Transmission device, transmission method, reception device, and reception method
There is provided a transmission device including circuitry configured to generate a physical layer frame. A time information descriptor is included in a preamble of the physical layer frame. The time information descriptor includes a time information flag that indicates presence or absence of time information in the time information descriptor. The circuitry is configured to transmit the physical layer frame including the preamble and a payload. The time information indicates a time of a predetermined position in a stream of the physical layer frame.
1. A reception device comprising:
a processor configured to:
receive a physical layer frame including a bootstrap, a preamble, and a payload, wherein
the preamble includes a time information flag that indicates presence or absence of time information in the physical layer frame,
in a case where the time information flag indicates the presence of the time information, the time information indicates a time at a head of the bootstrap, which is adjacent to the preamble, and
the time information is defined in accordance with a precise time protocol.
2. The reception device according to claim 1 , wherein two bits are allocated to the time information flag.
3. The reception device according to claim 1 , wherein, in a case where the time information is present, the preamble includes information representative of a precision of the time information.
4. The reception device according to claim 1 , wherein, in a case where the time information is present, a precision of the time information is a nanosecond or less than the nanosecond.
5. The reception device according to claim 1 , wherein, in a case where the time information is present, the time information includes a 32-bit second field.
6. The reception device according to claim 1 , wherein
the processor is configured to process the time information and to control a timing of presentation of an image and audio,
the reception device includes a display and a speaker, and
the image is supplied to the display and the audio is supplied to the speaker in accordance with the time information.
7. The reception device according to claim 1 , wherein the precise time protocol is defined by a standard belonging to:
IEEE1588,
3GPP, third Generation Partnership Project,
NTP, Network Time Protocol, or
GPS, Global Positioning System.
8. The reception device according to claim 5 , wherein the 32-bit second field includes 32 least significant bits of a number of seconds elapsed between the time at the head of the bootstrap and a second time.
9. The reception device according to claim 7 , wherein the processor is configured to restore a time relative to a Precision Time Protocol epoch using the 32-bit second field.
10. A reception method of a reception device, the method comprising:
receiving, by a processor of the reception device, a physical layer frame including a bootstrap, a preamble, and a payload, wherein
the preamble includes a time information flag that indicates presence or absence of time information in the physical layer frame,
in a case where the time information flag indicates the presence of the time information, the time information indicates a time at a head of the bootstrap, which is adjacent to the preamble, and
the time information is defined in accordance with a precise time protocol.
11. The reception method according to claim 10 , wherein two bits are allocated to the time information flag.
12. The reception method according to claim 10 , wherein, in a case where the time information is present, the preamble includes information representative of a precision of the time information.
13. The reception method according to claim 10 , wherein, in a case where the time information is present, a precision of the time information is a nanosecond or less than the nanosecond.
14. The reception method according to claim 10 , wherein, in a case where the time information is present, the time information includes a 32-bit second field.
15. The reception method according to claim 10 , further comprising
processing the time information;
controlling a timing of presentation of an image and audio; and
displaying the image on a display and outputting the audio on a speaker in accordance with the time information.
16. The reception method according to claim 10 , wherein the precise time protocol is defined by a standard belonging to:
IEEE1588,
3GPP, third Generation Partnership Project,
NTP, Network Time Protocol, or
GPS, Global Positioning System.
17. The reception method according to claim 14 , wherein the 32-bit second field includes 32 least significant bits of a number of seconds elapsed between the time at the head of the bootstrap and a second time.
18. The reception method according to claim 17 , further comprising restoring a time relative to a Precision Time Protocol epoch using the 32-bit second field.
19. A reception device comprising:
a tuner configured to receive a physical layer frame including a bootstrap, a preamble, and a payload, wherein
the preamble includes a time information flag that indicates presence or absence of time information in the physical layer frame,
in a case where the time information flag indicates the presence of the time information, the time information indicates a time at a head of the bootstrap, which is adjacent to the preamble, and
the time information is defined in accordance with a precise time protocol.
20. The reception device according to claim 19 , further comprising:
a processing unit configured to process the time information and to control a timing of presentation of an image and audio;
a display; and
a speaker,
wherein the image is supplied to the display and the audio is supplied to the speaker in accordance with the time information.
21. The reception device according to claim 19 , wherein the physical layer frame is an ATSC 3.0 physical layer frame.
22. The reception device according to claim 19 , wherein the precise time protocol is defined by a standard belonging to:
IEEE1588,
3GPP, third Generation Partnership Project,
NTP, Network Time Protocol, or
GPS, Global Positioning System.