文章目录

1.练练手，使用AVILib创建一个AVI视频播放器
- （1）首先下载transcode，并配置avilib。
- （2）创建AbstractPlayerActivity并实现native方法
- （3）配置native-lib，开启jnigraphics，连接avi-lib
- （4）jni graphics api
- （5）使用bitmap渲染来更新avi player
2.android studio 配置javah

1.练练手，使用AVILib创建一个AVI视频播放器

（1）首先下载transcode，并配置avilib。

http://www.linuxfromscratch.org/blfs/view/svn/multimedia/transcode.html

将transcode中的avilib文件复制到项目中。

编辑platform.h文件

#ifdef  HAVE_CONFIG_H#include "config.h"#endif

在avilib创建CMakeLists.txt

add_library( # Sets the name of the library.        avi-lib        # Sets the library as a shared library.        SHARED        # Provides a relative path to your source file(s).        avilib.c        platform_posix.c)

（2）创建AbstractPlayerActivity并实现native方法

提取共用代码抽象成一个类

public abstract class AbstractPlayerActivity extends Activity {             public static final String EXTRA_FILE_NAME = "cn.study.aviplayer.EXTRA_FILE_NAME";    protected long avi = 0;    @Override    protected void onStart() {             super.onStart();        try {                 avi = open(getFileName());        } catch (IOException e) {                 new AlertDialog.Builder(this)                    .setTitle("错误提示")                    .setMessage(e.getMessage())                    .show();        }    }    @Override    protected void onStop() {             super.onStop();        if (0 != avi) {                 close(avi);            avi = 0;        }    }    protected String getFileName() {             return getIntent().getExtras().getString(EXTRA_FILE_NAME);    }    /**     * 打开指定的avi文件     *     * @return     */    protected native static long open(String fileName) throws IOException;    /**     * 获取视频宽度     *     * @param avi     * @return     */    protected native static int getWidth(long avi);    /**     * 获取视频高度     *     * @param avi     * @return     */    protected native static int getHeight(long avi);    /**     * 获取帧速     *     * @param avi     * @return     */    protected native static double getFrameRate(long avi);    /**     * 基于给定的文件描述符关闭指定的avi文件     *     * @param avi     */    protected native static void close(long avi);}

使用javah来生成.h文件。

/* DO NOT EDIT THIS FILE - it is machine generated */#include /* Header for class cn_study_aviplayer_AbstractPlayerActivity */#ifndef _Included_cn_study_aviplayer_AbstractPlayerActivity#define _Included_cn_study_aviplayer_AbstractPlayerActivity#ifdef __cplusplusextern "C" {     #endif/* * Class:     cn_study_aviplayer_AbstractPlayerActivity * Method:    open * Signature: (Ljava/lang/String;)J */JNIEXPORT jlong JNICALL Java_cn_study_aviplayer_AbstractPlayerActivity_open  (JNIEnv *, jclass, jstring);/* * Class:     cn_study_aviplayer_AbstractPlayerActivity * Method:    getWidth * Signature: (J)I */JNIEXPORT jint JNICALL Java_cn_study_aviplayer_AbstractPlayerActivity_getWidth  (JNIEnv *, jclass, jlong);/* * Class:     cn_study_aviplayer_AbstractPlayerActivity * Method:    getHeight * Signature: (J)I */JNIEXPORT jint JNICALL Java_cn_study_aviplayer_AbstractPlayerActivity_getHeight  (JNIEnv *, jclass, jlong);/* * Class:     cn_study_aviplayer_AbstractPlayerActivity * Method:    getFrameRate * Signature: (J)D */JNIEXPORT jdouble JNICALL Java_cn_study_aviplayer_AbstractPlayerActivity_getFrameRate  (JNIEnv *, jclass, jlong);/* * Class:     cn_study_aviplayer_AbstractPlayerActivity * Method:    close * Signature: (J)V */JNIEXPORT void JNICALL Java_cn_study_aviplayer_AbstractPlayerActivity_close  (JNIEnv *, jclass, jlong);#ifdef __cplusplus}#endif#endif

