Method and device for generating the clock of the output stream from the input stream

• US 9,118,562 B2
• Filed: 05/28/2010
• Issued: 08/25/2015
• Est. Priority Date: 05/29/2009
• Status: Active Grant

• Current Assignee: Enensys Technologies
• Original Assignee: Enensys Technologies
• Inventors: Puton, Matthieu
• Primary Examiner(s): SINKANTARAKORN, PAWARIS
• Application Number:
  US13/375,003
• Publication Number:
  US 20120155270A1
• Time in Patent Office: 1,915 Days
• Field of Search: 370229-235, 370/350, 370503-516
• US Class Current: 1/1
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/22 Traffic shaping

Abstract

The present invention relates to the field of video stream transport. The invention specifically relates to a method for generating a clock signal controlling the transmission rate of an output signal device transmitting a stream from an input stream.

The invention describes a method for generating the clock of the output stream from a measurement of the clock of the input stream. Said measurement is permanently adjusted in order to increase the accuracy of the measurement as well as to monitor possible drifts of the input stream clock. Said decorrelation between the clock of the input stream generates a regular output clock, even when the clock of the input stream is irregular.

Claims

1. A method of generating a clock of the moments of sending data packets of a data stream sent by a device, said device receiving at least a first stream of data as an input and sending a stream of data as an output, characterized in that it comprises:

a step of measuring the transmission rate of the input stream received in a burst mode or in a continuous mode by counting the number of bytes received and by counting time taken to receive the bytes,

step of counting the number of bytes sent and the time taken to send the bytes,

a step of generating moments of sending the data packets of the stream sent at a different mode than the input stream, the moments being generated from the input transmission rate measured so as to comply with a sending transmission rate corresponding to the transmission rate of the input stream;

and moments of sending the data packets is determined by comparing the product of the number of bytes received and of the time taken to send the bytes to the product of the time taken to receive the bytes and of the number of bytes sent.

2. A method according to claim 1, characterized in that the step of measuring the transmission rate of the input stream is performed by accumulation in two counters, a first counter accumulates the quantity of data received, the second counter accumulates the time elapsed for receiving these data.

3. A method according to claim 2, characterized in that, the input stream being composed of data packets themselves composed of bytes, said counters are updated when the first byte of a data packet is received.

4. A method according to claim 1, characterized in that the method comprises a step of generating the moment of sending a packet when the quantity of data sent during the sending time becomes less than the quantity of data received during the reception time.

5. A method according to claim 4, characterized in that the step of generating the moment of sending a packet comprises a step of comparing two counters, a first counter accumulating the number of bytes received multiplied by the sending time, a second counter accumulating the number of bytes sent multiplied by the reception time.

6. A device receiving at least one first data stream as an input and sending a data stream as an output, comprising means of generating a clock of the moments of sending data packets of a data stream sent by a device, said device being characterized in that these generation means comprise:

means of measuring the transmission rate of the input stream received in a burst mode or in a continuous mode by counting the number of bytes received and by counting time taken to receive the bytes,

means of counting the number of bytes sent and the time taken to send the bytes,

means of generating the moments of sending the data packets of the stream sent at a different mode than the input stream, the moments being generated from the input transmission rate measured so as to comply with a transmission rate corresponding to the transmission rate of the input stream;

and moments of sending the data packets is determined by comparing the product of the number of bytes received and of the time taken to send the bytes to the product of the time taken to receive the bytes and of the number of bytes sent.