Lightroom Classic: Exported video size increases greatly

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  • Problem
  • Updated 2 months ago
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  • (Edited)

I'm finding that the exported size of MP4 videos in LR Classic is greatly increased compared to the original, which is slowing down the export process greatly. I would have expected a reduction in file size. While I have no expectations of doing anything but the most simple video trimming in LR, I expect it at least to not bloat the file size and take an inordinate amount of time doing it.

I tried a range of MOV (QuickTime) video files,  from various cameras of different ages, exporting them as format H.264 and quality Max. I am using LR Classic 9.2.1 on Windows 7 on a Dell N5010 Laptop, 4GB RAM.

The ratio of exported to original file size ranges from 0.33 (reduction) to 5.7 (expansion). On average the ratio was 1.8. Of 6 different videos, 4 were expanded in size.

This does not seem right. Generally, MP4 should reduce the file size, not expand it.

If I select to export the original unedited file, the export happens very quickly, obviously without a change in file size. But then what is the point of using LR to handle videos at all?

Can you please investigate and advise? This is slowing down my export process by a large amount whenever there are videos mixed in with still pictures.

Cheers, Frank
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Frank Rossi

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  • Disappointed

Posted 2 months ago

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Sumeet Choudhury, Employee

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Hi Frank,

Thanks for reporting the issue and bringing this to our light.

I could see your point here regarding the increase in size for the exported videos on an average to 1.8 times. 
I could however, also see few AVI files (PENTAX) size getting reduced from 140MB to 27MB (that would be 5 times reduction in size) after export. At the same time, I can see iPhone Videos not increasing in size much after export (in fact the slo-mo video size gets reduced after export). So yes, it's a mixed bag.

Will investigate further on this and log a bug accordingly if need be.