I have generated my second video using Shotcut. This movie is a combination of short GoPro movies.
This time I have noticed a bit degraded quality comparing to original ones. I know I am not using lossless presets, but I have made a test: assemble just two videos withouth any filters or effects. And yea - the result has noticeably better quality.
Settings for both files are below (one the left side better one; on the right side worse one):
As you can see the differences are very small. They were both generated using the same preset (H.264 Main Profile) - with custom settings, for example 34Mb/s bitrate.
The longer movie and the one with worse quality has some effects like rotation (180 degrees), slowdown, etc. Can this be a reason for the degraded quality? I have tried to remove the effects, but no change in the quality.
Can this be fixed?
Is that a known thing?
I know this might not be enough information so I will happily provide the missing parts.
What is the nature of the videos? 34Mb/s fixed rate is not particularly high for 60fps video. If there is a lot of fast action or camera movement, the bitrate will get spread thin very fast compared to a stationary camera shot. The fast-moving video would look worse than a stationary shot at a fixed bitrate.
This is mostly nature, people moving, but not very fast (recorded with GoPro + gimbal). I have also tried to generate the longer movie setting the codec quality to 90% for example. The file size was much bigger: 2,77GB compared to 762MB for the one with 34Mb/x. Still the quality seems to be the same. If you want I can also share a frame of the 90% quality video. Here are the file settings just in case:
Thanks Austin. I think you might be correct. Here are the properties of the timeline, I think:
In the ‘good movie’ it is 1920x1080, so the quality is better as well. But could that be changed automatically based on some operation, like filter, cut, edit, etc.? Or have I specified wrong settings while creating the project at the very beginning?
Indeed, that is the problem. You can change the Settings > Video Mode to 1080 and it should probably be okay so long as you keep the same frame rate. Ideally, the video mode should be set correctly at the very beginning of the project. The foolproof method is to set it to an actual profile rather than depending on Automatic mode to guess the resolution based on your first clip.