Transform coefficient coding

An encoder for encoding into a data stream information related to a plurality of transform coefficients associated with a video, the encoder comprising:

• a picture encoder configured to apply, using a processor, predictive coding on a block of a picture of the video to obtain a prediction residual signal related to the block;
• a context adaptive entropy encoder configured to, for a current transform coefficient related to the prediction residual signal, entropy encode, using a processor, a first symbol into the data stream using a context, wherein the context is determined based on an operation involving a first previously encoded transform coefficient;
• and
• a symbolizer configured to map, using a processor, a transform coefficient level of the current transform coefficient to a second symbol based on a symbolization parameter, wherein the transform coefficient level is greater than a maximum level associated with the first symbol and the symbolization parameter is determined based on the operation involving a second previously encoded transform coefficient,
• wherein the encoder is configured to determine the first previously encoded transform coefficient based on a relative spatial arrangement of the current transform coefficient relative to the plurality of transform coefficients.

A non-transitory computer-readable medium for storing information related to a plurality of transform coefficients associated with an encoded video, comprising:

• a data stream stored in the non-transitory computer-readable medium, the data stream comprising encoded information related to first and second symbols of a current transform coefficient, and instructions to process the first and second symbols based on a method comprising:
• entropy decoding, for a current transform coefficient, a first symbol using a context, wherein the context is determined based on an operation involving a first previously decoded transform coefficient;
• extracting a second symbol of the current transform coefficient from the data stream;
• mapping, for the current transform coefficient, the second symbol to a transform coefficient level based on a symbolization parameter, wherein the transform coefficient level is greater than a maximum level associated with the first symbol and the symbolization parameter is determined based on the operation involving a second previously decoded transform coefficient;
• and
• applying predictive coding based on a prediction residual signal to reconstruct a block of a picture of the video, wherein the prediction residual signal is associated with the entropy-decoded first symbol and the transform coefficient level,
• wherein the first previously decoded transform coefficient is determined based on a relative spatial arrangement of the current transform coefficient relative to the plurality of transform coefficients.

A method for decoding a data stream comprising an encoded video including information related to a plurality of transform coefficients associated with the encoded video, the method comprising:

• entropy decoding, for a current transform coefficient, a first symbol using a context, wherein the context is determined based on an operation involving a first previously decoded transform coefficient;
• extracting a second symbol of the current transform coefficient from the data stream;
• mapping, for the current transform coefficient, the second symbol to a transform coefficient level based on a symbolization parameter, wherein the transform coefficient level is greater than a maximum level associated with the first symbol and the symbolization parameter is determined based on the operation involving a second previously decoded transform coefficient;
• and
• applying predictive coding based on a prediction residual signal to reconstruct a block of a picture of the video, wherein the prediction residual signal is associated with the entropy-decoded first symbol and the transform coefficient level,
• wherein the first previously decoded transform coefficient is determined based on a relative spatial arrangement of the current transform coefficient relative to the plurality of transform coefficients.