Okay, after a couple hours of testing and pm messages, I think the problem comes down to the spoiler tag. I'll color label each example code for more clearer reading.
If this code below is used:
Playlist with added width/height, controls, showinfo, autoplay, loop, and start/end options. Placed inside a spoiler tag.
<div class="spoiler" title="Autoplay testing">
<iframe width="560" height="315" src="https://www.youtube.com/embed/videoseries?list=PLLeyPMXAKUnx2czK62Kxu0EC9mPl_RSiU&rel=1&&controls=1&&showinfo=1&autoplay=1&loop=1&start=0" frameborder="0" allowfullscreen></iframe></div>
The video will not autoplay and begin to perpetually buffer. That is, unless the spoiler button is clicked before the video autoplays.
Now, if the spoiler tags are removed like so:
Playlist with added width/height, controls, showinfo, autoplay, loop, and start/end options. No spoiler tag.
<iframe width="560" height="315" src="https://www.youtube.com/embed/videoseries?list=PLLeyPMXAKUnx2czK62Kxu0EC9mPl_RSiU&rel=1&&controls=1&&showinfo=1&autoplay=1&loop=1" frameborder="0" allowfullscreen></iframe>
Then the video will autoplay without any problem. Please note, the controls and showinfo, those do not affect autoplay. The problem is almost certainly the spoiler button.
Now I assumed this should be the case for all autoplaying videos in a spoiler tag, but if I place my own video (not playlist) into a spoiler tag like so:
Video with added width/height, controls, showinfo, autoplay, and start/end options. Placed inside a spoiler tag. No loop either.
<div class="spoiler" title="Autoplay testing">
<iframe width="12" height="12" src="https://www.youtube.com/embed/2ILJYTcqaPg?rel=0&controls=0&showinfo=0;autoplay=1;start=0&end=438
" frameborder="0" allowfullscreen></iframe><center></div>
Then the video will always autoplay, and not encounter the buffering. Again, the frame width, controls, showinfo, start/end, those things should not affect performance.
I found this odd, as I assumed the videos wouldn't be able to load due to the spoiler tag. So I tested another random video, adjusting the code as shown below:
Video with only autoplay and height/width option. Placed inside a spoiler tag.
<div class="spoiler" title="Autoplay testing">
<iframe width="560" height="315" src="https://www.youtube.com/embed/Q00cOxUD_pU?autoplay=1;" frameborder="0" allowfullscreen></iframe></div>
The buffer issue is present again. Removing the spoiler allows it to function. If I adjust the code to replicate the working autoplay video in the spoiler (the third code I provided), like this:
Video with added width/height, controls, showinfo, autoplay, and start/end options. Placed inside a spoiler tag. No loop.
<div class="spoiler" title="Autoplay testing">
<iframe width="560" height="315" src="https://www.youtube.com/embed/Q00cOxUD_pU?rel=0&controls=0&showinfo=0;autoplay=1;start=0&end=1015
" frameborder="0" allowfullscreen></iframe><center></div>
Then the video will autoplay. Interesting, sometimes the video will stutter then resume to produce clear audio, sometimes it will never stutter. But point is with the added controls, showinfo, start/end, whichever it is, it turns out it does effect the autoplaying.
So, I am going to restate what I have found through these last hours.
- Using the embed code that YouTube provides, while also using the autoplay=1 at the end of the url will autoplay.
- Using the embed code, the autoplay=1, and nesting it inside a spoiler block will cause an error from buffering.
- If the embed code is placed inside a spoiler, but before the page fully loads and the user clicks on the spoiler block, the video will play without buffering.
- Adjusting YouTube's default code with controls, showinfo, start/end, seems to have some sort of effect that causes the video to not buffer.
- However, adjusting YouTube's default code for PLAYLISTS with options such as controls or showinfo will produce the buffering again. The only thing I can assume is causing a problem is the start/end. But due to the nature of a playlist, a start/end button would mean that every video will start and end to the set time, right? Or it will cause some other sort of error.
Note, I can not guarantee that whoever is reading this will have the same results as me. I encourage testing this yourself and seeing if the results are the same. However, I am almost certain that because of the spoiler tag, videos and playlists will have some effect and buffer.
Now, here is what OP would like to have on their wall, an autoplaying playlist of videos that is placed inside a spoiler block. This as OP has found will cause buffering.
Sorry Polendina, I don't know what to say. If we could get some input from a mod or maybe James, then they perhaps then we'll have a proper explanation.
I guess if you are okay with only a single video inside a spoiler block, then leave it as is, as that should work without buffering. But if you really want a playlist, then you'll have to stick to leaving the spoiler out. If you think that takes too much space on your wall, don't forget you can change the aspect ratio with the height and width options I provided.
I only do light html, BBcode, and other sorts of scriptwriting as a hobby. While I understand the basic "language" and nature of these things, I can't offer a full explanation to why things work and function the way they do. I've only recently begun to fully practice things like javascript and java, so my coding and writing is far from what many others have.