移植 ffmpeg 到 ARM 平台

1，yasm：

到 下载yasm0.7.2（x264需要用到的汇编编译器）

for x86:

./configure --enable-shared --prefix=/usr/local
make
make install

for arm:
./configure --enable-shared --prefix=/usr/local/ --host=arm-linux
make
make install

2，x264：

到 下载x264库

for x86:

./configure --enable-shared --prefix=/usr/local
make
make install

for arm:
./configure --enable-shared --prefix=/usr/local/ --host=arm-linux
到common/cpu.c编译不过，未定义 cpu_set_t。这里改为 返回1.

x264_cpu_num_processors().
cpu_set_t unsinged long.

3，xvid：

到   下载xvid
for x86:

cd build/generic
./configure --prefix=/usr/local
make
make install

for arm:
#./configure --prefix=/usr/local/ --host=arm-linux --target=arm-linux
./configure --prefix=/usr/local/ --host=arm-hismall-linux --target=arm-hismall-linux
make
make install

4，ffmpeg:

svn co svn://svn.mplayerhq.hu/ffmpeg/trunk 下载ffmpeg源码

for x86:

./configure --prefix=/usr/local/ --enable-gpl --enable-shared --enable-xvid --enable-x264 --enable-pthreads --disable-ffserver --disable-ffplay --enable-faac --enable-faad

编译不过，I changed the line (about line number 596):

static always_inline long int lrintf(float x)

in /libavcodec/dsputil.h to:

static __inline__ long int lrintf(float x)

make
make install

在x86的linux上执行：

[root@localhost ffmpeg-0.4.9-p20051216]# ffmpeg -i ../test/beijing.mp4 -b 479k -s 320x240 ../test/beijing.h264
ffmpeg version CVS, build 3342336, Copyright (c) 2000-2004 Fabrice Bellard
  configuration:  --prefix=/usr/local/ --enable-gpl --enable-shared --enable-xvid --enable-x264 --enable-pthreads --disable-ffserver --disable-ffplay
  built on Nov 11 2008 08:48:14, gcc: 3.4.6 20060404 (Red Hat 3.4.6-8)
Input #0, mov,mp4,m4a,3gp,3g2, from '../test/beijing.mp4':
  Duration: 00:06:50.2, start: 0.000000, bitrate: 479 kb/s
  Stream #0.0, 23.98 fps: Video: mpeg4, yuv420p, 320x240
  Stream #0.1: Audio: mp4a / 0x6134706D, 16000 Hz, stereo
File '../test/beijing.h264' already exists. Overwrite ? [y/N]
Not overwriting - exiting
[root@localhost ffmpeg-0.4.9-p20051216]# ffmpeg -i ../test/beijing.mp4 -b 479k -s 320x240 ../test/beijing.h264
ffmpeg version CVS, build 3342336, Copyright (c) 2000-2004 Fabrice Bellard
  configuration:  --prefix=/usr/local/ --enable-gpl --enable-shared --enable-xvid --enable-x264 --enable-pthreads --disable-ffserver --disable-ffplay
  built on Nov 11 2008 08:48:14, gcc: 3.4.6 20060404 (Red Hat 3.4.6-8)
Input #0, mov,mp4,m4a,3gp,3g2, from '../test/beijing.mp4':
  Duration: 00:06:50.2, start: 0.000000, bitrate: 479 kb/s
  Stream #0.0, 23.98 fps: Video: mpeg4, yuv420p, 320x240
  Stream #0.1: Audio: mp4a / 0x6134706D, 16000 Hz, stereo
File '../test/beijing.h264' already exists. Overwrite ? [y/N] y
Output #0, h264, to '../test/beijing.h264':
  Stream #0.0,   nan fps: Video: h264, yuv420p, 320x240, q=2-31, 479 kb/s
Stream mapping:
  Stream #0.0 -> #0.0
[h264 @ 0x458428]using SAR=1/1
[h264 @ 0x458428]using cpu capabilities: MMX MMXEXT SSE SSE2
Press [q] to stop encoding
frame= 9835 q=9.0 Lsize=   24683kB time=410.2 bitrate= 492.9kbits/s   
video:24683kB audio:0kB global headers:0kB muxing overhead 0.000000%
[h264 @ 0x458428]slice I:1007  Avg QP:22.31  size:  9162  PSNR Mean Y:43.70 U:48.20 V:47.61 Avg:44.67 Global:43.74
[h264 @ 0x458428]slice P:8828  Avg QP:25.29  size:  1815  PSNR Mean Y:41.23 U:47.00 V:46.21 Avg:42.35 Global:41.02
[h264 @ 0x458428]mb I  I16..4: 23.8%  0.0% 76.2%
[h264 @ 0x458428]mb P  I16..4:  3.6%  0.0%  2.0%  P16..4: 41.9% 17.4%  6.5%  0.0%  0.0%    skip:28.5%
[h264 @ 0x458428]final ratefactor: 21.37
[h264 @ 0x458428]SSIM Mean Y:0.9803090
[h264 @ 0x458428]PSNR Mean Y:41.484 U:47.120 V:46.353 Avg:42.588 Global:41.228 kb/s:492.37
[root@localhost ffmpeg-0.4.9-p20051216]#

