Use Speech.Transcribe when you need a complete document with whole-recording speaker labels. Use Speech.TranscribeStream when you want final segments as bounded VAD-first chunks finish. The latter does not perform whole-file speaker clustering. Neither API requires retaining the entire PCM waveform.
Encoded files are decoded and resampled through OneAudio. Whole-recording diarization and recognition require separate bounded passes. Caller-owned encoded streams may be spooled to a temporary seekable file; ensure adequate disk space and dispose or finish enumeration to release it. Do not modify a file while it is being processed. The final document's words, text and turns necessarily grow with output length; constant audio working storage does not mean a constant-size returned document.
File calls have CancellationToken overloads, and asynchronous stream calls require explicit cancellation. Cancellation is checked at audio blocks, chunk boundaries and model operations where supported, not by interrupting arbitrary instructions. It throws OperationCanceledException. Progress in the low-level pipeline is audio time processed, not a wall-clock ETA. First-use model acquisition can dominate startup; pre-fetch before interactive use.
Streaming enumeration owns its decoder and loaded model resources. Early disposal releases them. Live cancellation discards pending speech instead of silently finalizing it; normal end-of-input flushes. See live sessions.
Standalone Speech.Align currently limits input to 60 seconds. Split longer alignment requests yourself and offset every returned time onto the original audio clock; do not concatenate chunk-relative times as if they were recording-relative. Recognition's timing pipeline has its own bounded chunks. Words that could not be aligned retain null boundaries.
Long-form reference equivalence and full working-set benchmark rows remain pending. VAD horizon boundaries and chunk-boundary speech can affect output; file streaming is not a promise of token identity with an oracle's whole-file policy.