Methods, architectures, apparatuses and systems directed to improved linear model estimation for template based video coding
Procedures, methods, architectures, apparatuses, systems, devices, and computer program products directed to improved linear model estimation for template-based video coding are provided. Included therein is a method comprising determining minimum and maximum (“min/max”) values of luma and chroma samples neighboring a coding block, wherein the min/max chroma values correspond to the min/max luma values; determining a first linear model parameter of a template-based video coding technique (i) based on a single look-up table and the min/max chroma values and (ii) at a precision no greater than 16 bits; determining a second linear model parameter of the template-based video coding technique (i) based on the first linear model parameter and the minimum chroma and luma values and (ii) at a precision no greater than 16 bits; and predicting chroma samples of the coding block based on reconstructed luma samples of the coding block and the first and second linear model parameters.
1. A method for encoding video data by an encoder, the method comprising:
coding a video block of the video data using a linear model of a template-based video coding technique, the coding comprises:
using a single look up table to determine a first parameter of the linear model, the single look up table including values for determining least significant bits, wherein the determining of the first parameter of the linear model comprises:
determining minimum and maximum values derived from luma samples neighboring the video block;
determining minimum and maximum values derived from chroma samples neighboring the video block; and
computing the first parameter of the linear model as a function of (i) the minimum and the maximum values of the chroma samples and (ii) a reciprocal of a difference between the minimum and the maximum values of the luma samples, wherein the reciprocal is derived from the single look up table, and
predicting samples of the video block based on the linear model.
2. The method according to claim 1 , further comprising:
computing a second parameter of the linear model as a function of the minimum value of the chroma samples, the minimum value of the luma samples, and the first parameter of the linear model.
3. The method according to claim 2 , wherein the second parameter is computed at a precision that is less than or equal to 16 bits.
4. The method according to claim 1 , wherein the first parameter is computed at a precision that is less than or equal to 16 bits.
5. The method according to claim 1 , wherein the template-based video coding technique is based on a cross component linear model (CCLM) or a local illumination compensation (LIC).
6. A method for decoding video data by a decoder, the method comprising:
decoding a video block of the video data using a linear model of a template-based video coding technique, the decoding comprises:
using a single look up table to determine a first parameter of the linear model, the single look up table including values for determining least significant bits, wherein the determining of the first parameter of the linear model comprises:
determining minimum and maximum values derived from luma samples neighboring the video block;
determining minimum and maximum values derived from chroma samples neighboring the video block; and
computing the first parameter of the linear model as a function of (i) the minimum and the maximum values of the chroma samples and (ii) a reciprocal of a difference between the minimum and the maximum values of the luma samples, wherein the reciprocal is derived from the single look up table, and
predicting samples of the video block based on the linear model.
7. The method according to claim 6 , further comprising:
computing a second parameter of the linear model as a function of the minimum value of the chroma samples, the minimum value of the luma samples, and the first parameter of the linear model.
8. The method according to claim 7 , wherein the second parameter is computed at a precision that is less than or equal to 16 bits.
9. The method according to claim 6 , wherein the first parameter is computed at a precision that is less than or equal to 16 bits.
10. The method according to claim 6 , wherein the template-based video coding technique is based on a cross component linear model (CCLM) or a local illumination compensation (LIC).
11. An encoder for encoding video data, comprising:
at least one processor; and
memory storing instructions that, when executed by the at least one processor, cause the encoder to:
code a video block of the video data using a linear model of a template-based video coding technique, the coding comprises:
using a single look up table to determine a first parameter of the linear model, the single look up table including values for determining least significant bits, wherein the determining of the first parameter of the linear model comprises:
determining minimum and maximum values derived from luma samples neighboring the video block;
determining minimum and maximum values derived from chroma samples neighboring the video block; and
computing the first parameter of the linear model as a function of (i) the minimum and the maximum values of the chroma samples and (ii) a reciprocal of a difference between the minimum and the maximum values of the luma samples, wherein the reciprocal is derived from the single look up table, and
predicting samples of the video block based on the linear model.
12. The encoder according to claim 11 , wherein the instructions further cause the encoder to:
compute a second parameter of the linear model as a function of the minimum value of the chroma samples, the minimum value of the luma samples, and the first parameter of the linear model.
13. The encoder according to claim 12 , wherein the second parameter is computed at a precision that is less than or equal to 16 bits.
14. The encoder according to claim 11 , wherein the first parameter is computed at a precision that is less than or equal to 16 bits.
15. The encoder according to claim 11 , wherein the template-based video coding technique is based on a cross component linear model (CCLM) or a local illumination compensation (LIC).
16. A decoder for decoding video data, comprising:
at least one processor; and
memory storing instructions that, when executed by the at least one processor, cause the decoder to:
decode a video block of the video data using a linear model of a template-based video coding technique, the decoding comprises:
using a single look up table to determine a first parameter of the linear model, the single look up table including values for determining least significant bits, wherein the determining of the first parameter of the linear model comprises:
determining minimum and maximum values derived from luma samples neighboring the video block;
determining minimum and maximum values derived from chroma samples neighboring the video block; and
computing the first parameter of the linear model as a function of (i) the minimum and the maximum values of the chroma samples and (ii) a reciprocal of a difference between the minimum and the maximum values of the luma samples, wherein the reciprocal is derived from the single look up table, and
predicting samples of the video block based on the linear model.
17. The decoder according to claim 16 , wherein the instructions further cause the decoder to:
compute a second parameter of the linear model as a function of the minimum value of the chroma samples, the minimum value of the luma samples, and the first parameter of the linear model.
18. The decoder according to claim 17 , wherein the second parameter is computed at a precision that is less than or equal to 16 bits.
19. The decoder according to claim 16 , wherein the first parameter is computed at a precision that is less than or equal to 16 bits.
20. The decoder according to claim 16 , wherein the template-based video coding technique is based on a cross component linear model (CCLM) or a local illumination compensation (LIC).