• Thanks: 2

Topic: SVP and 25fps vids, why does it drop frame ?

Hi,
I have notice a little problem that i don't understand.
When i play old PAL (25fps) video with svp i get dropped frame (1 per second say ctrl-j in mpc-hc)

But, as far as i understand with other answer of devs on other thread (https://www.svp-team.com/forum/viewtopic.php?id=1971) the use of SVP should prevent the drop of frame on 25fps video as SVP use each frame to calculate inter-frames whatever is the target frame-rate (with additionnal cost of course)

These point are not clear for me in this problem :

- Does the stats in mpc-hc consider the frame from the source point of view (1 frame of the original 25 are dropped) or from the svp out point of view (1 frame on 60 per second are lost, which is not a big deal) ?
- is the "dropped frame" indicator at the end of the stats in the same view related to the "1 frame dropped per second" at the begenning of the stats... ? Because i get 1 frame dropped but with no notable increase in the number ...

Your answer could help me to determine if it's my source vids which have saccadic behaviour or if it's the decodding.

Regards;

  • MAG79
  • SVP developer
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Re: SVP and 25fps vids, why does it drop frame ?

When you press Ctrl-J you will see statistics of current used renderer.
In general case it is madVR statistics.

In my case I open 23.976 fps movie. SVP interpolates new frames to get framerate 59.94 fps.
madVR renders these 59.94 fps at 59.972 Hz and gives 39 dropped frames at start. The number is not encreased while playing. It is mean no more dropped frames. It is good! Must to be so.
And I see message about 1 frame repeat every 1.29 minutes. It is not bad.

But it is only statistics of rendering frames (not of really showing frames). So, to make sure you have smoothness enough you need to launch tearing test line movements on the screen. If it moves smooth then all is good!

What numbers do you se? What is wrong in your case? Maybe screenshot?

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madVR_statistics.png 24.32 kb, 419 downloads since 2018-08-28 

  • MAG79
  • SVP developer
  • Offline

Re: SVP and 25fps vids, why does it drop frame ?

> is the "dropped frame" indicator at the end of the stats in the same view related to the "1 frame dropped per second" at the begenning of the stats.
"dropped frame" is measured fact of dropped frames.
"1 frame repeat|dropped every ..." is the prediction calculated at this moment. It can be changed in time.

"dropped frame" is more acurate

  • Thanks: 2

Re: SVP and 25fps vids, why does it drop frame ?

MAG79 wrote:

When you press Ctrl-J you will see statistics of current used renderer.
In general case it is madVR statistics.

In my case I open 23.976 fps movie. SVP interpolates new frames to get framerate 59.94 fps.
madVR renders these 59.94 fps at 59.972 Hz and gives 39 dropped frames at start. The number is not encreased while playing. It is mean no more dropped frames. It is good! Must to be so.
And I see message about 1 frame repeat every 1.29 minutes. It is not bad.

But it is only statistics of rendering frames (not of really showing frames). So, to make sure you have smoothness enough you need to launch tearing test line movements on the screen. If it moves smooth then all is good!

What numbers do you se? What is wrong in your case? Maybe screenshot?

Thanks for your answer. In my case the wrong thing is that on certains vidéo i see repetitive lag. After looking of what vids this is it appears to be 25fps video. (for a certain author, so i don't know if it's for all 25 fps video or if it's the author that encode thing with a lag)

After looking on the stats, i saw that the "1 frame dropped per second" appears very ofter. But the "dropped frame" number don't increase.
Like on this screen :
https://tof.cx/images/2018/08/28/27c9b96cf08bf171c8a26f34284aa533.jpg

The tearing test seem to give good result. at least at first glance.

So my question is : how to check if it is due to the video rather than with madvr of svp ?

  • Thanks: 2

Re: SVP and 25fps vids, why does it drop frame ?

MAG79 wrote:

> is the "dropped frame" indicator at the end of the stats in the same view related to the "1 frame dropped per second" at the begenning of the stats.
"dropped frame" is measured fact of dropped frames.
"1 frame repeat|dropped every ..." is the prediction calculated at this moment. It can be changed in time.

"dropped frame" is more acurate

But could the prediction be wrong at the point of it say 1 frame per second dropped at each second and update often, but are every time wrong if i look at the number ?

  • MAG79
  • SVP developer
  • Offline

Re: SVP and 25fps vids, why does it drop frame ?

> how to check if it is due to the video rather than with madvr of svp ?
1. disable or exit SVP
2. playback your video, rewind to place with lags, press pause
3. view your video frame-by-frame and look for picture changes. If each 24 frames contain movements and 25-th one is not - it is encoded doubled (dropped) frame. If it so you need to find correct source video with 24 fps. Or you can fix your video with decimation avisynth script. Ask for details if you need help with it.

Frame-by-frame navigation in pause mode:
MPC-HC: Ctrl+right/left arrow
PotPlayer: F/D