Flashback Turbo

Flashback Turbo patches the export pipeline of Flashback through Mixin, replacing serial, low-tuned operations with parallel ones. The author reports a median export time across real 1080p clips and states that a 10-second slice of a 1.21.11 replay at 1920×1080, 603 frames, exports up to 11 times faster, measured on an 8.5-second 1080p60 clip. Exports keep their quality: a parallel PNG writer uses N-1 threads, the zlib level and RGB color type are configurable, and the FFmpeg threading tunes for each encoder (h264, h264_nvenc, h264_qsv, h264_videotoolbox and libopenh264) leave the encoded bitstream unchanged.

Alongside the export changes, the mod lifts the quiet 4K downscaling limit, includes a fragmented MP4 muxer that the author reports finalizes roughly 10 percent quicker on hardware encoders, and displays an animated Saving overlay while the post-export work runs. Telemetry is off by default: since 0.4.0 it can send anonymous usage data to PostHog, with UUIDs, IP addresses and file paths sanitised, and it is disabled by setting enableTelemetry to false. The author reports an export failure rate of about 1 percent on long replays, and that a game closed mid-export is not a regression introduced by the mod.

Flashback Turbo requires Fabric API and Flashback. The license is All rights reserved, so the code is not open source, though the source code and issue tracker are public.