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Size of uncompressed WMV – larger than necessary
Forgive me if I am missing something obvious!
I used Premiere (CS4) to create a short video.
I used the export function(Windows Media, uncompressed).
The resulting file is very large. Of course, I expected it to produce a big file – but how big?The video has a resolution 1280*720,at 29 fps, and runs for 5 mins 13 secs. The resulting filesize was about 21Gb.
I realise the file will contain some additional data (headers, keyframes etc), but my simple maths suggest it would create a file of about 1Gb.
Number of pixels in a frame * fps * number of secs / (8*1024*1024)
=(1280*720) * 29 * 313 / (8*1024*1024) = 997megSo. What is the WMV file containing which makes it 20 times the expected size?
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4 Replies
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I think you missed 24 bits of data for each pixel * 921,000 pixels per frame= 22 MB per frame
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Yep, that’s a decent size. 1280×720 10-bit 4:2:2 “uncompressed” video (with whatever file extension) is about 9Gb/min. I’d have expected a 45Gb file!
James Brady
Senior Editor
Results Video & Animation
El Paso, Texas
http://www.resultsvideo.com -
Many, many thanks for Mike’s explanation. I now feel like an idiot!
Happily, it also explained to me why V210 and UYVY give different file sizes. -
Yep…I can just squeeze a 720p24 :30 spot onto a Data DVD…4+ Gigs.
TimK,
Director, Consultant
Kolb Productions,
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