The present invention relates to a recording/reproducing apparatus for bandwidth-compressing a video signal and a method thereof, in particular, to a recording/reproducing apparatus suitable for a portable digital video tape recorder with a built-in camera.
In a signal processing apparatus that digitally processes a video signal (for example, a signal processing apparatus for use with a high resolution portable digital video tape recorder with a built-in camera), a record time and a record density should be considered. Thus, an input video signal is compression-encoded. The resultant video signal is recorded to for example a video tape.
When the signal is recorded to the video tape, the signal is often encoded with a product code so as to correct an error. In the encoding process with the product code, data is arranged in a matrix shape symbol by symbol (for example, byte by byte). The arranged data is encoded in the column direction with for example Reed Solomon code. Thus, an outer code parity is generated. The data and the outer code parity are encoded in the line direction. Thus, an inner code parity is generated. With the outer code parity in the column direction and the inner code parity in the line direction, the data is encoded with the product code as an error correction code. In this case, the time sequence of the data accords with for example the line direction.
On the other hand, in the portable digital video tape recorder with the built-in camera, the power consumption and hardware scale should be considered. To satisfy energy saving that is a worldwide requirement, the power consumption of a desk top unit should be considered.
A video signal photographed by a video camera is output as a 4:4:4 signal from a CCD (Charge Coupled Device). In the 4:4:4 signal, the ratio of sampling frequencies of R (Red), G (Green), and B (Blue) is 4:4:4. In a video signal of HDVS (High Definition Video System) that provides a high resolution picture, 2200xc3x971125 pixels (1920xc3x971035 effective pixels)/(30 frames per second) is accomplished. The sampling frequency of each of RGB components is as high as 74.25 MHz. In this case, the field frequency is 60 Hz.
When this signal is supplied to a digital video tape recorder portion, the signal is converted into a 4:2:2 signal of which the ratio of sampling frequencies of a luminance signal Y, an R-Y color difference signal Pr, and a B-Y color difference signal Pb is 4:2:2. In the 4:2:2 signal, the signals Y, Pr, and Pb are transmitted in parallel at the above-described sampling frequency (74.25 MHz) corresponding to BTA S-002 standard. In this case, the rate of the luminance signal Y is still 74.25 MHz.
Since the power consumption necessary for processing a signal is proportional to the frequency, a high power is required. In addition, since the data rate is high, the data amount is large and the hardware scale becomes large.
On the other hand, when a signal is lost or changed outside the apparatus or when the apparatus gets defective, a discontinuous line may take place. In the conventional apparatus, there is no means for obtaining the transmission order of lines. Due to such a discontinuity of a signal, the length of a blanking portion may vary. In addition, even if the position of a picture deviates, there is no means for compensating it.
Thus, an object of the present invention is to provide a recording/reproducing apparatus and a method that allow a discontinuous point of a line that has been processed to be easily compensated.
Another object of the present invention is to provide a recoding/reproducing apparatus and a method that allow a hardware scale and power consumption to be decreased.
The present invention is a recording apparatus for bandwidth-compressing a digital video signal, compression-encoding the resultant signal, and recording the resultant signal to a record medium, comprising a compression-encoding means for compression-encoding a supplied digital video signal, wherein line numbers are added to the digital video signal supplied to the compression-encoding means.
The present invention is a reproducing apparatus for reproducing a digital video signal that has been bandwidth-compressed, compression-encoded, and recorded to a record medium, comprising a decoding means for decoding compressed code of a reproduction digital video signal reproduced from the record medium, wherein line numbers generated corresponding to the reproduction digital video signal are added to an output signal of the decoding means.
The present invention is a recording/reproducing apparatus for bandwidth-compressing a digital video signal, compression-encoding the resultant signal, recording the resultant signal to a record medium, and reproducing the recorded digital video signal, comprising a compression-encoding means for compression-encoding a supplied digital video signal, a recording means for recording the compression-encoded digital video signal to the record medium, a reproducing means for reproducing the digital video signal recorded on the record medium, and a decoding means for decoding compressed code of the reproduction digital video signal reproduced from the record medium, wherein in a recording mode, line numbers are added to the digital video signal supplied to the compression-encoding means and in a reproducing mode, line numbers generated corresponding to the reproduction digital video signal are added to an output signal of the decoding means.
The present invention is a recording method for bandwidth-compressing a digital video signal, compression-encoding the resultant signal, and recording the resultant signal to a record medium, comprising the step of compression-encoding a supplied digital video signal, wherein line numbers are added to the digital video signal supplied at the compression-encoding step.
The present invention is a reproducing method for reproducing a digital video signal that has been bandwidth-compressed, compression-encoded, and recorded to a record medium, comprising the step of decoding compressed code of a reproduction digital video signal reproduced from the record medium, wherein line numbers generated corresponding to the digital video signal are added to an output signal at the decoding step.
The present invention is a recording/reproducing method for bandwidth-compressing a digital video signal, compression-encoding the resultant signal, recording the resultant signal to a record medium, and reproducing the recorded digital video signal, comprising the steps of compression-encoding a supplied digital video signal, recoding the compression-encoded digital video signal to the record medium, reproducing the digital video signal recorded to the record medium, and decoding compressed code of the reproduction digital video signal reproduced from the record medium, wherein in a recording mode, line numbers are added to the digital video signal supplied at the compression-encoding step and in a reproducing mode, line numbers generated corresponding to the reproduction digital video signal are added to an output signal at the decoding step.
As described above, according to the present invention, in the recording mode, a line number is added to a digital video signal supplied to the compression-encoding means. In the reproducing mode, a line number is added to a digital video signal that is output from the decoding means that decodes a signal that has been compression-decoded. Thus, even if line numbers become discontinue, they can be easily compensated.
USPTO Backgrounds
USPTO Backgrounds