Huge AVI size!

fgras78
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Huge AVI size!

#1

Post by fgras78 »

Hello,

I use Sharpcap 3.2 (32 bits) with windows 10 (64) and a Mikrokular HD webcam (Bresser).
The AVI capture files generated are very huge :
example for 200 frames => more than 1.2 Gb !!!

I don't understand if it's a bug with Sharpcar and this camera.
Anybody experienced such thing?

Thanks for your support.
Best regards
Fabrice
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admin
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Re: Huge AVI size!

#2

Post by admin »

Hi,

What resolution does this camera use? The size of the output file in AVI mode should be

Width * Height * Number of Frames * 3 (bytes)

SharpCap does not use compression (deliberately) when writing output files to maintain best image quality, but it does give larger files.

thanks, Robin
fgras78
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Re: Huge AVI size!

#3

Post by fgras78 »

hello,

the capture size is 1920x1080.

if I capture in jpeg separated images, it's OK with a total size around 35Mo for the 200 jpeg images.

but for the AVI capture, the generated Avi size is 1.15 GigaOctets...

I tried with my built-in webcam and it's the same bug...
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Re: Huge AVI size!

#4

Post by admin »

Hi,

Yes, this is how it is supposed to work. When you capture to JPEG the image is compressed to give a smaller file size but the downside of this is that some detail in the images is lost. When saving to video file formats in SharpCap like AVI, there is no compression to ensure maximum image quality.

Cheers, Robin
altair
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Re: Huge AVI size!

#5

Post by altair »

I realize this is an old post but - -

I have habitually used Sharpcap v2.9, to acquire solar images. I collect 400 frame avis with a Bresser Mikrokular and they are about 40-60 Mb in size.

I tried Sharpcap v4 this morning and similar files were about 2.4 Gb!

After stacking both I could see no discernible difference in quality. Are there some settings somewhere in v4 I have missed?
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Re: Huge AVI size!

#6

Post by admin »

Hi,

no, there isn't anything you have missed - the way that SharpCap 2.9 worked meant that if your webcam sent compressed data to SharpCap, it could be saved to file while still compressed (a copy would be uncompressed for display). However, this prevented a lot of SharpCap features from working with webcams, since you couldn't make changes to the frame data in that approach.

So, in order to make all the cameras have the same level of functionality, the way that webcams worked changed in about SharpCap 3, which removed the possibility of saving the files in compressed form. Unfortunately re-compressing the data is nowhere near as easy as you might think (especially since unless the new compression is exactly the same as the old you will get two lots of compression artifacts in the video, which is not good).

I think the best of both worlds for you is to continue using the old version of SharpCap for capture with your webcam if you wish, and to use the more up-to-date versions for longer exposure imaging if you do that.

cheers,

Robin
altair
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Re: Huge AVI size!

#7

Post by altair »

Thanks. My problem is that I construct solar full-disc mosaics from between 4 and 12 individual files. The problem of shuffling the larger files around my domestic network and data archiving becomes extreme! I have v2.9 and 2.8 on my acquisition machines and I shall continue to use those. However, a problem will occur if I have to replace those machines. I believe it is no longer possible to download 2.9? For deep-sky images I do not use avis but a sequence of stills from a frame-grabber attached to a low-light video camera. I presume this will be ok? I still use avis for lunar or planetary though.
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Re: Huge AVI size!

#8

Post by admin »

Hi,

yes, I did take down the v2.9 installer, since people were installing it and then posting about bugs they had found that have long been fixed in newer versions :(

What you can do is just copy the c:\Program Files\SharpCap 2.9 folder to your new machine - do that and create a shortcut to SharpCap.exe on the desktop and you should be fine.

Capturing stills should be fine with no real change in file size since 2.9.

cheers,

Robin
altair
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Re: Huge AVI size!

#9

Post by altair »

Thanks again!

Out of interest you can see all my solar images on Spaceweather and in the BAA's solar section. (Typical interesting recent one here:https://spaceweathergallery.com/full_im ... 197572.jpg)
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Re: Huge AVI size!

#10

Post by oopfan »

@altair,

I visit Spaceweather.com several times a day.

I copied a section of your image. Can you describe what it is telling us? I'm afraid that very few of us have experience with Solar:
Screenshot from 2022-06-12 08-16-02.png
Screenshot from 2022-06-12 08-16-02.png (22.16 KiB) Viewed 641 times
For example:
Is it just Ha? What is the bandpass?
What is "Mikrokular"?
What is "Window sill"?
What is the exposure?
How many frames do you stack?
What software do you use beyond SharpCap?

Thanks,
Brian
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