Hi everyone,

I'm using Kdenlive since 9 months or so for a little youtube channel about a videogame, posting recap of developer's stream, guides and so on. For some of these videos I'm forced to download the source video from Twitch, cut it and add my commentary over it. Unfortunately I noticed that most of the time my re-encoded video isn't as smooth as the original one downloaded from Twitch.

Here's an example of what happens. You just need to watch the first 20-25 seconds.
This is the original, with perfectly smooth 60fps: https://youtu.be/mPTCq3LiZSE

And this is my version: https://youtu.be/mcDyqaVd7p0

I'm using the 1920x1080 h.264 mp4 encode, set to medium and using 7 threads (I have a ryzen 7 2700x CPU). The project is set to 60 fps before you ask
I tried to create a script to set it to slower and I tried to modify the g from 120 to 60 and even tried with 0. No changes.

I'm definitely not an expert in video encoding so I'm running out of ideas. What's the possible cause for this stuttering? Anything I can try to have a smoother result?

Kdenlive 17.12.2 on Ubuntu 18.04

You have doubled the frame rate.

The original video seems 30FPS 1623kb/s, Audio 126kb/s 44.1MHz AAC

Really? Wrong example then. The one I downloaded from twitch (and actually used for my movie) is 1920x1080, H.264, 60fps, 6004kbps.

So my question is still valid.

I download the video from Youtobe with your link above.

Put in the link from where you get the original and then I have a look.

Here's the Original one: https://www.twitch.tv/videos/281992560

The footage I took at the start of my video starts at 00:46:20

I cannot download the video from twitch.tv. But do you have checked your downloaded video from twitch.tv with Mediainfo (https://mediaarea.net/de/MediaInfo)? Does that get the same video info you have?

I assume uploading to youtube a 60 FPS video can be a problem because youtube convert always. Make sure that the uploaded video to youtube is exactly what youtube want’s in term of frame rates.

Worst case: you convert first before you upload to be sure about the result.

I asked on this forum because it's not a youtube conversion issue: the stutter is there on the output file from kdenlive as well. I just linked the youtube video because the issue is visible and it looks exactly the same as the file I have on my PC. I do have checked youtube's suggestions for video encoding and i'm on track with those. As long as it's not something like 59,90 or similar wacky numbers their converter should be happy. But again it's not a problem on their end.

The video info I posted were took from nautilus, here's the mediainfo output:

6003 kb/s 1912*1088 (16:9) at 60.00 FPS, AVC (High@L4.2) (CABAC / 4 Ref Frames)

My video:

5035 kb/s 1920*1080 (16:9) at 60.00 FPS, AVC (High@L4.2) (CABAC / 4 Ref Frames)

There's something odd with that resolution, tho. It's the only program that tells me that number. Other that that every other bit of info are the same.

On Youtube are 2 streams at 1080p available. 1 just called “1080p” and another called “1080p 60fps”. I downloaded both:
- 1080p: 2891kb/s, 1920*1080 (16:9), 30FPS, AVC (High@L4)(CABAC / 3 Ref Frame)
- 1080p 60fps: 4440kb/s, 1920*1080 (16:9), 60FPS, AVC (high@L4.2) (CBAC / 3 Ref Frames), Duration_FirstFrame : -17 ms

1080p 60fps has problem to run on my PC.

- Do you have “Duration_FirstFrame : -17 ms” as well? Strange.

The you tube videos have writing application: Lavf56.40.101

Try in Kdenlive render with “more option” -> encoder speed: put the slider to left / scanning to: force progressive.

Nope, no Duration_FirstFrame on any of my videos. Could that be a consequence of the fast start they add when converting uploaded videos?
Also, writing application on my files is lavf 57.83.100

I tried to redo the video with your suggested settings. No change whatsoever. I also tried to set threads to 1, thinking "maybe it's a multi threading issue in MLT". Unfortunately i got same results but, with a slightly smaller file size. Curious Here's the output from mediainfo for this new vid:
3442 kb/s, 1920*1080 (16:9) at 60.000 FPS, AVC (High@L5) (CABAC / 8 Ref frames)

I noticed that the video seems to be perfectly smooth while the image is fading from black at the very beginning; only after the "fading" ends the stuttering starts. If you pay attention the video seems to regain smoothness for a moment when there's a close-up of a hammer hitting the ground at 1:19-1:20. Could it be some sort of encoder bug that's causing this?

SgtRenny wrote:I noticed that the video seems to be perfectly smooth while the image is fading from black at the very beginning; only after the "fading" ends the stuttering starts. If you pay attention the video seems to regain smoothness for a moment when there's a close-up of a hammer hitting the ground at 1:19-1:20.

I see the same. I cannot really help. For me it looks like as it has slightly different frame rate from the original to the rendered one like a pull-down from 60FPS to 50FPS. Or 24FPS to 30FPS.

Try to render with 30FPS. Do you get the same stutter?

Is anyone able to watch in Full HD or 4k videos? I knew a few of HD streaming apps but want to watch in 4k on my curve Samsung TV.