共用时3分3秒45

ffmpeg -i ../test/beijing.mp4 -b 479k -s 320x240 -fs 1500 -y ../test/beijing.h264 录制1500kB的文件，用时9秒27

for arm:
./configure --prefix=/usr/local/  --enable-gpl  --cpu=arm --enable-xvid --enable-x264 --enable-pthreads --disable-ffserver --disable-ffplay  --cc=arm-hismall-linux-gcc --enable-shared
编译到最后报错：
arm-hismall-linux-gcc -Wl,--warn-common -rdynamic -g  -o ffmpeg_g ffmpeg.o cmdutils.o -L./libavformat -lavformat -L./libavcodec -lavcodec -L./libavutil -lavutil -lm -lxvidcore -lx264 -ldl -lpthread
./libavcodec/libavcodec.so: undefined reference to `roundf'
./libavcodec/libavcodec.so: undefined reference to `log2'
collect2: ld returned 1 exit status
make: *** [ffmpeg_g] 错误 1

在Makefile中加入-I/home/ellen/compiler/gcc-3.4.3-uClibc-0.9.28/，还是报错。

更换gcc为arm-linux-gcc-3.3.2.tar.bz2，还是报错。

在 libavcodec/Makefile 中加入 -I/home/ellen/compiler/gcc-3.4.3-uClibc-0.9.28/ （roundf和log2都包含在math.h中），还是报错。

在 libavcodec/Makefile 中 定义x264.o 的地方，加入 EXTRALIBS += -lm，还是报错。

用 nm -u libavcodec.so 可以查看so中未定义的函数。

自己写log的函数：
#define M_1_SQRT2 0.70710678118654752440084436210484904
#define POLYNOM1(x, a) ((a)[1]*(x)+(a)[0])
#define POLYNOM2(x, a) (POLYNOM1((x),(a)+1)*(x)+(a)[0])
#define POLYNOM3(x, a) (POLYNOM2((x),(a)+1)*(x)+(a)[0])

double
log(double x)
{
/* Algorithm and coefficients from:
   "Software manual for the elementary functions"
   by W.J. Cody and W. Waite, Prentice-Hall, 1980
*/
static double a[] = {
  -0.64124943423745581147e2,
   0.16383943563021534222e2,
  -0.78956112887491257267e0
};
static double b[] = {
  -0.76949932108494879777e3,
   0.31203222091924532844e3,
  -0.35667977739034646171e2,
   1.0
};

double znum, zden, z, w;
int exponent;

if (x < 0) {
  errno = EDOM;
  return -HUGE_VAL;
}
else if (x == 0) {
  errno = ERANGE;
  return -HUGE_VAL;
}

if (x <= DBL_MAX) {
}
else return x; /* for infinity and Nan */
x = frexp(x, &exponent);
if (x > M_1_SQRT2) {
  znum = (x - 0.5) - 0.5;
  zden = x * 0.5 + 0.5;
}
else {
  znum = x - 0.5;
  zden = znum * 0.5 + 0.5;
  exponent--;
}
z = znum/zden; w = z * z;
x = z + z * w * (POLYNOM2(w,a)/POLYNOM3(w,b));
z = exponent;
x += z * (-2.121944400546905827679e-4);
return x + z * 0.693359375;
}

double
log10(double x)
{
if (x < 0) {
  errno = EDOM;
  return -HUGE_VAL;
}
else if (x == 0) {
  errno = ERANGE;
  return -HUGE_VAL;
}

return log(x) / M_LN10;
}

double log2(double x)
{
return (log10(x) / log10(2) );
}

log2编译通过。

自己写roundf的函数：
double
copysign (double x, double y)
{
  if ((x < 0 && y > 0) || (x > 0 && y < 0))
    return -x;
  return x;
}

float
copysignf (float x, float y)
{
  /* We use the double version.  */
  return copysign (x, y);
}

float modff(float x, float * y)
{
    *y=((int)x);
    return (x-*y);
}

float
roundf(float Arg)
{
    float FracPart, IntPart;

