Error concealment

• US 20060188025A1
• Filed: 02/18/2005
• Published: 08/24/2006
• Est. Priority Date: 02/18/2005
• Status: Abandoned Application

• Current Assignee: Nokia Corporation
• Original Assignee: Nokia Corporation
• Inventors: Hannuksela, Miska
• Application Number:
  US11/062,114
• Publication Number:
  US 20060188025A1
• Time in Patent Office: Days
• US Class Current: 375/240.270
• CPC Class Codes: H04N 19/105 Selection of the reference unit for prediction within a chosen coding or prediction mode, e.g. adaptive choice of position and number of pixels used for prediction
• CPC Class Codes: H04N 19/107 between spatial and temporal predictive coding, e.g. picture refresh
• CPC Class Codes: H04N 19/109 among a plurality of temporal predictive coding modes
• CPC Class Codes: H04N 19/142 Detection of scene cut or scene change
• CPC Class Codes: H04N 19/146 Data rate or code amount at the encoder output
• CPC Class Codes: H04N 19/166 concerning the amount of transmission errors, e.g. bit error rate [BER]
• CPC Class Codes: H04N 19/172 the region being a picture, frame or field
• CPC Class Codes: H04N 19/44 Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder
• 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 19/61 in combination with predictive coding
• CPC Class Codes: H04N 19/895 in combination with error concealment

Abstract

An error concealment in decoding of inter-coded information, comprising normative error concealment within a decoding loop and proprietary error concealment outside the decoding loop. The normative error concealment provides meta-data and a reconstructed frame for the proprietary error concealment. Using these, the proprietary error concealment further enhances the reconstructed frame without effecting on the decoding of the inter-coded data. A mobile station, network element and a computer program product using the method have further been described.

Claims

1. An apparatus, comprising:

a decoder for decoding information;

a first error concealment block for applying a first concealment of errors in decoded information; and

a second error concealment block for applying a second concealment of errors in the decoded information, wherein the decoder is configured to at least occasionally decode the information based on previously decoded information using the first but not the second concealment of errors.

2. An apparatus according to claim 1, wherein the information is video information.

3. An apparatus according to claim 1, wherein said second error concealment block is configured to obtain error concealing information regarding the first error concealment, the error concealing information comprising at least one item selected from a group consisting of the following:

location of an error region comprising an error or errors, shape of the error region, and the size of the error region.

4. An apparatus according to claim 3, wherein the error concealing information further comprises information for identifying error concealment method or methods having been used in error concealing a subsequent decoded frame.

5. An apparatus according to claim 1, wherein the first error concealment block is configured to apply a normative error concealment specified in an information decoding standard.

6. An apparatus according to claim 2, wherein the first concealment complies with a first set of error concealment methods in order to guarantee a consistent minimum reconstructed image quality.

7. An apparatus according to claim 1, wherein the second error concealment provides non-normative error concealment.

8. An apparatus according to claim 1, wherein the second error concealment block is configured to adapt its operation to scale computation and/or power consumption demand of the apparatus to a desired level.

9. An apparatus according to claim 1, wherein the apparatus is selected from a group consisting of:

a video telephone, a mobile video telephone, a network element in a mobile telecommunications network, a media player and a mobile media player.

10. An apparatus according to claim 1, wherein the information comprises a series of information frames and the apparatus comprises a transmitter for sending to an originator of the information being decoded feedback information concerning success of decoding, the feedback information consisting of one of the following:

negative acknowledgement (NACK) message for a first corrupted information frame for any series of information frames affected by a given transmission error; and

acknowledgements for successfully decoded information frames and a negative acknowledgement (NACK) message for a first corrupted information frame for any series of information frames affected by a given transmission error.

11. An apparatus according to claim 1, further comprising an encoder for encoding information in a two-way session, wherein the encoder comprises a transmitter for transmitting encoded information to a recipient and a receiver for receiving feedback information from the recipient and wherein the encoder is configured to adapt its reference frames based on the feedback information.

12. An apparatus according to claim 11, wherein the adaptation of the reference frame is selected from the group consisting of:

receiving a NACK message identifying a given information frame or a particular portion thereof and, in response thereto, applying a pre-determined error concealment algorithm for the frame or portion thereof so that the encoder avoids using any reference frames between a reference frame corresponding to the NACK message, exclusive, and a latest coded reference frame, inclusive, as a reference frame for predictive coding; and

receiving a NACK message for an earlier transmitted information frame and, in response thereto, determining whether a transmission time and a current time is more than a present round-trip delay and if yes, encoding again intervening unsent information frames using a pre-determined error concealment algorithm for those information frames.

13. An error concealment method for error concealment comprising:

decoding information;

applying a first concealment of errors in decoded information; and

applying a second concealment of errors in the decoded information, wherein the step of decoding at least occasionally decodes information based on previously decoded information using the first concealment of errors but not the second concealment of errors.

14. An error concealment method according to claim 13, wherein the first error concealment is applied by a normative procedure comprising at least one particular predetermined error concealment method.

15. An error concealment method according to claim 13, wherein the first error concealment is applied by a proprietary procedure comprising at least one particular predetermined error concealment method.

16. An error concealment method according to claim 13, wherein the decoding further comprises sending to an originator of the information being decoded an indication of a detected defective decoding.

17. An error concealment method according to claim 13, wherein on the first error concealment, error concealing information is produced for the second error concealment, the error concealing information comprising at least one item selected from a group consisting of the following:

location of an error region comprising an error or errors, shape of the error region, and size of the error region.

18. An error concealment method according to claim 17, wherein the error concealing information further comprises information for identifying error concealment method or methods having been used in error concealing a subsequent decoded frame.

19. An error concealment method according to claim 13, wherein the information is video information and the first error concealment complies with a first set of error concealment methods in order to guarantee a consistent minimum reconstructed image quality.

20. An error concealment method according to claim 13, wherein the applying of the second concealment of errors is dynamically adapted to scale computation and/or power consumption demand to a desired level.

21. A computer program stored on a memory media which when executed by an apparatus causes the apparatus to conceal errors, comprising:

computer executable program means to enable the apparatus in decoding information;

computer executable program means to enable the apparatus applying a first concealment of errors in decoded information; and

computer executable program means to enable the apparatus applying a second concealment of errors in the decoded information, wherein the decoding at least occasionally decodes the information based on previously decoded information using the first concealment of errors but not the second concealment of errors.