arraybuffer

How to concat chunks of incoming binary into video (webm) file node js?

由 ▼魔方 西西 提交于 2019-12-24 17:54:53
问题 I am trying to upload chunks of base64 to node js server and save those chunks into one file let chunks = []; app.post('/api', (req, res) => { let {blob} = req.body; //converting chunks of base64 to buffer chunks.push(Buffer.from(blob, 'base64')); res.json({gotit:true}) }); app.post('/finish', (req, res) => { let buf = Buffer.concat(chunks); fs.writeFile('finalvideo.webm', buf, (err) => { console.log('Ahh....', err) }); console.log('SAVED') res.json({save:true}) }); Problem with the above

Appending property to ArrayBuffer sent over DataChannel

由 与世无争的帅哥 提交于 2019-12-24 07:12:46
问题 I am currently receiving chunks from a stream of a video that I send over the DataChannel to a peer who will then reconstruct the video on the other end. I have this part working just fine but I would like to add which chunk # it was that was received so that it doesn't matter if they happen to arrive in a different order than intended. Initially I thought that adding a parameter chunkId would work but when I do .data.chunkId on the receiver side, it is undefined. Then I tried to stringify

How to check the existence of a value in an ArrayBuffer?

由 谁说我不能喝 提交于 2019-12-24 02:25:56
问题 I am new in Scala and I am writing a program in which I have an ArrayBuffer of points of a binary image and I want to check in a loop if a specific point is existing in that ArrayBuffer do not add. This is the part of code I am working on : var vectVisitedPoint= new scala.collection.mutable.ArrayBuffer[Point]() var pTemp=new Point (0,0) var res = new Array[Byte](1) img.get(pTemp.x.toInt,pTemp.y.toInt,res) //img is a binary image var value1: Int=0 var value2: Int=0 scala.util.control.Breaks

How to test for equality in ArrayBuffer, DataView, and TypedArray

由 守給你的承諾、 提交于 2019-12-23 07:32:53
问题 Is there a way how to test if two JavaScript ArrayBuffers are equal? I would like to write test for message composing method. The only way I found is to convert the ArrayBuffer to string and then compare. Did I miss something? Following code is giving false, even if I think that it should be true: (function() { 'use strict'; /* Fill buffer with data of Verse header and user_auth * command */ var buf_pos = 0; var name_len = 6 var message_len = 4 + 1 + 1 + 1 + name_len + 1; var buf = new

How to test for equality in ArrayBuffer, DataView, and TypedArray

由 被刻印的时光 ゝ 提交于 2019-12-23 07:32:04
问题 Is there a way how to test if two JavaScript ArrayBuffers are equal? I would like to write test for message composing method. The only way I found is to convert the ArrayBuffer to string and then compare. Did I miss something? Following code is giving false, even if I think that it should be true: (function() { 'use strict'; /* Fill buffer with data of Verse header and user_auth * command */ var buf_pos = 0; var name_len = 6 var message_len = 4 + 1 + 1 + 1 + name_len + 1; var buf = new

Uint16Array to Uint8Array

由 隐身守侯 提交于 2019-12-22 10:35:14
问题 I have a basic question. Say I have a Uint16Array and I have number 4 in it. data_16=new Uint16Array([4]); Now I have a length 1 and byteLength 2; how do i convert this to Uint8Array. I do not want to create a new view. data_8 = new Uint8Array(data_16) If I do this I get array length 1 and byteLength 1. This is not what I want. I need to stretch that 16 bit value in 16array into 8 bit values so that 8bit array so it would end up with 2 values int 8 bit array. I can just create a funtion which

聊聊JS的二进制家族：Blob、ArrayBuffer和Buffer

由 夙愿已清 提交于 2019-12-21 08:37:37
事实上，前端很少涉及对二进制数据的处理，但即便如此，我们偶尔总能在角落里看见它们的身影。 今天我们就来聊一聊前端的二进制家族：Blob、ArrayBuffer和Buffer 概述 Blob: 前端的一个专门用于支持文件操作的二进制对象 ArrayBuffer：前端的一个通用的二进制缓冲区，类似数组，但在API和特性上却有诸多不同 Buffer：Node.js提供的一个二进制缓冲区，常用来处理I/O操作 Blob 我们首先来介绍Blob，Blob是用来支持文件操作的。简单的说：在JS中，有两个构造函数 File 和 Blob, 而File继承了所有Blob的属性。 所以在我们看来，File对象可以看作一种特殊的Blob对象。 在前端工程中，我们在哪些操作中可以获得File对象呢？ 请看： （备注：目前 File API规范的状态为Working Draft） 我们上面说了，File对象是一种特殊的Blob对象，那么它自然就可以直接调用Blob对象的方法。让我们看一看Blob具体有哪些方法，以及能够用它们实现哪些功能 Blob实战 通过window.URL.createObjectURL方法可以把一个blob转化为一个Blob URL，并且用做文件下载或者图片显示的链接。 Blob URL所实现的下载或者显示等功能，仅仅可以在单个浏览器内部进行。而不能在服务器上进行存储

Scala学习(三)----数组相关操作

由 让人想犯罪 __ 提交于 2019-12-21 05:47:02
数组相关操作 摘要: 本篇主要学习如何在Scala中操作数组。 Java 和 C++程序员 通常会选用 数组 或 近似的结构 （比如 数组列表 或 向量 ）来收集一组元素。在Scala中，我们的选择更多，不过现在我们先假定不关心其他选择，而只是想马上开始用数组。本篇的要点包括： 1. 若长度固定则使用Array，若长度可能有变化则使用ArrayBuffer 2. 提供初始值时不要使用new 3. 用()来访问元素 4. 用for (elem<-arr)来遍历元素 5. 用for (elem<-arr if…)…yield…来将原数组转型为新数组 6. Scala数组和java数组可以互操作；用AnayBuffer，使用scalacollection.JavaConversions中的转换函数 定长数组 如果你需要一个 长度不变的数组 ，可以用Scala中的 Array 。例如： val nums= new Array [Int] (10) //长度为10的整数数组，所有元素初始化为0 val a= new Array [String] (10) //长度为10的字符串数组，所有元素初始化为null val s= Array("Hello", "World") //长度为2的Array[String]类型是推断出来的， 已提供初始值 就不需要 new S (0) ="Goodbye"

Why I got `Not allowed to load local resource` error on chrome when I use blob to load resource from ArrayBuffer?

由 不羁的心 提交于 2019-12-20 07:09:15
问题 I need to load an image from ArrayBuffer. I saw some articles says using Blob is the most efficient way to make it. This is the code I wrote to convert arraybuffer to blob url. const blob = new Blob([new Uint8Array(arrayBuffer, offset,length)], { type: mimeType }); url = window.URL.createObjectURL(blob); The array buffer is instance of array buffer that is created by slicing another array buffer fetched by XMLHttpRequest. And then, I tried to fetch the image from generated object URL like

Three.js: How to create new 'morphing' geometry if I have all necessary buffers?

由 天涯浪子 提交于 2019-12-19 09:48:16
问题 I'm using a web-worker to load a .json file of an animated 3D model. For each of the big arrays (vertices, normals, etc.), I'm transferring an Float32Array buffer back to the UI thread. Since such buffers are transferable objects, this will take (almost) zero time . Now, it turns out that WebGL (and therefore, Three.js) use Float32Array buffers internally, too. This means I could probably load this 3D animation without copying anything, spending almost zero time in the main thread. Isn't that
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