Aspect ratio conversions cause huge rendering times

Help/How To
1

I have source videos that are 30 seconds or so in length and in 16:9 aspect ratio. If I export those without changing aspect ratios (even with fancy filters), the export only takes a few minutes. However, if convert those into 9:16 aspect ratio (required for youtube shorts), the same exact clip will take a few hours to export, even with hardware encoding enabled. My friend uses wondershare for this same process and only needs a few minutes for the same export and also has live previews without lowering quality. Am I missing some steps, or does shotcut just need this long to convert aspect ratios?

For reference, I have the project in 9:16, one main track for the scaled/cropped source video (which is 16:9), and one blurred background track based off the source video to fill out the top and bottom instead of having black bars there.

Thanks.

2

If this is turned off, what is the rendering time? Is it perhaps the blur filter taking a long time to process?

3

In addition to @Austin’s question…

Have you tried to enable “Parallel Processing” in the advanced section of the export tab?

4

It seems like the processing time is about the same unless I don’t have an aspect ratio conversion happening. Thanks.

5

That’s enabled already. Thanks.

6

I am also curious about this. In my experience, aspect ratio conversion is not particularly time consuming. But blur often is. Have you tried disabling filters one-by-one to see if one of your filters is causing the slow export?

7

You could give the Blur:pad filter a shot, it sounds like it’s exactly what you want and might be more efficient.

8

It does seem to be all about the blur filter. Thanks for the suggestions. I was using gaussian blur which makes a 4 minute export run for almost 3 hours… I’m testing with some of the other blur implementations. So far, they all seem significantly faster.

Thanks!

9

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