Low-delay buffering model in video coding
First Claim
Patent Images
1. A method of decoding video, the method comprising:
- receiving a first decoded picture buffer (DPB) output delay and a second DPB output delay;
determining whether a hypothetical reference decoder (HRD) operates at an access unit level or operates at a sub-picture level; and
based on a determination that the HRD operates at the access unit level, determining, by a video decoding device, for a decoded picture, a first DPB output time based on the first DPB output delay and a picture clock tick, orbased on a determination that the HRD operates at the sub-picture level;
deriving a sub-picture clock tick based on the picture clock tick and a tick divisor value; and
determining, by the video decoding device, for the decoded picture, a second DPB output time based on the second DPB output delay and the sub-picture clock tick.
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Abstract
Techniques for low-delay buffering in a video coding process are disclosed. Video decoding techniques may include receiving a first decoded picture buffer (DPB) output delay and a second DPB output delay for a decoded picture, determining, for the decoded picture, a first DPB output time using the first DPB output delay in the case a hypothetical reference decoder (HRD) setting for a video decoder indicates operation at a picture level, and determining, for the decoded picture, a second DPB output time using the second DPB output delay in the case that the HRD setting for the video decoder indicates operation at a sub-picture level.
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Citations
24 Claims
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1. A method of decoding video, the method comprising:
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receiving a first decoded picture buffer (DPB) output delay and a second DPB output delay; determining whether a hypothetical reference decoder (HRD) operates at an access unit level or operates at a sub-picture level; and based on a determination that the HRD operates at the access unit level, determining, by a video decoding device, for a decoded picture, a first DPB output time based on the first DPB output delay and a picture clock tick, or based on a determination that the HRD operates at the sub-picture level; deriving a sub-picture clock tick based on the picture clock tick and a tick divisor value; and determining, by the video decoding device, for the decoded picture, a second DPB output time based on the second DPB output delay and the sub-picture clock tick. - View Dependent Claims (2, 3, 4)
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5. A method of encoding video, the method comprising:
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signaling, in a picture timing supplemental enhancement information (SEI) message associated with an access unit, a first decoded picture buffer (DPB) output delay, the first DPB output delay being indicative of a number of picture clock ticks to wait after removal of a last decoding unit in the access unit from a coded picture buffer (CPB) before a decoded picture is output from a DPB; signaling a presence of sub-picture level parameters in the bitstream; signaling a tick divisor value; and in response to signaling the presence of sub-picture level parameters, signaling, in the picture timing SEI message associated with the access unit a second DPB output delay, the second DPB output delay being indicative of a number of sub-picture clock ticks to wait after removal of the last decoding unit in the access unit from the CPB before the decoded picture is output from the DPB, sub-picture clock ticks being derived based on picture clock ticks. - View Dependent Claims (6)
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7. An apparatus configured to decode video data, the apparatus comprising:
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a memory configured to store the video data; and a video decoder in communication with the memory, the video decoder configured to; receive a first decoded picture buffer (DPB) output delay and a second DPB output delay; determine whether a hypothetical reference decoder (HRD) operates at an access unit level or operates at a sub-picture level; and based on a determination that the HRD operates at the access unit level, determine, for a decoded picture, a first DPB output time based on the first DPB output delay and a picture clock tick, and based on a determination that the HRD operates at the sub-picture level; derive a sub-picture clock tick based on the picture clock tick and a tick divisor value; and determine, for the decoded picture, a second DPB output time based on the second DPB output delay and the sub-picture clock tick. - View Dependent Claims (8, 9, 10)
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11. An apparatus configured to encode video data, the apparatus comprising:
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a memory configured to store the video data; and a video encoder in communication with the memory, the video encoder configured to; signal, in a picture timing supplemental enhancement information (SEI) message associated with an access unit, a first decoded picture buffer (DPB) output time delay, the first DPB output delay being indicative of a number of picture clock ticks to wait after removal of a last decoding unit in the access unit from a coded picture buffer (CPB) before a decoded picture is output from a DPB; signal a presence of sub-picture level parameters in the bitstream; signal a tick divisor value; and in response to signaling the presence of sub-picture level parameters, signal, in the picture timing SEI message associated with the access unit, a second DPB output delay, the second DPB output delay being indicative of a number of sub-picture clock ticks to wait after removal of the last decoding unit in the access unit from the CPB before the decoded picture is output from the DPB, sub-picture clock ticks being derived based on picture clock ticks. - View Dependent Claims (12)
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13. An apparatus configured to decode video data, the apparatus comprising:
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means for receiving a first decoded picture buffer (DPB) output delay and a second DPB output delay; indication means for determining whether a hypothetical reference decoder (HRD) operates at an access unit level or operates at a sub-picture level; means, operable when the indication means determines operation of the HRD at the access unit level, for determining, for a decoded picture, a first DPB output time based on the first DPB output delay and a picture clock tick; means for deriving a sub-picture clock tick based on the picture clock tick and a tick divisor value; and means, operable when the indication means determines operation of the HRD at the sub-picture level, for determining, for the decoded picture, a second DPB output time based on the second DPB output delay and the sub-picture clock tick. - View Dependent Claims (14, 15, 16)
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17. An apparatus configured to encode video data, the apparatus comprising:
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means, for signaling, in a picture timing supplemental enhancement information (SEI) message associated with an access unit, a first decoded picture buffer (DPB) output delay, the first DPB output delay being indicative of a number of picture clock ticks to wait after removal of a last decoding unit in the access unit from a coded picture buffer (CPB) before a decoded picture is output from a DPB; means for signaling a presence of sub-picture level parameters in the bitstream; means for signaling a tick divisor value; means, operable in response to signaling the presence of sub-picture level parameters, for signaling, in the picture timing SEI message associated with the access unit, a second DPB output delay, the second DPB output delay being indicative of a number of sub-picture clock ticks to wait after removal of the last decoding unit in the access unit from the CPB before the decoded picture is output from the DPB, sub-picture clock ticks being derived based on picture clock ticks. - View Dependent Claims (18)
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19. A non-transitory computer-readable storage medium storing instructions that, when executed, causes one or more processors of a device configured to decode video data to:
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receive a first decoded picture buffer (DPB) output delay and a second DPB output delay; determine whether a hypothetical reference decoder (HRD) operates at an access unit level or operates at a sub-picture level; and based on a determination that the HRD operates at the access unit level, determine, for a decoded picture, a first DPB output time based on the first DPB output delay and a picture clock tick; and based on a determination that the HRD operates at the sub-picture level; derive a sub-picture clock tick based on the picture clock tick and a tick divisor value; and determine, for the decoded picture, a second DPB output time based on the second DPB output delay and the sub-picture clock tick. - View Dependent Claims (20, 21, 22)
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23. A non-transitory computer-readable storage medium storing instructions that, when executed, causes one or more processors of a device configured to encode video data to:
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signal, in a picture timing supplemental enhancement information (SEI) message associated with an access unit, a first decoded picture buffer (DPB) output time delay, the first DPB output delay being indicative of a number of picture clock ticks to wait after removal of a last decoding unit in the access unit from a coded picture buffer (CPB) before a decoded picture is output from a DPB; signal a presence of sub-picture level parameters in the bitstream; signal a tick divisor value; and in response to signaling the presence of sub-picture level parameters, signal, in the picture timing SEI message associated with the access unit, a second DPB output delay, the second DPB output delay being indicative of a number of sub-picture clock ticks to wait after removal of the last decoding unit in the access unit from the CPB before the decoded picture is output from the DPB, sub-picture clock ticks being derived based on picture clock ticks. - View Dependent Claims (24)
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Specification