A simple question about file size (sometimes it matters)

[mgshn]

I start with a 52 MB .mp4 file loaded into VS. Next I break it into about eight clips and delete half of them. The video is now about half as long. When I go to produce it the smallest .mp4 it will make is 92 MB.

How come?

More importantly, how can I get an appropriately small output file, about 1/2 the size of the original and still retain as much quality as possible?

Thanks in advance,

Bob

[BrianCee]

Did you make sure that frame size and bitrate were exactly the same in your output as they were in the input

if you want to reduce the file size further then reduce the bitrate a bit more

As a rule of thumb - for a given video length in a specified format then quality equates to file size - to get smaller file sizes you will lose some quality

[mgshn]

Did you make sure that frame size and bitrate were exactly the same in your output as they were in the input

if you want to reduce the file size further then reduce the bitrate a bit more

As a rule of thumb - for a given video length in a specified format then quality equates to file size - to get smaller file sizes you will lose some quality

Maybe it's a bad assumption but when I import a video wouldn't VSP set the frame size and bitrate to match what I've just imported?

And, maybe I wasn't clear with my original question. I deleted half the content from the imported file. When I produce the modified output file it was about twice as large as the original. I would have expected the result to be significantly smaller, not a lot larger.

[BrianCee]

are the frame size and bitrate identical in the input and output files ?

[mgshn]

Hi Brian,

I got them as close as I could. I couldn't match the input file specks exactly because VSP has restrictions on what values can be selected.

Please see the attached for details.

[BrianCee]

I see factors there which could well account for the file size increase

You have increased the frame rate from 24 fps to 30 fps - that's an increase of 25% in the number of frames - 25% more images requiring disk space.

you have doubled the bitrate (data rate) - there are tables around the internet which will calculate how much more disc space that takes up.

both videos are still the same length at 706 seconds - so you have not cut the video in half - if you had then the second file would be only a small fraction bigger than the input - even with the increased frame and data values.

have you tried rendering "same as first video clip"