1. A video decoding method for decoding encoded data obtained by subjecting a video image having luminance and two color differences to prediction encoding to the video image, comprising:
receiving an input of encoded data obtained by encoding, for one or more to-be-decoded blocks, a plurality of combinations comprising (1) a weighting factor for each luminance and for each of two color differences, (2) an offset for each luminance and for each of two color differences, (3) a flag indicating presence or non-presence of the weighting factor and the offset concerning luminance and (4) a flag indicating presence or non-presence of the weighting factors and the offsets concerning the two color differences, and encoding, for a to-be-decoded block, (A) a quantized orthogonal transform coefficient of a prediction error signal concerning luminance and two color differences, (B) information of a motion vector and (C) an index indicating (a) one combination of the plurality of combinations and (b) a reference image;
deriving the weighting factors and the offsets from the plurality of combinations and the index;
generating a prediction image by multiplying the reference image by the weighting factors and adding the offsets, based on the motion vector;
generating a prediction error signal by subjecting the quantized orthogonal transform coefficient to inverse quantization and inverse orthogonal transform; and
generating a decoded image by calculating a sum of the prediction error signal and the prediction image;
wherein two possible values of the index correspond to different reference images, and indicate an identical combination of the weighting factors and the offsets, and a value obtained by arithmetic-shifting right one of the two possible values by one bit is identical to a value obtained by arithmetic-shifting right the other value by one bit.
2. A video decoding apparatus for decoding encoded data obtained by subjecting a video image having luminance and two color differences to prediction encoding to the video image, comprising:
a receiver configured to receive an input of encoded data obtained by encoding, for one or more to-be-decoded blocks, a plurality of combinations comprising (1) a weighting factor for each luminance and for each of two color differences, (2) an offset for each luminance and for each of two color differences, (3) a flag indicating presence or non-presence of the weighting factor and the offset concerning luminance and (4) a flag indicating presence or non-presence of the weighting factors and the offsets concerning the two color differences, and encoding, for a to-be-decoded block, (A) a quantized orthogonal transform coefficient of a prediction error signal concerning luminance and two color differences, (B) information of a motion vector and (C) an index indicating (a) one combination of the plurality of combinations and (b) a reference image;
a deriving module configured to derive the weighting factors and the offsets from the plurality of combinations and the index;
a first generator configured to generate a prediction image by multiplying the reference image by the weighting factors and adding the offsets, based on the motion vector;
a second generator configured to generate a prediction error signal by subjecting the quantized orthogonal transform coefficient to inverse quantization and inverse orthogonal transform; and
a third generator configured to generate a decoded image by calculating a sum of the prediction error signal and the prediction image;
wherein two possible values of the index correspond to different reference images, and indicate an identical combination of the weighting factors and the offsets, and a value obtained by arithmetic-shifting right one of the two possible values by one bit is identical to a value obtained by arithmetic-shifting right the other value by one bit.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An electronic ballast for operating at least one discharge lamp, the electronic ballast comprising:
an input with a first and a second input connection for coupling to an input voltage;
a load circuit with an output that comprises a first and a second output connection for coupling to the at least one discharge lamp, the load circuit comprising a bridge circuit with at least a first and a second bridge switch;
an intermediate circuit capacitor that is coupled to the input of the load circuit, the voltage dropping across the intermediate Circuit capacitor during operation representing the intermediate circuit voltage;
a transformer that is coupled between the input of the electronic ballast and the intermediate circuit capacitor, the transformer comprising at least one transformer switch;
a control apparatus for driving the transformer switch and at least the first and the second bridge switch; and
a monitoring apparatus for monitoring at least one value correlated with the input voltage, the monitoring apparatus being coupled to the control apparatus, and the control apparatus being designed to deactivate the driving of the transformer switch upon detection of a deactivation criterion; and
a voltage measuring apparatus for measuring the intermediate circuit voltage, the voltage measuring apparatus being coupled to the control apparatus, the control apparatus being designed to reactivate the driving of the transformer switch after a deactivation phase when the sum of input and intermediate circuit voltage has dropped below a first prescribable threshold value,
wherein the transformer is an single-ended primary-inductor converter (SEPIC) transformer.
2. The electronic ballast as claimed in claim 1, wherein the monitoring apparatus is designed to monitor the input voltage, the deactivation criterion being present when the value of the input voltage has exceeded a second prescribable threshold value.
3. The electronic ballast as claimed in claim 1, wherein the monitoring apparatus is designed to monitor the sum of input voltage and intermediate circuit voltage, the deactivation criterion being present when the value of the sum of input voltage and intermediate circuit voltage has exceeded a third prescribable threshold value.
4. The electronic ballast as claimed in claim 1, wherein the control apparatus comprises an apparatus for determining the time derivative of the input voltage, the control apparatus being designed to monitor the time derivative of the input voltage, the deactivation criterion being present when the value of the time derivative of the input voltage has exceeded a fourth prescribable threshold value.
5. The electronic ballast as claimed in claim 1, wherein the control apparatus is designed to deactivate the driving at least of the first and the second bridge switch when the value of the intermediate circuit voltage has dropped below a fifth prescribable threshold value.
6. The electronic ballast as claimed in claim 5, wherein the control apparatus is designed to keep the driving at least of the first and the second bridge switch active during the deactivation phase of the driving of the transformer switch until the value of the intermediate circuit voltage has dropped below the fifth prescribable threshold value.
7. The electronic ballast as claimed in claim 1, further comprising: a time measuring apparatus that is coupled to the control apparatus, the control apparatus being designed to carry out cold starting of the lamp after a first prescribable period after the beginning of a deactivation phase at least of the first and the second bridge switch, and after the sum of input and intermediate circuit voltages has dropped below the first prescribable threshold value.
8. The electronic ballast as claimed in claim 7, further comprising: a memory apparatus configured to store values of the input voltage, the control apparatus being designed to carry out restarting of the lamp when the cold starting of the lamp has not led to ignition of the discharge lamp, and when at least one of the deactivation criteria for the transformer switch has been detected within a second prescribable period before the failed cold starting of the lamp.
9. The electronic ballast as claimed in claim 7, wherein the control apparatus is designed to deactivate the driving at least of the first and the second bridge switch when the cold starting of the lamp has not led to ignition of the discharge lamp and when none of the deactivation criteria has been detected within the second prescribable period before the failed cold starting of the lamp.
10. A method for operating at least one discharge lamp on an electronic ballast, the electronic ballast comprising:
an input with a first and a second input connection for coupling to an input voltage;
a load circuit with an output that comprises a first and a second output connection for coupling to the at least one discharge lamp, the load circuit comprising a bridge circuit with at least a first and a second bridge switch;
an intermediate circuit capacitor that is coupled to the input of the load circuit, the voltage present at the intermediate circuit capacitor representing the intermediate circuit voltage;
a transformer that is coupled between the input of the electronic ballast and the intermediate circuit capacitor, the transformer comprising at least one transformer switch;
a control apparatus for driving the transformer switch and at least the first and the second bridge switch; and
a monitoring apparatus configured to monitor at least one value correlated with the input voltage, the monitoring apparatus being coupled to the control apparatus, and the control apparatus being designed to deactivate the driving of the transformer switch upon detection of a deactivation criterion;
wherein the transformer is an single-ended primary-inductor converter (SEPIC) transformer;
the method comprising:
a) measuring the intermediate circuit voltage;
b) determining the sum of input and intermediate circuit voltages; and
c) activating the driving of the transformer switch if the sum of input and intermediate circuit voltages has dropped below a first prescribable threshold value after a deactivation phase of the transformer switch.