Video signal encoding and recording apparatus with variable transmission rate

• US 20040022316A1
• Filed: 07/01/2003
• Published: 02/05/2004
• Est. Priority Date: 06/17/1998
• Status: Active Grant

• Current Assignee: JVC Kenwood Corporation
• Original Assignee: Kenji Sugiyama, Motoharu Ueda
• Inventors: Sugiyama, Kenji, Ueda, Motoharu
• Granted Patent: US 7,313,318 B2
• Time in Patent Office: Days
• US Class Current: 375/240.05
• CPC Class Codes: G06T 9/005 Statistical coding, e.g. Huffman, run length coding
• CPC Class Codes: H04N 19/115 Selection of the code volume for a coding unit prior to coding
• CPC Class Codes: H04N 19/124 Quantisation
• CPC Class Codes: H04N 19/152 by measuring the fullness of the transmission buffer
• CPC Class Codes: H04N 19/156 Availability of hardware or computational resources, e.g. encoding based on power-saving criteria
• CPC Class Codes: H04N 19/172 the region being a picture, frame or field
• CPC Class Codes: H04N 19/177 the unit being a group of pictures [GOP]
• 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 5/907 using static stores, e.g. storage tubes or semiconductor memories H04N5/91 takes precedence
• CPC Class Codes: H04N 9/8042 involving data reduction

Abstract

In a video signal encoding and recording apparatus, a video signal is quantized into a quantization-resultant signal in response to a variable quantization scale. The quantization-resultant signal is recorded on a recording medium. The quantization scale is controlled in response to an encoding rate. The quantization scale is limited to within a range determined by a limit quantization scale. A remaining record capacity of the recording medium is measured. A remaining record time is measured. The encoding rate and the limit quantization scale are updated in response to the measured remaining record capacity and the measured remaining record time.

Claims

1. A video signal encoding and recording apparatus comprising:

first means for quantizing a video signal into a quantization-resultant signal in response to a variable quantization scale;

second means for recording the quantization-resultant signal generated by the first means on a recording medium;

third means for controlling the quantization scale used by the first means in response to an encoding rate;

fourth means for limiting the quantization scale used by the first means to within a range determined by a limit quantization scale;

fifth means for measuring a remaining record capacity of the recording medium;

sixth means for measuring a remaining record time; and

seventh means for updating the encoding rate used by the third means and the limit quantization scale used by the fourth means in response to the remaining record capacity measured by the fifth means and the remaining record time measured by the sixth means.

2. A video signal encoding and recording apparatus as recited in claim 1, wherein the limit quantization scale depends on an encoding type of a picture represented by the video signal.

3. A video signal encoding and recording apparatus as recited in claim 1, wherein the sixth means comprises a counter for counting a number of frames represented by the quantization-resultant signal which has been recorded, and means for detecting the remaining record time in response to a scheduled total record time and a result of the counting by the counter.

4. A video signal encoding and recording apparatus as recited in claim 3, further comprising means for changing the scheduled total record time.

5. A video signal encoding and recording apparatus as recited in claim 1, wherein the fifth means comprises means for integrating a number of bits of the quantization-result signal recorded on the recording medium, means for detecting a type of the recording medium, means for detecting a total record capacity of the recording medium in response to the detected type thereof, and means for detecting the remaining record capacity in response to a result of the integrating and the detected total record capacity.

6. A video signal encoding and recording apparatus as recited in claim 1, wherein the fifth means comprises means for detecting a currently-accessed position on the recording medium, and means for detecting the remaining record capacity in response to the detected currently-accessed position.

7. A video signal encoding and recording apparatus as recited in claim 1, further comprising means for displaying a picture represented by the video signal, and means for superimposing a visualized information of the remaining record capacity and the remaining record time on the displayed picture.

12. A video signal encoding and recording apparatus as recited in claim 3, wherein the seventh means comprises means for updating the encoding rate, the limit quantization scale, and the scheduled total record time according to a function having parameters including at least one of a total record capacity of the recording medium, a total record time, the remaining record capacity, the remaining record time, the limit quantization scale, and the scheduled total record time.

13. A video signal encoding and recording apparatus as recited in claim 1, wherein the seventh means comprises a register for storing a signal of a variation allowance code amount for covering a code amount variation, means for updating the signal of the variation allowance code amount in response to one of the remaining record capacity and the remaining record time, and means for updating the encoding rate according to a function having a parameter being the variation allowance code amount represented by the signal in the register.

8. A video signal encoding and recording apparatus comprising:

first means for quantizing a video signal into a quantization-resultant signal in response to a variable quantization step;

second means for recording the quantization-resultant signal generated by the first means on a recording medium;

third means for calculating a remaining record capacity of the recording medium;

fourth means for determining a capacity of a virtual buffer in response to the remaining record capacity calculated by the third means;

fifth means for calculating a degree of occupancy of the virtual buffer having the capacity determined by the fourth means; and

sixth means for controlling the quantization step used by the first means in response to the virtual-buffer occupancy degree calculated by the fifth means.

9. A video signal encoding and recording apparatus as recited in claim 8, wherein the fifth means comprises means for determining a target mean transmission rate in response to the remaining record capacity calculated by the third means, means for detecting a transmission rate of the quantization-resultant signal, and means for calculating the virtual-buffer occupancy degree in response to the target mean transmission rate, the detected transmission rate, and the virtual-buffer capacity determined by the fourth means.

10. A method of encoding and recording a video signal, comprising the steps of:

quantizing a video signal into a quantization-resultant signal in response to a variable quantization step;

recording the quantization-resultant signal on a recording medium;

calculating a remaining record capacity of the recording medium;

determining a capacity of a virtual buffer in response to the calculated remaining record capacity;

calculating a degree of occupancy of the virtual buffer having the determined capacity; and

controlling the quantization step in response to the calculated virtual-buffer occupancy degree.

11. A method as recited in claim 10, wherein the virtual-buffer occupancy degree calculating step comprises determining a target mean transmission rate in response to the calculated remaining record capacity, detecting a transmission rate of the quantization-resultant signal, and calculating the virtual-buffer occupancy degree in response to the target mean transmission rate, the detected transmission rate, and the determined virtual-buffer capacity.

14. A method comprising the steps of:

1) quantizing a video signal into a quantization-resultant signal in response to a variable quantization scale;

2) recording the quantization-resultant signal generated by the step

     1) on a recording medium;

3) controlling the quantization scale used by the step

     1) in response to an encoding rate;

4) limiting the quantization scale used by the step

     1) to within a range determined by a limit quantization scale;

5) measuring a remaining record capacity of the recording medium;

6) measuring a remaining record time; and

7) updating the encoding rate used by the step

     3) and the limit quantization scale used by the step

     4) in response to the remaining record capacity measured by the step

     5) and the remaining record time measured by the step

     6).