Speech model v3 (CC-BY-4.0)

Speech model used by NowCaption 1.2.0 and later. This is not an app release.

nowcaption-fastconformer-en-80ms-cc-by-v3.tar.bz2: NowCaption's own fine-tune of NVIDIA's
stt_en_fastconformer_hybrid_large_streaming_multi
(transducer branch, 80 ms lookahead), as an int8 ONNX export for sherpa-onnx. v2 trained further on
about 3,300 hours of CC0 and CC-BY English speech (Granary's YODAS part, Common Voice 22, AMI,
LibriSpeech, VoxPopuli), in items that join several clips with pauses between them, so it keeps
working after silences in a long stream. Same size, tokens and architecture as v2.

• Word errors on the eight ESB English test sets, through NowCaption's own caption pipeline: 13.31%
  against 17.31% for v2 in continuous use (as the app runs), 13.18% against 13.51% with a fresh stream
  per clip; 12.43% against 16.18% on 400 other clips per set never used to choose it. Accent test set
  (2,992 clips, 20 regions): 13.78% against 17.24%. Known limits, and the targets it did not meet, are
  in benchmark/README.md.
• License: CC-BY-4.0, © NVIDIA; fine-tuned, exported
  to ONNX and quantized to int8 by NowCaption. Training data, how it was trained and chosen, and the
  files' SHA-256 are in the archive's README.md.
• SHA-256: 5e7e38c57a217e197516325621694bb6380ab2a68e423d5558f2f32330044ddd