Android FAQ - ffmpeg

 

 

1.  Not found libffmpeg.so

Application.mk

APP_ABI := armeabi-v7a
APP_STL  :=  stlport_static
#APP_STL := gnustl_static
APP_CPPFLAGS := -fno-rtti
APP_CPPFLAGS += -fexceptions

 

Android.mk

LOCAL_PATH := $(call my-dir)

include $(CLEAR_VARS)
LOCAL_MODULE := ffmpeg
LOCAL_SRC_FILES := ../libffmpeg.so
include $(PREBUILT_SHARED_LIBRARY)

include $(CLEAR_VARS)
NDK_LIBDIR=/opt/android/ndk-r9d/platforms/android-19/arch-arm
FFMPEG_HOME=/usr/local/android/ffmpeg

LOCAL_MODULE := tt.x
LOCAL_SRC_FILES := ../tt.cpp

LOCAL_C_INCLUDES := $(ANDROID_NDK)/sources/cxx-stl/stlport/stlport
LOCAL_C_INCLUDES += ../
LOCAL_C_INCLUDES += include
LOCAL_C_INCLUDES += $(FFMPEG_HOME)/include

LOCAL_CPPFLAGS := -Wall -Wno-multichar  -D__STDC_CONSTANT_MACROS

LOCAL_LDLIBS := -L$(NDK_LIBDIR)/usr/lib -landroid -llog -L$(FFMPEG_HOME)/lib -lffmpeg

#LOCAL_LDLIBS += $(ANDROID_NDK)/sources/cxx-stl/stlport/libs/armeabi-v7a/libstlport_static.a

#LOCAL_SHARED_LIBRARIES := ffmpeg

include $(BUILD_EXECUTABLE)
#include $(BUILD_SHARED_LIBRARY)

当采用上述红色部分而不是蓝色部分来连接libffmpeg.so时候，执行tt.x时将报下述错误。

(即使你将libffmpeg.so拷贝到/system/lib/， 和  当前执行目录的obj/local/armeabi-v7a 目录下)

soinfo_link_image(linker.cpp:1635): could not load library
"./obj/local/armeabi-v7a/libffmpeg.so" needed by "./tt.x";
caused by load_library(linker.cpp:745): library "./obj/local
/armeabi-v7a/libffmpeg.so" not foundCANNOT LINK EXECUTABLE

 

2.  执行程序core dump

当你写一个基于omx解码执行程序， 并连接binder, android, stagefrighthw, stagefright etc

库， 同时连接libffmpeg.so库， 在执行程序中调用相关ffmpeg库函数， 但是执行程序发生

core dump。

 

刚开始我以为是ffmpeg库编译，连接有问题， 但后来发现， 如果去掉omx， binder相关部分，

执行程序能正确调用ffmpeg相关函数。

 

这个原因还没有找到， 写在这儿， 便于提醒自己。

 

3. libavcodec/log2_tab.o: multiple definition of 'ff_log2_tab' 解决办法

新增文件 libavutil/log2_tab.h, 其内容如下

#ifndef AV_LOG2TAB_H
#define AV_LOG2TAB_H

#include <stdint.h>
extern const uint8_t ff_log2_tab[256];

#endif

将所有报上述类似错误的， 做如下修改

如：修改 libavcodec/log2_tab.c, 将log2_tab.c改为log2_tab.h

// #include "libavutil/log2_tab.c"

#include "libavutil/log2_tab.h"

4. error: libavformat/golomb_tab.o: multiple definition of 'ff_interleaved_dirac_golomb_vlc_code' 解决方法

修改 libavformat/golomb_tab.c, 如下：

// #include "libavcodec/golomb.c"
#include "libavcodec/golomb.h"

 

5. libavutil/eval.o:eval.c:function av_strtod: error: undefined reference to 'avpriv_strtod'

将compat/strtod.c 中的代码复制粘贴到libavutil/eval.c

//////// pasted from compat/strtod.c begin ////////
#include "libavutil/avstring.h"
#include "libavutil/mathematics.h"

static char *check_nan_suffix(char *s)
{
    char *start = s;

    if (*s++ != '(')
        return start;

    while ((*s >= 'a' && *s <= 'z') || (*s >= 'A' && *s <= 'Z') ||
           (*s >= '0' && *s <= '9') ||  *s == '_')
        s++;

    return *s == ')' ? s + 1 : start;
}

#undef strtod
double strtod(const char *, char **);

double avpriv_strtod(const char *nptr, char **endptr)
{
    char *end;
    double res;

    /* Skip leading spaces */
    while (av_isspace(*nptr))
        nptr++;

    if (!av_strncasecmp(nptr, "infinity", 8)) {
        end = nptr + 8;
        res = INFINITY;
    } else if (!av_strncasecmp(nptr, "inf", 3)) {
        end = nptr + 3;
        res = INFINITY;
    } else if (!av_strncasecmp(nptr, "+infinity", 9)) {
        end = nptr + 9;
        res = INFINITY;
    } else if (!av_strncasecmp(nptr, "+inf", 4)) {
        end = nptr + 4;
        res = INFINITY;
    } else if (!av_strncasecmp(nptr, "-infinity", 9)) {
        end = nptr + 9;
        res = -INFINITY;
    } else if (!av_strncasecmp(nptr, "-inf", 4)) {
        end = nptr + 4;
        res = -INFINITY;
    } else if (!av_strncasecmp(nptr, "nan", 3)) {
        end = check_nan_suffix(nptr + 3);
        res = NAN;
    } else if (!av_strncasecmp(nptr, "+nan", 4) ||
               !av_strncasecmp(nptr, "-nan", 4)) {
        end = check_nan_suffix(nptr + 4);
        res = NAN;
    } else if (!av_strncasecmp(nptr, "0x", 2) ||
               !av_strncasecmp(nptr, "-0x", 3) ||
               !av_strncasecmp(nptr, "+0x", 3)) {
        /* FIXME this doesn't handle exponents, non-integers (float/double)
         * and numbers too large for long long */
        res = strtoll(nptr, &end, 16);
    } else {
        res = strtod(nptr, &end);
    }

    if (endptr)
        *endptr = end;

    return res;
}

//////// pasted from compat/strtod.c end ////////

typedef struct Parser {
    const AVClass *class;
    int stack_index;
    char *s;
    const double *const_values;
    const char * const *const_names;          // NULL terminated
    double (* const *funcs1)(void *, double a);           // NULL terminated
    const char * const *func1_names;          // NULL terminated
    double (* const *funcs2)(void *, double a, double b); // NULL terminated
    const char * const *func2_names;          // NULL terminated
    void *opaque;
    int log_offset;
    void *log_ctx;
#define VARS 10
    double *var;
} Parser;

 

然后注释掉compat/strtod.c中的代码