Bug 453883

Summary:	Version 21.12.3 and above are 4 times slower than 21.08.2 in rendering
Product:	[Applications] kdenlive	Reporter:	stephane.plantard
Component:	Rendering & Export	Assignee:	Jean-Baptiste Mardelle <jb>
Status:	RESOLVED WORKSFORME
Severity:	normal	CC:	arraybolt3, jsdeckerido, sam, snd.noise
Priority:	NOR
Version First Reported In:	21.12.3
Target Milestone:	---
Platform:	Gentoo Packages
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description stephane.plantard 2022-05-16 11:26:00 UTC

SUMMARY
Rendering has become very slow with version 21.12.3 compared to previous version that came with gentoo : 21.08.2
MLT is version 7.4.0
I use kdenlive for 3 years and it's the first time I see that drastic slowdown, I had to build 21.08.2 again to be able to use it. Whatever the video is simple (no filter or anything) or complex (multiple video and audio tracks, transformation...) the speed in rendering difference between 21.08.2 and 21.12.3 or any newer version is huge.
To be sure, I did build the 3 version in same system with no changes in any other components.

STEPS TO REPRODUCE
1. Set up a rendering with these parameters: f=mp4 movflags=+faststart vcodec=hevc_nvenc vb=24000k acodec=aac ab=160k real_time=-14
2. Render a 4k/30fps video
3. record the time it took

OBSERVED RESULT
Video is 12 minutes long 4k/30fps, nothing special applied on it except some volume parameters.
Rendering, with same MLT, same everything except the kdenlive version.

Version 21.08.2: 3"45 (225 secs), Video engine usage: around 85% max 93%
Version 21.12.3: 11"54 (714 secs), Video engine usage: around 30% max 33%
Version 22.07.70 (live git): 11"52 (712 secs), Video engine usage: around 30% max 37%

EXPECTED RESULT
Same rendering performance has 21.08.2 and older versions, not 4 times slower.

SOFTWARE/OS VERSIONS
Windows:
macOS:
Linux/KDE Plasma: Gentoo Linux x64
(available in About System)
KDE Plasma Version: 5.23.5
KDE Frameworks Version: 5.92.0
Qt Version: 5.13.3

ADDITIONAL INFORMATION
I use a Ryzen 7 3700X with 64GB DDR4-3600 Memory and nVidia GTX 1070-TI and nvenc encoder

Comment 1 Aaron Rainbolt 2022-05-16 18:48:24 UTC

Just reproduced this bug on Ubuntu Studio 22.04, Kdenlive 22.04.0 Appimage, on an HP Z220 SFF Workstation with a EVGA GeForce 1050 Ti Using the experimental hardware accelerated render profiles with NVENC. Render speeds were ~200 FPS in 21.04.3, now getting ~75 fps in 22.04.0. The videos I've been rendering are just screen captures made by OBS Studio of a 1080p screen @ 30fps, recording Impress presentations or VM installations.

For anyone else who hits this bug, you can get the older version of Kdenlive here: https://download.kde.org/Attic/kdenlive/21.04/linux/ The Appimage provides me the same high speeds that I was getting before.

Comment 2 farid 2022-08-26 14:29:46 UTC

Can you please test the latest version and see if you can still reproduce?

Comment 3 Bug Janitor Service 2022-09-10 04:36:48 UTC

Dear Bug Submitter,

This bug has been in NEEDSINFO status with no change for at least
15 days. Please provide the requested information as soon as
possible and set the bug status as REPORTED. Due to regular bug
tracker maintenance, if the bug is still in NEEDSINFO status with
no change in 30 days the bug will be closed as RESOLVED > WORKSFORME
due to lack of needed information.

For more information about our bug triaging procedures please read the
wiki located here:
https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging

If you have already provided the requested information, please
mark the bug as REPORTED so that the KDE team knows that the bug is
ready to be confirmed.

Thank you for helping us make KDE software even better for everyone!

Comment 4 Bug Janitor Service 2022-09-25 04:48:55 UTC

This bug has been in NEEDSINFO status with no change for at least
30 days. The bug is now closed as RESOLVED > WORKSFORME
due to lack of needed information.

For more information about our bug triaging procedures please read the
wiki located here:
https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging

Thank you for helping us make KDE software even better for everyone!