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KarWreck  
#1 Posted : Monday, March 1, 2021 7:19:50 AM(UTC)
KarWreck

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New Zealand

Hi All,

I'm fairly new to VMIX and had our first live-stream event happen yesterday.
What I found is I had tearing in the picture(sample here https://business.faceboo...eos/1092394847894941/).I also had the same issue/tearing with streaming to Youtube.

We have 3 Panasonic Cameras running NDI HX(1080p50@16Mbps). VMIX stream setting is H264 1080p 4.5mbps AAC 128k(although I tried the FB 720p 3.5mbps mode as well).

The internet speed onsite was fine(100Mb Up/Down). I also recorded direct to my laptop and there was no tearing in the video.
So I'm kind scratching my head.

Cheers,
Karwreck
kross  
#2 Posted : Thursday, March 4, 2021 5:56:27 AM(UTC)
kross

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Wow, that does look pretty bad. By the way, that isn't tearing, but rather artifacts from a very low bitrate. Tearing is something else entirely.

The bitrate you specified should be high enough. 1080p 4.5 Mbps, or 720p 3.5 Mbps should be enough for a smooth stream, especially for a pool tournament. Are you using software or hardware encoding? Can you share the stream encoder settings?

Since you say the internet is plenty fast, I'd experiment with higher bitrates. I just did a pool tournament this weekend at 8 Mbps, and it looked great.

I also stream pool tournaments (RailbirdsTV on YouTube), and often only stream around 2-3 Mbps over WiFi, and get good results.
KarWreck  
#3 Posted : Thursday, March 4, 2021 10:48:06 AM(UTC)
KarWreck

Rank: Newbie

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New Zealand

Hi Kross,

Thank you for the reply(I'm also a fan of RailbirdsTV). I'm using hardware encoding via the laptops GPU(Nvidia2070 8Gb).
On the day I tried 720p as well as 1080p on either FB or Youtube and the artifacts were the same.
I've since had feedback from VMIX to say they believe the fault was the PTZ Camera's(which is strange).

VMIX Encoder Settings.jpg (80kb) downloaded 0 time(s).
kross  
#4 Posted : Thursday, March 4, 2021 11:49:53 AM(UTC)
kross

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(You shouldn't post your stream key in public forums)

Since you say the local recordings look good, but not the live stream, I think that rules out the camera as being the culprit.

I just did some testing with low bitrates, and I had to drop the bitrate to 1/10 of what you're using to get anything to create artifacts like that. I was surprised how low I could go with the bitrate and still have it look decent. It's possible that the hardware encoding on your laptop isn't working properly, for whatever reason. Try unchecking the "use hardware encoder" and try a test (private or unlisted) stream. I'd add a video input into vMix, and use one of your (known good) match recordings as the source. That way you can simulate streaming a pool match.

-- Kevin
kross  
#5 Posted : Thursday, March 4, 2021 11:51:22 AM(UTC)
kross

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I should ask, did you change any of the quality settings by hitting the gear icon, or are you just using the presets? Just wondering if you changed something in the custom settings that threw things out of whack.
KarWreck  
#6 Posted : Friday, March 5, 2021 6:27:52 AM(UTC)
KarWreck

Rank: Newbie

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Joined: 3/1/2021(UTC)
Posts: 3
New Zealand

After some testing today I've found when using the h.264 1080p 6mbps preset that when I use the hardware encoder my stream bitrate drops to 2.3-3mbps.

If I disable hardware encoding it is consistently around the 6mbps mark. So I'm now wondering if this could be driver related for the gpu?

I've now checked CBR for my FB stream and the bitrate is higher and have not had any artifacts since.
kross  
#7 Posted : Friday, March 5, 2021 4:19:10 PM(UTC)
kross

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CBR shouldn't make that kind of a difference to quality, but hey, whatever works, right?
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