Patent EP0427108A2 successfully refreshed from Google Patents.
EP0427108A2
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Picture coding apparatus
Assignee: Mitsubishi Electric Corp
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Filing: 1990-10-31
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Granted: —
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Expires: 2010-10-31
Abstract
Abstract In the invention, a coding controller (7a) takes a buffer occupancy at present from a transmission buffer, and first normalized value evaluating means (76) outputs a first normalized value being independent of a video rate and a frame rate for the number of bits per n x QB and second normalized value evaluating means (77) outputs a second normalized value for the number of bits per one frame. When the number of bits is relatively small, a second quantization characteristics control table (79) is selected in a selector and the coding control every frame is performed. When the number of bits is large, a first quantization characteristics control table (78) is selected in the selector and the control every n x QB is performed instead of the control every frame and the quantization characteristics control signal is outputted.
Inventors
- 👤 Tokumichi C/O Mitsubishi Denki K. K. Murakami
- 👤 Kazuhiro C/O Mitsubishi Denki K. K. Matsuzaki
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 21:47
CPC Classifications
H; H04; H04N; H04N19/00; H04N19/50; H04N19/59; H04N19/10; H04N19/102; H04N19/124; H04N19/132; H04N19/134; H04N19/146; H04N19/152; H04N19/503; H04N19/587
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
207 words
A picture coding apparatus comprising differential signal generating means for outputting a differential signal using a digitized input picture data and a prediction signal, transmission picture data output means for quantizing and coding the differential signal using a quantization characteristics control signal and for outputting a transmission picture data, decoded picture signal generating means for decoding a quantization index according to the quantization characteristics control signal and getting the decoded differential signal and for outputting a decoded picture signal from the decoded differential signal and the prediction signal, a memory for storing the decoded picture signal and for outputting the prediction signal with time delay, and a coding controller for receiving the buffer occupancy from said transmission picture data output means and for outputting a quantization characteristics control signal, said coding controller comprising: first calculation means for calculating the number of bits created by coding the first prescribed processing unit; second calculation means for calculating the number of bits created by coding the second prescribed processing unit; and determination means for determining the quantization characteristics for the first or second prescribed processing unit among a plurality of quantization characteristics using the output from said first and second calculation means and for outputting the quantization characteristics control signal.
Claim 2
Dependent Claim
207 words
A picture coding apparatus comprising differential signal generating means for outputting a differential signal using a digitized input picture data and a prediction signal, transmission picture data output means for quantizing and coding the differential signal using a quantization characteristics control signal and for outputting a transmission picture data, decoded picture signal generating means for decoding a quantization index according to the quantization characteristics control signal and getting the decoded differential signal and for outputting a decoded picture signal from the decoded differential signal and the prediction signal, a memory for storing the decoded picture signal and for outputting the prediction signal with time delay, and a coding controller for receiving the buffer occupancy from said transmission picture data output means and for outputting a quantization characteristics control signal, said coding controller comprising: first calculation means for calculating the number of bits created by coding the first prescribed processing unit; second calculation means for calculating the number of bits created by coding the second prescribed processing unit; and determination means for determining the quantization characteristics for the first or second prescribed processing unit among a plurality of quantization characteristics using the output from said first and second calculation means and for outputting the quantization characteristics control signal.
Claim 3
Dependent Claim
149 words
A picture coding apparatus as set forth in claim 1, wherein said coding controller further comprises a frame skip control means for outputting a frame skip control signal according to the buffer storage amount, first quantization characteristics control means for selecting and outputting one among a plurality of quantization characteristics according to output of said first calculation means, and second quantization characteristics control means for selecting and outputting one among a plurality of quantization characteristics according to output of said second calculation means, said first calculation means calculating the variation of the buffer occupancy every quantization block (QB) of the prescribed number (n: natural number), said second calculation means calculating the variation of the buffer occupancy every frame, said determining means selecting either said first or second quantization characteristics control means and outputting the quantization characteristics control signal according to the output from said first or second calculation means.
Claim 4
Dependent Claim
88 words
A picture coding apparatus as set forth in claim 1 or claim 2, wherein said coding controller further comprises first and second information amount normalization means for normalizing outputs from said first and second calculation means into amount being independent of the video rate, the frame rate and size of the processing unit, said determining means determining prescribed quantization characteristics among a plurality of quantization characteristics using outputs N₁ and N₂ from said first and second information amount normalization means respectively, and outputting the quantization characteristics control signals.
Claim 5
Dependent Claim
94 words
A picture coding apparatus as set forth in claim 3, wherein if N₁ > N₂ + TH for arbitrarily determined threshold value TH, said determining means outputs the quantization characteristics control signal for changing the coding control unit from the second prescribed processing unit into the first prescribed processing unit, and if N₁ ≦ N₂ + TH after coding m x n x QB (m: natural number), said determining means outputs the quantization characteristics control signal for changing the coding control unit from the first prescribed processing unit into the second prescribed processing unit.
Claim 6
Dependent Claim
94 words
A picture coding apparatus as set forth in claim 3, wherein if N₁ < N₂ + TH′ for arbitrarily determined threshold value TH′, said determining means outputs the quantization characteristics control signal for changing the coding control unit from the first prescribed processing unit into the second prescribed processing unit, and if N₁ ≧ N₂ + TH′ after coding m x n x QB (m: natural number), said determining means outputs the quantization characteristics control signal for changing the coding control unit from the second prescribed processing unit into the first prescribed processing unit.
References Cited (Backward Citations)
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