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SceneCity - privacy-focussed live streaming and chat for the demoscene

category: general [glöplog]
The biggest codec challenge so far have been the shader showdown stuff. And yeah, the HEVC transcoder did shine there.

Also, it has been proven that with certain demoscene codec killer content you can actually crash the Intel Quicksync hardware encoder. But I am not going to debug drivers during the party, but have to be on alert for that...
added on the 2024-03-31 18:00:36 by scamp scamp
Maybe a good moment to mention that from now on, SceneCity is offering a full plug&play kit to demoparty organizers so they can do those HEVC streams themselves. We are shipping a box with all needed hardware to any location in the EU + UK. Just contact us on SceneCity.
added on the 2024-03-31 18:07:41 by scamp scamp
VOD services to replace the need for YouTube, and get high quality captures archived long-term in proper quality

thanks for taking care about this, this is important
added on the 2024-03-31 22:01:01 by wullon wullon
SceneCity.tv has just completely gone down.
added on the 2024-03-31 23:25:25 by Foebane72 Foebane72
And it came back up in time for me to enjoy the Revision 2024 Amiga Demo compo, so that's great!
added on the 2024-04-01 00:47:27 by Foebane72 Foebane72
I really, *really* wanted to watch the stream in HEVC which for this content is far superior when against x264.

Unfortunately I had to switch elsewhere. In the compos earlier I was able to overlook the ~1min lag that the HEVC had against the others and the occational disconnects. But it made chatting about the entries a bit difficult. And then it died completely at the beginning of the demo compo.

Dont get me wrong, I respect the work scenecity is doing. And I hope they will take this prototyping as a learning lesson. These things are extremely difficult to do, and I am not here to bash anyone.

Keep up the good work! You are nearly there! And I hope with all my heart you get there :)
added on the 2024-04-01 01:35:49 by T-101 T-101
Also: when the HEVC stream works, the bitrate and image fidelity is *chefskiss*

This is the way.
added on the 2024-04-01 01:57:31 by T-101 T-101
No worries, not offended. Constructive feedback is always fine.

WIth all the open source and self-build software involved, getting rid of all bugs will be next to impossible. So stuff needs to be monitored. Sadly from the current SceneCity team, I was the only one present at Revision, and I got... distracted... at times.

I had written watchdogs for all parts of the system that had been crashing in the past years, and those worked. But what still crashes is OBS at the source, and it's irritating on how many crash bugs OBS has, including the inability to cleanly auto-recover.

But most importantly it turns out that certain demo content can actually crash the Intel Quicksync hardware transcoders in a way that you can not recover from under Linux. I'll have to find a way to handle that watchdog-wise. That will be hard, as it did not happen with any demos that we had tested due to those being pre-compressed already. I'll have to see if reloading/resetting the Intel GPU drivers works on Linux without rebooting. If not, I would need an automatic fail-over there, too.

One thing that most likely is on your end: The end-to-end latency of the system is 4 seconds. It's never has been 1 minute. However, due to the option to seek back one hour, you might not have noticed that you can also seek the stream "into the future". If you seek all to the right, you are at 4 seconds end-to-end-latency, but then your internet connection must be stable.

When it comes to picture quality: Yeah, that was totally worth the effort. A lot of demos yesterday looked like shit after h264 encoding (both on the CCC stream and on our h264 fallback), but actually looked nice on h265 HEVC. I find that fascinating, as I can't understand how any algorithm would be able to predict movement of things in those demos.

Anyway: SceneCity streaming will be used at lots of parties this year again. Hopefully we will be able to catch a few more bugs, but the real challenge to the system sadly won't happen again prior to Revision 2025.

For Revision 2025, SceneCity will simply need a full stream team on-site and/or integrate with the existing one. Me handling all "shifts" is not realistic.
added on the 2024-04-01 11:34:54 by scamp scamp
Ah, another explanation for a 1 min lag would be a client not supporting LLHLS (low latency HLS). If you don't have that you will fall back to classic HLS, and in this case far more segments are buffered prior to playing.

But I don't know any current browser that can not yet do LLHLS, and current VLC and MPC also can do it.
added on the 2024-04-01 11:37:09 by scamp scamp
But most importantly: We need more staff. It's just 5 people handling all the servers, developing the apps, and run stuff live.

So - we are looking for:

- People providing us HQ demo captures for our upcoming VOD service
- People experienced in Linux server administration /devops
- Coders experienced or interested in GoLang, Pascal and/or C
- People willing to run the stuff at demopartys

For the last one: Once more, we are sending out free kits containing everything to run your own HEVC stream from your own party. We'll send the kit free to any party in the EU+UK.
added on the 2024-04-01 11:58:22 by scamp scamp
Cool initiative. But it seems H.265/HEVX is only supported by Safari. Why not AV1?
added on the 2024-04-01 18:01:10 by Photon Photon
h.265 works with Chrome, Android, IOS, VLC and MPC, and some others. Firefox sadly doesn't.

The reason for "why not AV1" - for this to be affordable as a hobbiest projects, I need access to a affordable transcoders. Intel Quicksync provides that. Our current HW array however can not yet do AV1. The next one should. Also, you need support for it in all of the tool chain unless you want to end up double-encoding again - and it's a long long long chain all the way from the compo PC output to your screen, with most standard tools in between today not being able to do VP9 nor AV1.

Once we are able to migrate away from h265, we will.

But to be honest: I'll first prioritize on Intel Quicksync GPU stuff not randomly locking up completely on demo content some times before I think about moving the goal post AGAIN.

Stability is now highest priority for the next few months.
added on the 2024-04-01 19:37:32 by scamp scamp
much <3 for the awesome scenecity team!
the hiccups were solved within seconds.
agree, that OBS + encoder pipeline must be more stable in the future.

feature ideas:
- being able to go back to the beginning of the part (longer VOD), similar to re-live from CCC
- chapter markers (for VOD) to find the compo block (or each prod) more easily (if the above is implemented)
- low-bitrate stream (for people with bad internet or on trains)
- bitrate shaping/lowering (for non-demo compos or pause screens)
- (a bit far fetched xD): multi-angle stream during concerts / shader showdowns

Is the software stack public (if yes please link the repo)? thanks!
added on the 2024-04-03 16:39:19 by krl krl


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