Exported videos are HUGE

Windows 10

What is your Shotcut version (see Help > About Shotcut)?

Can you repeat the problem? If so, what are the steps?

Yes, every time - the files are absolutely gigantic. I simply export, and I’ve used “YouTube” defaults, it doesn’t matter. The most recent actual Shotcut file is only 52 KB even with all edits, effects, sound, and multiple clips. The exported mp4 file is 703 KB.

I tried taking a short (3 min) video and just adding some effects (old projector/scratches), it went from 83 KB to 702 KB

Not a bug. 52, 703, and 702 KB are very small sizes. It is normal and good that an exported file is larger than its inputs due to lossy compression. Please learn a little about digital video compression and how the editing process affects that.


While lossy compression can help video be transmitted more rapidly and take up less space, this type of format suffers from generation loss. Over time if you continue to compress and decompress your file using lossy compression methods you will decrease the quality of your file over time.

Most video editors (at least any that offer multiple tracks and effects) must recompress. YouTube will also recompress to make the video streamable. With all of these generations of loss you want your export to be a little large to preserve quality. With that said, the export defaults (also Reset button or Default preset) will make something very similar to the YouTube preset but smaller and no quality loss. The YouTube preset was created to adhere to YouTube’s documented guidelines, but it accepts much more than what its guidelines suggest.

1 Like

This filter is probably a major contributing factor. The more detail and sharp contrast there is, the bigger the exported file has to be to faithfully represent it. A scratch filter creates more fine detail than the source video had, so it will naturally require a larger file to store it. The situation is worsened by the fact that the details (scratches) change position quickly from one frame to the next, so compression efficiency is lost there as well. Shotcut appears to be working as expected, given what it has to work with.

1 Like

I think you mean 83 MB and 702 MB.
I may be wrong, but 83 KB for a 3-minute video doesn’t seem possible.

That makes sense and, as they say, the proof is in the pudding:

I dragged an image (JPG) in the timeline and extended it to 30 seconds.

Before adding filters to the image, I exported the project using the Stock > Default preset:

Then I added a Old Film: Projector filter, a Old Film: Scratches filter, and exported again:


I’m not sure what happened to the zeroes in the previous email.

I have been using ShotCut to do these videos for well over 6 years. These specific type (a weekly edition) for the last three years. Please read the following, as I feel I am being simultaneously brushed off and insulted (which, frankly, I didn’t deserve): this is a NEW anomaly.

I feel as if you are answering questions I am not asking. Here is a couple of screenshots to show you what I mean:

The first one shows a typical file size with ALL FOUR FILTERS. This is indicative of the files size I have been exporting for the last three years, until two weeks ago.

To test a theory, I added the filters, one at a time, and exported each separately. The results are highlighted.

Again, I have been using the same four filters with the same saved settings for three years. The enormous file size after adding “Grain” is NEW as of two weeks ago.
Shotcut file sizes2
Shotcut file sizes

Please be kind.

This is normal. Most of our encoding presets use a quality-oriented compression level - not bitrate. A bitrate target targets a file size (along with duration), but a bitrate needs to be adjusted based on resolution and frame rate. Otherwise quality degrades. Likewise, adding more detailed information to the image (grain) makes the compression more difficult. So, if you want to maintain a certain quality level you would need to increase bitrate, which would increase file size. Using a quality-oriented compression setting (Export > Advanced > Code > Rate control) neatly automatically adjusts bitrate to meet all of these variables with the result being larger files when there is more information.

I feel I am being simultaneously brushed off and insulted (which, frankly, I didn’t deserve)

Denying this is a bug is not an insult, and giving a reply is not a brush off.

The enormous file size after adding “Grain” is NEW as of two weeks ago.

What changed? Are you using hardware encoder now? Are you using a higher resolution or increased frame rate? There are many variables. You would need to conduct before and after tests using the same project that includes the Grain filter to narrow it down. Otherwise, all I know to do is change the Shotcut version. I just ran one myself using versions 22.12 and 23.07 with the YouTube preset and resulting file sizes of 149.4 and 149.9 MB, which is a negligible difference.

A great test would be to export a project with the older version you were using. Then, export the exact same project with the new version you are using. @shotcut did that test in his previous post. But maybe your project is unique somehow.

Absolutely nothing has changed on my end, other than updating Shotcut. I’ve been using all four filters for these types of videos for three years with no issues. Now I just can’t use “grain.”

If you are using software encoder I do not reproduce a change as described above. If you are using a hardware encoder, then specify what you are using and I will try it.

I will be kind! Given your first post didn’t contain that information (!!), the file size question is low hanging fruit that has been asked here before and is often misunderstood. That might explain the response you got so please don’t be offended, as I am certain none was meant.

At least there is a solution, especially since it is a recent phenomenon. If you are unhappy with the larger file sizes, you could go back to the previous working version and only implement upgrades using portable installers, allowing you to keep more than one version. Maybe a new release at some stage won’t have this issue for your particular work case and then you can overwrite the old version.

Also, since you mention Youtube presets, I’m assuming you upload these. With that in mind…

In addition to this, have you checked the compressed file sizes of the different versions after uploading? It is possible YT will compress them both down to almost the same size, so the only difference will be your local storage. That might not be the case, but something to consider at least.

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