Motion video signal processing for recording or reproducing – Local trick play processing – With randomly accessible medium
Reexamination Certificate
1997-12-16
2001-01-16
Nguyen, Huy (Department: 2715)
Motion video signal processing for recording or reproducing
Local trick play processing
With randomly accessible medium
C386S349000
Reexamination Certificate
active
06175685
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a picture recording/reproducing method and apparatus for recording/reproducing a still picture.
2. Description of Related Art
In a conventional digital video tape recorder for digital recording/reproducing of video data, one frame of picture signals from an imager or other picture input signals is stored on a random access memory (RAM), in which the one-frame picture data are split into 8 by 8 pixel blocks and shuffled with a pre-set number of blocks as a unit. The resulting data is orthogonal-transformed, such as by discrete cosine transform (DCT), and quantized for compressing the one-frame video data. The compressed video data is framed and deshuffled, that is processed with an operation reversed from shuffling, on the RAM, for restoration to the original data array. An outer parity and an inner parity for error correction are then appended to the resulting data and encoded for recording. The encoded data is then recorded on a video tape.
In the playback system, the playback signals from the video tape are decoded, that is processed with an operation reversed from the encoding, to produce playback data, which his then error-corrected on the RAM using the outer parity and the inner parity, and shuffled. The resulting shuffled data is deframed and dequantized and the resulting dequantized data is inverse-orthogonal-transformed for expanding the one-frame playback data. The expanded one-frame playback data are deshuffled, that is processed with an operation reversed from the shuffling, and deblocked, for reproducing the video data having the original pixel array.
Meanwhile, the picture signals of the standard television system, such as the National Television System Committee (NTSC) system or the Phase Alternation by Line (PAL) system, are interlaced signals. Therefore, if, in the above-described conventional digital video tape recorder, the input picture signals are stored as still pictures in a RAM for shuffling or deshuffling, and the still pictures are directly recorded/reproduced as contiguous frame pictures, the picture portions having a significant amount of motion represent field period deflection on reproduction.
If one of the even-numbered frame and the odd-numbered frame making up an original one frame picture×2 is recorded as one frame for possibly evading the above-mentioned field period deflection, vertical resolution is deteriorated.
If the recording system has a dedicated still picture processor configured for storing one-frame video data in a RAM and the amount of motion within one frame is found so that a picture portion with a small amount of motion is directly outputted as a frame and the picture portion with a significant amount of motion is outputted as repetition of one of the fields, still pictures free of field period deflection can be recorded for reproducing still pictures of high definition by any reproducing device. However, since the dedicated still picture processor and a RAM for storing the video data for processing by this still picture processor need to be provided in the recording system, the circuit scale of the recording system is prohibitively increased.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a picture reproducing method and apparatus for recording/reproducing pictures of high picture quality without the necessity of providing a dedicated still picture processor or a RAM for storing the video data for processing by this still picture processor.
In one aspect, the present invention provides a picture recording/reproducing apparatus including a recording system for orthogonal-transforming input video signals in terms of a transform block as a unit, in which transform block has a pre-set number of two-dimensionally arrayed pixels, with all video input signals as a continuous frame picture. The recording system quantizes the orthogonal-transformed coefficient data and records the quantized coefficient data on a recording medium. The picture recording/reproducing apparatus also includes a reproducing system for inverse orthogonal-transforming the orthogonal-transformed coefficient data obtained on dequantizing the playback signals reproduced from the recording medium, for generating playback video signals, and effectuating motion detection from one transform block to another, based on the orthogonal-tranformed coefficient data. The reproducing system outputs playback video signals of a transform block, detected as being a still picture block, as a frame, while outputting playback video signals of a transform block, detected as being a moving picture block, as a twice-outputted single-field, thus enabling a high quality still picture to be outputted without requiring a dedicated still picture processor.
With the present picture recording/reproducing apparatus, the recording system has two sorts of the recording operation modes, that is a moving picture recording mode and a still picture recording mode. The recording system records the quantized orthogonal-tranformed coefficient data along with a flag indicating the recording operation mode on the recording medium during the still picture recording mode. The reproducing system also sets the still picture reproducing mode depending on the flag, and effects motion detection. The reproducing system outputs playback video signals of the transform block, detected as being a still picture block, as a frame, while outputting playback video signals of the transform block, detected as being a moving picture block, as twice-outputted single-field. This enables a high quality still picture to be outputted without requiring a dedicated still picture processor using the recording system having two recording operation modes, namely the moving picture recording mode and the still picture recording mode.
With the present picture recording/reproducing apparatus, motion detection can be performed from one transform block to another by comparing a value found from the distribution of respective coefficients of the orthogonal transform coefficient data obtained on dequantization to a pre-set threshold value.
With the present picture recording/reproducing apparatus, the reproducing system outputs, based on the results of detection by the motion detection means, two single-fields of playback picture signals of a macro-block containing a transform block detected as being a moving picture block.
With the present picture recording/reproducing apparatus, the reproducing system outputs, based on the results of detection by the motion detection means, two single-fields of playback picture signals of macro-blocks lying on upper and lower sides and on left and right sides of a macro-block containing a transform block detected as being a moving picture block.
In another aspect, the present invention provides a picture recording/reproducing method including orthogonal-transforming input video signals during recording in terms of a transform block as a unit, the transform block having a pre-set number of two-dimensionally arrayed pixels, with all video input signals as a continuous frame picture, the orthogonal-transformed coefficient data being quantized and recorded on a recording medium, inverse orthogonal-transforming the orthogonal-transformed coefficient data obtained on dequantizing the playback signals reproduced from the recording medium, during playback, for generating playback video signals, effectuating motion detection from one transform block to another, based on the orthogonal-tranformed coefficient data, such that playback video signals of a transform block, detected as being a still picture block, are outputted as a frame, while playback video signals of a transform block, detected as being a moving picture block, are outputted as a twice-outputted single-field. Thus, a still picture of high picture quality can be recorded/reproduced without requiring a dedicated still picture processor.
Also, with the picture recording/reproducing method according to the present invention, the q
Kiyama Yuka
Nikata Kenji
Tauchi Yoichiro
Frommer William S.
Frommer Lawrence & Haug LLP.
Nguyen Huy
Sony Corporation
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