This document specifies the procedures to test implementations
\nof VMR-WB-compatible variable-rate speech codecs, either by meeting
\nthe bit-exact implementation, or meeting recommended minimum
\nperformance requirements. The VMR-WB codec corresponds to Service
\nOption 62 for Rate-set II compliant modes and Service Option 63 for
\nthe Rate-set I compliant mode, as described in TIA-1016- A [1]. The
\nVMR-WB codec is used to digitally encode the speech signal for
\ntransmission using the encoding rates of 13300, 6200, 2700, or 1000
\nbps for Rate-set II operation (Modes 0, 1, and 2, or Mode 3), and
\nthe encoding rates of 8550, 4000, or 800 bps for Rate-set I
\noperation (Mode 4). Note that the encoding rate of 2000 bps is not
\nutilized in VMR-WB in Rate-Set I operation. Like some other speech
\ncoding standards, this standard provides a bit-exact method of
\ntesting the codec for minimum performance. In this procedure, a
\ngiven set of test vectors are input to the test codec, and the
\noutput vectors from the test codec must be bit-exact with the
\noutput vectors generated from the Software Distribution which is
\npart of this standard. If they are bit-exact, and the test codec
\ncomplies with Section 2.1.2, the codec passes the minimum
\nperformance requirement, and no further testing is required. The
\nbit-exact mode of testing, however, is only applicable to codecs
\nwhose design conforms in all respects to the algorithmic
\ndescription of the VMR-WB in TIA-1016-A [1]. The bit17 exact VMR-WB
\nvalidation includes specific testing of the OEM VMR-WB to the frame
\nerasure processing characteristics of the standard VMR-WB. Should
\nthe candidate VMR-WB differ in any of these components, the codec
\nshall be tested using the objective and subjective tests prescribed
\nby this standard. That is, VMR-WB compliance of a "test codec" can
\nbe achieved by either:<\/p>\n
\u2022 Complying with Section 2.1.2, and demonstrating bit-exactness
\naccording to the procedure described in Section 3.6, specifically
\nSections 3.6.5.1 to 3.6.5.4, or<\/p>\n
\u2022 Following the objective and subjective testing procedures set
\nforth in Sections 2.1 and 2.2 of this standard, using processes
\nadditionally defined in Section 3.6, specifically Sections 3.6.5.5
\nto 3.6.5.8.<\/p>\n
With the exception of Section 3.6, the remaining text applies
\nonly to implementations that do not satisfy the requirement for
\nbit-exactness.<\/p>\n
Testing the codec is based on two classes of procedures:
\nobjective tests and subjective tests. In the event that the test
\ncodec fails any of the objective or subjective tests, the test
\ncodec fails the compliance test. Objective tests are based upon
\nactual measurements from the speech codec function. Subjective
\ntests are based on listening tests to judge overall speech quality.
\nThe minimum subjective requirement for the test codec is based upon
\nthe ability of the test codec to demonstrate performance no worse
\nthan that of the VMR-WB master reference codec within a fixed
\nallowable statistical error.<\/p>\n
The purpose of the testing is not only to ensure adequate
\nperformance between one manufacturer's encoder and decoder but also
\nthat this level of performance is maintained with operation between
\nany pairing of manufacturers' encoders and decoders. This
\ninteroperability is a serious issue. Any variation in implementing
\nthe exact standard must be avoided if it cannot be ensured that
\nminimum performance levels are met when interoperating with all
\nother manufacturers' equipment meeting the standard. This standard
\nprovides a means for measuring performance levels while trying to
\nensure proper interoperation with other manufacturers'
\nequipment.<\/p>\n
The issue of interoperation can only be definitively answered by
\ntesting all combinations of encoder\/decoder pairings. With the
\nnumber of equipment manufacturers expected to supply equipment,
\nthis becomes a prohibitive task; therefore, the objective and
\nsubjective tests rely upon the use of a "master codec". The master
\ncodec is defined as the appropriate implementation of TIA-1016-A
\n[1] written in the C-programming language. The master codec
\nsoftware, described in Sections 3.4 and 3.5, are used as part of
\nthe interoperability testing. The master codec is available as a
\nSoftware Distribution associated with this document.<\/p>\n
By convention in this document, the Courier font is used to
\nindicate C-language and other software constructs, such as file and
\nvariable names.<\/p>\n","protected":false},"excerpt":{"rendered":"
Minimum Performance Specification for the Source-Controlled Variable-Rate Multimode Wideband Speech Codec (VMR-WB) – Service Option 62 for Spread Spectrum Systems<\/b><\/p>\n\n\n
\n Published By<\/td>\n Publication Date<\/td>\n Number of Pages<\/td>\n<\/tr>\n \n TIA<\/b><\/a><\/td>\n 2005<\/td>\n 120<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n","protected":false},"featured_media":690312,"template":"","meta":{"rank_math_lock_modified_date":false,"ep_exclude_from_search":false},"product_cat":[2646],"product_tag":[],"class_list":{"0":"post-690304","1":"product","2":"type-product","3":"status-publish","4":"has-post-thumbnail","6":"product_cat-tia","8":"first","9":"instock","10":"sold-individually","11":"shipping-taxable","12":"purchasable","13":"product-type-simple"},"_links":{"self":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product\/690304","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/types\/product"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/media\/690312"}],"wp:attachment":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/media?parent=690304"}],"wp:term":[{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_cat?post=690304"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_tag?post=690304"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}