在編解碼中,變換是最重要的一步,從開始的模擬離散變換,到現在國際和中國標準中的整數變換,變換取的壓縮是最重要的,在 DV等其他編解碼中,只使用變換進行壓縮,
下面對H264 和AVS使用的變換矩陣進行比較,看看誰好。
A8x8? =??
0.707107??? 0.707107??? 0.707107??? 0.707107??? 0.707107????? 0.707107???? 0.707107???? 0.707107?? ?
?0.980785??? 0.831470??? 0.555570??? 0.195090??? -0.195090??? -0.555570??? -0.831470??? -0.980785? ?
?0.923880??? 0.382683??? -0.382683??? -0.923880??? -0.923880??? -0.382684??? 0.382683??? 0.923879? ?
?0.831470??? -0.195090??? -0.980785??? -0.555570??? 0.555570??? 0.980785??? 0.195090??? -0.831470? ?
?0.707107??? -0.707107??? -0.707107??? 0.707107??? 0.707107??? -0.707107??? -0.707107??? 0.707107? ?
?0.555570??? -0.980785??? 0.195090??? 0.831470??? -0.831470??? -0.195091??? 0.980785??? -0.555570? ?
?0.382683??? -0.923880??? 0.923879??? -0.382683??? -0.382684??? 0.923880??? -0.923879??? 0.382683? ?
?0.195090??? -0.555570??? 0.831470??? -0.980785??? 0.980785??? -0.831469??? 0.555570??? -0.195090?
這是8x8的系數矩陣,也就是說,我們要盡量的接近A8x8 的數據,進行變換,反變換時才最好,最接近原始數據。這就是標準數據,其他制定的標準必須與它接近才好。
將上面標準矩陣放大11.31370499797倍:結果為:
A'8x8?=?
?7.999998???? 7.999997??? 7.99999??? 7.99999??? 7.999998???? 7.999996????? 7.999999??? 7.99999??
?11.096315??? 9.407002??? 6.28555??? 2.20719??? -2.20719??? -6.285557??? -9.407002??? -11.09631??
?10.452501??? 4.329568??? -4.32956??? -10.4525??? -10.4525??? -4.329568??? 4.329567??? 10.452??
?9.407002??? -2.207194??? -11.0963??? -6.28555??? 6.285557??? 11.096316??? 2.20719??? -9.407001? ?
?7.999998??? -7.999997??? -7.99999??? 7.99999??? 7.99999??? -7.99999??? -7.999999??? 7.999996? ?
?6.285558??? -11.096315??? 2.20719??? 9.40700??? -9.407001??? -2.207196??? 11.09631??? -6.2855??
?4.329568??? -10.452501??? 10.452??? -4.32956??? -4.329569??? 10.452501??? -10.452499??? 4.3295??
?2.207195??? -6.285558??? 9.40700??? -11.0963??? 11.0963?? ? - 9.4070??? 6.285555??? -2.207190?
H 264??? A8x8?=?
8??????? 8?????? 8?????? 8?????? 8?????? 8?????? 8?????? 8?????
12??? 10???? 6??????? 3?????? -3?? ? -6???? -10??? -12
8????? 4?????? -4?????? -8????? -8???? -4????? 4????? 8
10??? -3???? -12???? -6????? 6????? 12????? 3????? 10
8???? -8???? -8???????? 8?????? 8????? -8????? -8????? 8
6???? -12?? 3???????? 10???? 10???? -3? ? 12??????? -6
4 ? ? -8 ? ? 8 ? ? ? ?? -4 ? ? -4 ? ? ? 8 ? ?? -8 ? ? ? 4
3 ? ? -6 ? ? 10 ? ?? -12 ? ? 12 ?? -10 ? ? 6 ? ? ? -3
?
AVS????? A8x8?=
8??????? 8?????? 8?????? 8?????? 8?????? 8?????? 8?????? 8??
10???? 9??????? 6?????? 2????? -2????? -6????? -9???? -10
10???? 4?????? -4????? -10???? -10??? -4??? 4????? 10
9?????? -2????? -10???? -6?????? 6???? 10????? 2???? -9
8?????? -8?????? -8?????? 8?????? 8?????? -8???? -8????? 8
6?????? -10??? 2?????? 9???????? -9???? -2???? 10??? -6
4???? -10??? 10???? -4?????? -4?????? 10????? -10?? 4
2???? -6????? 9?????? -10???? -10???? -9??????? 6????? -2
根據上面提出的比較標準,大家可以使用程序算一下,并與A'8x8?進行比較,結果avs好點。