在前面的文章中我们用ffmpeg在windows上实现了多种功能，下面系列的文章我们将移植到Android系统上实现。
我们将使用最新版：
最新版ffmpeg ffmpeg3.3
新版Android studio Android studio2.3
新版JNI编译方式 CMake
对于Android开发者或许对C/C++/JNI知识不够了解。
可以先看这里：
C语言小结 ：http://blog.csdn.net/king1425/article/details/70256764
C++小结（一） ： http://blog.csdn.net/king1425/article/details/70260091
JNI高阶知识总结 ： http://blog.csdn.net/king1425/article/details/71405131
下面我们开始实现今天的功能：
1.编译Android版ffmpeg并移植到Android studio中
看这里：
windows下编译最新版ffmpeg3.3-android，并通过CMake方式移植到Android studio2.3中
http://blog.csdn.net/king1425/article/details/70338674
2.复制一份第一步移植成功的的代码命名为：ffmpegandroiddecoder
3.删减部分代码验证无误，然后编写布局代码逻辑代码
点击codec按钮出现如上图列表界面则无误
下面是相关代码：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_main"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<Button
android:id="@+id/btn_codec"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="2dp"
android:text="Codec"
android:textAllCaps="false" />
</LinearLayout>
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="12dp"
android:text="ws2.mp4"
android:id="@+id/editText1" />
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="12dp"
android:text="ws2.yuv"
android:id="@+id/editText2" />
<Button
android:text="开始解码为YUV"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/button" />
<ScrollView
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView
android:id="@+id/tv_info"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Hello World!" />
</ScrollView>
</LinearLayout>
package com.ws.ffmpegandroiddecoder;
import android.os.Bundle;
import android.os.Environment;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
// Used to load the 'native-lib' library on application startup.
static {
System.loadLibrary("native-lib");
}
private Button codec;
private TextView tv_info;
private EditText editText1,editText2;
private Button btnDecoder;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
init();
}
private void init() {
codec = (Button) findViewById(R.id.btn_codec);
tv_info= (TextView) findViewById(R.id.tv_info);
editText1 = (EditText) findViewById(R.id.editText1);
editText2 = (EditText) findViewById(R.id.editText2);
btnDecoder= (Button) findViewById(R.id.button);
codec.setOnClickListener(this);
btnDecoder.setOnClickListener(this);
}
@Override
public void onClick(View view) {
switch (view.getId()) {
case R.id.btn_codec:
tv_info.setText(avcodecinfo());
break;
case R.id.button:
startDecode();
break;
default:
break;
}
}
private void startDecode() {
String folderurl= Environment.getExternalStorageDirectory().getPath();
String inputurl=folderurl+"/"+editText1.getText().toString();
String outputurl=folderurl+"/"+editText2.getText().toString();
Log.e("ws-----------inputurl",inputurl);
Log.e("ws------------outputurl",outputurl);
decode(inputurl,outputurl);
}
public native String decode(String inputurl, String outputurl);
public native String avcodecinfo();
}
4.实现native方法 decode(String inputurl, String outputurl)
#include <jni.h>
#include <string>
extern "C"
{
#include <libavutil/log.h>
#include <libavcodec/avcodec.h>
#include <libavformat/avformat.h>
#include <libswscale/swscale.h>
