        no
static:        no
asm:           yes
interlaced:    yes
avs:           avxsynth
lavf:          no
ffms:          no
gpac:          no
gpl:           yes
thread:        posix
opencl:        yes
filters:       crop select_every
debug:         no
gprof:         no
strip:         no
PIC:           no
visualize:     no
bit depth:     8
chroma format: all

效果如何,我测试下看看

*************呃 不用试了,NDK头文件里虽然申明了方法,c库里却没有实现****************

好吧 解决方法当然是有的,修改x264/common/cpu.c
通过读取/sys/devices/system/cpu/present文件判断cpu核心数
0 单核
0-1 双核
0-3 四核
sched.h还是用以前的吧

int getNrOfCPUs()
{
    FILE* fp;
    int res, i = -1, j = -1;

    /* open file */
    fp = fopen("/sys/devices/system/cpu/present", "r");
    if (fp == 0)
    {
        return -1; /* failure */
    }

    /* read and interpret line */
    res = fscanf(fp, "%d-%d", &i, &j);

    /* close file */
    fclose(fp);

    /* interpret result */
    if (res == 1 && i == 0) /* single-core? */
    {
        return 1;
    }
    if (res == 2 && i == 0) /* 2+ cores */
    {
        return j+1;
    }

    return 1; /* failure */
}

int x264_cpu_num_processors( void )
{
    return getNrOfCPUs();
}

测试结果请移步这里Android环境 多核CPU x264编码性能测试

去下载Android x264 多线程版静态库

X264性能调优,请看Android,IOS平台上x264编码实时视频参数设置与优化