Introducing PrismCast: Browser-based Live TV Capture for Channels DVR and Plex

Playground Hacks
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#717

Have any docker users figured out how to enable graphics acceleration in Chrome? After some reading, it sounds to me like Prismcast looks good when hosted on a Mac because there Chrome uses graphics hardware, but in the docker, it does not - is this right?

I added this to the Portainer Stack (Unraid):
devices:
- "/dev/dri:/dev/dri"

and I have the Intel GPU TOP plugin, but don't see any difference - any thoughts on how to do this and whether or not it would improve picture quality?

(For reference, I am running Unraid on an Intel 12700K with a 4K HDMI dongle plugged in and Prismcast capturing at 1080p/high)

#718

It's not possible due to limitations in the Chrome implementation on Linux. Many fine minds have attacked this issue, dating back to the early days of cc4c, with no joy. Unless something changes in Linux Chrome (which is always possible), there's no magic to find here.

1 Like
#719

It's not possible due to limitations in the Chrome implementation on Linux. Many fine minds have attacked this issue, dating back to the early days of cc4c, with no joy. Unless something changes in Linux Chrome (which is always possible), there's no magic to find here.

As @bnhf said, @JT-DFW - these are not the droids you're looking for.

2 Likes
#720

I was just thinking that the GL.iNet Comet (GL-RM1) might be a pretty good solution to this issue; that ticks a bunch of boxes.

It has support for 2K and 4K resolutions (which would allow it to take the place of an HDMI dongle), provides remote KVM support (which seems very good at dealing with any issue that might come-up keeping one from accessing their Mac-Mini from afar), and has Tailscale built-in.

I'm using this one right now, many thousands of miles removed, and it's a sweet bit of kit:

screenshot-glkvm-2026_02_22-16_49_25
screenshot-glkvm-2026_02_22-16_49_251920×1010 76.6 KB

It's not dirt cheap, but the price is reasonable for what you get.

2 Likes
#721

How is your performance overall without the graphics acceleration?

#722

So interesting... I was on 1.3 and I guess my espn login stopped working. I did login, didn't work, decided to restart, and then didn't work, did upgrade via brew to 1.42 and still doesn't work, shows service is not running. Any ideas?

#723

Ran across that earlier where service shows as not running.
I now use sudo on all the commands (install/update/service ...) and it's been working fine.

#724

@tgenius I have done the 1.4.1 and 1.4.2 upgrades with brew on mac mini and both times the service does not restart. I tried "prismcast service restart" but no luck getting the service to run. I found that if I uninstall and then install the service it works after that. I used "prismcast service uninstall" and then "prismcast service install". After that everything was fine again. This does not uninstall prismcast just the service that controls starting and stopping prismcast.

I was going to report this to @hjd. This is a fantastic piece of software but I really do not have much time right now to test it out a lot.

#725

thank you! I had to remove and reinstalland it seems to be working again.. :slight_smile:

#726

Had a weird thing with the NBC gold medal game today, the tab got restarted but it didn't go fullscreen, was letterboxed with black borders all around. Later the tab got restarted again and it went fullscreen after that. Have also seen a few Olympic events where the timestamps get messed up, they show as 10-15 hour long shows. Have had to run fix timestamps on those.

2026/02/22 08:10:06.788] [nbc-yyt7ac] Streaming NBC (keyboardDynamic, FFmpeg). Tuned in 6.8s (direct).
[2026/02/22 08:55:49.636] [usa-llqj3q] Video element exists but not ready (count=1, maxReadyState=2). Treating as buffering.
[2026/02/22 08:57:25.327] [WARN] [nbc-yyt7ac] Detected 10 consecutive tiny segments (489941 bytes). Capture pipeline appears dead.
[2026/02/22 08:57:31.887] [WARN] [usa-llqj3q] Detected 10 consecutive tiny segments (416491 bytes). Capture pipeline appears dead.
[2026/02/22 08:57:35.068] [nbc-yyt7ac] Tab replacement complete. New capture started with segment continuity.
[2026/02/22 08:57:35.068] [nbc-yyt7ac] Recovered in 9.7s via tab replacement.
[2026/02/22 08:57:47.443] [usa-llqj3q] Tab replacement complete. New capture started with segment continuity.
[2026/02/22 08:57:47.443] [usa-llqj3q] Recovered in 15.6s via tab replacement.
[2026/02/22 09:00:44.570] [usa-llqj3q] Stream ended after 2h 0m. Recoveries: 2 (2× tab replacement), avg 10.5s.
[2026/02/22 10:38:26.239] [WARN] [nbc-yyt7ac] Detected 10 consecutive tiny segments (371820 bytes). Capture pipeline appears dead.
[2026/02/22 10:38:35.263] [nbc-yyt7ac] Tab replacement complete. New capture started with segment continuity.
[2026/02/22 10:38:35.263] [nbc-yyt7ac] Recovered in 9.0s via tab replacement.
[2026/02/22 11:03:01.755] [WARN] [nbc-yyt7ac] Video element not found (attempt 1/3). Context: main page, frames: 10, videoCount: 0.
[2026/02/22 11:03:07.360] [WARN] [nbc-yyt7ac] Playback paused. Attempting play/unmute...
[2026/02/22 11:03:09.509] [nbc-yyt7ac] Recovered in 2.1s via play/unmute.
[2026/02/22 11:53:03.049] [WARN] [nbc-yyt7ac] Video element not found (attempt 1/3). Context: main page, frames: 10, videoCount: 0.
[2026/02/22 11:53:09.045] [WARN] [nbc-yyt7ac] Playback paused. Attempting play/unmute...
[2026/02/22 11:53:11.170] [nbc-yyt7ac] Recovered in 2.1s via play/unmute.

