Firefox Community Forum

Hi team,

I am facing a persistent video playback issue specifically in Firefox (latest version), while the exact same stream works perfectly fine on Google Chrome and VLC player.

When I try to play a high-definition HLS live stream from my network provider site (vraitv.com), the video stalls and buffers every few seconds. Upon inspecting the Firefox Web Developer Console, I notice frequent NS_ERROR_NET_TIMEOUT errors during the loading of .ts video chunks, along with occasional CORS warning flags.

I have already tried the following troubleshooting steps:

1. Disabled Enhanced Tracking Protection for the site. 2. Started Firefox in Troubleshoot Mode (Safe Mode) with all extensions disabled. 3. Cleared all cookies and site cache.

Unfortunately, the issue persists. Are there any hidden settings in about:config (such as modifying network.http.max-persistent-connections-per-server or increasing the media cache size) that can optimize how Firefox handles concurrent video chunk loading?

Any technical guidance would be highly appreciated.

How to increase buffer time for video, how to load at least 2 min of video instead of how it's now about 30 seconds. I live in the countryside and I can't change my internet speed (I tried). I have the fastest speed that they can send, but still I can't watch anything normally because it constantly stops videos to load more

Hello, I noticed a few times that after waking my computer up from sleep mode, I seem to lose audio from the browser completely. I look into my audio mixer and I do see the browser is giving audio, but I can't hear it through my headphones.

Last time i fixed it, I had to restart my computer and it fixed the issue, but I don't want to continue in having this issue at times. I have also tried restarting firefox by ending it in the task manager and re-opening it, but that doesn't seem to fix it.

updated to 152.0.4 last night now no sounds on web, sounds work when using edge. I can't find any settings in firefox that will turn the sound back on for streaming videos.

I couldn't sign my Alejandra .com on my computer so i need to cahnge to Firefox aboutpreferences@tabsBrwosing so the video from Aljazeera video live news awork on my computer Thank kind regards Peter tan

(AI written summary of troubleshooting steps taken before making this support thread)

Firefox version: - 152.0.1 Release - 153.0 Nightly

OS: - Windows 11 build 26200

GPU: - NVIDIA GeForce RTX 4070 SUPER

Codec package: - Microsoft HEVC Video Extensions installed from Microsoft Store

Problem

Firefox does not expose HEVC playback support, causing Twitch to disable 1440p streams encoded with HEVC.

The same machine can play the same HEVC Twitch streams in Chrome immediately after installing HEVC Video Extensions.

Expected result

Firefox should report HEVC playback support and allow playback of HEVC streams, as Chrome does on the same system.

Actual result

Firefox reports HEVC as unsupported.

about:support:

codecSupportInfo: H264 SWDEC HWDEC VP9 SWDEC HWDEC VP8 SWDEC HWDEC AV1 SWDEC HWDEC HEVC NONE

Troubleshooting already performed

- Installed Microsoft HEVC Video Extensions - Rebooted Windows - Updated NVIDIA drivers - Verified hardware acceleration is enabled - Tested with a brand new Firefox profile - Tested with Firefox Nightly - Confirmed Chrome can play the same HEVC streams

Additional observations

Chrome: - Twitch 1440p becomes available immediately after installing HEVC Video Extensions - Twitch Stats for Nerds reports:

 hev1.1.6.L150.90.0.0.0.0.0

Firefox: - Twitch reports that the browser does not support the required resolution - 1440p remains greyed out - about:support continues to report HEVC NONE

Reproducible tests

Firefox console:

MediaSource.isTypeSupported('video/mp4; codecs="hev1.1.6.L150.90"')

Result: false

MediaSource.isTypeSupported('video/mp4; codecs="hvc1.1.6.L150.90"')

Result: false

navigator.mediaCapabilities.decodingInfo({

 type: "media-source",
 video: {
   contentType: 'video/mp4; codecs="hev1.1.6.L150.90"',
   width: 2560,
   height: 1440,
   bitrate: 8000000,
   framerate: 60
 }

})

Result: {

 supported: false,
 smooth: false,
 powerEfficient: false

}

For comparison:

MediaSource.isTypeSupported('video/mp4; codecs="av01.0.08M.08"')

Result: true

navigator.mediaCapabilities.decodingInfo({

 type: "file",
 video: {
   contentType: 'video/mp4; codecs="av01.0.08M.08"',
   width: 2560,
   height: 1440,
   bitrate: 8000000,
   framerate: 60
 }

})

Result: {

 supported: true,
 smooth: true,
 powerEfficient: true

}

Additional note

Setting:

dom.media.webcodecs.h265.enabled = true

causes HTML5 codec test (https://html5test.co/) to report H.265 support, but does not change:

- about:support - MediaSource.isTypeSupported() - MediaCapabilities.decodingInfo() - Twitch HEVC playback availability

Question

Is this a known issue with HEVC Media Source Extensions support on Windows 11 build 26200, or is there another requirement for Firefox to expose HEVC playback capability through MediaSource and MediaCapabilities when the Windows HEVC codec is installed and functioning in Chromium-based browsers?

audio stops completely for exactly 0.4 seconds when un-pausing video, this affects any "interruptions" including skipping around, clicking on timestamps and any ohter type. issue stops completely when another youtube tab with a video playing is currently active.

i have tried any regular troubleshooting tips, including any and all forums i've found online to no avail. this is not happening in any other browser.