上次已将ffmpeg的动态库编译出来了，并且使用了ffmpeg的转码功能，成功将mp4格式视频转化为yuv视频，这篇文章基于上次测试的demo，使用surfaceview显示解码完成的像素数据

布局设置和权限添加

布局

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:tools="http://schemas.android.com/tools"android:layout_width="match_parent"android:layout_height="match_parent" ><com.cj5785.ffmpegnativeplayer.view.MySurfaceViewandroid:id="@+id/surface_view"android:layout_width="fill_parent"android:layout_height="fill_parent"/><Buttonandroid:layout_width="wrap_content"android:layout_height="wrap_content"android:text="开始"android:onClick="mPlay" /></FrameLayout>

权限

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS" />

编写自定义view和控制器

自定义View

package com.cj5785.ffmpegnativeplayer.view;import android.content.Context;
import android.graphics.PixelFormat;
import android.util.AttributeSet;
import android.view.SurfaceHolder;
import android.view.SurfaceView;public class MySurfaceView extends SurfaceView {public MySurfaceView(Context context) {super(context);init();}public MySurfaceView(Context context, AttributeSet attrs) {super(context, attrs);init();}public MySurfaceView(Context context, AttributeSet attrs, int defStyle) {super(context, attrs, defStyle);init();}//初始化像素格式private void init() {SurfaceHolder holder = getHolder();holder.setFormat(PixelFormat.RGBA_8888);}
}

控制器

package com.cj5785.ffmpegnativeplayer;import android.view.Surface;public class NativePlayer {public native void render(String input, Surface surface);static {System.loadLibrary("avutil-54");System.loadLibrary("swresample-1");System.loadLibrary("avcodec-56");System.loadLibrary("avformat-56");System.loadLibrary("swscale-3");System.loadLibrary("postproc-53");System.loadLibrary("avfilter-5");System.loadLibrary("avdevice-56");System.loadLibrary("ffmpeg_native_player");}}

实现控制器native方法

• 使用javah生成头文件，这里可能存在无法找到Surface签名的问题，这时候需要指定classpath路径
  javah -classpath E:\eclipse-adt\sdk\platforms\android-15\android.jar;. com.cj5785.ffmpegnativeplayer.NativePlayer
  格式说明：-classpath后面跟的是android.jar路径，最后接native方法类的全名

• 新建jni文件夹，将头文件移至jni文件夹，添加本地依赖

• 复制生成ffmpeg的include目录和so动态库到jni目录

• 将之前的Android.mk和Application.mk复制到jni文件夹，并做适当修改
  Android.mk主要修改模块名，使其与控制器调用相统一
  Application.mk主要将APP_PLATFORM := android-8修改为APP_PLATFORM := android-9
  注意，此处如果不修改Application.mk将导致android/native_window_jni.h无法找到，同时，由于使用了这个头文件，需要在Android.mk配置-landroid

• 使用开源库libyuv实现yuv转化为RGBA_8888
  下载开源库libyuv，下载地址libyuv下载地址
  将libyuv下的所有文件放入jni目录(NDK工程规范，必须存在jni目录)
  修改libyuv的Android.mk文件，将最后的include $(BUILD_STATIC_LIBRARY)改为include $(BUILD_SHARED_LIBRARY)，这样就可以生成so动态库了
  还可以将LOCAL_MODULE := libyuv_static改为LOCAL_MODULE := libyuv，方便so管理
  在jni目录下执行ndk-build即可对libyuv进行编译
  编译生成的so动态库位于与jni目录同级的lib下
  将lib添加到工程jni目录下，为了便于管理，将jni的include目录进行重新分配，重新分配目录如下：(已将libyuv的include加入到工程，这里没有列出目录下包含的头文件)

│  Android.mk
│  Application.mk
│  com_cj5785_ffmpegnativeplayer_NativePlayer.h
│  ffmpeg_native_player.c
│
└─include├─ffmpeg│  │  libavcodec-56.so│  │  libavdevice-56.so│  │  libavfilter-5.so│  │  libavformat-56.so│  │  libavutil-54.so│  │  libpostproc-53.so│  │  libswresample-1.so│  │  libswscale-3.so│  │  │  ├─libavcodec│  ├─libavdevice│  ├─libavfilter│  ├─libavformat│  ├─libavutil│  ├─libpostproc│  ├─libswresample│  └─libswscale│          └─libyuv│  libyuv.h│  libyuv.so│  └─libyuv

