Encoding a transparency (alpha) channel in a video bitstream
First Claim
1. A method of transmitting image data for a composite image, wherein the transmitted data includes at least a foreground image and a transparency mask, the method comprising:
- encoding, by a video codec device, the foreground image;
encoding, by the video codec device, the transparency mask;
transmitting, by the video codec device, an image data stream comprising one or more syntax structures corresponding to the encoded foreground image and one or more syntax structures corresponding to the encoded transparency mask, wherein the one or more syntax structures corresponding to the transparency mask are delimited from and are located after the syntax structures corresponding to the foreground image in the data stream.
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Accused Products
Abstract
Disclosed herein is a technique for delimiting the alpha channel at the NAL layer in codecs like H.264 to facilitate the optional nature of the alpha channel. In coded video sequences that include alpha, there is one alpha picture for every primary coded (e.g., luma-chroma) picture, and the coded alpha picture is contained in the same access unit as its corresponding primary coded picture. The alpha coded slice NAL units of each access unit are sent after the NAL units of the primary coded picture and redundant coded pictures, if any. The presence or absence of the alpha NAL units does not affect the decoding of the remaining NAL units in any way.
44 Citations
21 Claims
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1. A method of transmitting image data for a composite image, wherein the transmitted data includes at least a foreground image and a transparency mask, the method comprising:
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encoding, by a video codec device, the foreground image; encoding, by the video codec device, the transparency mask; transmitting, by the video codec device, an image data stream comprising one or more syntax structures corresponding to the encoded foreground image and one or more syntax structures corresponding to the encoded transparency mask, wherein the one or more syntax structures corresponding to the transparency mask are delimited from and are located after the syntax structures corresponding to the foreground image in the data stream. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of receiving and processing an image data stream, the method comprising:
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receiving, by a video codec device, an image data stream comprising one or more syntax structures corresponding to an encoded foreground image and one or more syntax structures corresponding to an encoded transparency mask, wherein the one or more syntax structures corresponding to the transparency mask are delimited from and are located after the syntax structures corresponding to the foreground image in the data stream; decoding, by the video codec device, the syntax structures corresponding to the encoded foreground image; decoding, by the video codec device, the syntax structures corresponding to the transparency mask; and computing, by the video codec device, a displayed image as a function of the decoded foreground image and the decoded transparency mask. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15)
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16. A method of receiving and processing an image data stream, the method comprising:
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receiving, by a video codec device, an image data stream comprising one or more syntax structures corresponding to an encoded foreground image and one or more syntax structures corresponding to an encoded transparency mask, wherein the one or more syntax structures corresponding to the transparency mask are delimited from and are located after the syntax structures corresponding to the foreground image in the data stream; decoding, by the video codec device, the syntax structures corresponding to the encoded foreground image; discarding, by the video codec device, the syntax structures corresponding to the transparency mask; and computing, by the video codec device, a displayed image as a function of the decoded foreground image and not as a function of the discarded transparency mask. - View Dependent Claims (17, 18, 19, 20, 21)
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Specification