Android本地视频播放器开发--SDL编译

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Android本地视频播放器开发--ffmpeg解码视频文件中的音频(2)中使用OpenSL ES来播放视频的声音，遗留的问题是声音的不同步，由于视频实现部分也要同步，而且音视频也要同步，所以音频部分就不单独同步问题，当同时播放音视频的时候进行两者的同步问题，对于视频显示部分最后是要使用OpenGL es来实现，由于SDL可以和OpenGL ES进行搭配，所以使用SDL+OpenGL ES进行显示视频，所以这章将要讲解的是SDL的交叉编译.

一、到官网下载http://www.libsdl.org/hg.php 下载2.0的源码也可以通过hg来clone最新的源码

hg clone http://hg.libsdl.org/SDL

二、其实1.3以后的版本就添加了android的支持，所以下载完源码后，在SDL目录下创建一个jni的目录，然后将原先SDL目录下面的文件以及文件夹都拷贝到jni目录下面，在jni目录下面我们会看见一个android.mk的文件,这就是官方给我们编写的编译文件，由于手机基本上都是使用的arm编译器，所以我在里面添加了LOCAL_ARM_MODE=arm，模块的编译使用arm编译器来编译，具体的内容如下:

############################# SDL shared library############################include $(CLEAR_VARS)LOCAL_MODULE := SDL2LOCAL_ARM_MODE=armLOCAL_C_INCLUDES := $(LOCAL_PATH)/includeLOCAL_SRC_FILES := \        $(subst $(LOCAL_PATH)/,, \        $(wildcard $(LOCAL_PATH)/src/*.c) \        $(wildcard $(LOCAL_PATH)/src/audio/*.c) \        $(wildcard $(LOCAL_PATH)/src/audio/android/*.c) \        $(wildcard $(LOCAL_PATH)/src/audio/dummy/*.c) \        $(LOCAL_PATH)/src/atomic/SDL_atomic.c \        $(LOCAL_PATH)/src/atomic/SDL_spinlock.c.arm \        $(wildcard $(LOCAL_PATH)/src/core/android/*.cpp) \        $(wildcard $(LOCAL_PATH)/src/cpuinfo/*.c) \        $(wildcard $(LOCAL_PATH)/src/events/*.c) \        $(wildcard $(LOCAL_PATH)/src/file/*.c) \        $(wildcard $(LOCAL_PATH)/src/haptic/*.c) \        $(wildcard $(LOCAL_PATH)/src/haptic/dummy/*.c) \        $(wildcard $(LOCAL_PATH)/src/joystick/*.c) \        $(wildcard $(LOCAL_PATH)/src/joystick/android/*.c) \        $(wildcard $(LOCAL_PATH)/src/loadso/dlopen/*.c) \        $(wildcard $(LOCAL_PATH)/src/power/*.c) \        $(wildcard $(LOCAL_PATH)/src/power/android/*.c) \        $(wildcard $(LOCAL_PATH)/src/render/*.c) \        $(wildcard $(LOCAL_PATH)/src/render/*/*.c) \        $(wildcard $(LOCAL_PATH)/src/stdlib/*.c) \        $(wildcard $(LOCAL_PATH)/src/thread/*.c) \        $(wildcard $(LOCAL_PATH)/src/thread/pthread/*.c) \        $(wildcard $(LOCAL_PATH)/src/timer/*.c) \        $(wildcard $(LOCAL_PATH)/src/timer/unix/*.c) \        $(wildcard $(LOCAL_PATH)/src/video/*.c) \        $(wildcard $(LOCAL_PATH)/src/video/android/*.c))LOCAL_CFLAGS += -DGL_GLEXT_PROTOTYPESLOCAL_LDLIBS := -ldl -lGLESv1_CM -lGLESv2 -lloginclude $(BUILD_SHARED_LIBRARY)

三、如果直接编译的话会提示如下错误

/home/SDL/jni/src/core/android/SDL_android.cpp:30:21: fatal error: EGL/egl.h: No such file or directory

查看EGL的支持是在2.3版本以上，所以我们需要添加平台的支持，所以需要在jni目录下面创建一个Application.mk文件来指定编译平台，内容如下:

APP_ABI := armeabiAPP_PLATFORM := android-9

四、在jni目录终端下运行ndk-build，就会编译出libSDL2.so，编译过程如下:

