Moving picture encoding apparatus
Data of both MPEG-2 and MPEG-4 is generated simultaneously with a small circuit scale and a small power consumption. A moving picture encoding apparatus for encoding a moving picture through motion-compensated inter-frame prediction has: a MPEG-2 encoding unit including a motion vector estimator, a frame memory, a forward prediction circuit, a bidirectional prediction circuit, a prediction selection circuit, an intra-frame encoding circuit and a local decoding circuit; a MPEG-4 encoding unit including a frame extraction circuit for extracting a predetermined MPEG-2 frame and a transcoder for encoding the extracted frame; a motion vector calculator calculating a motion vector to be used for MPEG-4 prediction from a motion vector to be used for MPEG-2 prediction; and a prediction mode controller controlling the prediction mode of the MPEG-2 encoding unit in such that the MPEG-2 prediction mode becomes coincident with the MPEG-4 prediction mode.
1. A moving picture encoding apparatus for encoding a moving picture by utilizing motion-compensated inter-frame prediction, comprising:
a first encoding module for encoding the moving picture at a first frame rate and at a first image size, by performing at least motion compensation and DCT;
a second encoding module for encoding the moving picture at a second frame rate and at a second image size, by extracting data after the motion compensation or DCT by said first encoding module;
a motion vector calculation module for calculating a motion vector to be used by said second encoding module from a motion vector to be used by said first encoding module; and
a prediction mode control module for controlling to make a prediction mode of said first encoding module be coincident with a prediction mode of said second encoding module, so that said motion vector calculated by said motion vector calculation module can be used by said second encoding module.
2. A moving picture encoding apparatus for encoding a moving picture by utilizing motion-compensated inter-frame prediction, comprising:
a first encoding module for encoding an input moving picture at a first frame rate and at a first image size;
a second encoding module for extracting picture data under encoding by said first encoding module and encoding the picture data at a second frame rate and at a second image size;
a motion vector calculation module for calculating a motion vector to be used by said second encoding module from a motion vector to be used by said first encoding module; and
a prediction mode control module for controlling a prediction mode of said first encoding module so as to make the prediction mode of said first encoding module be coincident with a prediction mode of said second encoding module, so that said motion vector calculated by said motion vector calculation module can be used by said second encoding module.
3. A moving picture encoding apparatus according to claim 2 , wherein said prediction mode control module sets a forward prediction frame to the prediction mode of said first encoding module for the prediction mode of said second encoding module relative to the forward prediction frame using only prediction from past frames.
4. A moving picture encoding apparatus according to claim 2 , wherein said prediction mode control module controls in such a manner that the prediction mode of said first encoding module for each partial picture for the prediction mode of said second encoding module relative to the forward prediction frame using only prediction from past frames, encodes a difference value from a prediction value for each of all partial pictures in the same frame or encodes each of all partial pictures in the same frame without using prediction.
5. A moving picture encoding apparatus according to claim 4 , further comprising:
image quality deterioration detecting module for detecting an image quality deterioration of a frame obtained by said first encoding module by encoding difference values from the prediction value for all partial pictures in the same frame,
wherein when said image quality deterioration detecting module detects an image quality deterioration, said prediction mode control module controls in such a manner that the prediction mode of said first encoding module for each partial picture for the prediction mode of said second encoding module relative to the forward prediction frame using only prediction from past frames, encodes all partial pictures themselves in the same frame without using prediction.
6. A moving picture encoding apparatus according to claim 3 , wherein:
said motion vector calculation module calculates one motion vector from a plurality of motion vectors given to a plurality of partial pictures of said first encoding module, the partial pictures corresponding to one partial picture of said first encoding module; and
said apparatus further comprises difference value invalidating module for, if a motion vector of said first encoding module is greatly different from a motion vector calculated by said motion vector calculation module, replacing a difference value of said second encoding module corresponding to a partial picture of said first encoding module having such a motion vector with 0 to perform encoding.
7. A moving picture encoding method of encoding a moving picture by utilizing motion-compensated inter-frame prediction, comprising:
a first encoding step of encoding the moving picture at a first frame rate and at a first image size, by performing at least motion compensation and DCT;
a second encoding step of encoding the moving picture at a second frame rate and at a second image size, by extracting data after the motion compensation or DCT by said first encoding step;
a motion vector calculation step of calculating a motion vector to be used by said second encoding step from a motion vector to be used by said first encoding step; and
a prediction mode control step of controlling to make a prediction mode of said first encoding step be coincident with a prediction mode of said second encoding step, so that said motion vector calculated by said motion vector calculation step can be used by said second encoding step.
8. A moving picture encoding method of encoding a moving picture by utilizing motion-compensated inter-frame prediction, comprising:
a first encoding step of encoding an input moving picture at a first frame rate and at a first image size;
a second encoding step of extracting picture data under encoding by said first encoding step and encoding the picture data at a second frame rate and at a second image size;
a motion vector calculation step of calculating a motion vector to be used by said second encoding step from a motion vector to be used by said first encoding step; and
a prediction mode control step of controlling a prediction mode of said first encoding step so as to make the prediction mode of said first encoding step be coincident with a prediction mode of said second encoding step, so that said motion vector calculated by said motion vector calculation step can be used by said second encoding step.
9. A moving picture encoding apparatus for encoding a moving picture by utilizing motion-compensated inter-frame prediction, comprising:
a first encoding module for encoding an input moving picture at a first frame rate and at a first image size;
a second encoding module for extracting picture data under encoding by said first encoding module and encoding the picture data at a second frame rate and at a second image size;
a motion vector calculation module for calculating a second motion vector to be used for prediction by said second encoding module from a first motion vector to be used for prediction by said by said first encoding module; and
a prediction mode control module for controlling in such a manner that a reference frame of the second motion vector calculated by said motion vector calculation module is made coincident with a reference frame of the first motion vector under encoding by said first encoding module and extracted by said second encoding module.