I recently edited a video in Shotcut, but after exporting, I noticed the resolution seems inconsistent throughout—some parts look sharper while others appear lower quality or slightly blurry. I’ve checked the export settings, and they seem correct, but I’m not sure what’s causing this.
My guess, and it’s just that, is that the footage might have been shot in autofocus mode and the camera may have been having issues keeping the focus consistent. If so, that would show up in a careful viewing of the source files.
Variances in video quality can also occur due to export settings (choosing settings that result in too low a bit rate), but I suspect that’s probably not the issue here, as that tends to show up either all the time (if the bit rate is way too low) or during times of significant changes in the video content (if the bit rate is enough to handle small changes like a change in facial expression but not big changes like zooming in or out or a scene change), and I see changes in video quality even during sections where nothing much is changing in the frame.
I slowed down the footage in places, and I think that corresponds with the loss of resolution in that video.
But it’s more than that. Other projects I’ve worked begin as 1080 and end looking 720 by the time I’m finished. I didn’t matter when I was using Shotcut for animations, but for HD videos it’s quite noticeable.
I will confess to being a compulsive exporter. I don’t like having too many things going on in my timeline, so I export a video when I’ve made changes and then reintroduce it back into my timeline. Something like replicative fading?
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I’ll help explain lossy compression for BlueDisk based on the context of the discussion and the search results.
Lossy compression is a data compression technique where some original data is permanently lost during the compression process, typically to reduce file size. In video editing, this means that each time you export or re-encode a video, you potentially lose some quality.
From the context of BlueDisk’s issue, it sounds like they are experiencing “generation loss” - a phenomenon where repeatedly encoding and re-encoding a video gradually degrades its quality. This is a classic problem with lossy compression:
Every time you export a video, some visual information is discarded to reduce file size.
When you re-import that exported video and make further edits, then export again, you lose even more quality.
This can result in progressively lower resolution and blurriness.
BlueDisk mentioned: “Other projects I’ve worked begin as 1080 and end looking 720 by the time I’m finished.” This is exactly the generation loss effect of lossy compression.
Recommendations to minimize this:
Work with the original, high-quality source footage as much as possible.
Avoid multiple re-exports of the same project.
If you need to make multiple edits, keep an uncompressed or high-quality intermediate file.
Use lossless or high-quality export settings.
Consider using intermediate codec formats that preserve more quality during editing.
Would you like me to elaborate on any of these points about lossy compression?
Use an Export preset from the intermediate or lossless category. Lossless is usually much bigger. So, use it sparingly for shorter clips. From intermediate, DNxHR HQ and ProRes are the best choices; HQ is a little better than 422.
This may or may not be helpful for your situation … rather than exporting the video after doing some editing, then importing the resulting video file, try this: after doing some editing, save the project as a .mlt file, then import that .mlt file as the source video for further editing.
As I understand it (and I may not, so hopefully someone else will chime in to correct me), importing a .mlt file as the source video allows the editing that was done in that file to be “stacked” with the editing you do in the next project file. The rendering (that typically involves lossy compression) only happens once, taking the whole stack of edits into account.
Yup, it’s a useful feature. I used it in this video for the end of the opening titles and the end of the video itself, where I wanted the same thing (metallic panels closing over the scene and meeting with a loud clang - fans of the Terminator movies will recognize where I got the idea) in two places without having to build it twice.