Truncated bit depth support SEI messages
A method of video decoding includes receiving a coded video bitstream comprising coded information of one or more coded pictures, the coded information includes an SEI message associated with at least a first picture in the one or more coded pictures, the SEI message includes at least a syntax element indicative of at least one of a forward truncation function for converting an original picture of a first bit depth to the first picture of a second bit depth and/or a reverse truncation function corresponding to the forward truncation function, the second bit depth is lower than the first bit depth. The method also includes reconstructing at least the first picture comprising first reconstructed samples based on the coded information, a numbering range of sample values of the first reconstructed samples is determined by at least one of the forward truncation function and/or the reverse truncation function.
1 . A method of video decoding, comprising:
receiving a coded video bitstream comprising coded information of one or more coded pictures, the coded information including a supplemental enhancement information (SEI) message associated with at least a first picture in the one or more coded pictures, the SEI message comprising at least a syntax element indicative of at least one of a forward truncation function for converting an original picture of a first bit depth to the first picture of a second bit depth and/or a reverse truncation function corresponding to the forward truncation function, the second bit depth being lower than the first bit depth; and
reconstructing at least the first picture comprising first reconstructed samples based on the coded information, a numbering range of sample values of the first reconstructed samples being determined by at least one of the forward truncation function and/or the reverse truncation function.
2 . The method of claim 1 , wherein at least the syntax element indicates a bit shifting parameter in the forward truncation function and/or the reverse truncation function.
3 . The method of claim 2 , wherein at least the syntax element includes a left bit shifting parameter that is used in the reverse truncation function.
4 . The method of claim 2 , wherein at least the syntax element includes at least a first bit shifting parameter associated with a first color component, and a second bit shifting parameter associated with a second color component.
5 . The method of claim 1 , further comprising:
generating a first recovered picture having the first bit depth at least partially from the first reconstructed samples.
6 . The method of claim 5 , wherein the generating comprises:
left-shifting bits of a reconstructed sample to obtain a recovered sample having the first bit depth.
7 . The method of claim 5 , wherein the generating comprises:
combining bits of a first reconstructed sample with bits of a second reconstructed sample to obtain a recovered sample of the first recovered picture having the first bit depth.
8 . The method of claim 1 , wherein the SEI message is of an encoder optimization information (EOI) type.
9 . The method of claim 1 , wherein the SEI message is of a dedicated bit depth truncation type.
10 . A method of video encoding, comprising:
applying a forward truncation function on an original picture of a first bit depth to generate one or more pictures of a second bit depth, the second bit depth being lower than the first bit depth;
encoding the one or more pictures to generate coded information of the one or more pictures; and
including, in a coded video bitstream of the coded information, a supplemental enhancement information (SEI) message associated with the one or more pictures, the SEI message comprising at least a syntax element indicative of at least one of the forward truncation function and/or a reverse truncation function corresponding to the forward truncation function.
11 . The method of claim 10 , wherein at least the syntax element indicates a bit shifting parameter in the forward truncation function and/or the reverse truncation function.
12 . The method of claim 11 , wherein at least the syntax element includes a left bit shifting parameter that is used in the reverse truncation function.
13 . The method of claim 11 , wherein at least the syntax element includes at least a first bit shifting parameter associated with a first color component, and a second bit shifting parameter associated with a second color component.
14 . The method of claim 10 , wherein the applying comprises:
generating a sample of the one or more pictures using a subset of bits of an original sample in the original picture.
15 . The method of claim 10 , wherein the applying comprises:
forming at least a first picture and a second picture from the original picture, first samples of the first picture using a first subset of bits of original samples of the original picture, second samples of the second picture using a second subset of the bits of the original samples.
16 . The method of claim 10 , wherein the SEI message is of an encoder optimization information (EOI) type.
17 . The method of claim 10 , wherein the SEI message is of a dedicated bit depth truncation type.
18 . A method of video decoding, comprising:
receiving a coded video bitstream comprising coded information of one or more coded pictures, the coded information including a supplemental enhancement information (SEI) message associated with at least a first picture in the one or more coded pictures, the SEI message comprising at least a syntax element indicative of a conversion function between a first original picture of a first bit depth and the first picture of a second bit depth that is lower than the first bit depth, sample bits of the first picture being a subset of sample bits of the first original picture; and
reconstructing at least the first picture comprising first reconstructed samples based on the coded information, a numbering range of sample values of the first reconstructed samples being determined based on the conversion function.
19 . The method of claim 18 , wherein at least the syntax element indicates a bit shifting parameter for the conversion function.
20 . The method of claim 18 , wherein at least the syntax element indicates at least one of a forward truncation function and a reverse truncation function.