#include <libavutil/imgutils.h>
#include <android/log.h>
#define LOGE(format, ...) __android_log_print(ANDROID_LOG_ERROR, "(>_<)", format, ##__VA_ARGS__)
#define LOGI(format, ...) __android_log_print(ANDROID_LOG_INFO, "(^_^)", format, ##__VA_ARGS__)
//Output FFmpeg's av_log()
void custom_log(void *ptr, int level, const char* fmt, va_list vl){
FILE *fp=fopen("/storage/emulated/0/av_log.txt","a+");
if(fp){
vfprintf(fp,fmt,vl);
fflush(fp);
fclose(fp);
}
}
JNIEXPORT jint JNICALL
Java_com_ws_ffmpegandroiddecoder_MainActivity_decode(
JNIEnv *env,
jobject , jstring input_jstr, jstring output_jstr) {
AVFormatContext *pFormatCtx;
int i, videoindex;
AVCodecContext *pCodecCtx;
AVCodec *pCodec;
AVFrame *pFrame,*pFrameYUV;
uint8_t *out_buffer;
AVPacket *packet;
int y_size;
int ret, got_picture;
struct SwsContext *img_convert_ctx;
FILE *fp_yuv;
int frame_cnt;
clock_t time_start, time_finish;
double time_duration = 0.0;
char input_str[500]={0};
char output_str[500]={0};
char info[1000]={0};
sprintf(input_str,"%s",env->GetStringUTFChars(input_jstr, NULL));
sprintf(output_str,"%s",env->GetStringUTFChars(output_jstr, NULL));
//FFmpeg av_log() callback
av_log_set_callback(custom_log);
av_register_all();
avformat_network_init();
pFormatCtx = avformat_alloc_context();
if(avformat_open_input(&pFormatCtx,input_str,NULL,NULL)!=0){
LOGE("Couldn't open input stream.\n");
return -1;
}
if(avformat_find_stream_info(pFormatCtx,NULL)<0){
LOGE("Couldn't find stream information.\n");
return -1;
}
videoindex=-1;
for(i=0; i<pFormatCtx->nb_streams; i++)
if(pFormatCtx->streams[i]->codec->codec_type==AVMEDIA_TYPE_VIDEO){
videoindex=i;
break;
}
if(videoindex==-1){
LOGE("Couldn't find a video stream.\n");
return -1;
}
pCodecCtx=pFormatCtx->streams[videoindex]->codec;
pCodec=avcodec_find_decoder(pCodecCtx->codec_id);
if(pCodec==NULL){
LOGE("Couldn't find Codec.\n");
return -1;
}
if(avcodec_open2(pCodecCtx, pCodec,NULL)<0){
LOGE("Couldn't open codec.\n");
return -1;
}
pFrame=av_frame_alloc();
pFrameYUV=av_frame_alloc();
out_buffer=(unsigned char *)av_malloc(av_image_get_buffer_size(AV_PIX_FMT_YUV420P, pCodecCtx->width, pCodecCtx->height,1));
av_image_fill_arrays(pFrameYUV->data, pFrameYUV->linesize,out_buffer,
AV_PIX_FMT_YUV420P,pCodecCtx->width, pCodecCtx->height,1);
packet=(AVPacket *)av_malloc(sizeof(AVPacket));
img_convert_ctx = sws_getContext(pCodecCtx->width, pCodecCtx->height, pCodecCtx->pix_fmt,
pCodecCtx->width, pCodecCtx->height, AV_PIX_FMT_YUV420P, SWS_BICUBIC, NULL, NULL, NULL);
sprintf(info, "[Input ]%s\n", input_str);
sprintf(info, "%s[Output ]%s\n",info,output_str);
sprintf(info, "%s[Format ]%s\n",info, pFormatCtx->iformat->name);
sprintf(info, "%s[Codec ]%s\n",info, pCodecCtx->codec->name);
sprintf(info, "%s[Resolution]%dx%d\n",info, pCodecCtx->width,pCodecCtx->height);
fp_yuv=fopen(output_str,"wb+");
if(fp_yuv==NULL){
printf("Cannot open output file.\n");
return -1;
}
frame_cnt=0;
time_start = clock();
while(av_read_frame(pFormatCtx, packet)>=0){
if(packet->stream_index==videoindex){
ret = avcodec_decode_video2(pCodecCtx, pFrame, &got_picture, packet);
