High dynamic range data format conversions for digital media
First Claim
1. A method for encoding digital media comprising:
- by a computing device configured to implement the method, receiving digital media data in a first format, the digital media data in the first format including a plurality of still image sample values that collectively form a still image, each of the plurality of sample values of the digital media data in the first format comprising a sign bit, an exponent and a mantissa having a first bit length;
by the computing device configured to implement the method, converting the still image sample values from the first format to a second format, including, for each of the plurality of still image sample values, obtaining a scaled exponent by scaling the exponent for the sample value with a specified exponent bias value and adjusting the bit length of the mantissa to a second bit length different from the first bit length, the digital media data in the second format having a different dynamic range than the first format, each of the plurality of sample values of the digital media data in the second format comprising the scaled exponent scaled by the specified exponent bias value, the mantissa for the sample value, and no separate sign bit;
by the computing device configured to implement the method, encoding the converted still image sample values; and
by the computing device configured to implement the method, generating a bitstream comprising the encoded still image sample values, a first bitstream syntax element that indicates the exponent bias value for the encoded still image sample values, a second bitstream syntax element that indicates the second bit length of the mantissa, and a third bitstream syntax element that indicates the first format from among multiple possible source formats and that indicates the bit depth and format type using a single syntax element, wherein the first bitstream syntax element, the second bitstream syntax element, and the third bitstream syntax element are part of the image header layer of the bitstream.
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Accused Products
Abstract
One or more continuous mappings are defined at a digital media encoder to convert input digital media data in a first high dynamic range format to a second format with a smaller dynamic range than the first format. The encoder converts the input digital media data to the second format with the smaller dynamic range using the continuous mapping and one or more conversion parameters relating to the continuous mapping. The encoder encodes the converted digital media data in a bitstream along with the conversion parameter(s). The conversion parameter(s) enable a digital media decoder to convert the converted digital media data back to the first high dynamic range format from the second format with the smaller dynamic range. Techniques for converting different input formats with different dynamic ranges are described.
125 Citations
27 Claims
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1. A method for encoding digital media comprising:
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by a computing device configured to implement the method, receiving digital media data in a first format, the digital media data in the first format including a plurality of still image sample values that collectively form a still image, each of the plurality of sample values of the digital media data in the first format comprising a sign bit, an exponent and a mantissa having a first bit length; by the computing device configured to implement the method, converting the still image sample values from the first format to a second format, including, for each of the plurality of still image sample values, obtaining a scaled exponent by scaling the exponent for the sample value with a specified exponent bias value and adjusting the bit length of the mantissa to a second bit length different from the first bit length, the digital media data in the second format having a different dynamic range than the first format, each of the plurality of sample values of the digital media data in the second format comprising the scaled exponent scaled by the specified exponent bias value, the mantissa for the sample value, and no separate sign bit; by the computing device configured to implement the method, encoding the converted still image sample values; and by the computing device configured to implement the method, generating a bitstream comprising the encoded still image sample values, a first bitstream syntax element that indicates the exponent bias value for the encoded still image sample values, a second bitstream syntax element that indicates the second bit length of the mantissa, and a third bitstream syntax element that indicates the first format from among multiple possible source formats and that indicates the bit depth and format type using a single syntax element, wherein the first bitstream syntax element, the second bitstream syntax element, and the third bitstream syntax element are part of the image header layer of the bitstream. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A computer-readable storage medium storing computer-executable instructions for performing a method, the method comprising:
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receiving digital media data in a first format, the digital media data in the first format including a plurality of still image sample values, each of the plurality of still image sample values of the digital media data in the first format comprising a sign bit, an exponent and a mantissa having a first bit length; converting the still image sample values from the first format to a second format, including, for each of the plurality of still image sample values, obtaining a scaled exponent by scaling the exponent for the sample value with a specified exponent bias value and adjusting the bit length of the mantissa to a second bit length different from the first bit length, the digital media data in the second format having a different dynamic range than the first format, each of the plurality of sample values of the digital media data in the second format consisting of the scaled exponent scaled by the specified exponent bias value and the mantissa for the sample value; encoding the converted still image sample values; and generating a bitstream comprising the encoded still image sample values, a first bitstream syntax element that indicates the exponent bias value for the encoded still image sample values, a second bitstream syntax element that indicates the second bit length of the mantissa, and a third bitstream syntax element that indicates the first format from among multiple possible source formats and that indicates the bit depth and format type using a single syntax element, wherein the first bitstream syntax element, the second bitstream syntax element, and the third bitstream syntax element are part of the image header layer of the bitstream. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A method for decoding digital media comprising:
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by a computing device configured to implement the method, receiving a bitstream comprising encoded still image sample values, a first bitstream syntax element that indicates the exponent bias value for the encoded still image sample values, a second bitstream syntax element that indicates a first bit length of the mantissa, and a third bitstream syntax element that indicates a second format from among multiple possible formats and that indicates the bit depth and format type of the second format using a single syntax element, wherein the first bitstream syntax element, the second bitstream syntax element, and the third bitstream syntax element are part of the image header layer of the bitstream; by the computing device configured to implement the method, decoding the encoded still image sample values into still image sample values in a first format; and by the computing device configured to implement the method, converting the still image sample values in the first format into still image sample values in the second format using the first bitstream syntax element, the second bitstream syntax element, and the third bitstream syntax element, each of the still image sample values in the first format comprising a scaled exponent scaled by the exponent bias value specified by the first bitstream syntax element, a mantissa having the first bit length specified by the second bitstream syntax element, and no separate sign bit, each of the still image sample values in the second format comprising a sign bit, an exponent having the exponent bias value removed, and a mantissa having a second length. - View Dependent Claims (24, 25, 26, 27)
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Specification