Zoom Recording and Openshot Editing

[Kyle1974]

Hi

Hope this is the right place!

So last week I did a Zoom interview with someone remotely and the video file came in at 75.4mb. I wanted to just make a couple of quick edits and then upload the video to Facebook but every time I export the video using Openshot, it comes out about at about 300mb. I did find a site that gave me some presets to put into Openshot for HD and SD but the same result. Do those sizes sound about right? Should I re-encode using handbrake? What would be the best settings if I wanted to do that? Is Openshot even the best (free!) thing for me to edit the video down with?

Thank you!

[zing269]

IIRC, zoom video is variable frame rate (vfr) and openshot is converting it to a constant frame rate (cfr) which will increase the size. I'm not familiar with openshot so I don't know if there is a way to stop it from converting vfr to cfr.

[Kyle1974]

IIRC, zoom video is variable frame rate (vfr) and openshot is converting it to a constant frame rate (cfr) which will increase the size. I'm not familiar with openshot so I don't know if there is a way to stop it from converting vfr to cfr.

Ah thank you zing269 - even that information is new to me! So in terms of editing, is there something you would recommend for editing (free preferably!) that is vfr and would keep it that way please?

[super8rescue]

Hi

The video file came in at 75.4mb.

every time I export the video using Openshot, it comes out about at about 300mb.

Assuming you are using windows

Right click/properties the zoom video file, choose the 'details' tab and note the bit rate.

Right click the OpenShot video export and do the same.

What are the bitrates you find on both videos?


[Attachment 58162 - Click to enlarge]


It sounds like you just need to change/lower the export bitrate settings in Openshot to bring it down to a size you are happy with.


For example, I screen record in OBS at 6500 kbs

Editing in Davinci Resolve, I could choose 'Best' or 'Good' preset for export which will produce a massive file size with no improvement to quality, as the original video was only at 6500kbs so no point in exporting at say, 15000kbs

On export I choose to 'restrict' the bitrate to 7000 to 7500kbs to keep things about the same.

Skip to 5'40 in the video below, it shows you where the bitrate settings are in Openshot

https://www.youtube.com/watch?v=9ak-FlKkXaQ

Try another export and choose a similar bitrate in openshot to export with, to the bitrate of the zoom video, and see how that suits you.

Perhaps try out a few short clips with different bitrates on export so you can see the difference in file size v picture/sound quality.


__________________________________________________ __________________________________________________ __________

As for your question, what is best to edit with, that really depends on your computer specs.

I use the free version of davinci resolve on a fujitsu i7 laptop, 32gb RAM, it does need at least i7 with 8gb ram for basic cut, edits and export, it wouldn't run on my i5 with 8gb ram without grinding to a halt on a basic edit.

Ideally you want 16gb RAM with an i7 or better.

OpenShot is capable, you just need to understand it's different settings, perhaps watch some youtube tutorials in areas that you need to know better

[smrpix]

Zoom uses a "secret sauce" of very long GOPs, low bitrate filtered audio and small raster dimensions to achieve ridiculously small file sizes. The only way to stay close is to use a smart rendering editor like TMPGenc Smart Renderer or VideoRedo. (I have used the TMPGenc, not the VideoRedo.) Anything else will balloon your file -- as you have observed.

[poisondeathray]

for the zoom cfr vs vfr ; >version 3.5 is CFR

https://support.zoom.us/hc/en-us/articles/203650745-Recording-formats

Zoom local recording and cloud recording save recording in MP4 (video), M4A (audio) and txt (chat) formats.

With Version 3.5 and above, the MP4 recording is a single-resolution with fixed frame rate format to ensure better compatibility with media players.
Versions prior to 3.5 are created using individual MP4 files and multi-resolution with variable frame rate format.

Zoom uses a "secret sauce" of very long GOPs, low bitrate filtered audio and small raster dimensions to achieve ridiculously small file sizes. The only way to stay close is to use a smart rendering editor like TMPGenc Smart Renderer or VideoRedo. (I have used the TMPGenc, not the VideoRedo.) Anything else will balloon your file -- as you have observed.

If that's the reason, why couldn't you use very long GOP's (or even infinite) and very low bitrate audio ? Sure, there would be some quality loss, but if you use ideal settings it should be minimal. You could even use HEVC or AV1, and/or make it VFR to reduce bitrate even more for a given level of quality


Does anyone have a native zoom MP4 sample ?

[Kyle1974]

Hi

The video file came in at 75.4mb.

every time I export the video using Openshot, it comes out about at about 300mb.

Assuming you are using windows

Right click/properties the zoom video file, choose the 'details' tab and note the bit rate.

Right click the OpenShot video export and do the same.

What are the bitrates you find on both videos?


[Attachment 58162 - Click to enlarge]


It sounds like you just need to change/lower the export bitrate settings in Openshot to bring it down to a size you are happy with.


For example, I screen record in OBS at 6500 kbs

Editing in Davinci Resolve, I could choose 'Best' or 'Good' preset for export which will produce a massive file size with no improvement to quality, as the original video was only at 6500kbs so no point in exporting at say, 15000kbs

On export I choose to 'restrict' the bitrate to 7000 to 7500kbs to keep things about the same.

Skip to 5'40 in the video below, it shows you where the bitrate settings are in Openshot

https://www.youtube.com/watch?v=9ak-FlKkXaQ

Try another export and choose a similar bitrate in openshot to export with, to the bitrate of the zoom video, and see how that suits you.

Perhaps try out a few short clips with different bitrates on export so you can see the difference in file size v picture/sound quality.


__________________________________________________ __________________________________________________ __________

As for your question, what is best to edit with, that really depends on your computer specs.

I use the free version of davinci resolve on a fujitsu i7 laptop, 32gb RAM, it does need at least i7 with 8gb ram for basic cut, edits and export, it wouldn't run on my i5 with 8gb ram without grinding to a halt on a basic edit.

Ideally you want 16gb RAM with an i7 or better.

OpenShot is capable, you just need to understand it's different settings, perhaps watch some youtube tutorials in areas that you need to know better

Thank you - I am slowly getting there I think - my processor is AMD Ryzen 5 3600 and I have 16gb of memory so I thought for a 13 min export it would be fairly quick?

The data stats I have from the zoom clip are 25fps, 508kbps datarate and 634kbps total bitrate. I think I said above, I have added into Zoom, the two exporting presets now for Zoom SD and Zoom HD.

[super8rescue]

I have been processing video for 15 years and I still learn something every day.
Keep at it. You'll get there.

13 minute export on my laptop, with no effects or text, would take around 16-25 minutes.