Android全格式播放器开发(第五节ffplay android移植)

第五节ffplay android移植

作者：[email protected]

博客：http://www.weibo.com/xdpan

工程地址：http://code.google.com/p/kudou-player/

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之前我们已经做了好了准备工作，现在还做ffplay的移植，这是最难的一关，也是最复杂的一关。这里主要是要分为两步：ffplay使用sdl-1.3移植和ffplay的android接口编写调试。

 

1.     Ffplay sdl-1.3移植

android上能够使用的sdl版本必须是sdl-1.3及以上，sdl-1.3的移植如下，主要修改视频显示接口，将SDL_DisplayYUVOverlay(vp->bmp, &rect) 改为SDL_CreateTexture()方式，主要是将YUV的显示模式改为RGB的显示模式。主要修改点如下：

变量定义修改

以前使用SDL_Surfaces显示，新版使用SDL_Window作为显示区域，新版支持多窗口显示，SDL_Renderer是显示程序，SDL_Texture为数据容器。

#ifdef SDL12

    SDL_Overlay *bmp;

#else

    AVFrame *pFrameRGB;

    int numBytes;

    uint8_t *buffer;

#endif

 

#ifdef SDL12

static SDL_Surface*screen = NULL;

#else

staticSDL_Window *window = NULL;

staticSDL_Renderer *renderer = NULL;

staticSDL_Texture *texture = NULL;

#endif

以上是变量定义部分，我们使用的是texture代替Overlay的方式

 

显示创建修改

使用SDL_CreateRenderer来创建用于显示的Render：

static int video_open(VideoState *is, intforce_set_video_mode)的修改：

#ifdef SDL12

    if (screen && is->width ==screen->w && screen->w == w

            && is->height==screen->h && screen->h == h && !force_set_video_mode)

    return 0;

    screen = SDL_SetVideoMode(w, h, 0, flags);

    if(!screen) {

        fprintf(stderr, "SDL: could notset video mode - exiting\n");

        do_exit(is);

    }

    if (!window_title)

    window_title = input_filename;

    SDL_WM_SetCaption(window_title,window_title);

 

    is->width = screen->w;

    is->height = screen->h;

#else

    //SDL_SetVideoMode(w, h, 32, 0);

    window =SDL_CreateWindow("MySDL", SDL_WINDOWPOS_CENTERED,

            SDL_WINDOWPOS_CENTERED, w, h,SDL_WINDOW_SHOWN|SDL_WINDOW_OPENGL);

    if (window == NULL ) {

        fprintf(stderr, "SDL: could notset video window - exiting\n");

        exit(1);

    }

 

    //renderer = SDL_CreateRenderer(window, -1,SDL_RENDERER_ACCELERATED);

    renderer = SDL_CreateRenderer(window, -1,SDL_RENDERER_TARGETTEXTURE);

 

    if (!renderer) {

        fprintf(stderr, "Couldn't setcreate renderer: %s\n", SDL_GetError());

        exit(1);

    }

 

    is->width = w;

    is->height = h;

#endif

 

 

图片内存空间分配修改

static void alloc_picture(AllocEventProps*event_props) 图片获取部分修改

#ifdef SDL12

    if (vp->bmp)

    SDL_FreeYUVOverlay(vp->bmp);

#else

    if (vp->pFrameRGB) {

        // we already have one make another,bigger/smaller

        if (vp->pFrameRGB) {

            av_free(vp->pFrameRGB);

            vp->pFrameRGB = 0;

        }

        if (vp->buffer) {

            av_free(vp->buffer);

            vp->buffer = 0;

        }

    }

#endif

    vp->width = frame->width;

    vp->height = frame->height;

    vp->pix_fmt = frame->format;

 

    //video_open(event_props->is, 0);

 

#ifdef SDL12

    vp->bmp =SDL_CreateYUVOverlay(vp->width, vp->height,

            SDL_YV12_OVERLAY,

            screen);

    if (!vp->bmp ||vp->bmp->pitches[0] < vp->width) {

        /* SDL allocates a buffer smaller thanrequested if the video

         * overlay hardware is unable tosupport the requested size. */

        fprintf(stderr, "Error: the videosystem does not support an image\n"

                "size of %dx%d pixels. Tryusing -lowres or -vf \"scale=w:h\"\n"

                "to reduce the imagesize.\n", vp->width, vp->height );

        do_exit(is);

    }

#else

    vp->pFrameRGB = avcodec_alloc_frame();

