why do some YouTube videos on lemmy have a thumbnail, while some don't?
from Cris_Color@lemmy.world to fediverse@lemmy.world on 19 Dec 05:45
https://lemmy.world/post/23301380

If you go to !videos@lemmy.world and scroll you’ll see some of the posts have a youtube thumbnail image, but not all.

I wanna post YouTube videos, but no one seems to engage much without a thumbnail, which makes sense, but I’m not sure what would result in the post actually having a thumbnail

If anyone has advice or guidance I’d appreciate it :) Thanks!

EDIT: so far it seems like it’s potentially a combination of what version of lemmy the posters account is running, and how that instance is configured…

#fediverse

threaded - newest

andrew_s@piefed.social on 19 Dec 06:07 next collapse

It depends on what youtube is willing to provide. It seems more likely to provide a thumbnail if you use a youtu.be link than a youtube.com link.

Instances running Lemmy from 0.19.4 onwards (I think) provide the option of providing a separate thumbnail manually, which is useful, but your instance is on 0.19.3.

Cris_Color@lemmy.world on 19 Dec 06:46 next collapse

I tried again with a youtu.be link and unfortunately no dice, so it seems it might be an instance issue, I’m gonna go take a look at the videos comm and see if there’s anyone on .world who posted and got a thumbnail. I might also try again from my .ee account

Cris_Color@lemmy.world on 19 Dec 06:58 collapse

Okay so it seems like the only people getting thumbnails on !videos@lemmy.world are from shitjustworks.

No dice on using my .ee account though, that didn’t seem to result in a thumbnail either. But in the app I’m using, when on my .ee account there’s a field to put in a thumbnail URL which is interesting

hono4kami@slrpnk.net on 19 Dec 06:13 next collapse

It’s because Lemmy can’t fetch YouTube thumbnails. I swear it used to fetch thumbnail and title automatically before, hmm

TehBamski@lemmy.world on 19 Dec 06:26 next collapse

I can testify to this. I was there. I was there when Lemmy so valiantly fetched ye old YouTube thumbnails.

limer@lemmy.dbzer0.com on 19 Dec 06:28 collapse

Uphill, in the snow, both ways

TehBamski@lemmy.world on 19 Dec 06:40 collapse

Into the depths of Moria and through Lothlórien forest.

[deleted] on 19 Dec 06:38 next collapse

.

flamingos@feddit.uk on 19 Dec 06:59 collapse

It’s because YouTube puts a bunch of JavaScript at the start of the file (1MiB) before the opengraph tags and Lemmy only fetches the first 512 KiB (a fix was merged a couple days ago).

hono4kami@slrpnk.net on 19 Dec 07:05 collapse

If you don’t put a whopping 1MB of JavaScript in your website, you’re doing web development wrong.

/s

Enoril@jlai.lu on 19 Dec 10:42 collapse

Don’t forget to add also the 2856 partners intrusive code lines and cookies to have a “better experience”

CaptDust@sh.itjust.works on 19 Dec 06:26 next collapse

I have no clue what’s different, but viewing the community using my instance shows thumbnails for nearly everything.

sh.itjust.works/c/videos@lemmy.world

Cris_Color@lemmy.world on 19 Dec 06:37 collapse

Most of them have it for me, but I just posted a video to the Souls-like comm and it doesn’t have one, which is really what I’m trying to fix :/

sundrei@lemmy.sdf.org on 19 Dec 06:48 next collapse

I dunno, but it depends on the instance. Here’s a screenshot from lemmus.org:

<img alt="" src="https://lemmy.sdf.org/pictrs/image/aec27554-c04f-47cf-b9e2-417b8838fd4b.png">

And here’s the same community seen from lemmy.sdf.org:

<img alt="" src="https://lemmy.sdf.org/pictrs/image/d619f2b4-28cf-4be4-8fed-c8459a08d030.png">

MelonYellow@lemmy.ca on 19 Dec 06:51 next collapse

Here it is from lemmy.ca (sorted by new):

<img alt="" src="https://lemmy.ca/pictrs/image/c43b5a01-6960-4daa-9c57-ecb03f82127f.png">

Cris_Color@lemmy.world on 19 Dec 07:03 collapse

Interesting, so I guess maybe the reason shitjustsworks users posting on !videos@lemmy.world are showing up as thumbnails for me is because their instance is getting the thumbnail and that’s federating to me on .world

hono4kami@slrpnk.net on 19 Dec 06:50 next collapse

So I take a peek at the Lemmy’s source code.

When you see a thumbnail and title of a URL (including YouTube video links) on Lemmy, what happens is that Lemmy server fetched the website HTML file and get the og:title and og:image (this convention is called OpenGraph protocol ^1) located inside <head> HTML tag.

