Intra-prediction mode concept for block-wise picture coding

A method for designing a neural network or a sequence of one or more linear functions in which each linear function is followed by a respective non-linear function for assisting in selecting among a set of intra-prediction modes for block-based picture coding, the method comprising:

• predicting, using each of the set of intra-prediction modes, a first picture test block from a first set of neighboring samples neighboring the first picture test block to acquire, for each of the set of intra-prediction modes, a prediction signal for the first picture test block;
• applying the first set of neighboring samples onto the neural network or the sequence of one or more linear functions to acquire, for each of the set of intra-prediction modes, a probability value indicative of a probability of a respective intra-prediction mode;
• determining, for each of the set of intra-prediction modes, a cost estimate for coding costs related to prediction error coding and mode signalization using the prediction signal acquired for the respective intra-prediction mode;
• updating parameters of the neural network or the sequence of one or more linear functions to reduce a coding cost function having a first addend forming a residual rate estimate depending on the prediction signal acquired for the intra-prediction mode of lowest coding cost estimate, and a second addend forming a mode signaling side information rate estimate depending on the prediction signal and the probability value acquired for the intra-prediction mode of lowest coding cost estimate;
• and
• using the updated parameters:
• predicting, using each of the set of intra-prediction modes, a second picture test block from a second set of neighboring samples neighboring the second picture test block to acquire, for each of the set of intra-prediction modes, a prediction signal for the second picture test block;
• and
• applying the second set of neighboring samples onto one of the neural network or the sequence of one or more linear functions in which each linear function is followed by a respective non-linear function to acquire, for each of the set of intra-prediction modes, a probability value indicative of a probability of the respective intra-prediction mode.

A non-transitory digital storage medium having a computer program stored thereon which, when executed by a processor, causes an apparatus to perform a method for assisting in selecting among a set of intra-prediction modes for block-based picture coding, the method comprising:

• predicting, using each of the set of intra-prediction modes, a first picture test block from a first set of neighboring samples neighboring the first picture test block to acquire, for each of the set of intra-prediction modes, a prediction signal for the first picture test block;
• applying the first set of neighboring samples onto the neural network or the sequence of one or more linear functions to acquire, for each of the set of intra-prediction modes, a probability value indicative of a probability of a respective intra-prediction mode;
• determining, for each of the set of intra-prediction modes, a cost estimate for coding costs related to prediction error coding and mode signalization using the prediction signal acquired for the respective intra-prediction mode;
• updating parameters of the neural network or the sequence of one or more linear functions to reduce a coding cost function having a first addend forming a residual rate estimate depending on the prediction signal acquired for the intra-prediction mode of lowest coding cost estimate, and a second addend forming a mode signaling side information rate estimate depending on the prediction signal and the probability value acquired for the intra-prediction mode of lowest coding cost estimate;
• and
• using the updated parameters:
• predicting, using each of the set of intra-prediction modes, a second picture test block from a second set of neighboring samples neighboring the second picture test block to acquire, for each of the set of intra-prediction modes, a prediction signal for the second picture test block;
• and
• applying the second set of neighboring samples onto one of the neural network or the sequence of one or more linear functions in which each linear function is followed by a respective non-linear function to acquire, for each of the set of intra-prediction modes, a probability value indicative of a probability of the respective intra-prediction mode.