Meteor-Files: Base64 .webm fail after 1sec

I capture a mediaStream with RecordRTC which I upload as a base64. But when I want to play the video, it drops after one second. I can confirm the health of the RecordRTC return, for I view the video before it is uploaded. The stack is: meteor@1.4, react, localhost

//UPLOAD
this.state.videoRecorder.getDataURL((data) => {
      var uploadData = {
        file: data,
        fileName: 'Bewerbung.webm',
        isBase64: true,
        streams: 'dynamic',
        // transport: 'http',
        chunkSize: 'dynamic'
      }
      var uploadInstance = Videos.insert(uploadData, false);
      uploadInstance.on('end', (error, fileObj) => {
          browserHistory.push('/view/'+fileObj._id)
      });
      uploadInstance.start()
    })

And

//DOWNLOAD
const video = Videos.findOne(props.params.id)

---
<video src={this.props.video.link()} autoPlay controls ref='video' />

debug: true returns: (CLIENT)

Stopped recording video stream.
RecordRTC.js:137 video/webm -> 1.09 MB
Record.js:81 Object {blob: Blob, bufferSize: 0, sampleRate: 0, buffer: null, view: null}
ostrio_files.js?hash=88573d1…:2632 [FilesCollection] [insert()]
ostrio_files.js?hash=88573d1…:3104 [FilesCollection] [insert] [Tracker] [continue]
ostrio_files.js?hash=88573d1…:3212 [FilesCollection] [insert] [.continue()]
ostrio_files.js?hash=88573d1…:3135 [FilesCollection] [insert] using WebWorkers
ostrio_files.js?hash=88573d1…:2839 loadFile Bewerbung.webm: 103.563ms
ostrio_files.js?hash=88573d1…:2800 insert Bewerbung.webm: 281.376ms
Record.js:101 Object {name: "Bewerbung.webm", extension: "webm", path: "assets/app/uploads/Videos/4uBxEWvj2GgTQKdBC.webm", meta: Object, type: "video/webm"…}
ostrio_files.js?hash=88573d1…:2542 [FilesCollection] [findOne("4uBxEWvj2GgTQKdBC", undefined)]
ostrio_files.js?hash=88573d1…:2542 [FilesCollection] [findOne("4uBxEWvj2GgTQKdBC", undefined)]
ostrio_files.js?hash=88573d1…:777 [FilesCollection] [FileCursor] [link(undefined)]
ostrio_files.js?hash=88573d1…:3715 [FilesCollection] [link(4uBxEWvj2GgTQKdBC, original)]

and SERVER:

I20160902-03:09:59.607(2)? [FilesCollection] [File Start Method] Bewerbung.webm - 4uBxEWvj2GgTQKdBC
I20160902-03:09:59.609(2)? [FilesCollection] [Upload] [Start Method] Got #-1/4 chunks, dst: Bewerbung.webm
I20160902-03:09:59.767(2)? [FilesCollection] [Upload] [DDP] Got #1/4 chunks, dst: Bewerbung.webm
I20160902-03:09:59.778(2)? [FilesCollection] [Upload] [DDP] Got #2/4 chunks, dst: Bewerbung.webm
I20160902-03:09:59.796(2)? [FilesCollection] [Upload] [DDP] Got #3/4 chunks, dst: Bewerbung.webm
I20160902-03:09:59.805(2)? [FilesCollection] [Upload] [DDP] Got #4/4 chunks, dst: Bewerbung.webm
I20160902-03:09:59.810(2)? [FilesCollection] [Upload] [DDP] Got #-1/4 chunks, dst: Bewerbung.webm
I20160902-03:09:59.811(2)? [FilesCollection] [Upload] [finish(ing)Upload] -> assets/app/uploads/Videos/4uBxEWvj2GgTQKdBC.webm
I20160902-03:09:59.873(2)? [FilesCollection] [Upload] [finish(ed)Upload] -> assets/app/uploads/Videos/4uBxEWvj2GgTQKdBC.webm
I20160902-03:09:59.875(2)? [FilesCollection] [_preCollectionCursor.observeChanges] [removed]: 4uBxEWvj2GgTQKdBC
I20160902-03:09:59.926(2)? [FilesCollection] [download(/cdn/storage/Videos/4uBxEWvj2GgTQKdBC/original/4uBxEWvj2GgTQKdBC.webm, original)]
I20160902-03:09:59.929(2)? [FilesCollection] [serve(assets/app/uploads/Videos/4uBxEWvj2GgTQKdBC.webm, original)] [206]
I20160902-03:09:59.973(2)? [FilesCollection] [download(/cdn/storage/Videos/4uBxEWvj2GgTQKdBC/original/4uBxEWvj2GgTQKdBC.webm, original)]
I20160902-03:09:59.974(2)? [FilesCollection] [serve(assets/app/uploads/Videos/4uBxEWvj2GgTQKdBC.webm, original)] [206]