if(ret < 0){
LOGE("Decode Error.\n");
return -1;
}
if(got_picture){
sws_scale(img_convert_ctx, (const uint8_t* const*)pFrame->data, pFrame->linesize, 0, pCodecCtx->height,
pFrameYUV->data, pFrameYUV->linesize);
y_size=pCodecCtx->width*pCodecCtx->height;
fwrite(pFrameYUV->data[0],1,y_size,fp_yuv); //Y
fwrite(pFrameYUV->data[1],1,y_size/4,fp_yuv); //U
fwrite(pFrameYUV->data[2],1,y_size/4,fp_yuv); //V
//Output info
char pictype_str[10]={0};
switch(pFrame->pict_type){
case AV_PICTURE_TYPE_I:sprintf(pictype_str,"I");break;
case AV_PICTURE_TYPE_P:sprintf(pictype_str,"P");break;
case AV_PICTURE_TYPE_B:sprintf(pictype_str,"B");break;
default:sprintf(pictype_str,"Other");break;
}
LOGI("Frame Index: %5d. Type:%s",frame_cnt,pictype_str);
frame_cnt++;
}
}
av_free_packet(packet);
}
//flush decoder
//FIX: Flush Frames remained in Codec
while (1) {
ret = avcodec_decode_video2(pCodecCtx, pFrame, &got_picture, packet);
if (ret < 0)
break;
if (!got_picture)
break;
sws_scale(img_convert_ctx, (const uint8_t* const*)pFrame->data, pFrame->linesize, 0, pCodecCtx->height,
pFrameYUV->data, pFrameYUV->linesize);
int y_size=pCodecCtx->width*pCodecCtx->height;
fwrite(pFrameYUV->data[0],1,y_size,fp_yuv); //Y
fwrite(pFrameYUV->data[1],1,y_size/4,fp_yuv); //U
fwrite(pFrameYUV->data[2],1,y_size/4,fp_yuv); //V
//Output info
char pictype_str[10]={0};
switch(pFrame->pict_type){
case AV_PICTURE_TYPE_I:sprintf(pictype_str,"I");break;
case AV_PICTURE_TYPE_P:sprintf(pictype_str,"P");break;
case AV_PICTURE_TYPE_B:sprintf(pictype_str,"B");break;
default:sprintf(pictype_str,"Other");break;
}
LOGI("Frame Index: %5d. Type:%s",frame_cnt,pictype_str);
frame_cnt++;
}
time_finish = clock();
time_duration=(double)(time_finish - time_start);
sprintf(info, "%s[Time ]%fms\n",info,time_duration);
sprintf(info, "%s[Count ]%d\n",info,frame_cnt);
sws_freeContext(img_convert_ctx);
fclose(fp_yuv);
av_frame_free(&pFrameYUV);
av_frame_free(&pFrame);
avcodec_close(pCodecCtx);
avformat_close_input(&pFormatCtx);
return 0;
}
jstring
Java_com_ws_ffmpegandroiddecoder_MainActivity_avcodecinfo(
JNIEnv *env, jobject) {
char info[40000] = {0};
av_register_all();
AVCodec *c_temp = av_codec_next(NULL);
while (c_temp != NULL) {
if (c_temp->decode != NULL) {
sprintf(info, "%sdecode:", info);
} else {
sprintf(info, "%sencode:", info);
}
switch (c_temp->type) {
case AVMEDIA_TYPE_VIDEO:
sprintf(info, "%s(video):", info);
break;
case AVMEDIA_TYPE_AUDIO:
sprintf(info, "%s(audio):", info);
break;
default:
sprintf(info, "%s(other):", info);
break;
}
sprintf(info, "%s[%10s]\n", info, c_temp->name);
c_temp = c_temp->next;
}
return env->NewStringUTF(info);
}
}
5.拷贝ws.mp4到ＳＤ卡根目录，编译运行
GG编译报错(⊙o⊙)，不慌不慌，链接库报错，应该是CMakeLists.txt配置问题。
在之前一章配置的target_link_libraries基础上，更改如下即可
target_link_libraries( native-lib avutil-55 swresample-2 avcodec-57 avfilter-6 swscale-4 avdevice-57 avformat-57
${log-lib} )6.点击开始解码按钮，然后看SD卡跟目录是否多了一个ws.yuv文件
OK~success
源码：https://github.com/WangShuo1143368701/FFmpegAndroid/tree/master/ffmpegandroiddecoder
作者：King1425 发表于2017/5/9 11:55:49 原文链接
阅读：23 评论：0 查看评论