在native-lib.cpp中导入avilib.h需要。

extern "C" {     #include "avilib/avilib.h"}

native-lib.cpp

#include #include #include "cn_study_aviplayer_AbstractPlayerActivity.h"#include "Common.h"#include extern "C" {     #include "avilib/avilib.h"}extern "C" JNIEXPORT jstring JNICALLJava_cn_study_aviplayer_MainActivity_stringFromJNI(        JNIEnv *env,        jobject /* this */) {         std::string hello = "Hello from C++";    return env->NewStringUTF(hello.c_str());}extern "C"JNIEXPORT jlong JNICALLJava_cn_study_aviplayer_AbstractPlayerActivity_open(JNIEnv *env, jclass clazz, jstring file_name) {         avi_t *avi = 0;    //获取文件名字并转换成字符串变量    const char *cFileName = env->GetStringUTFChars(file_name, 0);    if (0 == cFileName) {             goto exit;    }    avi = AVI_open_input_file(cFileName, 1);    env->ReleaseStringUTFChars(file_name, cFileName);    if (0 == avi) {             ThrowException(env, "java/io/IOException", AVI_strerror());    }    exit:    return (jlong) avi;}extern "C"JNIEXPORT jint JNICALLJava_cn_study_aviplayer_AbstractPlayerActivity_getWidth(JNIEnv *env, jclass clazz, jlong avi) {         return AVI_video_width((avi_t *) avi);}extern "C"JNIEXPORT jint JNICALLJava_cn_study_aviplayer_AbstractPlayerActivity_getHeight(JNIEnv *env, jclass clazz, jlong avi) {         return AVI_video_height((avi_t *) avi);}extern "C"JNIEXPORT jdouble JNICALLJava_cn_study_aviplayer_AbstractPlayerActivity_getFrameRate(JNIEnv *env, jclass clazz, jlong avi) {         return AVI_frame_rate((avi_t *) avi);}extern "C"JNIEXPORT void JNICALLJava_cn_study_aviplayer_AbstractPlayerActivity_close(JNIEnv *env, jclass clazz, jlong avi) {         AVI_close((avi_t *) avi);}

（3）配置native-lib，开启jnigraphics，连接avi-lib

cmake_minimum_required(VERSION 3.4.1)add_library( # Sets the name of the library.        native-lib        # Sets the library as a shared library.        SHARED        # Provides a relative path to your source file(s).        native-lib.cpp        Common.cpp        cn_study_aviplayer_BitmapPlayerActivity.cpp)#添加子目录add_subdirectory(avilib)find_library( # Sets the name of the path variable.        log-lib        # Specifies the name of the NDK library that        # you want CMake to locate.        log)find_library( # Sets the name of the path variable.        jnigraphics-lib        jnigraphics)target_link_libraries( # Specifies the target library.        native-lib        # Links the target library to the log library        # included in the NDK.        ${     jnigraphics-lib}#开启jnigraphics        ${     log-lib}        avi-lib)

（4）jni graphics api

检索bitmap对象信息，如大小、像素格式。成功返回0，失败返回一个负数。int AndroidBitmap_getInfo(JNIEnv* env, jobject jbitmap,AndroidBitmapInfo* info);

访问原生像素缓存，锁定像素缓存以确保像素的内存不会移动。成功返回0，失败返回负数。int AndroidBitmap_lockPixels(JNIEnv* env, jobject jbitmap, void** addrPtr);

释放原生像素缓存成功返回0，失败返回负数int AndroidBitmap_unlockPixels(JNIEnv* env, jobject jbitmap);

