BitJazz
SheerVideo Power
Y'CbCr 8bw 4:2:2p Data
The following table shows the compression statistics for the Sheer Y'CbCr 8bw 4:2:2p codec for each of the Kodak images.
When encoding Y'CBCR 8bw 4:2:2p images with the Sheer Y'CbCr 8bw 4:2:2p codec,
SheerVideo's compression power ranges from 1.74 in image 13 to 2.67 in image 03, averaging 2.32.
SheerVideo's space savings ranges from 43% to 63%, averaging around 56%.
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uncom-
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Sheer-
Video |
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| # |
image |
'yuv2' |
'Shr4' |
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| 01 |  | 786432
1.00
0% | 378047
2.08
52% | bytes
power
space savings | | 02 |  | 786432
1.00
0% | 323075
2.43
59% | bytes
power
space savings | | 03 |  | 786432
1.00
0% | 294066
2.67
63% | bytes
power
space savings | | 04 |  | 786432
1.00
0% | 328592
2.39
58% | bytes
power
space savings | | 05 |  | 786432
1.00
0% | 404452
1.94
49% | bytes
power
space savings | | 06 |  | 786432
1.00
0% | 357548
2.20
55% | bytes
power
space savings | | 07 |  | 786432
1.00
0% | 307764
2.56
61% | bytes
power
space savings | | 08 |  | 786432
1.00
0% | 405884
1.94
48% | bytes
power
space savings | | 09 |  | 786432
1.00
0% | 308219
2.55
61% | bytes
power
space savings | | 10 |  | 786432
1.00
0% | 309537
2.54
61% | bytes
power
space savings | | 11 |  | 786432
1.00
0% | 337346
2.33
57% | bytes
power
space savings | | 12 |  | 786432
1.00
0% | 298207
2.64
62% | bytes
power
space savings | | 13 |  | 786432
1.00
0% | 452094
1.74
43% | bytes
power
space savings | | 14 |  | 786432
1.00
0% | 375932
2.09
52% | bytes
power
space savings | | 15 |  | 786432
1.00
0% | 318869
2.47
59% | bytes
power
space savings | | 16 |  | 786432
1.00
0% | 313185
2.51
60% | bytes
power
space savings | | 17 |  | 786432
1.00
0% | 314130
2.50
60% | bytes
power
space savings | | 18 |  | 786432
1.00
0% | 393604
2.00
50% | bytes
power
space savings | | 19 |  | 786432
1.00
0% | 345254
2.28
56% | bytes
power
space savings | | 20 |  | 786432
1.00
0% | 315798
2.49
60% | bytes
power
space savings | | 21 |  | 786432
1.00
0% | 352879
2.23
55% | bytes
power
space savings | | 22 |  | 786432
1.00
0% | 355174
2.21
55% | bytes
power
space savings | | 23 |  | 786432
1.00
0% | 295495
2.66
62% | bytes
power
space savings | | 24 |  | 786432
1.00
0% | 369533
2.13
53% | bytes
power
space savings |
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| Mean |
786432
1.00
0% | 343945
2.32
56% | bytes
power
space savings |
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The Y'CBCR 8bw 4:2:2 format,
found in the pixel formats 'yuv2' and 'yuvu',
is a popular older format which does not comply with modern ITU or SMPTE standards,
and has been superseded by the Y'CBCR 8bv 4:2:2 format.
Y'CBCR 8bw 4:2:2 contains only two 8-bit values per pixel.
While luma (Y') is represented at every pixel, each pixel only retains a single chroma value,
alternating between CB and CR.
- Y': luma
- CB: blue-yellow chroma
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- Y': luma
- CR: red-cyan chroma
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Y'CBCR 8bw 4:2:2 has wide-range chroma components
represented as two's-complement signed integers [-127..127]->[-1/2..1/2]
and a full-range luma component [0..255]->[0..1].
While this format leaves no play for filter slop,
it can represent significantly more displayable colors than the corresponding 601-compliant format,
making it more useful for storage of video from higher-precision sources.
To convert the original RGB footage to Y'CBCR 8bw 4:2:2 format,
we encoded the RGB movie with Apple's Component Video codec.
Rather than reduce or crop the frames down to SD resolution,
we decided to test them at their original nonstandard video resolution to simplify comparison.
The Sheer Y'CbCr 8bw 4:2:2 encoder was used with the settings: Millions of Colors, Progressive.
With only 2 byte-size components per pixel,
the uncompressed size of each these Y'CBCR 8bw 4:2:2 frames
is 2 x 768 x 512 = 786432 bytes.
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