    FracPart = modff(Arg, &IntPart);

    if (fabsf(FracPart) >= 0.5f)
           IntPart += copysignf(1.0, IntPart);

    return IntPart;
}
编译通过。

编译好的ffmpeg放到arm平台上，把libavcodec.so和libavformat.so放到板子上，运行，报错：
/usr/local/lib $ ls -l
-rwxrwxrwx    1 root     root      4984743 Nov 10 15:02 libavcodec.so
-rwxrwxrwx    1 root     root      1466472 Nov 10 15:07 libavformat.so
lrwxrwxrwx    1 root     root           14 Nov 10 15:03 libavformat.so.50 -> libavformat.so
/usr/local/lib $ /ffmpeg
Can't modify /usr/local/lib/libavformat.so.50's text section. Use GCC option -fPIC for shared objects, please.
/usr/local/lib $

在libavformat和libavcodec的makefile中添加 -fPIC,还是不行。

./configure --prefix=/usr/local/  --enable-gpl  --cpu=arm --enable-xvid --enable-x264 --enable-pthreads --disable-ffserver --disable-ffplay  --cc=arm-hismall-linux-gcc  --disable-strip
不用shared，用静态编译，把libavcodec和libavformat都编到ffmpeg中，在板子上运行，需要链接 libx264.so时，还是报错不能 -fPIC，于是想办法把libx264静态编译到ffmepg中。

重新编译x264，不用shared。把libx264.a 和libxvidcore.a 拷贝到libavcodec和libavformat目录下，修改 ffmpeg/Makefile，添加：
LIBSUF += libx264.a libxvidcore.a

放在arm上运行时，还是会报错：

[h264 @ 0x3705fc]no ratecontrol method specified
Error while opening codec for output stream #0.0 - maybe incorrect parameters such as bit_rate, rate, width or height

修改x264/common/common.c的x264_param_default()中：
//param->rc.i_rc_method = X264_RC_NONE;
param->rc.i_rc_method = X264_RC_ABR;
重新编译264，重新编译ffmpeg：
./ffmpeg -i beijing.mp4 -b 479k -s 320x240 -fs 1500 -y beijing.h264
/mnt $ ./ffmpeg -i beijing.mp4 -b 479k -s 320x240 -fs 1500 -y beijing.h264
ffmpeg version CVS, build 3342336, Copyright (c) 2000-2004 Fabrice Bellard
  configuration:  --prefix=/usr/local/ --enable-gpl --cpu=arm --enable-xvid --enable-x264 --enable-pthreads --disable-ffserver --disable-ffplay --cc=arm-hismall-linux-gcc --disable-strip
  built on Nov 11 2008 09:47:01, gcc: 3.4.3 (release) (CodeSourcery ARM Q3cvs 2004)
Input #0, mov,mp4,m4a,3gp,3g2, from 'beijing.mp4':
  Duration: 00:06:50.2, start: 0.000000, bitrate: 479 kb/s
  Stream #0.0, 23.98 fps: Video: mpeg4, yuv420p, 320x240
  Stream #0.1: Audio: mp4a / 0x6134706D, 16000 Hz, stereo
Output #0, h264, to 'beijing.h264':
  Stream #0.0,   nan fps: Video: h264, yuv420p, 320x240, q=2-31, 479 kb/s
Stream mapping:
  Stream #0.0 -> #0.0
[h264 @ 0x3705fc]using SAR=1/1
[h264 @ 0x3705fc]using cpu capabilities: none!
Press [q] to stop encoding
frame=  519 q=25.0 Lsize=    1501kB time=21.6 bitrate= 568.2kbits/s   
video:1501kB audio:0kB global headers:0kB muxing overhead 0.000000%
[h264 @ 0x3705fc]slice I:48    Avg QP:18.17  size: 10418  PSNR Mean Y:48.72 U:52.93 V:51.90 Avg:49.57 Global:45.65
[h264 @ 0x3705fc]slice P:471   Avg QP:22.15  size:  2198  PSNR Mean Y:45.54 U:51.02 V:49.82 Avg:46.54 Global:42.61
[h264 @ 0x3705fc]mb I  I16..4: 24.5%  0.0% 75.5%
[h264 @ 0x3705fc]mb P  I16..4:  8.2%  0.0%  4.8%  P16..4: 42.0% 15.7%  5.8%  0.0%  0.0%    skip:23.5%
[h264 @ 0x3705fc]final ratefactor: 20.83
[h264 @ 0x3705fc]SSIM Mean Y:0.9833328
[h264 @ 0x3705fc]PSNR Mean Y:45.838 U:51.198 V:50.012 Avg:46.823 Global:42.820 kb/s:567.41
/mnt $
共519帧，568.2kbits/s。共用时10分56秒88