Heavy artifacting

[softworkz 3336]

Are you seeing this:

• with a single specific video?
• with multiple videos (but from the same/similar source)?
• with all videos?

Do you still see artifacts when you enforce transcoding?
(e.g. by lowering the bandwidth/resolution selection)

[softworkz 3336]

In this context, it is important to understand the following:

• We are streaming to clients via HLS
  (where video is chopped into segments of 3 or 6s length)
• For HLS streaming, there are certain requirements on how the video is encoded
  (e.g. each segments needs to start with a key frame, each segments needs to be a closed GOP, i.e. references to frames outside of the GOP are disallowed, etc.)
• When we are streaming HLS while only re-muxing (=not re-encoding) the video, this is often violating the requirements above

In the majority of cases, this works out well, but not always. When the video is encoded in certain ways, this can in fact cause such artifacts that you are seeing, and the only way to work around this is to re-encode such videos.

[rickrian 0]

Im seeing this with multiple videos (not all). I got it from different places.

I get you about re-encode videos, but i have no idea how to do this. If the file is .mkv, i need a source to create new .mkv file?

[softworkz 3336]

Just try to switch to a lower quality (resolution/bitrate) by clicking the gear icon during playback, so we know whether it can be really fixed by transcoding.

[rickrian 0]

Ah, yes, i already tried and as i said before it more-less works for me if i set 25Mbps bitrate - no artifacts in video i mentioned, but they are in some other video. But this is WA isnt it?

[softworkz 3336]

6 hours ago, rickrian said:

Ah, yes, i already tried and as i said before it more-less works for me if i set 25Mbps bitrate - no artifacts in video i mentioned, but they are in some other video. But this is WA isnt it?

It depends on whether it's transcoded or remuxed. When you set 25Mbps and the video has less, it might still get remuxed instead of transcoded. 
Which method is applied can easily be seen from the ffmpeg log files names.

[softworkz 3336]

5 hours ago, Jax13 said:

I have the same issue with some 4k 7.1 atoms files on both my LG tvs G1 and C9 , however when i change the audio from 7.1 to 5.1 it goes away. really a bummer that  i cannot enjoy 7.1 atmos 

Please create your own issue and provide log files from both cases to compare.

[rickrian 0]

Maybe we can analyze another case. Watching this video i can see artifacts even i set 25Mbps

 

embyserver.txt ffmpeg-remux-7cd3cc62-863e-4b81-8a9d-a7d0e73a09f3_1.txt

[softworkz 3336]

On 12/31/2021 at 6:09 PM, softworkz said:

It depends on whether it's transcoded or remuxed. When you set 25Mbps and the video has less, it might still get remuxed instead of transcoded. 
Which method is applied can easily be seen from the ffmpeg log files names.

[rickrian 0]

Okay... so we need it transcoded, how to get it? Or it is automatic thing?

[softworkz 3336]

@Luke - any idea how to prevent remuxing in this case?

[rickrian 0]

Hello @Luke @softworkz friendly reminder ^.

[rickrian 0]

I have many episodes from different seasons of soap opera - all of them has same dynamic intro and some of them has problems with artifacts, some of them - not. I can compare source files so we can try to understand root cause. Do you know any video analyze tool for that?

[Luke 37071]

Have you tried Microsoft edge? It might be able to direct play this file without any transcoding.

[rickrian 0]

You are right, in Edge there are no artifacts. So it is something inside of my Firefox browser when transcoding is happened?

[Luke 37071]

The video player in Firefox is not quite as robust as chromium based browsers.