Also I have my server set to 2560x1440 with an HDMI dongle and I only access it with VNC, but my res config in prism says I'm limited to 720p high even if I set to 1080p. Not sure what's going on there.

EDIT: figured out the res deal, had my font scaling too high in Windows.

1 Like
#727

@tgenius I have done the 1.4.1 and 1.4.2 upgrades with brew on mac mini and both times the service does not restart. I tried "prismcast service restart" but no luck getting the service to run. I found that if I uninstall and then install the service it works after that. I used "prismcast service uninstall" and then "prismcast service install". After that everything was fine again. This does not uninstall prismcast just the service that controls starting and stopping prismcast.

I was going to report this to @hjd. This is a fantastic piece of software but I really do not have much time right now to test it out a lot.

Consider it reported. It's on my radar...I'll look into this one. Sorry about that guys!

1 Like
#728

Had a weird thing with the NBC gold medal game today, the tab got restarted but it didn't go fullscreen, was letterboxed with black borders all around. Later the tab got restarted again and it went fullscreen after that. Have also seen a few Olympic events where the timestamps get messed up, they show as 10-15 hour long shows. Have had to run fix timestamps on those.

This is the nature of the beast, unfortunately. PrismCast is working correctly and performing as it should - detecting issues and self-healing. USA, NBC, and the Versant/NBC channels tend to be flaky at times as I've mentioned previously. PrismCast is correctly detecting the streams or Chrome have frozen on them and reloads them. Reloading the streams will, necessarily, reset the timestamps which Channels DVR detects and notes the discontinuity. Channels isn't especially elegant about how it handles this type of situation, so it is what it is, unfortunately.

It's a situation that I run into every couple of days at least with these providers, so it's certainly something that's front-and-center for me to continue to think through new ways to help Channels DVR not choke on interrupted streams and be a little more resilient. :smile:

#729

Performance is OK - right now the overall CPU in the Unraid dashboard is around 10%-20% while watching a Prismcast channel, but at the same time, my son is watching remotely and so there's also a transcode of a 2nd channel going on - picture quality is not as good as ADBTuner - I need to figure out if I can improve it or, if it's as good as it gets (right now set to 1080p high, 20 Mbps)
I should probably mention that with only 1 Prismcast channel active, I've seen around 6-12%

#730

Maybe the solution for the GPU problem is to run Prismcast with brave instead of chrome?

Just a thought.

#731

I've found the same. I do an uninstall the service then run brew update && brew upgrade then reinstall the service to get it to run again. I think it has to do with the service calling Prismcast from a specific folder, that no longer exists with the newer version (looks like I'm 2 versions behind):
image

Now updated to 1.4.2
image

#732

@scottuf As I mentioned above…this is on my radar. No more info needed. Appreciate the enthusiasm!

1 Like
#733

Been lurking here and listening for a bit. I would love to give this a shot, but I have no Macs in the house - just PCs and a Synology NAS. I have great OTA service here, so the only thing I'm missing now is ESPN channels, and I'd be happy with a single stream. I recently upgraded my wife's computer and now have her old one available. Worth trying on this one? Could I get one 720p or 1080p stream?

  • Core i3-4010v @ 1.7Ghz
  • 8GB RAM
  • Integrated graphics
1 Like
#734

Questionable to doubtful if you could get a single stream out of it. Best is to set it up and give it a try. I would make sure no other CPU intensive tasks are running in the background. What model is your Synology? I was able to get a single stream to work for about 5 minutes during testing on my DS1520+, but I wasn't doing any transcoding on that box at that time from Channels, so I suspect anything that tasks the CPU (possibly even Comskip) would impact the performance on that box.

1 Like
#735

4th Gen i3? Not a good candidate. Less powerful than modern low end systems like the N100 (also not recommended), while requiring 3x (or more) the energy to run it.

2 Likes
#736

FYI for those interested in PrismCast/DirecTV integration. I figured out how to get PrismCast to tune DirecTV Stream. I submitted a PR - only requires a small edit to the site profiles to add it.

The tricky part was finding the UID for each channel (what directv uses for channel name/number) but that little scraper I built for ADB works and I have it exporting a PrismCast M3U/XML.

I don’t subscribe to DirecTV so not quite sure if it grabs paid channels, but I got it working with their FAST channels.

If HJD accepts the PR, I’ll provide instructions for others to give this a shot.