Matsushita Electric Industrial Co., Ltd.

Hiroko Yoshida

Akihisa Kawamura

Masaharu Matsumoto

Mitsuhiko Serikawa

Katsuaki Sato

Ryo Tagami

Hikari Hashimoto

Control codes for controlling processing of an audio signal by a sound field variation circuit to produce desired sound fields are recorded on a monaural track of a video tape concurrent with recording of video and audio signals, and can thereby be subsequently played back for producing sound fields which are respectively synchronized with video images.

Apparatus for supplying control codes to sound field reproduction

A reflection sound compression apparatus extracts and compresses, most appropriately with a physical evaluation value, an impulse response of a hall, etc. which is obtained by calculation and actual experiments to reflection sounds in a number required by a sound field controller by using a learning identification method.

Reflection sound compression apparatus

A sound field switcher inputs an output sound field signal from a sound field producer. The inputted sound field signal is delayed sequentially by plural delayers, after which they are multiplied by coefficients by plural multipliers, and the multiplied results are all added by an adder. Coefficients stored in an area of a memory indicated by a coefficient counter are read out and set to the plural multipliers. The sound field switcher carries out control of the timing for switching the sound field signal produced by the sound field producer and the timing for the coefficient counter to commence counting. Assuming the time required for switching the sound field to be N sampling periods, in case of carrying out a sound field switching from a sound field A to a sound field B, a sound field switching controller issues an order to the coefficient counter so as to count up one by one from 0 to N, and on each count the coefficients stored in an area of the coefficient memory is set to the multipliers. When the count value of the coefficient counter comes to (N/2) or nearest to (N/2), the sound field switching controller issues an order to the sound field producer to output the sound field signal of the sound field B. When the count value of the coefficient counter comes to N, the switching from the sound field A to the sound field B is completed.

Growing community of inventors

Hirakata, Japan

Hiroko Yoshida