High dynamic range HDR video processing method, encoding device, and decoding device
This application provides a high dynamic range HDR video processing method, an encoding device, and a decoding device. The method includes: obtaining dynamic metadata of an N th HDR video frame according to a dynamic metadata generation algorithm; calculating a tone-mapping (tone-mapping) curve parameter of the N th HDR video frame based on the dynamic metadata of the N th HDR video frame; generating a tone-mapping curve based on the curve parameter; determining, according to a quality assessment algorithm, distortion D′ caused by the tone-mapping curve; comparing D′ and D T , to determine a mode used by the N th HDR video frame, where the mode is an automatic mode or a director mode, and D T is a threshold value; and determining metadata of the N th HDR video frame based on the determined mode used by the N th HDR video frame.
1 . A high dynamic range (HDR) video processing method, wherein the method is applied by an encoding device and comprises:
obtaining dynamic metadata of an N th HDR video frame according to a dynamic metadata generation algorithm, wherein N is greater than 0;
calculating a tone-mapping curve parameter of the N th HDR video frame based on the dynamic metadata of the N th HDR video frame;
generating a tone-mapping curve based on the curve parameter, wherein the tone-mapping curve is the formula (1):
L
′
=
F
(
L
)
=
a
⨯
(
p
⨯
L
n
(
p
-
1
)
⨯
L
n
+
1
)
m
+
b
,
(
1
)
wherein
curve parameters a and p are based on the dynamic metadata of the N th HDR video frame, curve parameters b, n, and m are preset values, L is input luminance, and L′ is output luminance;
determining, according to a quality assessment algorithm, distortion D′ caused by the tone-mapping curve;
comparing D′ and D T , wherein D T is a threshold value; and
generating metadata of the N th HDR video frame based on the comparing, wherein:
when D′ is not greater than D T the metadata comprises first curve parameters configured to enable a decoder to generate a tone-mapping curve, and the metadata of the N th HDR video frame comprises the dynamic metadata of the N th HDR video frame, and
when D′ is greater than D T the metadata is configured to enable the decoder to calculate second curve parameters to similarly enable the decoder to generate a tone-mapping curve, and the metadata of the N th HDR video frame comprises the dynamic metadata of the N th HDR video frame and P[N], wherein P[N] is a curve parameter P used when D′ is greater than D T .
2 . The method according to claim 1 , wherein the comparing D′ and D T comprises:
determining that the N th HDR video frame will use a director mode when D′ is greater than D T , wherein D T is a distortion of the N th HDR video frame in the director mode; or
determining that the N th HDR video frame will use an automatic mode when D′ is less than or equal to D T .
3 . The method according to claim 2 , wherein the method further comprises:
obtaining an offset deltaC [N] of the tone-mapping curve parameter of the N th HDR video frame based on metadata of frames in an M-frame window, the tone-mapping curve parameter, and D′, wherein M is greater than 0 and a lower boundary of the M-frame window is an N-M th frame, and an upper boundary of the M-frame window is the N th frame.
4 . The method according to claim 3 , wherein the generating metadata of the N th HDR video frame comprises:
generating the metadata of the N th HDR video frame based on the mode to be used for the N th HDR video frame, the dynamic metadata generation algorithm, and the offset deltaC [N] of the tone-mapping curve parameter.
5 . The method according to claim 1 , wherein after the obtaining the dynamic metadata of the N th HDR video frame, the method further comprises:
performing display adaptation based on one or more preset configuration parameters; wherein the preset configuration parameters comprise one or more of the following:
1000-nit, 500-nit, and a standard dynamic range (SDR).
6 . The method according to claim 1 , wherein the metadata of the N th HDR video frame comprises a flag bit, and the flag bit indicates that the mode to be used for the N th HDR video frame is the director mode, or the flag bit indicates that the mode to be used for the N th HDR video frame is the automatic mode.
7 . An encoding device, comprising:
at least one processor; and
at least one memory coupled to the at least one processor and storing instructions for execution by the at least one processor to cause the at least one processor to:
obtain dynamic metadata of an N th HDR video frame according to a dynamic metadata generation algorithm, and N is greater than 0; and
calculate a tone-mapping curve parameter of the N th HDR video frame based on the dynamic metadata of the N th HDR video frame;
generate a tone-mapping curve based on the curve parameter, wherein the tone-mapping curve is the formula (1):
L
′
=
F
(
L
)
=
a
⨯
(
p
⨯
L
n
(
p
-
1
)
⨯
L
n
+
1
)
m
+
b
,
(
1
)
wherein
curve parameters a and p are based on the dynamic metadata of the N th HDR video frame, curve parameters b, n, and m are preset values, Lis input luminance, and L′ is output luminance;
determine, according to a quality assessment algorithm, distortion D′ caused by the tone-mapping curve;
compare D′ and D T , wherein Dr is a threshold value; and
generate metadata of the N th HDR video frame based on the comparing, wherein:
when D′ is not greater than D T the metadata comprises first curve parameters configured to enable a decoder to generate a tone-mapping curve, and the metadata of the N th HDR video frame comprises the dynamic metadata of the N th HDR video frame, and
when D′ is greater than D T the metadata is configured to enable the decoder to calculate second curve parameters to similarly enable the decoder to generate a tone-mapping curve, and the metadata of the N th HDR video frame comprises the dynamic metadata of the N th HDR video frame and P[N], wherein P[N] is a curve parameter P used when D′ is greater than D T .