（5）使用bitmap渲染来更新avi player

public class BitmapPlayerActivity extends AbstractPlayerActivity {         private final AtomicBoolean isPlaying = new AtomicBoolean();    private SurfaceHolder surfaceHolder;    private SurfaceView surfaceView;    @Override    protected void onCreate(Bundle savedInstanceState) {             super.onCreate(savedInstanceState);        setContentView(R.layout.activity_bitmap_player);        surfaceView = findViewById(R.id.surface_view);        surfaceHolder = surfaceView.getHolder();        surfaceHolder.addCallback(shCallback);    }    private final SurfaceHolder.Callback shCallback = new SurfaceHolder.Callback2() {             @Override        public void surfaceRedrawNeeded(SurfaceHolder holder) {             }        @Override        public void surfaceCreated(SurfaceHolder holder) {                 isPlaying.set(true);            new Thread(renderer).start();        }        @Override        public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {             }        @Override        public void surfaceDestroyed(SurfaceHolder holder) {                 isPlaying.set(false);        }    };    private final Runnable renderer = new Runnable() {             @Override        public void run() {                 Paint paint = new Paint();            paint.setAntiAlias(true);            paint.setColor(Color.BLACK);            paint.setStyle(Paint.Style.FILL);            int width = getWidth(avi);            int height = getHeight(avi);            Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.RGB_565);            float sx = 2.0f;            float sy = 2.0f;            Matrix matrix = new Matrix();            matrix.postScale(sx, sy);            int vWidth = (int) (width * sx);            int vHeight = (int) (height * sy);            int x = (1080 - vWidth) / 2;            int y = (1920 - vHeight) / 2;            matrix.postTranslate(x, y);            //延迟            long frameDelay = (long) (1000 / getFrameRate(avi));            while (isPlaying.get()) {                     render(avi, bitmap);                Canvas canvas = surfaceHolder.lockCanvas();                canvas.drawBitmap(bitmap, matrix, null);                surfaceHolder.unlockCanvasAndPost(canvas);                //等待下一针                try {                         Thread.sleep(frameDelay);                } catch (InterruptedException e) {                         break;                }            }        }    };    /**     * 从avi文件描述符输出到指定bitmap来渲染帧     *     * @param avi     * @param bitmap     * @return     */    private native static boolean render(long avi, Bitmap bitmap);}

cn_study_aviplayer_BitmapPlayerActivity.cpp

#include "Common.h"#include "cn_study_aviplayer_BitmapPlayerActivity.h"extern "C" {     #include "avilib/avilib.h"}#include extern "C"JNIEXPORT jboolean JNICALLJava_cn_study_aviplayer_BitmapPlayerActivity_render(JNIEnv *env, jclass clazz, jlong avi,                                                    jobject bitmap) {         jboolean isFrameRead = JNI_FALSE;    char *frameBuffer = 0;    long frameSize = 0;    int keyFrame = 0;    if (0 > AndroidBitmap_lockPixels(env, bitmap, (void **) &frameBuffer)) {             ThrowException(env, "java/io/IOException", "不能够锁定像素");        goto exit;    }    //将avi帧byte读取到bitmap中    frameSize = AVI_read_frame((avi_t *) avi, frameBuffer, &keyFrame);    //解锁    if (0 > AndroidBitmap_unlockPixels(env, bitmap)) {             ThrowException(env, "java/io/IOException", "不能够解锁像素");        goto exit;    }    //是否读取成功    if (0 < frameSize) {             isFrameRead = JNI_TRUE;    }    exit:    return isFrameRead;}

想使用这个avi播放器，视频文件格式必须是avi格式，希望视频负载是通过RGB565颜色空间的未压缩原始帧来提供的。
将视频放到指定目录，运行效果如下：

详细代码和视频文件

https://gitee.com/xd_box/AviPlayer

2.android studio 配置javah

file>Setting>Tools>External Tools 点击+号。

program：$JDKPath$\bin\javah.exearguments：-classpath . -jni -d $ModuleFileDir$\src\main\cpp $FileClass$working directory：$ModuleFileDir$\src\main\java

NDK学习笔记(十二) 原生图形api，使用AVILib创建一个AVI视频播放器