I’m using my FW13 with my living room TV and finding that after just a few minutes of watching videos, the audio coming out of the HDMI interface has developed a latency of ~1 full second. If I go to the laptop’s internal speakers for a bit then go back to the HDMI audio output, the latency is resolved but the audio will start to drift pretty quickly again. If I pause the video once this starts happening, that audio keeps coming out of the TV until its caught up to the point in the video I actually paused at.
I’m using a 25 foot HDMI cable connected to the HDMI expander card on my FW - using the back left slot. TV output is at 3840x2160x60Hz. The TV I’m connected to is an LG 55SK8000PUA
There’s your problem - some cables are rated to long distances but in reality they rarely work as intended.
I’m an ex-video tech and personally I’d never exceed 5 meter runs as beyond that you start to hit into problems.
Your TV may have an option in the sound menu to compensate for the delay but that might not give you a whole second of adjustment.
I tried with a 6 foot Twisted Veins cable and the same thing is happening. A full second of audio latency relative to the video signal once I let the video play a while
Ultimately, there’s going to be some reason that a small difference in 29.97 or 59.94 FPS video gets played at 30 or 60 FPS (respectively) while the audio comes along with 44,100 or 48,000 samples per second. Check that your frame rates really line up.
HDMI audio to a TV adds a latency to the audio that can only be adjusted with support from the application creating the audio/video.
Audio to the laptop speakers or laptop headphones do not have that latency.
As you have found, the TV controls only increase the latency.
Media players like xine, mpv and mplayer have controls to adjust the latency so that they work with HDMI TVs.
I am not aware of firefox or chrome having such controls, but they would need it in order to fix your problem.
I guess a real fix would be the Linux OS reporting to the application, not only the buffer latency, but also an additional fixed latency that is introduced by HDMI and similar. Currently Linux audio only reports the buffer latency/delay.
The problem is that delay isn’t even a constant value. When I start playing something the audio is spot-on aligned with the video, but as I keep playing the content, the audio builds up latency. This hasn’t been a problem with any of my other devices connected to this TV.
Hardware Accelerated, and I know it’s not a problem with the video stream as once the latency is built up, even sounds from the Plasma shell have this latency (tested by moving the Plasma System Tray volume slider during playback. The sound made when the slider is released shared the full audio latency of the video)
After installing LXDE, Gnome, and KDE Neon, I’ve determined this issue is isolated to the specifically the Plasma Desktop Environment and occurring in both Fedora and KDE Neon. I’ve submitted a bug report to KDE