Coding method and coding apparatus

A coding method comprising:

• determining a context for a current block in an image, from among a plurality of contexts;
• and
• performing arithmetic coding on a control parameter for the current block, using the determined context to generate a bitstream corresponding to the current block,
• wherein the determining further includes:
• determining a signal type under which the control parameter for the current block is classified;
• determining the context by using both of coded control parameters for a left block and an upper block, when the signal type is a first type, the left block being a neighboring block to the left of the current block, and the upper block being a neighboring block on top of the current block;
• and
• determining the context by using a predetermined fixed value, without using any coded control parameters for the left block and the upper block, when the signal type is a second type different from first type,
• wherein one of a split flag and a skip flag is classified under the first type, the split flag indicating whether or not the current block is partitioned into a plurality of blocks, and the skip flag indicating whether or not the current block is to be skipped, and
• wherein a reference picture index is classified under the second type, the reference picture index indicating a reference picture used to predict the current block.