An encoder on borrowed time
The last US AVC patent expires in November 2027. Until then ffmpeg-wasi's H.264 encoder ships on sufferance, on Cisco's binaries taught to run under WASI.
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ffmpeg-wasi
The engine behind afmpeg, and, despite the name, not really FFmpeg at all: a custom, direct interface built straight over the libav* libraries that just masquerades as FFmpeg. It does away with the ffmpeg CLI entirely, so tools hook into one consistent programmatic layer instead of stitching together brittle argument strings. It provides both the WASM backend afmpeg runs by default and the native backend it reaches for when a performance edge case calls for it.
One input, many outputs
afmpeg shipped single input to single output. Adding multi-pad filter graphs and multi-output muxing: one decode, two files, one pass.
The afternoon the agent earned its keep
Adding stream-copy remux to a WebAssembly FFmpeg build, where writing Matroska hung forever and the identical MP4 path did not.
