Quality of films after rendering

Good day

I want to edit my films with Shotcut and encounter the following problem:

When I render movies in Shotcut in factory settings (quality-based 60%), I get the impression that the image becomes softer/blur even though the average data rate increases. E.B. with an Mp4 file 6.20 min long 1280x720p, 10009 Kb/s 25pps, 460 MB increases after rendering (without change) the data rate and size with 60% quality, but the image appears a shade blurrier.

But I would like to cut without loss of quality.

When sharpening, there is now the possibility to set between 50 - 100%. Does anyone have tips for recommended setting values to achieve a meaningful and natural re-sharpening?

I work with current 6- and 8-core processors and would like to effectively limit the processor power to 70 - 80% when rendering, so that the processor and chipset are not damaged during long rendering operations. With temperature control, it is still far from 90 - 100 °C, but begins to crack like a heater and relaxes again after rendering by cracking. How can I do this?

How long does it take you to render 15 min films?

Thank you and best regards


You can turn on Hardware encoding, So that it uses your GPU to render, You can apply filters like sharpening and color grade to get back the original result. Also try to see what bitrate you are exporting in, And human eye can only see maximum around 68% of the quality. So try to stay below it, and anything above that will not worth.

Do you aim for best/good video quality or fast render time?
Both of it is contratictory - the better the render quality the longer the encoding and vice versa.
If you encode in mpeg4 h.264 you can set the render quality to 60…70% which is already very good,
you won’t see an improvement when going higher with the naked eye. I hardly can see any video quality improvement when going above 60%.
The sharpening filter in general will tend to introduce artefacts in the video, already 50% is more than enough. I tend to go 30…45% sharpening with a medium/small radius. If you overdue it you will get harsh results and bigger file sizes. The file size also increases a lot when you increase render quality (above 60…65%). Try to experiment with GOP-settings (30…150).

15min. video will take approx. 30min. render time but very much depends on the filters you use. If you use demanding filters like sharpening, color corrections it will increase render times with a factor 3…10.

Is there a chance the Video Mode (timeline resolution) is in 1920x1080? If the sources are 1280x720, they could be getting upscaled to 1080p, which could explain the blurriness and larger file size.

There are commercially available programs for limiting processes, like Process Lasso, but nothing directly in Shotcut.

Regardless, the real fix is to get better thermal management in the computer. Even if Shotcut was constrained to 80%, some other process like anti-virus or help-us-all Windows Cortana will be banging around in the background filling up the other 20% and your computer will crack anyway. A computer without adequate cooling will always be on dangerous territory.

You don’t say what operating system you are using. If it is windows see below for some suggestions:

This topic was automatically closed after 90 days. New replies are no longer allowed.