4k youtube playback, hitches, stutter, framedrops #13991
Replies: 8 comments 18 replies
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[ 0.008][v][cplayer] Applying profile 'default'...
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doesn't make a difference
I already am using this |
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Their GPU is at 15-20% I doubt it is rendering bottleneck. @geextahslex Could you show stats page 2? shift+i and 2 Also does it happen with local files? Maybe you see buffering issue, those can happen with youtube. Check page 3 of stats to see if you have healthy cache. |
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Yes I have stated that in the last part of my post
Here is the screenshot, stats page 2 @llyyr |
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Looks like decoding performance issue, can you make sure |
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Where do you see if hwdec is on or off? |
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hardware decoding enable it should be there... Hmmm when tried on the weaker system get a lot of frame drops even there's not eat system resource too much downloaded the vp9 google video FSR.zip |
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Doesn't support VP9 hwdec. Your hardware is probably too weak for 4K60 YouTube playback. |
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I don't know if it is to weak, maybe. But when I limit the FPS to 30, the CPU is at 50-60% and the GPU at 15% load, there is still jitter all over the place. I can watch 4k HDR with tonemapping with no issues. Bootleneck representation with slapped filters on it (HDR tonemapping, debanding, sharpening, denoise, glsl saturation, vibrance shaders)CPU bottleneckWhen CPU limited, there are small variations (delta between max and min frame) but overall the FPS is at a constant level, without random spikes GPU bottleneckWhen GPU limited you have an almost flat FPS line at the performance you can hit, no jitter 4k60FPSflat 60
This is reproducible, everytime at this scene (02:22) the playback literally stops ^^ |
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The amount of CPU needed for decoding depends on the scene complexity. For highly dynamic scenes more CPU is needed. It seems that your CPU is barely powerful enough that it can handle most scenes, but not for these specific ones. That's how these reproducible "jitters" happen. |
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You could easily plot the cpu usage and see if there is corelation visible with "jitters". I would expect so. Also if your hardware is not capable of VP9 hardware decoding, set ytdl to prefer h264, you will have a lot better experience. Lastly, check other players like VLC or MPC-HC if they behave better. |
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@kasper93 I monitored each core (4) usage while playback and no core hits above 87%. |
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87% is very high for media playback and if it is sporadic higher load you may not see it in usage% which is often smoothed.
It is possible to debug it with profiler (Visual Studio profiler would be easiest on Windows) and seem where is the bottleneck, but it is not something that is done by mpv itself, at least not with modification. |
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Here is a scene with a still image (opened map) and you can see the cpu is at 30-50% usage. But you can count 6 jitters, 2 you can see on the graph in the background. There seems to be a pattern to those dopped frames. |
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Okay and why is this video running smoothly? It's 4k60 VP9 |
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I have noticed eacht time there is this pattern the framerate drops from 60 to 8, isn't that a bit drastic?
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Okay thats interesting. Yeah this seems to me like a "bug" or optimization issue. |
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You could try AV1 version if VP9 have some weirdness.
Would be interesting to see where exactly does it choke. |
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@kasper93 The default yt-dlp setting already sets AV01 above VP9 |
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Default yt-dlp picks AV1 above VP9? That would be news to me. Are you sure it is not your config? Also, what is the 'problematic' sample? |
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@hrxn I don't know, this information is on their github page |
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Important Information
Provide following Information:
Reproduction steps
Start playback of a 4k 60 fps youtube video with latest yt-dlp
Expected behavior
Normal playback, stutterfree
Actual behavior
Random hitches, stutter while playback
Log file
output.txt
Sample files
used youtube video
https://www.youtube.com/watch?v=xmJUZgQ5HpQ
Side note
the behaviour is the same when I downloaded the same file and watched it from the HDD
So yt-dlp/webstream can be excluded as a source of the stutters
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