Digital video signal recording apparatus using variable-length coding

• US 5,911,033 A
• Filed: 06/05/1995
• Issued: 06/08/1999
• Est. Priority Date: 11/29/1991
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Satake, Yoshifumi, Fujii, Akio, Enari, Masahiko
• Primary Examiner(s): Chevalier, Robert
• Application Number:
  US08/465,603
• Time in Patent Office: 1,464 Days
• Field of Search: 358/335, 358/311, 358/313, 358/338, 358/342, 348/784, 360/32, 360/13, 360/14.1, 386/109, 386/111, 386/112, 386/27, 386/33, 386/114, 386/107, 386/117, 386/125, 386/126, 386/81
• US Class Current: 386/328
• CPC Class Codes: G11B 27/034 on discs G11B27/036, G11B27/038 take precedence
• CPC Class Codes: H04N 19/15 by monitoring actual compressed data size at the memory before deciding storage at the transmission buffer
• CPC Class Codes: H04N 19/152 by measuring the fullness of the transmission buffer
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 5/781 on disks or drums
• CPC Class Codes: H04N 5/85 on discs or drums
• CPC Class Codes: H04N 5/91 Television signal processing therefor
• CPC Class Codes: H04N 5/917 for bandwidth reduction
• CPC Class Codes: H04N 9/7921 for more than one processing mode
• CPC Class Codes: H04N 9/8042 involving data reduction

Abstract

In a digital video signal recording apparatus of the kind arranged to output a coded signal with its length per picture arranged to be variable by compressing the amount of information of the digital video signal and to record the coded signal while forming many tracks in parallel on a tape-shaped recording medium, a compression ratio is adjusted in such a way as to make the coded signal corresponding to m pictures (m: an integer of 2 or more) have an amount of information recordable in n tracks (n: an integer of 1 or more).

Claims

1. A video signal recording apparatus comprising,

a) input means for inputting a digital video signal;

b) variable-length coding means arranged to compress an amount of information of the digital video signal and to output a coded signal; and

c) recording means for recording the coded signal on a recording medium while forming many tracks in parallel on the recording medium,

wherein said variable-length coding means is arranged to adjust a compression ratio thereof in such a way as to make the coded signal corresponding to the digital video signal of m frames (m;

an integer of 2 or more) have an amount of information recordable in n tracks (n;

an integer of 1 or more) the coded signal corresponding to the digital video signal of each frame having a variable amount of information and each track having a fixed amount of information,

an amount of the coded signal corresponding to the digital video signal of m frame is controlled to be equal to or less than the amount of information recordable in the tracks and code groups each corresponding to the digital video signal of m frames are respectively recorded on different track groups each having n tracks, with each track group being all the time recorded with a constant number of code groups.

2. An apparatus according to claim 1, wherein said variable-length coding means includes an orthogonal transforming circuit arranged to orthogonally transform the digital video signal and a quantizing circuit arranged to quantize output data of said orthogonal transforming circuit, and wherein the amount of information of the coded signal to be outputted from said variable-length coding means is adjusted by changing quantizing steps of said quantizing circuit.

3. An apparatus according to claim 2, wherein said variable-length coding means further includes a coding circuit arranged to variable-length code an output of said quantizing circuit, and a detecting circuit arranged to detect the amount of information of the coded signal outputted from said coding circuit.

4. An apparatus according to claim 1, further comprising marking means for recording a mark signal on the recording medium for every portion of the coded signal corresponding to the digital video signal for m frames.

5. An apparatus according to claim 4, wherein said marking means is arranged to record the mark signal in a track separate from tracks formed by said recording means.

6. A video signal recording apparatus comprising:

a) input means for inputting a digital video signal;

b) variable-length coding means arranged to compress an amount of information of the digital video signal and to output a coded signal having a variable length per unit amount of information;

c) recording means for recording the coded signal on a recording medium while forming many tracks in parallel on the recording medium, wherein said variable-length coding means is arranged to adjust a compression ratio thereof in such a way as to make the coded signal corresponding to the digital video signal for m frames (m;

an integer of 2 or more) have an amount of information recordable in n tracks (n;

an integer of 1 or more), each frame having a variable amount of information and each track having a fixed amount of information, and said recording means records the coded signal corresponding to the digital video signal for m frames respectively on different n tracks; and

d) marking means for recording a mark signal on the recording medium for every portion of the coded signal corresponding to the digital video signal for m frames and for recording on the recording medium control information which specifies a useless frame included in the m frames.

