android 使用ffmpeg音视频播放（一）

从这篇开始进入深水期，编译C/C++库，配NDK，编写native，编译APP，真累，全是坑。这篇的主要内容是讲ffmpeg解码视频文件并在android上显示播放。

编译ffmpeg

参照FFmpeg的Android平台移植—编译篇，编译需要注意的地方是版本、脚本的编写、对库的裁剪。

编写Android代码

使用surfaceview播放本地视频，调用代码mplay()，在子线程播放。

player = new YoungPlayer(); public void mPlay(View btn){ String video = sp_video.getSelectedItem().toString(); final String input = new File(Environment.getExternalStorageDirectory(),video).getAbsolutePath(); //Surface传入到Native函数中，用于绘制 final Surface surface = videoView.getHolder().getSurface(); new Thread(new Runnable() { public void run() { player.render(input,surface); } }).start(); }

需要传入的videoview自定义如下：

public class VideoView extends SurfaceView { public VideoView(Context context) { super(context); init(); } public VideoView(Context context, AttributeSet attrs) { super(context, attrs); init(); } public VideoView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); init(); } private void init(){ //初始化，SufaceView绘制的像素格式 SurfaceHolder holder = getHolder(); holder.setFormat(PixelFormat.RGBA_8888); } }

过一个代理类来执行相关的操作：

public class YoungPlayer { public native void render(String input,Surface surface); public native void sound(String input,String output); public native void play(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("yuv"); System.loadLibrary("myffmpeg"); } }

所以，只需要编写代理类YoungPlayer里面的native方法，通过javah命令生成头文件，不同JDK版本，javah命令格式不一样，也可以按jni语法直接手写头文件com_yang_ffmpegDemo_YoungPlayer.h。

