TrackTime, LLC v. Amazon.com Services LLC — Federal Circuit Vacates MPF Indefiniteness Ruling, Orders Dyfan Reanalysis

Background

TrackTime, LLC owns two patents — U.S. Patent Nos. 8,856,638 and 8,862,978 — covering methods and systems for navigating within multimedia files on a mobile device using a time-correlated text transcript. The core innovation is a “tap-to-jump” feature: a user taps highlighted words in a synchronized transcript to instantly jump to that moment in the audio playback. The patents also cover annotation and social-sharing of these synchronized transcripts.

TrackTime sued Amazon in the U.S. District Court for the District of Delaware, alleging infringement by Amazon’s products including Kindle Immersion Reading, Amazon Music X-Ray Lyrics, and Whispersync for Voice. The district court dealt the case two decisive blows. First, it construed two limitations of the ‘978 patent — “executable program code configured to facilitate annotation” and “executable program code configured to synchronously play . . . multimedia” — as means-plus-function (MPF) terms under 35 U.S.C. § 112(f), then held those claims invalid for indefiniteness because the patent’s specification failed to disclose adequate corresponding structure. Second, a jury found claim 9 of the ‘638 patent invalid for anticipation by prior art, and the district court denied TrackTime’s post-trial motions.

The Court’s Holding

The Federal Circuit issued a mixed ruling, vacating in part and affirming in part.

On the ‘978 patent — vacated and remanded: Judge Taranto, writing for the panel, held that the district court’s means-plus-function analysis for the “executable program code” limitations must be redone in light of the Federal Circuit’s intervening decision in Dyfan, LLC v. Target Corp., 28 F.4th 1360 (Fed. Cir. 2022), which issued after the district court ruled. Under Dyfan, the pivotal question is not merely whether the non-functional term (“executable program code”) calls to mind a general structure, but whether the claim language surrounding it describes sufficient structure by explaining how the code operates within the invention — its specific inputs, outputs, and operational interactions. Because neither the parties nor the district court had analyzed the issue under this framework, the Federal Circuit vacated the indefiniteness ruling and remanded for further proceedings, allowing new factual and legal submissions.

On the ‘638 patent — affirmed: The Federal Circuit affirmed the jury’s verdict that claim 9 of the ‘638 patent is invalid under 35 U.S.C. § 102 for anticipation by prior art. TrackTime raised several challenges to the verdict, but the court found the anticipation ruling dispositive and declined to reach the other issues.

Key Takeaways

• Software-implemented patent claims using terms like “executable program code” are not automatically means-plus-function claims — the Dyfan analysis must account for how surrounding claim language contextualizes the code’s operation.
• Patentees can benefit from intervening Federal Circuit precedent: if case law shifts after a district court’s ruling, the appellate court will vacate and remand rather than affirm under an outdated framework.
• Mixed outcomes are common in multi-patent cases: here one patent’s claims earned a remand while the other’s anticipation finding was affirmed as final.
• Amazon’s Whispersync, Immersion Reading, and X-Ray Lyrics products remain at risk on the ‘978 patent remand — if the district court finds § 112(f) does not apply, full infringement analysis resumes.

Why It Matters

Means-plus-function claim construction is among the most consequential doctrines in software patent litigation. A claim construed under § 112(f) is limited to the specific structures disclosed in the specification that correspond to the claimed function, often narrowing its scope dramatically. Whether a software claim’s language sufficiently evokes “structure” to escape § 112(f) can therefore determine whether the patent survives.

This precedential ruling reinforces that courts must apply Dyfan’s nuanced, context-sensitive test — examining the claim’s operational description, not just the bare term — before invoking the MPF machinery. For innovators in the audio-text synchronization space (a technology now embedded in products from Amazon, Apple, and many audiobook platforms), the remand keeps TrackTime’s ‘978 patent alive as a litigation asset while Amazon faces continuing uncertainty.