Invalidity dossier
US 5825419
Coding device and decoding device of digital image signal
Current assignee: Mitsubishi Electric Corp
Added 9/23/2026, 12:58:52 PM
Active provider: DeepSeek · deepseek-flash
Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview: US 5,825,419 A
Title: Coding device and decoding device of digital image signal
Assignee: Mitsubishi Electric Corp (original assignee per the supplied record)
Key dates: Priority date 1995-09-29; application number US08/723,950; filing date 1996-09-26; granted/publication date 1998-10-20. Status listed as "Expired – Lifetime," with anticipated expiration 2016-09-26. Legal status is explicitly an assumption, not a legal conclusion.
Purpose: The invention addresses a recognized problem in MPEG-1 coding: prediction memories must store large amounts of data (about 8M bits for NTSC, at 720×480 pixels per frame, 8 bits per pixel, including brightness and color signals). The stated object is "to provide a coding and/or decoding device capable of restraining as small as possible the capacity of a memory that is used in coding and [decoding]" (excerpt truncated).
Plain-language scope: The supplied text describes a coder and decoder for digital image signals operating per MPEG-1. In the coder, an image signal from a video input unit is transformed by DCT, quantized, and coded; motion-compensated prediction is drawn from two prediction memories, with an averaging circuit rounding forward and backward predictions. Picture types include I, P, and B pictures, with bidirectional prediction. The decoder dequantizes and inverse-transforms, using two prediction memories and switches controlled by macroblock type, since decoded I and P pictures must be held until intervening B pictures are decoded. Time information—PTS (Presentation Time Stamp) and DTS (Decoding Time Stamp)—is multiplexed in the PES (Packetized Elementary Stream) format to handle frame-order rearrangement.
What the excerpt does not establish: The provided text contains only the "Definitions" section, ending mid-sentence. It does not include any claims, so the actual claimed scope is not established here. It also does not identify specific prior-art references, embodiments beyond the described MPEG-1 background, or the specific memory-reduction implementation. No litigation, ownership-transfer, validity, or prior-art conclusions are drawn.
Generated 10/1/2026, 9:53:20 PM
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Litigation summary
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PTAB challenges
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Assignment history
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Prior art
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Obviousness
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Extensions
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Derivative works
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