Converting with "Best" quality in newer versions is taking longer

Really enjoy using ShotCut. I searched the forum and did not find anything related to my issue.

I have an i7-10750H @ 2.60GHZ installed on my laptop running Windows 10. I cannot use any version newer than 24.09.13, otherwise the converting process for opening any video file is taking what seems like forever.

I installed 25.01.25 and after about 11 minutes, the processing was less than 50% complete for a 400MB MP4 file. Using 24.09.13, it took less than 3 minutes to finish converting.

I always use Open File/Convert to Edit-friendly/Best/Advanced/Override Frame Rate checked & Duplicate Fast.

Is there a setting on the newer versions that I should check or are they just meant to be used on much faster CPUs?

I always do a clean install of the new version.

What am I doing wrong?

Thanks in advance.

ffmpeg changed behavior and no longer created fixed frame rate from variable frame rate. So we were forced to go a more heavy and slower approach.

Thanks for the reply. So would uncheck Override Frame Rate in the newer version make converting go a bit faster or should I just stay with the older version? That long converting is really causing high CPU temps as well.

We use an FFMpeg command line to perform the conversion. In the case of “Override Frame Rate”, we have not changed anything between the two releases. Both versions produce the same command line. I downloaded both versions and performed a test using only the FFMpeg command that Shotcut generates. I am seeing an order of magnitude difference in the speed between the two commands:

Command (25.01.25):
C:/Users/Owner/Downloads/shotcut-win64-250125/Shotcut/ffmpeg -loglevel verbose -i bbb.mp4 -max_muxing_queue_size 9999 -map 0:V? -map 0:a? -map_metadata 0 -ignore_unknown -vf scale=flags=accurate_rnd+full_chroma_inp+full_chroma_int:in_range=mpeg:out_range=mpeg,minterpolate='mi_mode=dup:mc_mode=aobmc:me_mode=bidir:vsbmc=1:fps=60.000000' -color_range 1 -f matroska -codec:a pcm_f32le -codec:v utvideo -pix_fmt yuv422p -colorspace bt709 -y bbb2.mkv

Result (25.01.25):
frame=38071 fps= 14 q=-0.0 Lsize=51699319KiB time=00:10:34.14 bitrate=667862.2kbits/s speed=0.236x

Command (24.09.13):
C:/Users/Owner/Downloads/shotcut-win64-240913/Shotcut/ffmpeg -loglevel verbose -i bbb.mp4 -max_muxing_queue_size 9999 -map 0:V? -map 0:a? -map_metadata 0 -ignore_unknown -vf scale=flags=accurate_rnd+full_chroma_inp+full_chroma_int:in_range=mpeg:out_range=mpeg,minterpolate='mi_mode=dup:mc_mode=aobmc:me_mode=bidir:vsbmc=1:fps=60.000000' -color_range 1 -f matroska -codec:a pcm_f32le -codec:v utvideo -pix_fmt yuv422p -colorspace bt709 -y bbb2.mkv

Result (24.09.13):
frame=38071 fps=135 q=-0.0 Lsize=50999382KiB time=00:10:34.14 bitrate=658820.3kbits/s speed=2.24x

So something must have changed with FFMpeg.

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In my testing, the Override Frame Rate does not make a difference. It seems to depend on the quality:

I did some tests with a 1 minute clip I had on my Windows computer:

24.09.13 25.01.25
Good 00:01:20 00:01:18
Better 00:00:36 00:00:35
Best 00:00:25 00:04:09

So, it seems that while “Good” and “Better” got slightly faster, “Best” has become considerably slower.

I suggest you either go back to version 24.09.13 or use “Better” with the new version.

I marked this as a bug since it is a regression from previous versions. But I do not know if we will find a solution since it depends on FFMpeg.

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We can check if a codec option was added for Ut Video to affect its speed. The code change to ensure constant frame rate output with FFmpeg 7 is that now Shotcut always turns on the override frame rate option based on the guesstimated frame rate.

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