上次说到视频编码和转码，得到了yuv格式的文件，我们平常看到的视频画面实际都是yuv格式，今天来实现在APP中播放视频，代码和上次差不多，只需将转码文件换成输出到屏幕上
1.自定义View继承SurfaceView，把SurfaceView传入native层进行绘制
代码语言：javascript
复制package com.aruba.ffmpegapplication;
import android.content.Context;
import android.graphics.PixelFormat;
import android.util.AttributeSet;
import android.view.Surface;
import android.view.SurfaceView;
import java.lang.ref.WeakReference;
/**
* Created by aruba on 2020/6/30.
*/
public class YuvPlayView extends SurfaceView {
static {
System.loadLibrary("native-lib");
}
private PlayThread playThread;
public YuvPlayView(Context context) {
this(context, null);
}
public YuvPlayView(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public YuvPlayView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
}
private void init() {
setKeepScreenOn(true);
//设置一个像素占4字节
getHolder().setFormat(PixelFormat.RGBA_8888);
playThread = new PlayThread(this);
}
/**
* 开始播放
*/
public void play(String filePath) {
if (isPlaying()) {
playThread.stopPlay();
}
playThread = new PlayThread(this);
playThread.filePath = filePath;
playThread.start();
}
public void stop() {
if (isPlaying()) {
playThread.stopPlay();
}
}
public boolean isPlaying() {
return playThread.isPlaying();
}
@Override
protected void onDetachedFromWindow() {
super.onDetachedFromWindow();
stop();
}
static class PlayThread extends Thread {
public boolean isPlaying;
public String filePath;
private WeakReference<YuvPlayView> playViewWeakReference;
public PlayThread(YuvPlayView yuvPlayView) {
this.playViewWeakReference = new WeakReference<>(yuvPlayView);
}
@Override
public void run() {
isPlaying = true;
//阻塞方法，不断将视频内容绘制到屏幕
if (playViewWeakReference.get() != null) {
int ret = render(filePath, playViewWeakReference.get().getHolder().getSurface());
}
isPlaying = false;
}
public boolean isPlaying() {
return isPlaying;
}
public native int render(String filePath, Surface surface);
public native void stopPlay();
}
}
编写相应的native方法
代码语言：javascript
复制#include <jni.h>
#include <string>
#include <android/log.h>
#include <android/native_window_jni.h>
#include <unistd.h>
extern "C" {
//编码
#include "libavcodec/avcodec.h"
//封装格式处理
#include "libavformat/avformat.h"
//像素处理
#include "libswscale/swscale.h"
}
#define LOG_TAG "aruba"
#define LOGE(...) __android_log_print(ANDROID_LOG_ERROR,LOG_TAG,__VA_ARGS__)
bool is_playing = false;
extern "C"
JNIEXPORT jint JNICALL
Java_com_aruba_ffmpegapplication_YuvPlayView_00024PlayThread_render(JNIEnv *env, jobject instance,
jstring filePath_,
jobject surface) {
const char *filePath = env->GetStringUTFChars(filePath_, 0);
//注册FFmpeg中各大组件
av_register_all();
//打开文件
AVFormatContext *formatContext = avformat_alloc_context();
if (avformat_open_input(&formatContext, filePath, NULL, NULL) != 0) {
LOGE("打开失败");
avformat_free_context(formatContext);
env->ReleaseStringUTFChars(filePath_, filePath);
return 1;
}
//将文件信息填充进AVFormatContext
if (avformat_find_stream_info(formatContext, NULL) < 0) {
LOGE("获取文件信息失败");
avformat_free_context(formatContext);
env->ReleaseStringUTFChars(filePath_, filePath);
return 2;
}
//获取视频流的编解码器上下文
AVCodecContext *codecContext = NULL;
int vidio_stream_idx = -1;
for (int i = 0; i < formatContext->nb_streams; i) {
if (formatContext->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO) {//如果是视频流
