Signal processing device and moving image capturing device

A signal processing device for compressing image data of a plurality of frames to generate a stream, comprising:

• an encoder configured to encode input image data;
• an image processor configured to obtain spatial frequency information of an image within one frame of the image data and to obtain image movement information indicating an amount of a movement of a same image between two frames;
• an encoding determination unit configured to compare the image movement information with an encoding determination threshold, thereby determining whether or not encoding is to be performed, wherein the encoding determination unit determines whether or not encoding is to be performed, after temporarily changing the encoding determination threshold so as to cause a frame skipping control if encoding is not to be performed to be less strict when the spatial frequency information of an image within one frame indicates a high spatial frequency, or without changing the encoding determination threshold when the spatial frequency information of an image within one frame indicates a low spatial frequency;
• a frame skipping controller configured to perform a frame skipping control when the encoding determination unit determines that encoding is not to be performed;
• and
• a threshold correction unit configured to correct the encoding determination threshold of the encoding determination unit,
• wherein the encoder selectively performs the encoding in accordance with a result of determination obtained by the encoding determination unit, and the threshold correction unit corrects the encoding determination threshold of the encoding determination unit based on the number of bits allocated for encoding and a quantization parameter value in a frame encoded by the encoder, or a motion vector value or the number of intra-macroblocks in a frame encoded by the encoder.