diff --git a/lib/file_uploader.js b/lib/file_uploader.js
index ffaf1b94..8faab551 100644
--- a/lib/file_uploader.js
+++ b/lib/file_uploader.js
@@ -5,6 +5,9 @@ var util = require('util');
 
 var MAX_FILE_SIZE_BYTES = 15 * 1024 * 1024;
 var MAX_FILE_CHUNK_BYTES = 5 * 1024 * 1024;
+var MAX_VIDEO_SIZE_BYTES = 512 * 1024 * 1024;
+var MAX_VIDEO_CHUNK_BYTES =
+  parseInt(process.env.MAX_VIDEO_CHUNK_BYTES) || 15 * 1024 * 1024;
 
 /**
  * FileUploader class used to upload a file to twitter via the /media/upload (chunked) API.
@@ -42,9 +45,10 @@ FileUploader.prototype.upload = function (cb) {
       cb(err);
       return;
     } else {
+      var MAX_CHUNK_BYTES = bodyObj.MAX_CHUNK_BYTES || MAX_FILE_CHUNK_BYTES;
       var mediaTmpId = bodyObj.media_id_string;
       var chunkNumber = 0;
-      var mediaFile = fs.createReadStream(self._file_path, { highWatermark: MAX_FILE_CHUNK_BYTES });
+      var mediaFile = fs.createReadStream(self._file_path, { highWaterMark: MAX_CHUNK_BYTES });
 
       mediaFile.on('data', function (chunk) {
         // Pause our file stream from emitting `data` events until the upload of this chunk completes.
@@ -128,25 +132,35 @@ FileUploader.prototype._initMedia = function (cb) {
   var mediaFileSizeBytes = fs.statSync(self._file_path).size;
   var shared = self._isSharedMedia;
   var media_category = 'tweet_image';
+  var MAX_FILE_BYTES = MAX_FILE_SIZE_BYTES;
+  var MAX_CHUNK_BYTES = MAX_FILE_CHUNK_BYTES;
+  if(mediaType.toLowerCase().indexOf('octet-stream') > -1) {
+    mediaType = 'video/mp4';
+  }
 
   if (mediaType.toLowerCase().indexOf('gif') > -1) {
     media_category = 'tweet_gif';
   } else if (mediaType.toLowerCase().indexOf('video') > -1) {
+    MAX_FILE_BYTES = MAX_VIDEO_SIZE_BYTES;
+    MAX_CHUNK_BYTES = MAX_VIDEO_CHUNK_BYTES;
     media_category = 'tweet_video';
   }
 
   // Check the file size - it should not go over 15MB for video.
   // See https://dev.twitter.com/rest/reference/post/media/upload-chunked
-  if (mediaFileSizeBytes < MAX_FILE_SIZE_BYTES) {
+  if (mediaFileSizeBytes < MAX_FILE_BYTES) {
     self._twit.post('media/upload', {
       'command': 'INIT',
       'media_type': mediaType,
       'total_bytes': mediaFileSizeBytes,
       'shared': shared,
       'media_category': media_category
-    }, cb);
+    }, function(err, bodyObj, resp) {
+      bodyObj.MAX_CHUNK_BYTES = MAX_CHUNK_BYTES;
+      cb(err, bodyObj, resp);
+    });
   } else {
-    var errMsg = util.format('This file is too large. Max size is %dB. Got: %dB.', MAX_FILE_SIZE_BYTES, mediaFileSizeBytes);
+    var errMsg = util.format('This file is too large. Max size is %dB. Got: %dB.', MAX_FILE_BYTES, mediaFileSizeBytes);
     cb(new Error(errMsg));
   }
 }