Method and system for multi-layer rate control for a multi-codec system
View Patent ↗A video transmitter comprising a plurality of encoders may be operable to determine, for a transport stream, a constant overall number of bits per time interval corresponding to a frame in the transport stream. For each time interval corresponding to a start and an end of encoding of each of frames using each of the encoders, the video transmitter may allocate a target number of bits to each of the frames to achieve the constant overall number of bits. The allocation of the target number of bits may be based on frame types of the frames and CODEC types of the encoders, where the allocated target number of bits for each of the frames meets buffer overflow/underflow requirements associated with each of the encoders. A quantization parameter (QP) may be calculated and adjusted at each of one or more layers for generating an actual number of bits during encoding.
1. A method comprising:
determining an overall number of bits per time interval that corresponds to transferring a frame in a transport stream, the transport stream including a plurality of streams each generated according to a different encoding standard; and
allocating, by circuitry, a target number of bits to each of a plurality of frames of the plurality of streams to achieve the overall number of bits for the transport stream based on a frame type of each of the plurality of frames and the different encoding standards according to which each of the plurality of streams is generated.
2. The method of claim 1 , comprising:
determining a target number of bits for a macroblock of each of the plurality of frames based on the target number of bits allocated to each of the plurality of frames.
3. The method of claim 2 , comprising:
calculating a quantization parameter for the macroblock based on the target number of bits determined for the macroblock.
4. The method of claim 3 , comprising:
determining rate control information associated with the macroblock at each of one or more layers of each of the plurality of streams.
5. The method of claim 4 , comprising:
adjusting the quantization parameter calculated for each of the one or more layers based on the rate control information at each of the one or more layers to generate a final quantization parameter.
6. The method of claim 4 , wherein
the rate control information at a layer comprises a bit error that corresponds to a difference between an actual number of bits generated during encoding for the layer and a target number of bits corresponding to the actual number of bits for the layer.
7. The method of claim 6 , comprising:
adjusting the quantization parameter based on a proportional value, an integral value or a derivative value of the bit error at each of the one or more layers.
8. The method of claim 4 , wherein
at least one of the one or more layers includes a multi-group of pictures, a group of pictures, a frame, a multi-macroblock or a macroblock.
9. The method of claim 1 , comprising:
adjusting a total number of frames in a group of pictures for each of one or more of the plurality of streams for the allocation of the target number of bits to each of the plurality of frames.
10. A system comprising:
circuitry configured to
determine an overall number of bits per time interval that corresponds to transferring a frame in a transport stream, the transport stream including a plurality of streams each generated according to a different encoding standard; and
allocate a target number of bits to each of a plurality of frames of the plurality of streams to achieve the overall number of bits for the transport stream based on a frame type of each of the plurality of frames and the different encoding standards according to which each of the plurality of streams is generated.
11. The system of claim 10 , wherein
the circuitry is configured to determine a target number of bits for a macroblock of each of the plurality of frames based on the target number of bits allocated to each of the plurality of frames.
12. The system of claim 11 , wherein
the circuitry is configured to calculate a quantization parameter for the macroblock based on the target number of bits determined for the macroblock.
13. The system of claim 12 , wherein
the circuitry is configured to determine rate control information associated with the macroblock at each of one or more layers of each of the plurality of streams.
14. The system of claim 13 , wherein
the circuitry is configured to adjust the quantization parameter calculated for each of the one or more layers based on the rate control information at each of the one or more layers to generate a final quantization parameter.
15. The system of claim 10 , wherein
the rate control information at a layer comprises a bit error that corresponds to a difference between an actual number of bits generated during encoding for the layer and a target number of bits corresponding to the actual number of bits for the layer.
16. The system of claim 15 , wherein
the circuitry is configured to adjust the quantization parameter based on a proportional value, an integral value or a derivative value of the bit error at one or more layers of each of the plurality of streams.
17. The system of claim 13 , wherein
at least one of the one or more layers includes a multi-group of pictures, a group of pictures, a frame, a multi-macroblock or a macroblock.
18. The system of claim 10 , wherein,
the circuitry is configured to adjust a total number of frames in a group of pictures for each of one or more of the plurality of streams for the allocation of the target number of bits to each of the plurality of frames.
19. The system of claim 10 , wherein
the circuitry includes a rate control module.
20. A non-transitory computer-readable medium including computer program instructions, which when executed by circuitry, causes the circuitry to:
determine an overall number of bits per time interval that corresponds to transferring a frame in a transport stream, the transport stream including a plurality of streams each generated according to a different encoding standard; and
allocate a target number of bits to each of a plurality of frames of the plurality of streams to achieve the overall number of bits for the transport stream based on a frame type of each of the plurality of frames and the different encoding standards according to which each of the plurality of streams is generated.