如何在nodejs中获取视频的快照？
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How do I get a snapshot still of a video in nodejs?
提问by MYR
I am trying to write a nodejs server that will take a time input (possibly part of url path) and then provide a still of the video frame at that time index as a jpeg picture.
我正在尝试编写一个 nodejs 服务器，它将需要一个时间输入（可能是 url 路径的一部分），然后提供当时视频帧的静止索引作为 jpeg 图片。
I can do this easily in plain Javascript, but I cant see a way to do this in nodejs. I know I will probably need to use a canvas plugin like node-canvas to do the snapshot.
我可以用普通的 Javascript 轻松地做到这一点，但我看不到在 nodejs 中做到这一点的方法。我知道我可能需要使用像 node-canvas 这样的画布插件来做快照。
Any ideas welcome.
欢迎任何想法。
The following is how I do it in Javascript at the moment:
以下是我目前在 Javascript 中的做法：
myjavascript.js
我的javascript.js
function capture(video, scaleFactor) {
if(scaleFactor == null){
scaleFactor = 1;
}
var w = video.videoWidth * scaleFactor;
var h = video.videoHeight * scaleFactor;
stdout("<br/> w: "+ w+ "<br/> h: "+ h);
var canvas = document.createElement('canvas');
canvas.width = w;
canvas.height = h;
var ctx = canvas.getContext('2d');
ctx.drawImage(video, 0, 0, w, h);
return canvas;
}
function shoot(){
var video = document.getElementById("videoTag");
var output = document.getElementById("output");
var canvas = capture(video, 1);
output.innerHTML = '';
output.appendChild(canvas);
}
index.html
索引.html
<html>
<head>
<title>video snap</title>
<script type="text/javascript" src="myjavascript.js"></script>
</head>
<body>
<div id="video_container" >
<video id="videoTag" width="640" height="360" autobuffer="" controls="true">
<source src="frozenplanet.mp4" type="video/mp4">
<source src="frozenplanet.ogv" type="video/ogg">
</video>
</div>
<div id="output"></div>
</body>
</html>
回答by fent
node-fluent-ffmpeghas a nice takeScreenshotsfunction.
node-fluent-ffmpeg有一个很好的takeScreenshots功能。
var proc = new ffmpeg('/path/to/your_movie.avi')
.takeScreenshots({
count: 1,
timemarks: [ '600' ] // number of seconds
}, '/path/to/thumbnail/folder', function(err) {
console.log('screenshots were saved')
});
回答by Steven Oosterbeek
As 'node-fluent-ffmpeg' wasn't not working for me for some reason, I figured this out myself - based on the code of video-thumb(which also wasn't working for me). You do need to install FFMPEG before you can use this code, hereis tutorial on how to do so for Mac.
由于 'node-fluent-ffmpeg' 出于某种原因对我不起作用，我自己想出了这个 - 基于video-thumb的代码（这对我也不起作用）。在使用此代码之前，您确实需要安装 FFMPEG，这里是有关如何在 Mac 上安装的教程。
var path = require('path'), // Default node module
pathToFile = path.join(__dirname, 'folder', 'file.mov'),
pathToSnapshot = path.join(__dirname, 'folder', 'file-snapshot.jpg');
// Also a default node module
require('child_process').exec(('ffmpeg -ss 00:00:25 -i ' + pathToFile + ' -vframes 1 -q:v 2 ' + pathToSnapshot), function () {
console.log('Saved the thumb to:', pathToSnapshot);
});
回答by Steven Westmoreland
You can use the node-fluent-ffmpegmodule for this. You'll need to install ffmpeg; on MacOS, install Homebrewthen use the brew install ffmpegcommand.
您可以为此使用node-fluent-ffmpeg模块。你需要安装 ffmpeg；在 MacOS 上，安装Homebrew然后使用brew install ffmpeg命令。
var ffmpeg = require('fluent-ffmpeg');
ffmpeg('/path/to/video.mp4')
.on('end', function() {
console.log('Screenshots taken');
})
.on('error', function(err) {
console.error(err);
})
.screenshots({
// Will take screenshots at 20%, 40%, 60% and 80% of the video
count: 4,
folder: '/path/to/output'
});