• 修改Android.mk，使其能找到so动态库

LOCAL_PATH := $(call my-dir)include $(CLEAR_VARS)
LOCAL_MODULE := avcodec
LOCAL_SRC_FILES := include/ffmpeg/libavcodec-56.so
include $(PREBUILT_SHARED_LIBRARY)include $(CLEAR_VARS)
LOCAL_MODULE := avdevice
LOCAL_SRC_FILES := include/ffmpeg/libavdevice-56.so
include $(PREBUILT_SHARED_LIBRARY)include $(CLEAR_VARS)
LOCAL_MODULE := avfilter
LOCAL_SRC_FILES := include/ffmpeg/libavfilter-5.so
include $(PREBUILT_SHARED_LIBRARY)include $(CLEAR_VARS)
LOCAL_MODULE := avformat
LOCAL_SRC_FILES := include/ffmpeg/libavformat-56.so
include $(PREBUILT_SHARED_LIBRARY)include $(CLEAR_VARS)
LOCAL_MODULE := avutil
LOCAL_SRC_FILES := include/ffmpeg/libavutil-54.so
include $(PREBUILT_SHARED_LIBRARY)include $(CLEAR_VARS)
LOCAL_MODULE := postproc
LOCAL_SRC_FILES := include/ffmpeg/libpostproc-53.so
include $(PREBUILT_SHARED_LIBRARY)include $(CLEAR_VARS)
LOCAL_MODULE := swresample
LOCAL_SRC_FILES := include/ffmpeg/libswresample-1.so
include $(PREBUILT_SHARED_LIBRARY)include $(CLEAR_VARS)
LOCAL_MODULE := swscale
LOCAL_SRC_FILES := include/ffmpeg/libswscale-3.so
include $(PREBUILT_SHARED_LIBRARY)include $(CLEAR_VARS)
LOCAL_MODULE := yuv
LOCAL_SRC_FILES := include/libyuv/libyuv.so
include $(PREBUILT_SHARED_LIBRARY)include $(CLEAR_VARS)
LOCAL_MODULE := ffmpeg_native_player
LOCAL_SRC_FILES := ffmpeg_native_player.c
LOCAL_C_INCLUDES += $(LOCAL_PATH)/include/ffmpeg
LOCAL_C_INCLUDES += $(LOCAL_PATH)/include/libyuv
LOCAL_LDLIBS := -llog -landroid
LOCAL_SHARED_LIBRARIES := avcodec avdevice avfilter avformat avutil postproc swresample swscale yuv
include $(BUILD_SHARED_LIBRARY)

• 修改Application.mk，更改APP_PLATFORM，使其可以使用android/native_window_jni.h和android/native_window.h头文件

APP_ABI := armeabi armeabi-v7a
APP_PLATFORM := android-9

• 实现jni头文件声明的函数

#include <android/log.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <android/native_window.h>
#include <android/native_window_jni.h>#include "com_cj5785_ffmpegnativeplayer_NativePlayer.h"//封装格式
#include "include/ffmpeg/libavformat/avformat.h"
//解码
#include "include/ffmpeg/libavcodec/avcodec.h"
//像素处理
#include "include/ffmpeg/libswscale/swscale.h"
//包含yuvlib头文件
#include "include/libyuv/libyuv.h"#define LOGI(FORMAT,...) __android_log_print(4,"cj5785",FORMAT,##__VA_ARGS__);
#define LOGE(FORMAT,...) __android_log_print(6,"cj5785",FORMAT,##__VA_ARGS__);JNIEXPORT void JNICALL Java_com_cj5785_ffmpegnativeplayer_NativePlayer_render(JNIEnv *env, jobject jobj, jstring jstr_path, jobject obj_surface)
{LOGE("%s", "开始");const char *input_cstr = (*env)->GetStringUTFChars(env, jstr_path, NULL);//1.注册组件av_register_all();AVFormatContext *pFormatCtx = avformat_alloc_context();//2.打开视频文件if(avformat_open_input(&pFormatCtx, input_cstr, NULL, NULL) != 0){LOGE("%s", "打开文件失败!");return;}//3.获取视频相关信息if(avformat_find_stream_info(pFormatCtx, NULL) < 0){LOGE("%s", "获取视频信息失败!");return;}int i = 0;int video_stream_index = -1;for (i = 0; i < pFormatCtx->nb_streams; i++) {if(pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO){video_stream_index = i;break;}}if (video_stream_index == -1){LOGE("%s","找不到视频流\n");return;}//4.获取解码器AVCodecContext *pCodecCtx = pFormatCtx->streams[video_stream_index]->codec;AVCodec *pCodec = avcodec_find_decoder(pCodecCtx->codec_id);if(pCodec == NULL){LOGE("%s", "无法解码!");return;}//5.打开解码器if(avcodec_open2(pCodecCtx, pCodec, NULL) < 0){LOGE("%s", "解码失败!");return;}//6.以帧为单位读取视频文件AVPacket *packet = (AVPacket *)av_malloc(sizeof(AVPacket));AVFrame *pFrame = av_frame_alloc();AVFrame *pRGBFrame = av_frame_alloc();//native绘制//窗体设置ANativeWindow *nativeWindow = ANativeWindow_fromSurface(env, obj_surface);//缓冲区设置ANativeWindow_Buffer outBuffer;int len, got_frame, frame_count = 0;while(av_read_frame(pFormatCtx, packet) >= 0){if(packet->stream_index == video_stream_index){len = avcodec_decode_video2(pCodecCtx, pFrame, &got_frame, packet);if(len < 0){LOGE("%s","解码错误!");return;}if(got_frame){LOGI("解码第%d帧", frame_count++);//a.lock//设置缓冲区属性（宽，高，像素格式）ANativeWindow_setBuffersGeometry(nativeWindow, pCodecCtx->width, pCodecCtx->height, WINDOW_FORMAT_RGBA_8888);ANativeWindow_lock(nativeWindow, &outBuffer, NULL);//b.fix buffer//设置RGB的缓冲区以及属性（像素格式，宽高），RGB缓冲区和outBuffer.bits是同一块内存avpicture_fill((AVPicture *)pRGBFrame, outBuffer.bits, AV_PIX_FMT_RGBA, pCodecCtx->width, pCodecCtx->height);//YUV转化为RGBI420ToARGB(pFrame->data[0], pFrame->linesize[0],pFrame->data[2], pFrame->linesize[2],pFrame->data[1], pFrame->linesize[1],pRGBFrame->data[0], pRGBFrame->linesize[0],pCodecCtx->width, pCodecCtx->height);//c.unlockANativeWindow_unlockAndPost(nativeWindow);usleep(16 * 1000);}}av_free_packet(packet);}ANativeWindow_release(nativeWindow);av_frame_free(&pFrame);av_frame_free(&pRGBFrame);avcodec_close(pCodecCtx);avformat_free_context(pFormatCtx);(*env)->ReleaseStringUTFChars(env, jstr_path, input_cstr);
}