root@zhangjie:/home/SDL/jni# ndk-buildCompile arm    : SDL2 <= SDL_assert.cCompile arm    : SDL2 <= SDL.cCompile arm    : SDL2 <= SDL_error.cCompile arm    : SDL2 <= SDL_fatal.cCompile arm    : SDL2 <= SDL_hints.cCompile arm    : SDL2 <= SDL_log.cCompile arm    : SDL2 <= SDL_audio.cCompile arm    : SDL2 <= SDL_audiocvt.cCompile arm    : SDL2 <= SDL_audiodev.cCompile arm    : SDL2 <= SDL_audiotypecvt.cCompile arm    : SDL2 <= SDL_mixer.cCompile arm    : SDL2 <= SDL_wave.cCompile arm    : SDL2 <= SDL_androidaudio.cCompile arm    : SDL2 <= SDL_dummyaudio.cCompile arm    : SDL2 <= SDL_atomic.cCompile arm    : SDL2 <= SDL_spinlock.cCompile++ arm    : SDL2 <= SDL_android.cppCompile arm    : SDL2 <= SDL_cpuinfo.cCompile arm    : SDL2 <= SDL_clipboardevents.cCompile arm    : SDL2 <= SDL_dropevents.cCompile arm    : SDL2 <= SDL_events.cCompile arm    : SDL2 <= SDL_gesture.cCompile arm    : SDL2 <= SDL_keyboard.cCompile arm    : SDL2 <= SDL_mouse.cCompile arm    : SDL2 <= SDL_quit.cCompile arm    : SDL2 <= SDL_touch.cCompile arm    : SDL2 <= SDL_windowevents.cCompile arm    : SDL2 <= SDL_rwops.cCompile arm    : SDL2 <= SDL_haptic.cCompile arm    : SDL2 <= SDL_syshaptic.cCompile arm    : SDL2 <= SDL_gamecontroller.cCompile arm    : SDL2 <= SDL_joystick.cCompile arm    : SDL2 <= SDL_sysjoystick.cCompile arm    : SDL2 <= SDL_sysloadso.cCompile arm    : SDL2 <= SDL_power.cCompile arm    : SDL2 <= SDL_syspower.cCompile arm    : SDL2 <= SDL_render.cCompile arm    : SDL2 <= SDL_yuv_mmx.cCompile arm    : SDL2 <= SDL_yuv_sw.cCompile arm    : SDL2 <= SDL_render_d3d.cCompile arm    : SDL2 <= SDL_render_gles2.cCompile arm    : SDL2 <= SDL_shaders_gles2.cCompile arm    : SDL2 <= SDL_render_gles.cCompile arm    : SDL2 <= SDL_render_gl.cCompile arm    : SDL2 <= SDL_shaders_gl.cCompile arm    : SDL2 <= SDL_render_psp.cCompile arm    : SDL2 <= SDL_blendfillrect.cCompile arm    : SDL2 <= SDL_blendline.cCompile arm    : SDL2 <= SDL_blendpoint.cCompile arm    : SDL2 <= SDL_drawline.cCompile arm    : SDL2 <= SDL_drawpoint.cCompile arm    : SDL2 <= SDL_render_sw.cCompile arm    : SDL2 <= SDL_rotate.cCompile arm    : SDL2 <= SDL_getenv.cCompile arm    : SDL2 <= SDL_iconv.cCompile arm    : SDL2 <= SDL_malloc.cCompile arm    : SDL2 <= SDL_qsort.cCompile arm    : SDL2 <= SDL_stdlib.cCompile arm    : SDL2 <= SDL_string.cCompile arm    : SDL2 <= SDL_thread.cCompile arm    : SDL2 <= SDL_syscond.cCompile arm    : SDL2 <= SDL_sysmutex.cCompile arm    : SDL2 <= SDL_syssem.cCompile arm    : SDL2 <= SDL_systhread.cCompile arm    : SDL2 <= SDL_timer.cCompile arm    : SDL2 <= SDL_systimer.cCompile arm    : SDL2 <= SDL_blit_0.cCompile arm    : SDL2 <= SDL_blit_1.cCompile arm    : SDL2 <= SDL_blit_A.cCompile arm    : SDL2 <= SDL_blit_auto.cCompile arm    : SDL2 <= SDL_blit.cCompile arm    : SDL2 <= SDL_blit_copy.cCompile arm    : SDL2 <= SDL_blit_N.cCompile arm    : SDL2 <= SDL_blit_slow.cCompile arm    : SDL2 <= SDL_bmp.cCompile arm    : SDL2 <= SDL_clipboard.cCompile arm    : SDL2 <= SDL_fillrect.cCompile arm    : SDL2 <= SDL_pixels.cCompile arm    : SDL2 <= SDL_rect.cCompile arm    : SDL2 <= SDL_RLEaccel.cCompile arm    : SDL2 <= SDL_shape.cCompile arm    : SDL2 <= SDL_stretch.cCompile arm    : SDL2 <= SDL_surface.cCompile arm    : SDL2 <= SDL_video.cCompile arm    : SDL2 <= SDL_androidclipboard.cCompile arm    : SDL2 <= SDL_androidevents.cCompile arm    : SDL2 <= SDL_androidgl.cCompile arm    : SDL2 <= SDL_androidkeyboard.cCompile arm    : SDL2 <= SDL_androidtouch.cCompile arm    : SDL2 <= SDL_androidvideo.cCompile arm    : SDL2 <= SDL_androidwindow.cStaticLibrary  : libstdc++.aSharedLibrary  : libSDL2.soInstall        : libSDL2.so => libs/armeabi/libSDL2.so

编译出sdl库后，我们就可以调用它的相关函数来实现我们的功能了。

下一章将要使用ffmpeg来解码视频文件