 

    vp->width =is->video_st->codec->width;

    vp->height = is->video_st->codec->height;

 

    vp->numBytes =avpicture_get_size(dst_fix_fmt, vp->width, vp->height);

    vp->buffer = (uint8_t *)av_malloc(vp->numBytes * sizeof(uint8_t));

 

    if (!vp->pFrameRGB || !vp->buffer) {

        printf("can not get frame memory,exit\n");

    }

 

    avpicture_fill((AVPicture*)vp->pFrameRGB, vp->buffer, dst_fix_fmt,

            vp->width, vp->height);

#endif

 

 

 

色彩转换方面修改

在static int queue_picture(VideoState *is,…)函数中，之前版本使用的YUV显示，Android只能显示RGB数据，因此改用RGB显示，主要使用的sws_scale(…)函数，此函数是一个非常耗时函数，对此函数的优化对画面显示和程序效率都有很大帮助。  sws_scale(…)的画面显示是没有问题，但是显示效率不够优化，此内容在后面优化部分再说

#ifdef SDL12

    if (vp->bmp) {

#else

    if (vp->pFrameRGB) {

#endif

 

#ifdef SDL12

        AVPicture pict = { {0}};

 

        /* get a pointer on the bitmap */

        SDL_LockYUVOverlay (vp->bmp);

 

        pict.data[0] =vp->bmp->pixels[0];

        pict.data[1] =vp->bmp->pixels[2];

        pict.data[2] = vp->bmp->pixels[1];

                SDL_CondWait(is->pictq_cond,is->pictq_mutex);

            }

        }

        SDL_UnlockMutex(is->pictq_mutex);

 

        if (is->videoq.abort_request)

            return -1;

    }

 

    /* if the frame is not skipped, thendisplay it */

#ifdef SDL12

    if (vp->bmp) {

#else

    if (vp->pFrameRGB) {

#endif

 

#ifdef SDL12

        AVPicture pict = { {0}};

 

        /* get a pointer on the bitmap */

        SDL_LockYUVOverlay (vp->bmp);

 

        pict.data[0] = vp->bmp->pixels[0];

        pict.data[1] =vp->bmp->pixels[2];

        pict.data[2] =vp->bmp->pixels[1];

 

        pict.linesize[0] =vp->bmp->pitches[0];

        pict.linesize[1] =vp->bmp->pitches[2];

        pict.linesize[2] =vp->bmp->pitches[1];

 

        is->img_convert_ctx =sws_getCachedContext(is->img_convert_ctx,

                vp->width, vp->height,vp->pix_fmt, vp->width, vp->height,

                PIX_FMT_YUV420P, sws_flags,NULL, NULL, NULL);

 

        if (is->img_convert_ctx == NULL) {

            LOGV( "Cannot initialize theconversion context\n");

            exit(1);

        }

        sws_scale(is->img_convert_ctx,src_frame->data, src_frame->linesize,

                0, vp->height, pict.data,pict.linesize);

        vp->sample_aspect_ratio =av_guess_sample_aspect_ratio(is->ic, is->video_st, src_frame);

 

        /* update the bitmap content */

        SDL_UnlockYUVOverlay(vp->bmp);

#else

        if (is->img_convert_ctx == NULL ) {

            is->img_convert_ctx =sws_getCachedContext(is->img_convert_ctx,

                    vp->width, vp->height,vp->pix_fmt, vp->width, vp->height,

                    dst_fix_fmt, sws_flags,NULL, NULL, NULL );

            if (is->img_convert_ctx == NULL) {

                LOGV( "Cannot initializethe conversion context!\n");

                exit(1);

            }

        }

        sws_scale(is->img_convert_ctx,src_frame->data, src_frame->linesize, 0,

               is->video_st->codec->height, vp->pFrameRGB->data,

                vp->pFrameRGB->linesize);

        vp->sample_aspect_ratio =av_guess_sample_aspect_ratio(is->ic,

                is->video_st, src_frame);

#endif

 

 

显示部分修改

在static void video_image_display(VideoState *is)中,使用SDL_UpdateTexture(…)来填充显示区域，使用SDL_RenderPresent(...)来将Rect中的数据刷新到屏幕：

#ifdef SDL12

    if (vp->bmp) {

#else

    if (vp->pFrameRGB) {

#endif

        if (vp->sample_aspect_ratio.num ==0)

            aspect_ratio = 0;

        else

            aspect_ratio =av_q2d(vp->sample_aspect_ratio);

