1- TCP和UDP套接字哪个更适合用于流媒体?为什么?
2- 在直播时,音频和视频是分别从服务器传输的,如何确保我显示的视频和在设备上播放的音频同步?
1- TCP和UDP套接字哪个更适合用于流媒体?为什么?
2- 在直播时,音频和视频是分别从服务器传输的,如何确保我显示的视频和在设备上播放的音频同步?
我会选择使用UDP。但这取决于你的需求。UDP会丢失数据包而不是等待(TCP)。权衡的是,你想要一个稳定的,但有时慢且成本高的方案,还是一个高效的方案,但有时可能无法传递。当涉及到如何实现和使用它时,选择权在你手中。
如今,即使是YouTube也通过HTTP进行流媒体传输...这里有一个Node.js应用程序,可以将文件流式传输到浏览器客户端...可作为实时流式传输视频和音频的良好起点。
// usage
// do following on server side (your laptop running nodejs)
// node this_file.js
//
// then once above is running point your browser at
// http://localhost:8888
//
// of course your browser could be on your mobile or own custom app
var http = require('http'),
fs = require('fs'),
util = require('util');
var path = "/path/to/audio/or/video/file/local/to/server/cool.mp4"; // put any audio or video file here
var port = 8888;
var host = "localhost";
http.createServer(function (req, res) {
var stat = fs.statSync(path);
var total = stat.size;
if (req.headers.range) { // meaning client (browser) has moved the forward/back slider
// which has sent this request back to this server logic ... cool
var range = req.headers.range;
var parts = range.replace(/bytes=/, "").split("-");
var partialstart = parts[0];
var partialend = parts[1];
var start = parseInt(partialstart, 10);
var end = partialend ? parseInt(partialend, 10) : total-1;
var chunksize = (end-start)+1;
console.log('RANGE: ' + start + ' - ' + end + ' = ' + chunksize);
var file = fs.createReadStream(path, {start: start, end: end});
res.writeHead(206, { 'Content-Range': 'bytes ' + start + '-' + end + '/' + total, 'Accept-Ranges': 'bytes', 'Content-Length': chunksize, 'Content-Type': 'video/mp4' });
file.pipe(res);
} else {
console.log('ALL: ' + total);
res.writeHead(200, { 'Content-Length': total, 'Content-Type': 'video/mp4' });
fs.createReadStream(path).pipe(res);
}
}).listen(port, host);
console.log("Server running at http://" + host + ":" + port + "/");