Frame synchronization apparatus for a video signal
View Patent ↗A frame synchronization apparatus according to an embodiment includes a reception unit, a frame memory, a time generation unit, a reception time acquisition unit, a timestamp acquisition unit, and a control unit. The reception unit is configured to receive packet data including video data and a timestamp. The frame memory is configured to store the packet data. The time generation unit is configured to generate a time based on a reference synchronization signal. The reception time acquisition unit is configured to acquire a reception time of packet data satisfying a condition based on the time. The timestamp acquisition unit is configured to acquire a timestamp from the packet data satisfying the condition. The control unit is configured to read packet data from the frame memory in accordance with a variation in a difference between the reception time and a time indicated by the timestamp.
1. A frame synchronization apparatus comprising:
a reception unit configured to receive packet data including video data and a timestamp;
a frame memory configured to store the packet data received by the reception unit;
a time generation unit configured to generate a time based on a reference synchronization signal;
a reception time acquisition unit configured to acquire a reception time of packet data satisfying a predetermined condition based on the time generated by the time generation unit;
a timestamp acquisition unit configured to acquire the timestamp from the packet data satisfying the predetermined condition; and
a control unit configured to obtain a difference between the reception time and a time indicated by the timestamp, and read packet data from the frame memory in accordance with a variation in the difference, wherein
the video data of one frame is divided into a plurality of consecutive packet data and stored,
the packet data includes a marker bit indicating a boundary between frames in a case where subsequent packet data includes video data of another frame,
the reception time acquisition unit acquires the reception time of the packet data including the marker bit based on the time generated by the time generation unit, and
the timestamp acquisition unit acquires the timestamp from the packet data including the marker bit.
2. The frame synchronization apparatus according to claim 1 , wherein
the control unit obtains a difference between the reception time and the time indicated by the timestamp for each of two consecutive frames, and reads packet data from the frame memory in accordance with a variation in difference between the two.
3. The frame synchronization apparatus according to claim 1 , wherein
the control unit obtains a difference between the reception time and the time indicated by the timestamp for each of two nonconsecutive frames, and reads packet data from the frame memory in accordance with a variation in difference between the two.
4. The frame synchronization apparatus according to claim 1 , wherein
the control unit reads packet data from the frame memory by frame skip or frame repeat in accordance with the variation.
5. A frame synchronization apparatus comprising:
a reception unit configured to receive packet data including video data and a sequence number;
a frame memory configured to store the packet data received by the reception unit;
a time generation unit configured to generate a time based on a reference synchronization signal;
a stored number acquisition unit configured to acquire the number of pieces of packet data stored in the frame memory at a predetermined timing based on the time generated by the time generation unit;
a sequence number acquisition unit configured to acquire a sequence number from packet data satisfying a predetermined condition; and
a control unit configured to read packet data from the frame memory in accordance with a variation in the number of pieces of packet data acquired by the stored number acquisition unit and a variation in the sequence number acquired by the sequence number acquisition unit.
6. The frame synchronization apparatus according to claim 5 , wherein
the video data of one frame is divided into a plurality of consecutive packet data and stored,
the packet data includes a marker bit indicating a boundary between frames in a case where subsequent packet data includes video data of another frame,
the stored number acquisition unit acquires the number of pieces of packet data stored in the frame memory at a timing of a time corresponding to the frame based on the time generated by the time generation unit, and
the sequence number acquisition unit acquires a sequence number from the packet data including the marker bit.
7. The frame synchronization apparatus according to claim 6 , wherein
the control unit obtains a variation in the number of pieces of packet data acquired by the stored number acquisition unit and a variation in the sequence number acquired by the sequence number acquisition unit for each of two consecutive frames, and reads packet data from the frame memory in accordance with the variation in the number of pieces of packet data and the variation in the sequence number.
8. The frame synchronization apparatus according to claim 6 , wherein
the control unit obtains a variation in the number of pieces of packet data acquired by the stored number acquisition unit and a variation in the sequence number acquired by the sequence number acquisition unit for each of two nonconsecutive frames, and reads packet data from the frame memory in accordance with the variation in the number of pieces of packet data and the variation in the sequence number.
9. A frame synchronization apparatus comprising:
a reception unit configured to receive packet data including video data and a sequence number;
a frame memory configured to store the packet data received by the reception unit;
a time generation unit configured to generate a time based on a reference synchronization signal;
a sequence number acquisition unit configured to acquire a sequence number from packet data; and
a control unit configured to read packet data from the frame memory in accordance with a variation in a sequence number acquired from packet data satisfying a predetermined condition and a variation in a sequence number acquired from packet data received at a timing based on the time generated by the time generation unit.
10. A frame synchronization apparatus comprising:
a reception unit configured to receive packet data including video data and a sequence number;
a frame memory configured to store the packet data received by the reception unit;
a time generation unit configured to generate a time based on a reference synchronization signal;
a received number acquisition unit configured to acquire a received number of pieces of packet data at a predetermined timing based on the time generated by the time generation unit;
a sequence number acquisition unit configured to acquire a sequence number from packet data satisfying a predetermined condition; and
a control unit configured to read packet data from the frame memory in accordance with a variation in the received number of pieces of packet data acquired by the received number acquisition unit and a variation in the sequence number acquired by the sequence number acquisition unit.
11. The frame synchronization apparatus according to claim 5 , wherein
the control unit reads packet data from the frame memory by frame skip or frame repeat in accordance with the variation in the number of pieces of packet data and the variation in the sequence number.
12. The frame synchronization apparatus according to claim 1 , further comprising
a stamping unit configured to replace a timestamp included in the packet data read by the control unit with a timestamp based on the time.
13. The frame synchronization apparatus according to claim 5 , further comprising
a replacement unit configured to renumber the sequence number included in the packet data read by the control unit.