调用native，使其能够播放

package com.cj5785.ffmpegnativeplayer;import java.io.File;import com.cj5785.ffmpegnativeplayer.view.MySurfaceView;import android.app.Activity;
import android.os.Bundle;
import android.os.Environment;
import android.view.Surface;
import android.view.View;public class MainActivity extends Activity {private NativePlayer player;private MySurfaceView mySurfaceView;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);mySurfaceView = (MySurfaceView) findViewById(R.id.surface_view);player = new NativePlayer();}public void mPlay(View view) {String input = Environment.getExternalStorageDirectory().getAbsolutePath() + File.separatorChar + "oneplus.mp4";Surface surface = mySurfaceView.getHolder().getSurface();player.render(input, surface);}
}

至此，已经可以编译生成apk了，在手机上测试也没有问题

更改布局和主活动，使其可以播放多个测试视频

MainActivity.java

package com.cj5785.ffmpegnativeplayer;import java.io.File;import com.cj5785.ffmpegnativeplayer.view.MySurfaceView;import android.app.Activity;
import android.os.Bundle;
import android.os.Environment;
import android.view.Surface;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Spinner;public class MainActivity extends Activity {private NativePlayer player;private MySurfaceView mySurfaceView;private Spinner sp_video;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);mySurfaceView = (MySurfaceView) findViewById(R.id.surface_view);sp_video = (Spinner)findViewById(R.id.sp_video);player = new NativePlayer();//视频列表String[] videoArray = getResources().getStringArray(R.array.video_list);ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, android.R.id.text1,videoArray);sp_video.setAdapter(adapter);}public void mPlay(View view) {String filename = sp_video.getSelectedItem().toString();String input = Environment.getExternalStorageDirectory().getAbsolutePath() + File.separatorChar + filename;Surface surface = mySurfaceView.getHolder().getSurface();player.render(input, surface);}
}

activity_main.xml

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:tools="http://schemas.android.com/tools"android:layout_width="match_parent"android:layout_height="match_parent" ><com.cj5785.ffmpegnativeplayer.view.MySurfaceViewandroid:id="@+id/surface_view"android:layout_width="fill_parent"android:layout_height="fill_parent"/><LinearLayoutandroid:layout_width="wrap_content"android:layout_height="wrap_content"android:orientation="horizontal"><Spinner android:id="@+id/sp_video"android:layout_width="wrap_content"android:layout_height="wrap_content"/><Buttonandroid:layout_width="wrap_content"android:layout_height="wrap_content"android:text="开始"android:onClick="mPlay" /></LinearLayout></FrameLayout>

在string.xml中添加数组值

<string-array name="video_list"><item>naxienian.mp4</item><item>cuc_ieschool.mkv</item><item>sintel.wmv</item><item>Nocturne.m4a</item>
</string-array>

需要注意的问题

在native的实现过程中，I420ToARGB()方法在调用的时候，UV的位置是颠倒的，需要对调UV的位置
在这个示例程序中，旨在说明native是怎么绘制的，其代码存在严重不足，比如在主线程中绘制界面
部分视频会出现花屏现象，这个问题在后面多线程解码的时候会解决