7. A video signal recording apparatus comprising:

a) input means for inputting a digital video signal;

b) variable-length coding means arranged to compress an amount of information of the digital video signal and to output a coded signal; and

c) recording means for recording the coded signal on a recording medium while forming many tracks in parallel on the recording medium,

wherein said variable-length coding means is arranged to adjust a compression ratio thereof in such a way as to make the coded signal corresponding to the digital video signal of m frames (m;

an integer of 2 or more) have an amount of information equal to or less than an amount of information An recordable in n tracks (n;

an integer of 1 or more),

the coded signal corresponding to the digital video signal of each frame having a variable amount of information and each track having a fixed amount of information, and code groups each corresponding to the digital video signal of m frames are respectively recorded on different track groups each having n tracks, with each track group being all the time recorded with a constant number of code groups.

8. A video signal recording apparatus comprising:

a) input means for inputting a digital video signal;

b) variable-length coding means arranged to compress an amount of information of the digital video signal and to output a coded signal having a variable length per unit amount of information;

c) recording means for recording the coded signal on a recording medium while forming many tracks in parallel on the recording medium; and

d) marking means for recording, on the recording medium, control information specifying a useless frame among serial m frames (m;

an integer of 2 or more) carried by the digital video signal,

wherein said variable-length coding means is arranged to adjust a compression ratio thereof in such a way as to make the coded signal corresponding to the digital video signal for m frames (m;

an integer of 2 or more) have an amount of information recordable in n tracks (n;

an integer of 1 or more), each frame having a variable amount of information,

said recording means records the coded signal corresponding to the digital video signal for m frames respectively on different n tracks.

9. A video signal recording apparatus comprising:

a) input means for inputting a digital video signal;

b) variable-length coding means arranged to compress an amount of information of the digital video signal and to output a coded signal; and

c) recording means for recording the coded signal on a recording medium while forming many tracks in parallel on the recording medium,

wherein said variable-length coding means is arranged to adjust a compression ratio thereof in such a way as to make the coded signal corresponding to the digital video signal of m frames (m;

an integer of 2 or more) have an amount of information recordable in n tracks (n;

an integer of 1 or more), the coded signal corresponding to the digital video signal of each frame having a variable amount of information and each track having a fixed amount of information,

code groups each corresponding to the digital video signal of m frames are respectively recorded on different track groups each having n tracks, with one track group being all the time recorded with a constant number of code groups.

10. A video signal recording and reproducing apparatus comprising:

a) input means for inputting a digital video signal;

b) variable-length coding means arranged to compress an amount of information of the digital video signal and to output a coded signal having a variable length per unit amount of information;

c) recording means for recording the coded signal on a recording medium while forming many tracks in parallel on the recording medium,

wherein said variable-length coding means is arranged to adjust a compression ratio thereof in such a way as to make the coded signal corresponding to the digital video signal for m frames (m;

an integer of 2 or more) have an amount of information recordable in n tracks (n;

an integer of 1 or more), each frame having a variable amount of information,

said recording means recording the coded signal corresponding to the digital video signal for m frames respectively on different n tracks;

d) marking means for recording, on the recording medium, control information specifying a useless frame among serial m frames (m;

an integer of 2 or more) carried by the digital video signal;

e) reproducing means for reproducing the coded signal and the control information from the recording medium;

f) decoding means arranged to decode the coded signal reproduced by said reproducing means and to restore the digital video signal to its original state; and

g) output means for forming an output video signal from frames carried by the digital video signal restored by said decoding means, excluding said useless frame, in accordance with the control information.

