Method of operating encoder and method of operating system on chip including the encoder
A method of operating an encoder capable of predicting a band position and maximizing a compression ratio using variable length coding and a method of operating a system on chip (SoC) including the encoder are provided. The method includes determining a predicted band position of a first block included in a video frame, determining a first actual band position of the first block, and coding a difference value between the predicted band position and the first actual band position.
1. A method of operating an encoder, the method comprising:
determining, using the encoder, a predicted band position of a first block included in a video frame;
determining, using the encoder, a first actual band position of the first block; and
coding, using the encoder, a difference value of the predicted band position and the first actual band position.
2. The method of claim 1 , wherein the determining the predicted band position comprises determining a second actual band position of a second block processed prior to a processing of the first block as the predicted band position.
3. The method of claim 2 , wherein the second block is closest to the first block based on an order of processing among one or more blocks processed prior to the processing of the first block.
4. The method of claim 1 , wherein the determining the predicted band position comprises determining the predicted band position using a mean value of actual band positions of one or more blocks processed prior to the first block.
5. The method of claim 1 , wherein the determining the predicted band position comprises:
dividing a full range of pixel values of the first block into a plurality of bands;
calculating a frequency of a desired pixel value in each of the plurality of bands; and
determining a band having a maximum frequency of the desired pixel value among the plurality of bands as the predicted band position.
6. The method of claim 1 , wherein the determining the predicted band position comprises determining the predicted band position using one of maximum, minimum, or mean values of at least one pixel value associated with the first block.
7. The method of claim 1 , wherein the coding the difference value comprises coding the difference value using a first number of bits which is based on the difference value.
8. The method of claim 1 , further comprising:
determining, using the encoder, whether there is a second actual band position of a second block processed prior to the first block; and
coding, using the encoder, the first actual band position in a second number of bits corresponding to a result of the determination of the second actual band position.
9. A method of operating an encoder on a system on chip, the system on chip including the encoder and a processor, the method comprising:
receiving, using the encoder, a video frame from the processor, the video frame including a first block and a second block;
determining, using the encoder, a first band position of the first block; and
coding, using the encoder, a difference value of a second band position of the second block and the first band position using a first number of bits, the first number of bits varying in accordance with the difference value.
10. The method of claim 9 , further comprising:
coding, using the encoder, the first band position using a second number of bits.
11. The method of claim 9 , wherein when the first block is equal to the second block, the determining the first band position comprises predicting the first band position using one or more pixel values associated with the second block.
12. The method of claim 11 , wherein the predicting the first band position is performed using at least one among a maximum value of the one or more pixel values, a minimum value of the one or more pixel values, a mean value of the one or more pixel values, and a frequency of a desired value among the one or more pixel values.