Video Skips First Few Seconds When Using DASH Streaming

[Ulsah]

#3335 ### Environment

• The MPD passes the DASH-IF Conformance Tool on https://conformance.dashif.org/
• [] The stream has correct Access-Control-Allow-Origin headers (CORS)
• There are no network errors such as 404s in the browser console when trying to play the stream
• The issue observed is not mentioned on https://github.com/Dash-Industry-Forum/dash.js/wiki/FAQ
• [] The issue occurs in the latest reference client on http://reference.dashif.org/dash.js/ and not just on my page

• Link to playable MPD file:
• Dash.js version: 3.1.1
• Browser name/version: Mozilla Firefox/68.8.0esr
• OS name/version: Debian 10

Description

I'm developing a e learning platform that needs video streaming. I user vuejs and laravel for backend. I use DASH streaming to play videos. I use video js with dash.js a videojs-contrib-dash packages. When I try to stream the player skips first few seconds of the video and plays flawlessly. I tested the same source .mpd file in VLC media player and it played with no issues. Can someone please point me in the right direction?

Steps to reproduce

1. Use ffmpeg to segment videos into 480p and 720p chunks and generate the .mpd file
2. Pass the .mpd file as source to video.js src attribute and type as application/dash+xml
3. Try playing the video

Observed behaviour

Video plays after buffering for few seconds from the passed time location

Additional Information

Here's the code I use in vue js:

// Video Options
videoOptions: {
autoplay: false,
controls: true,
preload: true,
sources: []
}
//Pushing source to videoOptions:
// Sets video URL
var source = video.link.replace('/public/', '/storage/');
var url = 'http://localhost:8000'+source+'video.mpd';
// The src and type attributes is added into videoOptions to be played
var object = {
src: url,
type: 'application/dash+xml'
}
this.videoOptions.sources.push(object);
this.videoKey += 1;

[dsilhavy]

Can you please host your content so we can check? Moreover, please test in plain dash.js:
http://reference.dashif.org/dash.js/nightly/samples/dash-if-reference-player/index.html

[Ulsah]

We hosted a sample .mpd file on our cloud storage for you to test. Here is the link:

https://storage.cloud.google.com/know-it-282016.appspot.com//storage/testchunks/Intro%20to%20CPU.mpd

I tested it in the link given above, but it was failing because CORS requests were getting blocked. Please check the link and see what's the issue.

Thank you.

[dsilhavy]

@Ulsah I need a playable sample in order to help you, just looking at the manifest won't help. Please host the content and the media segments on a server with CORS enabled.

[Ulsah]

The content and media segments are hosted and CORS is enabled in our cloud storage. The link I provided is the is URL to the manifest file which can be used to play the content. Its the link we used to test the playing on our live server and that's where I found out the issue.

[dsilhavy]

@Ulsah I still see the CORS issues:
Access to XMLHttpRequest at 'https://storage.cloud.google.com/know-it-282016.appspot.com//storage/testchunks/Intro%20to%20CPU.mpd' from origin 'http://reference.dashif.org' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.
XHRLoader.js:79 GET https://storage.cloud.google.com/know-it-282016.appspot.com//storage/testchunks/Intro%20to%20CPU.mpd net::ERR_FAILED

[Ulsah]

I apologize. We're currently performing some maintenance on our server and storage. I will post a new link here once its finished. I will get back asap. Thank you.

[Ulsah]

Here is a working link https://storage.googleapis.com/know-it-282016.appspot.com//storage/public/CPU/video/1/9/streamHWvkse.mpd. I tested it in the site you've mentioned. And as I said I have to either wait or skip the first few seconds for the video to play correctly.

[the-provost]

Still persists

[dsilhavy]

@Ulsah I checked in the ref client with Firefox 79 on MacOS: http://reference.dashif.org/dash.js/nightly/samples/dash-if-reference-player/index.html

Video starts fine for me, please check if the problem occurs for you in the ref demo page as well. I do not have a Debian system with a Firefox 68 so I will not be able to test your environment

[Ulsah]

The video playback is fine now in the reference player. It wasn't earlier. Did you make any changes or perhaps is there a workaround for this issue?

There is also a discussion happening in the video.js repo. Here is the link: videojs/video.js#6757

[dsilhavy]

The seek logic at startup was changed in 3.1.2, maybe that fixed your issue. If it is not working with video.js it might be related to an older version of dash.js or a different initialization of dash.js.

[Ulsah]

I've worked around the issue for now using an older version of video.js and video-http-streaming. If there's an update I'll post it here

[dsilhavy]

Ok I will close this for now as this is not an issue in the current version of dash.js