CODEWITHSUNDEEP
videosignal-processingcodecyuvbitrate
Balamurugan A
Balamurugan A

Reputation: 1964

Video Bitrate calculation for uncompressed video

I am trying to understand the bit rate for uncompressed video. But could not understand exactly while referring http://web.forret.com/tools/video_fps.asp?width=3840&height=2176&fps=30&space=yuv420&depth=4

For a 3840x2176(width x stride) video with 30fps, YUV420 colorformat:

Calculating one uncompressed frame:

PixelPerFrame      = 3840 x 2176
                   = 8,355,840 pixel

I think, for yuv420 with 4bits per color, bits per pixel = 12

So, bits per frame = 12 * 8355840  
                   = 100,270,080 bits
                   = 95.625 Megabits
                   = 11.953125 MegaBytes

This value is atleast nearby with the reference link.

When calculating uncompressed Video:

30 fps bit rate    = 30 * sizeof one uncompressed frame.
                   = 30 * 100270080 Bits
                   = 3008,102,400 BitsPerSecond
                   = 2868.75 MegabitsPerSecond 
                   = 358.59375 MegaBytesPerSecond

But from the reference link i see its "188,01 MB 179,3 MiB"

Can anyone help me to understand ?

Upvotes: 3

Views: 4097

Answers (1)

ben
ben

Reputation: 1390

Short: YUV420 with 4 Bit per Color has 6 Bit per pixel.

Long: In YUV420 you have one U and one V value per 2x2 group of Y(which means the two chroma components are sampled at half the sample rate of luma both horizontally and vertically. See this picture.

That means a 2x2 block of your picture has 4*4 Bit Y values + one 4 Bit U + 4 bit V.

that means: 2x2 pixel: 16 + 4 + 4 = 24 bit and so : 1 pixel: 6 bit

Upvotes: 3

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