编写C/C++实现文件解码播放

编写yang_video_player.c，按步骤解码视频文件（请忽略LOG >_<），解码遵循的步骤一般如下图：

#include "com_yang_ffmpegDemo_YoungPlayer.h" #include <stdlib.h> #include <stdio.h> #include <unistd.h> #include <android/log.h> #include <android/native_window_jni.h> #include <android/native_window.h> #define LOGI(FORMAT,...) __android_log_print(ANDROID_LOG_INFO,"yang",FORMAT,##__VA_ARGS__); #define LOGE(FORMAT,...) __android_log_print(ANDROID_LOG_ERROR,"yang",FORMAT,##__VA_ARGS__); #include "libyuv.h" //封装格式 #include "libavformat/avformat.h" //解码 #include "libavcodec/avcodec.h" //缩放 #include "libswscale/swscale.h" JNIEXPORT void JNICALL Java_com_td_youngplayer_YoungPlayer_render (JNIEnv *env, jobject jobj, jstring input_jstr, jobject surface){ const char* input_cstr = (*env)->GetStringUTFChars(env,input_jstr,NULL); //1.注册组件 av_register_all(); //封装格式上下文 AVFormatContext *pFormatCtx = avformat_alloc_context(); //2.打开输入视频文件 if(avformat_open_input(&pFormatCtx,input_cstr,NULL,NULL) != 0){ LOGE("%s","打开输入视频文件失败"); return; } //3.获取视频信息 if(avformat_find_stream_info(pFormatCtx,NULL) < 0){ LOGE("%s","获取视频信息失败"); return; } int64_t duration = pFormatCtx->duration; int bit_rate = pFormatCtx->bit_rate; LOGI("视频时长%llu:%llu",duration/1000000/60,duration/1000000%60); LOGI("比特率%dkps",bit_rate/1000); //视频解码，需要找到视频对应的AVStream所在pFormatCtx->streams的索引位置 int video_stream_idx = -1; int i = 0; for(; i < pFormatCtx->nb_streams;i++){ //根据类型判断，是否是视频流 if(pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO){ video_stream_idx = i; break; } } //4.获取视频解码器 AVCodecContext *pCodeCtx = pFormatCtx->streams[video_stream_idx]->codec; AVStream *avstream =pFormatCtx->streams[video_stream_idx]; AVCodec *pCodec = avcodec_find_decoder(pCodeCtx->codec_id); if(pCodec == NULL){ LOGE("%s","无法解码"); return; } //5.打开解码器 if(avcodec_open2(pCodeCtx,pCodec,NULL) < 0){ LOGE("%s","解码器无法打开"); return; } //编码数据 AVPacket *packet = (AVPacket *)av_malloc(sizeof(AVPacket)); //像素数据（解码数据） AVFrame *yuv_frame = av_frame_alloc(); AVFrame *rgb_frame = av_frame_alloc(); //native绘制 //窗体 ANativeWindow* nativeWindow = ANativeWindow_fromSurface(env,surface); //绘制时的缓冲区 ANativeWindow_Buffer outBuffer; AVRational framerate = pCodeCtx->framerate; AVRational time_base = pCodeCtx->time_base; //宽高比 AVRational sample_aspect_ratio = pCodeCtx->sample_aspect_ratio; //播放器宽高 int32_t width = ANativeWindow_getWidth(nativeWindow); int32_t height = ANativeWindow_getHeight(nativeWindow); int showWidth = pCodeCtx->width; int showHeight = pCodeCtx->height; int a = sample_aspect_ratio.num; int b = sample_aspect_ratio.den; // if(width<height*showWidth/showHeight){ // showHeight=width*showHeight/showWidth; // }else{ // showHeight = height; // } // showHeight = 300; // showWidth = width; // showWidth = 640; // showHeight = 360; LOGI("showWidth%d",showWidth); LOGI("showHeight%d",showHeight); int len ,got_frame, framecount = 0; //6.一阵一阵读取压缩的视频数据AVPacket while(av_read_frame(pFormatCtx,packet) >= 0){ if(packet->stream_index == video_stream_idx){ //解码AVPacket->AVFrame len = avcodec_decode_video2(pCodeCtx, yuv_frame, &got_frame, packet); //Zero if no frame could be decompressed //非零，正在解码 if(got_frame){ LOGI("packet大小%hhu",packet->data); LOGI("packet显示时间戳%llu",packet->pts); LOGI("width%d",yuv_frame->width); LOGI("height%d",yuv_frame->height); LOGI("控件width%d",width); LOGI("控件height%d",height); LOGI("packet显示时间%llu",packet->pts*1000*(avstream->time_base.num)/(avstream->time_base.den)); LOGI("avstream->time_base.den%d",avstream->time_base.den); LOGI("avstream->time_base.num%d",avstream->time_base.num); LOGI("解码后原始数据类型%d",yuv_frame->format); LOGI("是否是关键帧%d",yuv_frame->key_frame); LOGI("宽高比%d",yuv_frame->sample_aspect_ratio.den); LOGI("编码帧序号%d",yuv_frame->coded_picture_number); LOGI("显示帧序号%d",yuv_frame->display_picture_number); LOGI("packet解码时间戳%llu",packet->dts/1000); LOGI("解码%d帧 开始",framecount); LOGI("帧数%d",framerate.num); LOGI("时间num%d",time_base.num); LOGI("时间den%d",time_base.den); //lock //设置缓冲区的属性（宽、高、像素格式） ANativeWindow_setBuffersGeometry(nativeWindow, showWidth, showHeight,WINDOW_FORMAT_RGBA_8888); ANativeWindow_lock(nativeWindow,&outBuffer,NULL); //设置rgb_frame的属性（像素格式、宽高）和缓冲区 //rgb_frame缓冲区与outBuffer.bits是同一块内存 avpicture_fill((AVPicture *)rgb_frame, outBuffer.bits, AV_PIX_FMT_RGBA, showWidth, showHeight); //YUV->RGBA_8888 I420ToARGB(yuv_frame->data[0],yuv_frame->linesize[0], yuv_frame->data[2],yuv_frame->linesize[2], yuv_frame->data[1],yuv_frame->linesize[1], rgb_frame->data[0], rgb_frame->linesize[0], showWidth,showHeight); //unlock ANativeWindow_unlockAndPost(nativeWindow); LOGI("解码%d帧 结束",framecount++); // usleep(1000 * 10); } } av_free_packet(packet); } ANativeWindow_release(nativeWindow); av_frame_free(&yuv_frame); avcodec_close(pCodeCtx); avformat_free_context(pFormatCtx); (*env)->ReleaseStringUTFChars(env,input_jstr,input_cstr); }

解码出 yuv_frame 在 nativewindow 播放需要转码成 rgb_frame，转码原来用的是yuvlib的I420ToARGB方法，此方法效率较如下方法慢，可改为：

sws_scale(sws_ctx, (uint8_t const * const *) pFrame->data, pFrame->linesize, 0, pCodecCtx->height, pFrameRGBA->data, pFrameRGBA->linesize);

下面方法省去从rgb_frame内存逐行memcpy到outBuffer的步骤，使用同一块内存空间。

avpicture_fill((AVPicture *)rgb_frame, outBuffer.bits, AV_PIX_FMT_RGBA, showWidth, showHeight);

再完善mk文件即可，编译发布。

demo下载