 

        if (aspect_ratio <= 0.0)

            aspect_ratio = 1.0;

        aspect_ratio *= (float) vp->width /(float) vp->height;

 

        /* XXX: we suppose the screen has a 1.0pixel ratio */

        height = is->height;

        width = ((int) rint(height *aspect_ratio)) & ~1;

        if (width > is->width) {

            width = is->width;

            height = ((int) rint(width /aspect_ratio)) & ~1;

        }

        x= (is->width - width) / 2;

        y = (is->height - height) / 2;

        is->no_background = 0;

        rect.x = is->xleft + x;

        rect.y = is->ytop + y;

        rect.w = FFMAX(width, 1);

        rect.h = FFMAX(height, 1);

#ifdef SDL12

        SDL_DisplayYUVOverlay(vp->bmp,&rect);

#else

        if (NULL == texture) {

            texture =SDL_CreateTexture(renderer, display_fix_fmt,

                    SDL_TEXTUREACCESS_STATIC,is->video_st->codec->width,

                    is->video_st->codec->height);

            if (!texture) {

                LOGV( "Couldn't set createtexture: %s\n", SDL_GetError());

                exit(1);

            }

            SDL_SetTextureBlendMode(texture,SDL_BLENDMODE_BLEND );

            //best scale mode

            //SDL_SetTextureScaleMode(texture,SDL_TEXTURESCALEMODE_BEST);

        }

        SDL_RenderClear(renderer);

        SDL_UpdateTexture(texture, NULL,vp->pFrameRGB->data[0],

               vp->pFrameRGB->linesize[0]);

        SDL_RenderCopy(renderer, texture, NULL,&rect);

 

        g_current_duration = (int)get_master_clock(is) * 1000;

        SDL_RenderPresent(renderer);

 

#endif

 

 

流关闭修改

static void stream_close(VideoState *is) 修改如下：

#ifdef SDL12

        if (vp->bmp) {

            SDL_FreeYUVOverlay(vp->bmp);

            vp->bmp = NULL;

        }

#else

        if (vp->pFrameRGB) {

            av_free(vp->pFrameRGB);

            vp->pFrameRGB = 0;

        }

        if (vp->buffer) {

            av_free(vp->buffer);

            vp->buffer = 0;

        }

#endif

 

 

以上是基本上是所以基于SDL-1.3的ffplay的修改。主要是将YUV(Overlay)的方式改为RGB(Texture)方式，SDL内部使用的OpenGL ES方式进行渲染。由于SDL已经封装好了，我们这里也就不去探究了。如果不想使用SDL作为显示，可以直接显示OpenGL ES接口进行，但是移植的代价就大些。

 

 

2.      Android接口编写

Android程序对c的调用采用jni的方式，jni编写规范可以参考http://developer.android.com/training/articles/perf-jni.html或者其他文档。

对于播放器接口的设计，我们可以参考Android的MediaPlayer设计(http://developer.android.com/reference/android/media/MediaPlayer.html)。播放器中，最关键的有Init(初始化)、InitEd(初始化完成，可以设置回调函数)、Play（播放）、Stop(停止)，Seek(拖动)、Exit(退出)，getDuration(获取播放位置)、getTotalDuration(获取播放时长)。建立一个叫native.cpp的文件，接口设计如下：

#include

#include

#include

 

extern"C" {

#include"play.h"

}

 

#ifdefANDROID

 

/* Includethe SDL main definition header */

 

/*******************************************************************************

                 Functions called by JNI

*******************************************************************************/

 

 

// Libraryinit

//extern"C" jint JNI_OnLoad(JavaVM* vm, void* reserved)

//{

//    return JNI_VERSION_1_4;

//}

 

// Start upthe SDL app

extern"C" int Java_org_libsdl_app_SDLActivity_PlayerInit(JNIEnv* env,  jobject obj)

{

   return player_init();

}

 

extern"C" int Java_org_libsdl_app_SDLActivity_PlayerPrepare(JNIEnv*env,  jobject obj, jstring jfileName)

{

        jboolean isCopy;

        char localFileName[1024];

        const char *fileString     = env->GetStringUTFChars(jfileName,&isCopy);

 

        strncpy(localFileName, fileString,1024);

       env->ReleaseStringUTFChars(jfileName, fileString);

        return player_prepare(localFileName);

