This invention can play back a smooth moving image in both normal and slow playback modes in consideration of the human visual recognition level, even when moving image data to be decoded (played back) is recorded (encoded) at a high frame rate. To this end, in this invention, respective frames, which form a moving image at 60 frames/sec, are compressed to be independently decodable. In the normal playback mode, since frames are played back using one of two frames (decimating one of two frames), a moving image is played back at 30 frames/sec which can assure sufficiently high image quality as a moving image. On the other hand, in the slow play back mode, since the number of frames to be decimated is set to be zero, and 60 frames are played back for 2 sec, a moving image is played back at the same frame rate of 30 frames/sec as that in the normal playback mode.