前端获取视频编码

https://github.com/gpac/mp4box.js

var MP4Box = require('mp4box'); // Or whatever import method you prefer.
var mp4boxfile = MP4Box.createFile();
mp4boxfile.onError = function(e) {};
mp4boxfile.onReady = function(info) {
// info -> codec
{
  "duration":360002,
  "timescale":600,
  "isFragmented":false,
  "isProgressive":true,
  "hasIOD":true,
  "brands":["isom"],
  "created":"2014-04-15T18:24:40.000Z",
  "modified":"2014-04-15T18:24:40.000Z",
  "tracks":[
    {
	  "id":2,
	  "created":"2012-02-13T23:07:31.000Z",
	  "modified":"2014-04-16T12:22:56.000Z",
	  "movie_duration":360000,
	  "layer":0,
	  "alternate_group":0,
	  "volume":0,
	  "track_width":320,
	  "track_height":180,
	  "timescale":25000,
	  "duration":15000000,
	  "bitrate":120000,
	  "codec":"avc1.42c00d",
	  "video":{
	    "width":320,"height":180
	  },
	  "language":"und",
	  "nb_samples":15000
	},
	{
	  "id":3,
	  "created":"2012-09-12T11:14:57.000Z",
	  "modified":"2014-04-16T12:22:56.000Z",
	  "movie_duration":360002,
	  "layer":0,
	  "alternate_group":0,
	  "volume":1,
	  "track_width":0,
	  "track_height":0,
	  "timescale":44100,
	  "duration":26460160,
	  "bitrate":60000,
	  "codec":"mp4a.40.2",
	  "audio":{
	    "sample_rate":44100,
		"channel_count":1,
		"sample_size":16
	  },
	  "language":"und",
	  "nb_samples":25840
	}
  ]
}
};