Transmission bit-rate control in a video encoder
AssigneeTexas Instruments Incorporated
InventorsSoyeb Nagori, Naveen Srinivasamurthy, Anurag Jain
Life of this patent
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Abstract
A video encoder receives a minimum number of bits (MIN) and a maximum number of bits (MAX) to be used to encode a segment of a sequence of image frames, the segment including a set of pictures contained in the sequence of image frames. The video encoder encodes the set of pictures using a total number of bits greater than the minimum number of bits (MIN), and not exceeding the maximum number of bits (MAX). Thus, the transmission bit-rate of the video encoder can be constrained to lie within a maximum and minimum rate. In an embodiment, the constraints are enforced over relatively short time intervals.
Claims11
A method comprising:
- obtaining a maximum number of bits for encoding a sequence of image frames, the sequence including a set of pictures included in the sequence of image frames;
- determining a base quantization scale for a picture in the set of pictures based on a target average bit rate;
- determining an average quantization scale value as an average of a plurality of quantization values used for encoding pictures in the set of pictures;
- determining a minimum quantization scale for the picture using:
- (a) the average quantization scale value, (b) a first number of previously encoded pictures, and (c) the maximum number of bits;
- determining a quantization scale for encoding the picture based on a comparison to determine a maximum between (A) the base quantization scale and (B) the minimum quantization scale;
- and
- encoding the picture using the quantization scale.
An encoder comprising one or more processors, the one or more processors configured to:
- obtain a maximum number of bits for encoding a sequence of image frames, the sequence including a set of pictures;
- and
- determine a base quantization scale for a picture in the set of pictures based on a target average bit rate;
- determine an average quantization scale value as an average of a plurality of quantization values used for encoding pictures in the set of pictures;
- determine a minimum quantization scale for the picture based on:
- (a) the average quantization scale value, (b) a first number of previously encoded pictures, and (c) the maximum number of bits;
- determine a quantization scale for encoding the picture based on a comparison to determine a maximum between (A) the base quantization scale and (B) the minimum quantization scale;
- and
- encode the set of pictures using the quantization scale.
A non-transitory computer readable medium comprising instructions that when executed by one or more processors contained in a video encoder causes the video encoder to at least:
- determine a base quantization scale for a picture in a set of pictures included in a sequence of image frames, the base quantization scale is based on a target average bit rate;
- determine an average quantization scale value as an average of a plurality of quantization values used for encoding pictures in the set of pictures;
- determine a minimum quantization scale for the picture using:
- (a) the average quantization scale value, (b) a first number of previously encoded pictures, and (c) a maximum number of bits for encoding the sequence;
- determine a quantization scale for encoding the picture based on a comparison to determine a maximum between (A) the base quantization scale and (B) the minimum quantization scale;
- and
- encode the set of pictures using the quantization scale.
Dependencies are inferred from the claim text.