For example, for this video www.youtube.com/watch?v=MbYuEEU5e50, the OpenGraph metadata inside the HTML looks like this:

<meta property="og:title" content="Flume - Lose It feat. Vic Mensa">
<meta property="og:image" content="https://i.ytimg.com/vi/MbYuEEU5e50/maxresdefault.jpg">

Try opening the “Create Post” page, then enter URL of a YouTube video. You might notice that a loading spinner will appear. During this, the frontend of Lemmy is actually creating a request to /api/v3/post/site_metadata?url=[insert your URL]. When the backend side of Lemmy receives the request from front end, it will run this code ^2 to fetch the HTML and parse it to find the OpenGraph metadata. If the metadata is found, the backend will return it to front end, and you willl see recommended title and the “Thumbnail URL” field should be filled.

In theory, this should work fine, regardless of any website. I personally tried to view the HTML code of a YouTube video and the HTML file indeed contains OpenGraph metadata.

But it doesn’t for YouTube videos in Lemmy somehow. And I’m not sure.

I’m suspecting YouTube thought that Lemmy servers are bots and because of that instead of receiving the HTML file of a YouTube video, instead it received a HTML file of a captcha page. I think I’m gonna try contacting admins of my instance to see whether YouTube URL works or not.

Cris_Color@lemmy.world on 19 Dec 06:57 next collapse

Thats a very helpful response, thank you!

It seems like the only people getting thumbnails on !videos@lemmy.world are from shitjustworks (how fitting lol)

hono4kami@slrpnk.net on 19 Dec 07:04 collapse

See the other reply: seems that it was caused by Lemmy backend only fetches the first 512kb of the HTML, meanwhile YouTube puts bunch of JavaScript in the beginning of the HTML

Here’s the fix that was only merged couple days ago apparently, github.com/LemmyNet/lemmy/pull/5266

Crazy, right

Cris_Color@lemmy.world on 19 Dec 07:06 collapse

Interesting…

hono4kami@slrpnk.net on 19 Dec 06:59 collapse

Also, this is a good tip in general:

You can’t fetch title and thumbnail for YouTube links that starts with youtu.be. This applies not only in Lemmy, but other websites too, for example Twitter (even before Elon’s era).

This is, IMO due to the link doesn’t really contain HTML and OpenGraph metadata. It only redirects you. If you try cURL-ing the youtu.be link, you will see that it doesn’t have a response body, only some header including Location header that will tell you where to redirect. The response code itself is 301.

Cris_Color@lemmy.world on 19 Dec 07:05 collapse

There are people on shitjustworks posting youtu.be links on !videos@lemmy.world that do have thumbnails, so whatever they’re doing doesn’t seem to have that problem

My .ee account has a field to put in a thumbnail URL, so other comments in this thread are kinda leading me to believe it may be a combination of instance version, and how the instance is configured

hono4kami@slrpnk.net on 19 Dec 07:07 collapse

My Lemmy instance actually can’t fetch YouTube thumbnail, so I actually have to put it manually lol.

See www.get-youtube-thumbnail.com

Cris_Color@lemmy.world on 19 Dec 07:09 collapse

Thats a super helpful site, thank you! If nothing else now I can remake my post from my .ee account and add the thumbnail manually

hanrahan@slrpnk.net on 19 Dec 07:19 next collapse

From here on skrpnk.net using Boost, scolling down they all seem to have thumbnails?

<img alt="" src="https://slrpnk.net/pictrs/image/0a7d82d2-fd86-4007-be2b-2da5766fe3a8.png">

Cris_Color@lemmy.world on 19 Dec 07:22 collapse

Interesting, I guess maybe boost separately fetches thumbnails for link posts that are missing them…

Skiluros@sh.itjust.works on 19 Dec 08:11 next collapse

Instances running 0.19.5 (I think) allow manually adding a thumbnail.

I extract them from youtube-thumbnail-grabber.com and manually add them in.

Really annoying.

treadful@lemmy.zip on 19 Dec 10:51 collapse

Or shift+right click on the unplayed video and copy image link to get the thumbnail.

I’ve been doing it manually because otherwise nobody watches it.

Skiluros@sh.itjust.works on 19 Dec 11:01 collapse

Will need to try this. Grabbing the thumbnail via an external site is annoying.

muntedcrocodile@lemm.ee on 19 Dec 10:54 collapse

U can configure ur instance to proxy thumbnails so u cant just scoop up ips from users directly. Youtube imposes strict rate limmits on ips hence if some wont load. I assume idk for certain tho.