Moving picture encoding apparatus

An apparatus for encoding a moving picture in which an encoded datastream is generated by encoding a moving picture datastream, formed by pixel data in a spatial domain, for compression, said apparatus comprising:

• orthogonal transform means for orthogonal transforming pixel data of said moving picture datastream, in terms of a preset pixel block as a unit, to generate a moving picture datastream, composed of pixel data in the frequency domain;
• quantization means for quantizing the moving picture stream, composed of pixel data of the frequency domain output from said orthogonal transform means, based on the quantization scale set from one said preset pixel block to another;
• encoding means for converting the moving picture datastream, quantized by said quantization means, into an encoded datastream which is in keeping with a preset encoding system, to output the resulting encoded datastream;
• inverse quantization means for inverse quantizing the moving picture datastream, quantized by said quantization means, based on the quantization scale used at the time of quantization;
• inverse orthogonal transform means for inverse orthogonal transforming the moving picture datastream, inverse quantized by said inverse quantization means, in terms of a preset pixel block as a unit, to generate a moving picture datastream formed by pixel data in the spatial domain;
• and
• S/N (signal/noise) ratio calculating means for finding the S/N ratio based on pixel data of the original moving picture datastream supplied to said orthogonal transform means and pixel data of the encoded moving picture datastream output from said inverse orthogonal transform means.

An apparatus for transmitting a moving picture comprising:

• frame rate controlling means for controlling the frame rate of an input moving picture datastream composed of a plurality of chronologically arrayed frames;
• frame rate calculating means for calculating a setting value of the frame rate of said moving picture datastream;
• encoding means for encoding said moving picture datastream, output from said frame rate controlling means, for compression, and for outputting an encoded datastream, generated on said encoding for compression;
• and
• transmitting/receiving means for transmitting the datastream, encoded by said encoding means, to a receiving apparatus over a network, and transmitting/receiving control data with said receiving apparatus;
• said transmitting/receiving means detecting the state of the network based on control data received by said receiving apparatus and calculating a target bitrate based on the detected network status;
• said encoding means controlling the bitrate of said encoded datastream responsive to the target bitrate calculated by said transmitting/receiving means;
• said frame rate calculating means calculating the setting value of the frame rate based on the picture quality of the encoded datastream output from said encoding means;
• said frame rate controlling means controlling the frame rate of said moving picture datastream to the setting value calculated by said frame rate calculating means.