11. A video signal recording and reproducing apparatus comprising:

a) input means for inputting a digital video signal;

b) variable-length coding means arranged to compress an amount of information of the digital video signal and to output a coded signal having a variable length per unit amount of information;

c) recording means for recording the coded signal on a recording medium while forming many tracks in parallel on the recording medium,

wherein said variable-length coding means is arranged to adjust a compression ratio thereof in such a way as to make the coded signal corresponding to the digital video signal for m frames (m;

an integer of 2 or more) have an amount of information recordable in n tracks (n;

an integer of 1 or more), each frame having a variable amount of information,

said recording means records the coded signal corresponding to the digital video signal for m frames respectively on different n tracks;

d) marking means for recording, on the recording medium, control information specifying a useless frame among serial m frames (m;

an integer of 2 or more) carried by the digital video signal;

e) reproducing means for reproducing the coded signal and the control information from the recording medium; and

f) output means for forming an output video signal from frames carried by the coded signal reproduced by said reproducing means, excluding a coded signal portion corresponding to said useless frame, in accordance with the control information.

12. A video signal reproducing apparatus comprising

a) reproducing means for reproducing a coded signal recorded on a recording medium,

said coded signal being a signal obtained by variable-length coding of a digital video signal and recorded on a number of tracks located in parallel on said recording medium,

wherein the variable length coding process is arranged to adjust a compression ratio thereof in such a way as to make the coded signal corresponding to the digital video signal of m frames (m:

an integer of 2 or more) have an amount of information recordable in n tracks (n;

an integer of 1 or more), the coded signal corresponding to the digital video signal of each frame having a variable amount of information and each track having a fixed amount of information,

code groups each corresponding to the digital video signal of m frames are respectively recorded on different track groups each having n tracks,

with one track group being all the time recorded with a constant number of code groups; and

b) decoding means for decoding the coded signal reproduced by said reproducing means.

13. A method of recording a video signal comprising

a) inputting a digital video signal;

b) variable-length coding to compress an amount of information of the digital video signal and to output a coded signal; and

c) recording the coded signal on a recording medium while forming many tracks in parallel on the recording medium,

wherein said variable-length coding adjusts a compression ratio thereof in such a way as to make the coded signal corresponding to the digital video signal of m frames (m;

an integer of 2 or more) have an amount of information recordable in n tracks (n;

an integer of 1 or more), the coded signal corresponding to the digital video signal of each frame having a variable amount of information and each track having a fixed amount of information,

an amount of the coded signal corresponding to the digital video signal of m frame is controlled to be equal to or less than the amount of information recordable in the tracks and code groups each corresponding to the digital video signal of m frames are respectively recorded on different track groups each having n tracks, with each track group being all the time recorded with a constant number of code groups.

14. A method of recording a video signal comprising:

a) inputting a digital video signal;

b) variable-length coding to compress an amount of information of the digital video signal and to output a coded signal having a variable length per unit amount of information;

c) recording the coded signal on a recording medium while forming many tracks in parallel on the recording medium, wherein said variable-length coding is arranged to adjust a compression ratio thereof in such a way as to make the coded signal corresponding to the digital video signal for m frames (m;

an integer of 2 or more) have an amount of information recordable in n tracks (n;

an integer of 1 or more), each frame having a variable amount of information and each track having a fixed amount of information, and said recording records the coded signal corresponding to the digital video signal for m frames respectively on different n tracks; and

d) marking by recording a mark signal on the recording medium for every portion of the coded signal corresponding to the digital video signal for m frames and recording on the recording medium control information which specifies a useless frame included in the m frames.

15. A method for recording a video signal comprising:

a) inputting a digital video signal;

b) variable-length coding to compress an amount of information of the digital video signal and to output a coded signal; and

c) recording the coded signal on a recording medium while forming many tracks in parallel on the recording medium,

wherein said variable-length coding adjusts a compression ratio thereof in such a way as to make the coded signal corresponding to the digital video signal of m frames (m;

an integer of 2 or more) have an amount of information equal to or less than an amount of information An recordable in n tracks (n;

an integer of 1 or more),

the coded signal corresponding to the digital video signal of each frame having a variable amount of information and each track having a fixed amount of information, and code groups each corresponding to the digital video signal of m frames are respectively recorded on different track groups each having n tracks, with each track group being all the time recorded with a constant number of code groups.

