如何使用node js通过ffmpeg从上传的视频中提取帧？

Question

我已经创建了用户上传视频的应用程序，我想在 nodejs 中使用 ffmpeg 从该视频中提取 50 张图像，但是在将其上传到特定文件夹后我无法获取该文件。我正在通过 multer 上传视频，因为它将视频存储在指定文件夹中，之后我使用读取流读取了该视频，但它没有提供有关该特定视频的正确信息

代码：

var express = require('express');

var app = express();

var bodyParser = require('body-parser');

var path = require('path');

var multer = require('multer');

var cfenv = require('cfenv');

var watson = require('watson-developer-cloud');

var ffmpeg = require('ffmpeg');

app.use(bodyParser.json());

app.use(bodyParser.urlencoded({"extended": false}));

app.use(express.static(__dirname + '/public'));

var storage = multer.diskStorage({
    destination: function(req, file, callback){
        callback(null, './public/class'); // set the destination
    },
    filename: function(req, file, callback){
        callback(null, 199212+ '.avi'); // set the file name and extension
    }
});

var upload = multer({storage: storage});
 
 app.upload = upload;
 
 // get the app environment from Cloud Foundry
 var appEnv = cfenv.getAppEnv();

var VisualRecognitionV3 = require('watson-developer-cloud/visual-recognition/v3');

var fs = require('fs');


var visualRecognition = new VisualRecognitionV3({
  version: '2018-03-19',
  iam_apikey: 'aaIFu-fHWBXgj09eVarEQUFlIaTeH9bpgvRqHIJxu_8N'
});


app.post('/imgtable',app.upload.single('video-upl'),function(req,res){
                
    var video_file = fs.createReadStream(req.file.path);
                                    
 try {
    var process = new ffmpeg('./public/class/199212.avi');
    process.then(function (video) {
        // Video metadata
        console.log('******************************');
        console.log(video);
        // FFmpeg configuration
        console.log('*********************************');
        console.log(video.info_configuration);
    }, function (err) {
        console.log('Error: ' + err);
    });
} catch (e) {
    console.log(e.code);
    console.log(e.msg);
}

    
})

app.listen(3000);`

Answer 1

如果您使用的是 ffmpeg npm package，您只需稍作调整即可使用 fnExtractFrameToJPG 函数：

try {
        var process = new ffmpeg(file);
        process.then(function (video) {
            video.fnExtractFrameToJPG("this/is/a/directory", {
                every_n_frames : 1
            }, myCallbackFunction())
        }, function (err) {
            console.log('Error: ' + err);
        });
    } catch (e) {
        console.log(e.code);
        console.log(e.msg);
    }

every_n_frames 参数可让您选择要提取帧的帧间隔。文档中提供了一些其他参数。

Answer 2

这是一个代码 sn-p，它可以让我在 1 分 30 秒的视频中提取单个帧。希望对你有帮助:)

var ffmpeg = require('ffmpeg');

try {
  var process = new ffmpeg('./video.mp4');
  process.then(function (video) {
    video.addCommand('-ss', '00:01:30')
    video.addCommand('-vframes', '1')
    video.save('./test.jpg', function (error, file) {
        if (!error)
          console.log('Video file: ' + file);
      });
  }, function (err) {
    console.log('Error: ' + err);
  });
} catch (e) {
  console.log(e.code);
  console.log(e.msg);
}

Answer 3

愚蠢的错误是';'，我忘了保留它，所以它会无限循环

var express = require('express');

var app = express();

var bodyParser = require('body-parser');

var path = require('path');

var multer = require('multer');

var cfenv = require('cfenv');

var watson = require('watson-developer-cloud');

var ffmpeg = require('ffmpeg');

var stat = require('fs').statSync;

var zipFolder = require('zip-folder');


app.use(bodyParser.json());

app.use(bodyParser.urlencoded({"extended": false}));

app.use(express.static(__dirname + '/public'));

var storage = multer.diskStorage({
    destination: function(req, file, callback){
        callback(null, './public/class/'); // set the destination
    },
    filename: function(req, file, callback){
        callback(null,'NotUseful.mp4'); // set the file name and extension
    }
});

var upload = multer({storage: storage});
 
 app.upload = upload;
 
 // get the app environment from Cloud Foundry
 var appEnv = cfenv.getAppEnv();

var VisualRecognitionV3 = require('watson-developer-cloud/visual-recognition/v3');

var fs = require('fs');


var visualRecognition = new VisualRecognitionV3({
  version: '2018-03-19',
  iam_apikey: 'aaIFu-fHWBXgj09eVarEQUFlIaTeH9bpgvRqHIJxu_8N'
});

function tosplit(request)
{
    var value = request;
    valueArray = value.split("\\");
    return valueArray;
}

function extsplit(request)
{
    var value = request;
    nameArray = value.split('.');
    return nameArray;
}

function makeZip(pathname,zipname){
        
        zipFolder(pathname,zipname, function(err) {
            
    if(err) {
        console.log('oh no!', err);
        
    } else {
        
        console.log('Zip Created...');
    }
  });
}

app.post('/upload',app.upload.single('video-upl'),function(req,res){
                
    var video_file = fs.createReadStream(req.file.path); // Storing File path
    var video_String = JSON.stringify(video_file); // Converting Json into String of req.file.path
    var video_res = JSON.parse(video_String); // Parsing req.file.path  
    
    var valueArray = tosplit(video_res.path);  //Splitting Path in values
    
    var filenme = req.file.originalname; // Requesting Original File name
    var filnameStringify = JSON.stringify(filenme); //Stringify file original name
    var filnameParse = JSON.parse(filnameStringify); //Parsing file Original name
    
    var filename = extsplit(filnameParse);  // Spliting File name from path
    
    var finalpath = './public/class/'+valueArray[2]; // Path to Video for Extracting Images
    
    var destpath = './public/class/'+filename[0]+'/'; //Destinaton Path to Store Images
    
    var zipdest = './public/class/'+filename[0]; //Destination of File to be Zip
    
    var articleid = extsplit(valueArray[2]);  //For ArticleId through Video Name
        
    try {
    var process = new ffmpeg(finalpath);
    process.then(function (video) {
        // Callback mode
        video.fnExtractFrameToJPG(destpath, {
            frame_rate: 1,
            number: 50,
            keep_pixel_aspect_ratio : true,
            keep_aspect_ratio: true,
            file_name : filename[0]+'_%s'
        }, function (error,files){
                
            if(!error)
                {   
                    var fileJsonStr = JSON.stringify(files);
                    
                    makeZip(zipdest,'./public/class/'+filename[0]+'.zip');
                    
                    console.log(res);
                    
                    res.send(fileJsonStr).responseJSON;
                }
        });
    }, function (err) {
         console.log('Error: ' + err);
    });
  }
    
    catch (e) {
    console.log(e.code);
    console.log(e.msg);
}
});
app.listen(3000);