Graphics Reference
In-Depth Information
Start 4x4 subblock
Context depends on luma/chroma,
whether in DC subblock, number of
trailing ones in previous 4x4
subblock
[Fig. 8.24]
Absolute level greater than 1
(
coeff_abs_level_greater1_flag
)
Repeat minimum of
(number of non-zero
sig_coeff_flag
, 8)
Absolute level greater than 2
(
coeff_abs_level_greater2_flag
)
Context depends on luma/chroma,
whether in DC subblock
Repeat minimum of
(number of non-zero
coeff_abs_level_greater1_flag
, 1)
If sign data hiding enabled, infer
hidden bin based on number of
non-zero coefficient between the
first and last non-zero coefficients in
4x4 subblock is greater than 4
Coefficient sign
(
coeff_sign_flag
)
Repeat number of non-zero
sig_coeff_flag
(minus one if sign
data hiding enabled)
Truncated Rice binarization where
Rice parameter
k
can increase
based on previous coefficient level.
k
resets to 0 for each 4x4 subblock.
[Tab. 8.12, 8.13, 8.14]
Repeat minimum of
(number of non-zero
sig_coeff_flag
- 8
+ number of non-zero
coeff_abs_level_greater1_flag
+ number of non-zero
coeff_abs_level_greater2_flag
, 16)
Absolute level remaining
(
coeff_abs_level_remaining
)
End 4x4 subblock
Fig. 8.25
Flow chart for coding the syntax elements of absolute level minus 1 and sign for a 4
4 subblock in HEVC