Methods and apparatus for context based line coding

• US 9,307,266 B2
• Filed: 12/22/2014
• Issued: 04/05/2016
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Whitby-Strevens, Colin
• Primary Examiner(s): Mai, Lam T
• Application Number:
  US14/579,855
• Publication Number:
  US 20150181238A1
• Time in Patent Office: 470 Days
• Field of Search: 341/50, 341/51, 341/56, 341/58, 341/68, 375/240.01, 375/292, 375/342, 375/296, 375/341, 725/20, 725/131, 714/759, 714/777, 398/79, 398/155
• US Class Current: 1/1
• CPC Class Codes: H03M 13/31 combining coding for error detection or correction and efficient use of the spectrum without error detection or correction H03M5/14 , H03M5/145
• CPC Class Codes: H03M 13/35 Unequal or adaptive error protection, e.g. by providing a different level of protection according to significance of source information or by adapting the coding according to the change of transmission channel characteristics
• CPC Class Codes: H03M 5/145 Conversion to or from block codes or representations thereof
• CPC Class Codes: H04N 19/46 Embedding additional information in the video signal during the compression process H04N19/517, H04N19/68, H04N19/70 take precedence
• CPC Class Codes: H04N 19/65 using error resilience

Abstract

Methods and apparatus intelligently switching between line coding schemes based on context. In one exemplary embodiment, an High Definition Multimedia Interface (HDMI) system is configured to transmit control and video data according to an 8B/10B line coding protocol, and data island data according to TERC4 (TMDS (Transition Minimized Differential Signaling) Error Reduction Coding 4-bit). Various elements of the disclosed HDMI devices are configured to determine when a context switch occurs, and thereafter seamlessly transition between the appropriate line code protocol.

Claims

1. A method for intelligently switching between line coding schemes based on context, comprising:

receiving one or more symbols according to a first context, at a receiving apparatus, the first context characterized by a first line coding scheme;

detecting, by the receiving apparatus, when a context switch to a second context will occur based on one or more media parameters; and

when the context switch occurs, changing, by the receiving apparatus, to the second context.

2. The method of claim 1, wherein the context switch occurs when preamble symbol is received during a blanking interval configured in accordance with the one or more media parameters.

3. The method of claim 1, wherein the first context is associated with a first state, and the second context is associated with a second state.

4. The method of claim 3, wherein the first context comprises an 8B/10B line coding context and the first state is an active video state or blanking state.

5. The method of claim 3, wherein the second context comprises a TMDS (Transition Minimized Differential Signaling) Error Reduction Coding 4-bit (TERC4) line coding context and the second state is a data island state.

6. The method of claim 3, wherein transitioning between the first state and the second state is based at least in part on receiving a preamble during a blanking interval, where the blanking interval is determined from the one or more media parameters.

7. The method of claim 1, wherein a blanking interval is determined at least in part by the one or more media parameters.

8. The method of claim 7, wherein the one or more media parameters additionally includes at least one or more of a fixed number of scan lines and a length of each scan line.

9. An apparatus configured to intelligently switch between line coding schemes based on context, comprising:

a first interface configured to receive one or more symbols according to at least one of;

(i) a first context, the first context characterized by a first line coding scheme, and (ii) a second context, the second context characterized by a second line coding scheme;

a processor coupled to the first interface; and

a non-transitory computer-readable medium comprising one or more instructions which when executed by the processor, cause the apparatus to;

detect when the context switch will occur based on one or more media parameters and a current state of a state machine; and

when a context switch occurs, change context.

10. The apparatus of claim 9, wherein the state machine comprises an active video state, a blanking state, and a data island state.

11. The apparatus of claim 10, wherein the state machine is configured to transition between the active video state and the blanking state based on one or more preamble symbols.

12. The apparatus of claim 10, wherein the blanking state is based on the one or more media parameters.

13. The apparatus of claim 10, wherein the one or more media parameters comprise one or more attributes selected from the group consisting of:

a display size, a frame rate, and a blanking interval length.

14. The apparatus of claim 10, wherein the context switch occurs when a preamble symbol is received during a blanking interval configured in accordance with the one or more media parameters.

15. An apparatus configured to intelligently switch between line coding schemes based on context, comprising:

a sink configured to receive one or more symbols according to at least one of;

(i) a first context, the first context characterized by a first line coding scheme, and (ii) a second context, the second context characterized by a second line coding scheme;

a source configured to transmit the one or more symbols according to the first and second contexts;

a display element;

a processor; and

a non-transitory computer-readable medium comprising one or more instructions which when executed by the processor, cause the apparatus to;

determine when a context switch should occur based on one or more media parameters and a current state of a state machine; and

when a context switch occurs, cause the source to change the context.

16. The apparatus of claim 15, wherein the one or more media parameters are associated with a media file stored within the non-transitory computer-readable medium.

17. The apparatus of claim 16, wherein the one or more media parameters are based at least in part on a display size, a frame rate, and a blanking interval length associated with the display element.

18. The apparatus of claim 15, wherein the first context comprises an 8B/10B line coding context and the first state is an active video state or blanking state.

19. The apparatus of claim 15, wherein the second context comprises a TMDS (Transition Minimized Differential Signaling) Error Reduction Coding 4-bit (TERC4) line coding context and the second state is a data island state.