}

 

extern"C" int Java_org_libsdl_app_SDLActivity_PlayerMain(JNIEnv* env,  jobject obj)

{

   return player_main();

}

 

extern"C" int Java_org_libsdl_app_SDLActivity_PlayerExit(JNIEnv* env,  jobject obj)

{

   return player_exit();

}

 

extern"C" int Java_org_libsdl_app_SDLActivity_PlayerSeekTo(JNIEnv*env,  jobject obj, jint msec)

{

   int pos = msec;

   return seekTo(pos);

}

 

extern"C" int Java_org_libsdl_app_SDLActivity_PlayerPause(JNIEnv* env,  jobject obj)

{

   return streamPause();

}

 

extern"C" int Java_org_libsdl_app_SDLActivity_PlayerIsPlay(JNIEnv*env,  jobject obj)

{

   return isPlay();

}

 

extern"C" int Java_org_libsdl_app_SDLActivity_PlayerGetDuration(JNIEnv*env,  jobject obj)

{

   return getDuration();

}

 

extern"C" intJava_org_libsdl_app_SDLActivity_PlayergetCurrentPosition(JNIEnv* env,  jobject obj)

{

   return getCurrentPosition();

}

 

#endif /*ANDROID */

 

 

3.      Jni和Java通信

Java调用Jni接口是比较简单的，但是如果Jni中的程序想通知Java程序某事事件已经发生，就需要Jni和Java通信了。Jni上也有C调用Java的例子，主要分为两种情况：调用进程为Jvm进程或者为子进程，方法有点不同。

我们本次设计的通信接口是采用类似信号的方式，在C中调用Java中预先写好的方法，然后触发事件，C中函数如下：

打开第四节中工程，找到jni/SDL/src/core/android/SDL_android.cpp

添加：

extern"C" void Android_Notify(int id){

    int status;

    JNIEnv *env;

    static bool isAttached = false;   

    status = mJavaVM->GetEnv((void **)&env, JNI_VERSION_1_4);

    if(status < 0) {

        LOGE("callback_handler: failed toget JNI environment, assuming native thread");

        status =mJavaVM->AttachCurrentThread(&env, NULL);

        if(status < 0) {

            LOGE("callback_handler: failedto attach current thread");

            return;

        }

        isAttached = true;

    }

 

    env->CallStaticVoidMethod(mActivityClass,mNotify, id);

 

    if (isAttached) {

        mJavaVM->DetachCurrentThread();

    }

 

}

将头文件添加到

jni/SDL/include/SDL_notify.h中

如下：

#ifndefNOTIFY_H

#defineNOTIFY_H

 

voidAndroid_Notify(int id);

 

#endif

这样就完成了

 

4.      编译工程

修改jni/src/Android.mk如下：

LOCAL_PATH :=$(call my-dir)

 

include$(CLEAR_VARS)

 

LOCAL_MODULE:= main

 

SDL_PATH :=../SDL

FFMPEG_PATH =../ffmpeg

 

LOCAL_C_INCLUDES:= $(LOCAL_PATH)/$(SDL_PATH)/include \

                                                                           $(LOCAL_PATH)/$(FFMPEG_PATH)/include\

                                                                           $(LOCAL_PATH)/include

 

# Add your applicationsource files here...

LOCAL_SRC_FILES:= $(SDL_PATH)/src/main/android/SDL_android_main.cpp  kuplayer_android.c native.cpp

 

LOCAL_CFLAGS+= -DANDROID

LOCAL_SHARED_LIBRARIES:= SDL

 

LOCAL_LDLIBS:= -lGLESv1_CM -llog

LOCAL_LDLIBS+= $(LOCAL_PATH)/"libffmpeg.so"

include$(BUILD_SHARED_LIBRARY)

 

 

include$(CLEAR_VARS)

LOCAL_MODULE:= ffmpeg

NDK_MODULE_PATH:= $(LOCAL_PATH)

LOCAL_SRC_FILES:= libffmpeg.so

include$(PREBUILT_SHARED_LIBRARY)

将第三节中的编译的ffmpeg的头文件拷贝过来

cd /home/xdpan/work/android-project/jni/

cp -R ../../ffmpeg-0.11.1/android/armv7-a/include./

cp ../../ffmpeg-0.11.1/android/armv7-a/lib/libffmpeg.so  ./src/

在jni目下执行ndk-build –j2就编译好了

 

 

源文件如下（或者到虚拟机相应的目录中提取）

kuplayer_android.c

native.cpp