ISO/IEC JTC 1/SC 29
| Projekta Nr. | ISO/IEC 23002-1:2006 |
|---|---|
| Nosaukums | <p>A number of image and video coding related standards include a requirement for decoders to implement an integer-output 8x8 inverse discrete cosine transform (IDCT) for the generation of inverse-transformed sample differences with a nominal range from -2<sup>B</sup> to (2<sup>B</sup>)-1 for some integer number of bits <i>B</i>, where <i>B</i> is greater than or equal to 8. ISO/IEC 23002-1:2006 specifies conformance requirements for establishing sufficient accuracy in such an integer-output IDCT implementation. It is intended to be suitable for reference to establish partial or complete requirements for IDCT accuracy for conformance to other standards that require IDCT use. </p> <p>The accuracy requirements specified in the main body of ISO/IEC 23002-1:2006 are essentially the same as those previously specified in IEEE 1180-1990 (which has since been withdrawn), in Annex A of ITU-T Rec. H.261, and in Annex A of ITU-T Rec. H.263. These requirements have been specified herein to resolve normative references to IEEE 1180-1990 in MPEG standards after its withdrawal and to provide improved clarity for the specification of IDCT accuracy requirements. </p> <p>An additional requirement on encoded-bitstream intra refresh frequency was also previously specified in IEEE 1180-1990, establishing a requirement of bitstream conformance that each macroblock be intra-coded at least once within each series of 132 times that it is coded in a predicted picture without an intervening intra picture. That additional requirement is not specified in ISO/IEC 23002-1:2006 , in order to confine its scope to the domain of decoder conformance specification. </p> <p>Some allowances for modification of the specified accuracy requirements are made within ISO/IEC 23002-1:2006. Additional accuracy requirements that may be invoked by a referencing specification are specified in Annexes A and B. </p> |
| Reģistrācijas numurs (WIID) | 42030 |
| Darbības sfēra | <p>A number of image and video coding related standards include a requirement for decoders to implement an integer-output 8x8 inverse discrete cosine transform (IDCT) for the generation of inverse-transformed sample differences with a nominal range from -2<sup>B</sup> to (2<sup>B</sup>)-1 for some integer number of bits <i>B</i>, where <i>B</i> is greater than or equal to 8. ISO/IEC 23002-1:2006 specifies conformance requirements for establishing sufficient accuracy in such an integer-output IDCT implementation. It is intended to be suitable for reference to establish partial or complete requirements for IDCT accuracy for conformance to other standards that require IDCT use. </p> <p>The accuracy requirements specified in the main body of ISO/IEC 23002-1:2006 are essentially the same as those previously specified in IEEE 1180-1990 (which has since been withdrawn), in Annex A of ITU-T Rec. H.261, and in Annex A of ITU-T Rec. H.263. These requirements have been specified herein to resolve normative references to IEEE 1180-1990 in MPEG standards after its withdrawal and to provide improved clarity for the specification of IDCT accuracy requirements. </p> <p>An additional requirement on encoded-bitstream intra refresh frequency was also previously specified in IEEE 1180-1990, establishing a requirement of bitstream conformance that each macroblock be intra-coded at least once within each series of 132 times that it is coded in a predicted picture without an intervening intra picture. That additional requirement is not specified in ISO/IEC 23002-1:2006 , in order to confine its scope to the domain of decoder conformance specification. </p> <p>Some allowances for modification of the specified accuracy requirements are made within ISO/IEC 23002-1:2006. Additional accuracy requirements that may be invoked by a referencing specification are specified in Annexes A and B. </p> |
| Statuss | Standarts spēkā |
| ICS grupa | 35.040 35.040.40 |