16. A method of recording a video signal comprising:

a) inputting a digital video signal;

b) variable-length coding to compress an amount of information of the digital video signal and to output a coded signal having a variable length per unit amount of information;

c) recording the coded signal on a recording medium while forming many tracks in parallel on the recording medium; and

d) marking by recording, on the recording medium, control information specifying a useless frame among serial m frames (m;

an integer of 1 or more), each frame having a variable amount of information,

said recording records also boundary position information indicating boundary positions between the respective n tracks on said recording medium.

17. A method of recording a video signal comprising:

a) inputting a digital video signal;

b) variable-length coding to compress an amount of information of the digital video signal and to output a coded signal; and

c) recording the coded signal on a recording medium while forming many tracks in parallel on the recording medium,

wherein said variable-length coding adjusts a compression ratio thereof in such a way as to make the coded signal corresponding to the digital video signal of m frames (m;

an integer of 2 or more) have an amount of information recordable in n tracks (n;

an integer of 1 or more), the coded signal corresponding to the digital video signal of each frame having a variable amount of information and each track having a fixed amount of information,

code groups each corresponding to the digital video signal of m frames are respectively recorded on different track groups each having n tracks, with each track group being all the time recorded with a constant number of code groups.

18. A method of recording and reproducing a video signal comprising:

a) inputting a digital video signal;

b) variable-length coding to compress an amount of information of the digital video signal and to output a coded signal having a variable length per unit amount of information;

c) recording the coded signal on a recording medium while forming many tracks in parallel on the recording medium,

wherein said variable-length coding adjusts a compression ratio thereof in such a way as to make the coded signal corresponding to the digital video signal for m frames (m;

an integer of 2 or more) have an amount of information recordable in n tracks (n;

an integer of 1 or more), each frame having a variable amount of information,

said recording step recording the coded signal corresponding to the digital video signal for m frames respectively on different n tracks;

d) marking by recording, on the recording medium, control information specifying a useless frame among serial m frames (m;

an integer of 2 or more) carried by the digital video signal;

e) reproducing the coded signal and the control information from the recording medium;

f) decoding the coded signal reproduced by said reproducing step to restore the digital video signal to its original state; and

g) forming an output video signal from frames carried by the digital video signal restored by said decoding step, excluding said useless frame, in accordance with the control information.

19. A method of recording and reproducing a video signal comprising:

a) inputting a digital video signal;

b) variable-length coding to compress an amount of information of the digital video signal and to output a coded signal having a variable length per unit amount of information;

c) recording the coded signal on a recording medium while forming many tracks in parallel on the recording medium,

wherein said variable-length coding adjusts a compression ratio thereof in such a way as to make the coded signal corresponding to the digital video signal for m frames (m;

an integer of 2 or more) have an amount of information recordable in n tracks (n;

an integer of 1 or more), each frame having a variable amount of information,

said recording records the coded signal corresponding to the digital video signal for m frames respectively on different n tracks;

d) marking by recording, on the recording medium, control information specifying a useless frame among serial m frames (m;

an integer of 2 or more) carried by the digital video signal;

e) reproducing the coded signal and the control information from the recording medium; and

f) forming an output video signal from frames carried by the coded signal reproduced by said reproducing step, excluding a coded signal portion corresponding to said useless frame, in accordance with the control information.

20. A method of reproducing a video signal comprising:

a) reproducing a coded signal recorded on a recording medium,

said coded signal being a signal obtained by variable-length coding of a digital video signal and recorded on a number of tracks located in parallel on said recording medium,

wherein the variable length coding process is arranged to adjust a compression ratio thereof in such a way as to make the coded signal corresponding to the digital video signal of m frames (m;

an integer of 2 or more) have an amount of information recordable in n tracks (n;

an integer of 1 or more), the coded signal corresponding to the digital video signal of each frame having a variable amount of information and each track having a fixed amount of information,

code groups each corresponding to the digital video signal of m frames are respectively recorded on different track groups each having n tracks,

with each track group being all the time recorded with a constant number of code groups; and

b) decoding the coded signal reproduced in said reproducing step.