US 5442390

Summary of U.S. Patent No. 5,442,390 (US5442390A)

Search note: I searched for the specific patent number 5442390 (published as US5442390A; also written 5,442,390). I did not find any CAFC 2026 docket or pending Federal Circuit appeal referencing this patent. This is consistent with the patent's status — it expired on its anticipated expiration date of 2013-07-07 (status: "Expired – Lifetime"). The 2026 district-court case involving Adeia entities (e.g., Adeia Tech Inc v. DISH Network Corp., 1:26-cv-01373) asserts different patents (e.g., 9,661,049 and others), not 5,442,390. I also confirmed that JP5442390B2 is an unrelated Japanese vehicle refrigeration patent, not the U.S. patent at issue. I found no authoritative record of any 2026 CAFC appeal for 5,442,390; if one exists it is not surfacing in public search results.

Bibliographic data (from Google Patents / USPTO records)

Abstract (verbatim, as published)

"In a system for interactively viewing videos, a selected video is transmitted as a plurality of frames of digitized video data for playback on a viewing device. The system receives the transmitted video data and includes a memory buffer for storing a segment of a selected one of the videos. The segment includes a predetermined number of frames representing a predetermined time interval of the selected video. In addition, the memory buffer including a write pointer and a read pointer. Software controlled servers are provided for witting and reading video data of the selected video to and from the memory buffer, independently, at locations indicated by the write and read pointers to transfer the selected video to the viewing device. By using a remote controller the viewer can position the read and write pointers to view any portion of the selected video interactively."

("witting" is as printed in the source — a typo for "writing.")

Independent claims — plain-language overview

The patent has 10 claims total. The independent claims are 1 (system), 5 (method), and 9 (method). The remaining claims (2–4, 6–8, 10) are dependent.

Claim 1 (system) — A system for interactively viewing a selected video whose frames carry digitally encoded video/audio data and time stamps, transmitted over a network. It requires: (a) means to request transmission of the selected video; (b) a network interface receiving the video as a first stream; (c) a memory buffer storing a segment of the video — the segment being a forward-moving time interval; (d) a write pointer associated with the incoming first stream; (e) a read pointer associated with a second stream read out for display; (f) means writing the first stream into the buffer while it is received; (g) means reading the second stream from the buffer independently of the writing, so any part of the buffered segment can be displayed while the first stream continues to arrive; and (h) an index linking the frames' time stamps to their memory addresses in the buffer.

Claim 5 (method) — A method for interactively viewing a selected video: request transmission over the network; receive the video data as a first stream; store a segment (a substantially forward-moving time interval of the first stream) in a memory buffer having a write pointer and at least one read pointer; write the first stream at the write pointer; read a second stream at the read pointer while the first stream is being written, so any data in the segment can be displayed while reception continues; and index the stored data by time stamps.

Claim 9 (method) — A method for viewing videos: request distribution of a video over the network as a first stream; receive that first stream; write it, while receiving, into a buffer as a substantially continuously forward-moving time interval; read a second stream from the buffer independently of the writing, while still receiving the first stream; convert the second stream to video signals; display them while the first stream is still being received; and — notably — read the second stream from the buffer in reverse chronological order while the first stream continues to arrive in forward chronological order (i.e., support for reverse/replay during ongoing download).

Dependent claims (brief)

• Claims 2 & 7 — circular buffer management: pointers wrap from end to beginning; write pointer overwrites data only after it has been read.
• Claims 3 & 10 — write and read rates differ.
• Claim 4 & 8 — the buffer fills at a higher rate than reading when not full (fast-fill).
• Claim 6 — allows starting delivery at a particular selected frame.

Key technology context

The specification describes a video-on-demand architecture with customer premises equipment, a gateway/video/library server system, MPEG-compressed packetized video, "broadcast streams" shared among customers, and a "segment cache" (server-side or customer-side) implemented as a circular buffer with fill/play pointers, a cache index keyed by time stamps, a safety zone around the play pointer, and fast-fill synchronization of out-of-sync streams.

Uncertainty caveats

• CAFC 2026 docket: No authoritative evidence of a 2026 Federal Circuit appeal involving 5,442,390 was found. Given the patent expired in 2013, any 2026 appellate activity would be unusual (e.g., a lingering damages/licensing dispute), and I cannot confirm one exists.
• Current assignee: Google Patents lists "Adeia Media Solutions Inc." as current assignee but disclaims accuracy; the recorded assignment chain (Digital Equipment → Compaq → Hewlett-Packard → TiVo) is the more reliable public record.