Prior art

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Based on the information provided, US patent 8175148, titled "Method and device for indicating quantizer parameters in a video coding system," cites the following prior art:

Prior Art References for US8175148B2:

Unfortunately, I don't have access to the detailed citation list and analyses that would be present in a full USPTO file wrapper for patent 8175148. However, based on the provided text, the patent itself mentions a highly relevant document in its "BACKGROUND OF THE INVENTION" and "Definitions" sections:

• Full Citation: T. Wiegand, "Joint Model Number 1", Doc. JVT-A003, Joint Video Team (JVT) of ISO/IEC MPEG and ITU-T VCEG, January 2002.
• Publication/Filing Date: January 2002. (This is a publication date of the document itself, not necessarily a patent filing date).
• Brief Description: This document is cited as part of the ITU-T recommendation H.26L, which allows macroblocks to be organized into "slices" and discusses the optional variation of the quantization parameter (QP) at the macroblock level using a quantizer change parameter (Dquant). It also describes how spatial prediction is applied to INTRA coded macroblocks before coding the INTRA prediction error with DCT in modern video coding systems.
• Potential Anticipation (35 U.S.C. § 102): This reference appears to anticipate aspects of video coding systems that use slices and allow for QP variation. The invention of US8175148B2 aims to improve upon these prior art solutions by introducing a sequence-level QP to reduce bit-rate. Therefore, any claims in US8175148B2 that pertain broadly to the existence of slices or the ability to vary QP (without the specific improvement of a sequence-level QP as a reference for differences) could potentially be anticipated. Specifically, the general concepts of macroblocks, slices, INTRA/INTER coding, DCT, and quantization, as foundational elements, are explicitly described as known prior art. Claims that focus on transmitting a difference (ΔQP) from a sequence-level QP rather than an absolute QP for each slice/picture would likely represent the inventive step over this reference.