[M4IF Technotes] Method 1 Quantisation

Yossi yossi neomagic.co.il
Tue Jun 5 17:02:11 EDT 2001


Sirs,
MPEG4 Video Verification Model (VM 16.0) presents two quantisation methods:
H263 and MPEG4 (pp. 61-63).
Section 3.4.4.2 describes Method 1 (H263), where Intra DC quantisation is
level = dc_coeff // 8
Section 3.4.5.1.1 describes Method 2 (MPEG4), where Intra DC quantisation is
level = dc_coeff//dc_scaler, where dc_scaler is a non-linear scaler based on
Qp.
However, Section 3.4.5.1.1 states, "Note: This section is valid for H.263
quantisation also."
Is the Intra DC quantisation method presented in Sec. 3.4.4.2 incorrect? In
particular, I am looking at the Simple Profile that allows only Method 1 for
quantization (see Table 9-1 in Part 2 of the MPEG4 Standard, page 201).
Should Intra DC quantisation for Simple Profile follow Section 3.4.4.2 or
Section 3.4.5.1.1?
Thank you,
Yossi Shain
NeoMagic Israel


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