8 . The encoding device according to claim 7 , wherein execution by the at least one processor further causes the at least one processor to:
determine that the N th HDR video frame will use a director mode when D′ is greater than D T , wherein D T is a distortion of the N th HDR video frame in the director mode; or
determine that the N th HDR video frame will use an automatic mode when D′ is less than or equal to D T .
9 . The encoding device according to claim 8 , wherein execution by the at least one processor further causes the at least one processor to:
obtain an offset deltaC [N] of the tone-mapping curve parameter of the N th HDR video frame based on metadata of frames in an M-frame window, the tone-mapping curve parameter, and D′, wherein M is greater than 0 and a lower boundary of the M-frame window is an N-M th frame, and a upper boundary of the M-frame window is the N th frame.
10 . The encoding device according to claim 8 , wherein execution by the at least one processor further causes the at least one processor to:
generate the metadata of the N th HDR video frame based on the mode to be used for the N th HDR video frame, the dynamic metadata generation algorithm, and the offset deltaC [N] of the tone-mapping curve parameter.
11 . The encoding device according to claim 7 , wherein after the obtaining the dynamic metadata of the N th HDR video frame, the encoding device is further configured to perform display adaptation base on any one or more of the following preset configuration parameters:
1000-nit, 500-nit, and a standard dynamic range (SDR).
12 . The encoding device according to claim 7 , wherein the metadata of the N th HDR video frame comprises a flag bit, and the flag bit indicates that the mode to be used for the N th HDR video frame is the director mode, or the flag bit indicates that the mode to be used for the N th HDR video frame is the automatic mode.
13 . A non-transitory computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, cause an encoding device to:
obtain dynamic metadata of an N th HDR video frame according to a dynamic metadata generation algorithm, and N is greater than 0; and
calculate a tone-mapping curve parameter of the N th HDR video frame based on the dynamic metadata of the N th HDR video frame;
generate a tone-mapping curve based on the curve parameter, wherein the tone-mapping curve is the formula (1):
L
′
=
F
(
L
)
=
a
×
(
p
×
L
n
(
p
-
1
)
×
L
n
+
1
)
m
+
b
,
(
1
)
wherein
curve parameters a and p are based on the dynamic metadata of the N th HDR video frame, curve parameters b, n, and m are preset values, Lis input luminance, and L′ is output luminance;
determine, according to a quality assessment algorithm, distortion D′ caused by the tone-mapping curve;
compare D′ and D T , wherein Dr is a threshold value; and
generate metadata of the N th HDR video frame based on the comparing, wherein:
when D′ is not greater than D T the metadata comprises first curve parameters configured to enable a decoder to generate a tone-mapping curve, and the metadata of the N th HDR video frame comprises the dynamic metadata of the N th HDR video frame, and
when D′ is greater than D T the metadata is configured to enable the decoder to calculate second curve parameters to similarly enable the decoder to generate a tone-mapping curve, and the metadata of the N th HDR video frame comprises the dynamic metadata of the N th HDR video frame and P[N], wherein PIN is a curve parameter P used when D′ is greater than D T .
14 . The non-transitory computer readable medium according to claim 13 , wherein when the computer program is executed the processor is further configured to:
determine that the N th HDR video frame will use a director mode when D′ is greater than D T , wherein D T is a distortion of the N th HDR video frame in the director mode; or
determine that the N th HDR video frame will use an automatic mode when D′ is less than or equal to D T .
15 . The non-transitory computer readable medium according to claim 13 , wherein when the computer program is executed the processor is further configured to:
obtain an offset deltaC [N] of the tone-mapping curve parameter of the N th HDR video frame based on metadata of frames in an M-frame window, the tone-mapping curve parameter, and D′, wherein M is greater than 0 and a lower boundary of the M-frame window is an N-M th frame, and a upper boundary of the M-frame window is the N th frame.
16 . The non-transitory computer readable medium according to claim 13 , wherein when the computer program is executed the processor is further configured to:
generate the metadata of the N th HDR video frame based on the mode to be used for the N th HDR video frame, the dynamic metadata generation algorithm, and the offset deltaC [N] of the tone-mapping curve parameter.