codecContext = formatContext->streams[i]->codec;
vidio_stream_idx = i;
break;
}
}
if (codecContext == NULL) {
LOGE("获取编解码器上下文失败");
avformat_free_context(formatContext);
env->ReleaseStringUTFChars(filePath_, filePath);
return 3;
}
//根据编解码器上下文的id获取视频流解码器
AVCodec *codec = avcodec_find_decoder(codecContext->codec_id);
//打开解码器
if (avcodec_open2(codecContext, codec, NULL) < 0) {
LOGE("打开解码失败");
avformat_free_context(formatContext);
env->ReleaseStringUTFChars(filePath_, filePath);
return 4;
}
//开始读每一帧
is_playing = true;
//存放压缩数据
AVPacket *pkt = (AVPacket *) (av_malloc(sizeof(AVPacket)));
av_init_packet(pkt);
//存放解压数据
AVFrame *picture = av_frame_alloc();
//存放转码数据
AVFrame *picture_rgb = av_frame_alloc();
//为转码数据分配内存
uint8_t *data_size = (uint8_t *) (av_malloc(
(size_t) avpicture_get_size(AV_PIX_FMT_RGBA, codecContext->width,
codecContext->height)));
avpicture_fill((AVPicture *) picture_rgb, data_size, AV_PIX_FMT_RGBA, codecContext->width,
codecContext->height);
int picture_ptr = 0;
//获取底层绘制对象
ANativeWindow *aNativeWindow = ANativeWindow_fromSurface(env, surface);
//为Window配置长宽和像素编码
ANativeWindow_setBuffersGeometry(aNativeWindow, codecContext->width, codecContext->height,
AHARDWAREBUFFER_FORMAT_R8G8B8A8_UNORM);
//视频缓存区
ANativeWindow_Buffer out_buff;
//转码组件上下文,前三个参数为原视频的宽高和编码，后三个为转码后的视频宽高和编码，还可以传入过滤器对视频做处理，这边不做处理
SwsContext *swsContext = sws_getContext(codecContext->width, codecContext->height,
codecContext->pix_fmt,
codecContext->width, codecContext->height,
AV_PIX_FMT_RGBA, SWS_BILINEAR, NULL, NULL, NULL
);
while (av_read_frame(formatContext, pkt) == 0 && is_playing) {//读到每一帧的压缩数据存放在AVPacket
if (pkt->stream_index == vidio_stream_idx) {
//解码
avcodec_decode_video2(codecContext, picture, &picture_ptr, pkt);
LOGE("picture_ptr %d", picture_ptr);
if (picture_ptr > 0) {
//转码 data中存放着真实数据，linesize为一行的数据，0为转码起始位置，高度为整个画面高
sws_scale(swsContext, picture->data, picture->linesize, 0, picture->height,
picture_rgb->data, picture_rgb->linesize);
//锁定
ANativeWindow_lock(aNativeWindow, &out_buff, NULL);
//将转码后的frame（picture_rgb）中的数据复制到window的视频缓冲区（out_buff）
//picture_rgb中二维数据的首地址
uint8_t *frame_data_p = picture_rgb->data[0];
//视频缓存区中二维数据的首地址
uint8_t *buff_data_p = (uint8_t *) (out_buff.bits);
//视频缓存区有多少个字节 RGBA8888占4个字节
int destStride = out_buff.stride * 4;
for (int i = 0; i < codecContext->height; i ) {
memcpy(buff_data_p, frame_data_p, picture_rgb->linesize[0]);
buff_data_p = destStride;
frame_data_p = picture_rgb->linesize[0];
}
ANativeWindow_unlockAndPost(aNativeWindow);
//16ms播放一帧
usleep(16 * 1000);
}
}
av_free_packet(pkt);
}
//释放资源
sws_freeContext(swsContext);
ANativeWindow_release(aNativeWindow);
av_frame_free(&picture_rgb);
av_frame_free(&picture);
avcodec_close(codecContext);
avformat_free_context(formatContext);
env->ReleaseStringUTFChars(filePath_, filePath);
return 0;
}
extern "C"
JNIEXPORT void JNICALL
Java_com_aruba_ffmpegapplication_YuvPlayView_00024PlayThread_stopPlay(JNIEnv *env,
jobject instance) {
is_playing = false;
}
通过ANativeWindow进行绘制，要注意的是两个缓冲区数据复制时，指针的位移量，思路是：由于每一帧的数据其实就是一个二维数组，将数据进行逐行复制。最后别忘了在cmake中增加ANativeWindow的支持
代码语言：javascript
复制target_link_libraries(
native-lib
avcodec-56
avdevice-56
avfilter-5
avformat-56
avutil-54
postproc-53
swresample-1
swscale-3
android
${log-lib})
最后效果：
