feat[notask]: add RNN-T (Transducer) support to transcription-parakeet

packages/transcription-parakeet/CHANGELOG.md

@@ -5,6 +5,19 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+
+### Added
+
+- `rnnt` model type: plain RNN-T (Transducer) checkpoints — e.g. the Transducer
+  branch of NeMo hybrid `EncDecHybridRNNTCTCBPEModel` models such as the Georgian
+  `stt_ka_fastconformer_hybrid_large_pc` — auto-detected from GGUF metadata and
+  exposed in the public `ModelType` union. The vendored converter gains rnnt
+  export (`parakeet.rnnt.*` metadata + `rnnt.predict/joint` tensors, `--type
+  rnnt` in `convert-nemo.sh`). Requires a `parakeet-cpp` engine that ships the
+  rnnt head; the registry port pin must be bumped past the engine-side merge
+  before this is functional.
+
 ## [0.9.1] - 2026-07-08
 
 ### Fixed

packages/transcription-parakeet/README.md

@@ -1,6 +1,6 @@
 # transcription-parakeet
 
-This library simplifies running NVIDIA Parakeet speech-to-text and Sortformer speaker-diarization inference within QVAC runtime applications. It provides an easy interface to load, execute, and manage Parakeet inference instances, supporting CTC, TDT, EOU, and Sortformer checkpoints from a single binding.
+This library simplifies running NVIDIA Parakeet speech-to-text and Sortformer speaker-diarization inference within QVAC runtime applications. It provides an easy interface to load, execute, and manage Parakeet inference instances, supporting CTC, TDT, RNNT, EOU, and Sortformer checkpoints from a single binding.
 
 ## Table of Contents
 
@@ -179,7 +179,7 @@ The three underlying scripts are also flag-driven if you want to run them separa
 setup-venv.sh      [--python <bin>] [--venv <path>] [--force] [--help]
 download-models.sh [--type ctc|tdt|eou|sortformer|sortformer-streaming-v2.1|all]
                    [--output <dir>] [--force] [--help]
-convert-nemo.sh    [--type ctc|tdt|eou|sortformer|sortformer-streaming-v2.1|all]
+convert-nemo.sh    [--type ctc|tdt|rnnt|eou|sortformer|sortformer-streaming-v2.1|all]
                    [--quant f16|q8_0|q5_0|q4_0|f32]
                    [--python <bin>]
                    [--nemo-dir <dir>] [--output <dir>] [--force] [--help]
@@ -194,6 +194,7 @@ convert-nemo.sh    [--type ctc|tdt|eou|sortformer|sortformer-streaming-v2.1|all]
 | `eou` | [`nvidia/parakeet_realtime_eou_120m-v1`](https://huggingface.co/nvidia/parakeet_realtime_eou_120m-v1) |
 | `sortformer` | [`nvidia/diar_sortformer_4spk-v1`](https://huggingface.co/nvidia/diar_sortformer_4spk-v1) |
 | `sortformer-streaming-v2.1` | [`nvidia/diar_streaming_sortformer_4spk-v2.1`](https://huggingface.co/nvidia/diar_streaming_sortformer_4spk-v2.1) |
+| `rnnt` | [`nvidia/stt_ka_fastconformer_hybrid_large_pc`](https://huggingface.co/nvidia/stt_ka_fastconformer_hybrid_large_pc) — convert-only; `download-models.sh` has no `rnnt` entry yet, place the `.nemo` manually |
 
 NVIDIA Open Model License -- see each repo's model card for terms.
 
@@ -224,7 +225,7 @@ Most users interact with the package through `index.js`. From that entrypoint we
 | | `backendsDir` | Root directory for dynamically-loaded ggml backend `.so` files (Vulkan, OpenCL, per-arch CPU variants on Android). Defaults to the package's `prebuilds/` folder; the native addon appends `<bare-target>/<module-name>` before scanning. Pass an explicit path when prebuilds live elsewhere — e.g. Android `ApplicationInfo.nativeLibraryDir` when backend libs ship inside the APK. No-op on Apple (statically linked). |
 | | `openclCacheDir` | Persistent directory for ggml-opencl's compiled program-binary cache (`$GGML_OPENCL_CACHE_DIR`). Android-only; pass the host app's cache directory (e.g. `Context.getCacheDir()`) to skip cold `clBuildProgram` on every process start. Ignored on other platforms. |
 
-The model type (CTC / TDT / EOU / Sortformer) is **auto-detected from the GGUF metadata**, so callers don't need to pass `modelType`. Other knobs (`captionEnabled`, `timestampsEnabled`, `seed`, `sampleRate`, `channels`) keep sensible defaults.
+The model type (CTC / TDT / RNNT / EOU / Sortformer) is **auto-detected from the GGUF metadata**, so callers don't need to pass `modelType`. Other knobs (`captionEnabled`, `timestampsEnabled`, `seed`, `sampleRate`, `channels`) keep sensible defaults.
 
 **Sortformer Streaming Diarization (v2.1 + AOSC).** parakeet-cpp ships
 two streaming-diarization paths picked automatically by the GGUF:
@@ -462,7 +463,7 @@ npm run setup-models -- -t tdt -q q8_0
 ### 3. Run the bundled examples
 
 ```bash
-# Single-file transcription (any model type -- CTC / TDT / EOU / Sortformer)
+# Single-file transcription (any model type -- CTC / TDT / RNNT / EOU / Sortformer)
 bare examples/transcribe.js \
      --model models/parakeet-tdt-0.6b-v3.q8_0.gguf \
      --audio examples/samples/sample-16k.wav
@@ -499,6 +500,7 @@ The live-mic examples capture the default input device via `sox -d` (install: `b
 | **CTC** | English | argmax CTC | ~ 700 MiB | Fast, no PnC. |
 | **TDT** | ~25 | RNN-T greedy + duration | ~ 715 MiB | Recommended default; PnC + auto-detect. |
 | **EOU** | English | RNN-T greedy + `<EOU>` | ~ 132 MiB | Streaming-trained; native end-of-turn token. |
+| **RNNT** | checkpoint-dependent (e.g. Georgian for `stt_ka_fastconformer_hybrid_large_pc`) | plain RNN-T greedy | checkpoint-dependent | Duration-less Transducer heads, incl. the RNN-T branch of hybrid transducer+CTC checkpoints. Requires a parakeet-cpp engine with the `rnnt` head. |
 | **Sortformer v1** | n/a | Diarization head (sliding history) | ~ 141 MiB | 4-speaker. **Default for offline diarization.** |
 | **Sortformer v2.1 + AOSC** | n/a | Diarization head + speaker cache | ~ 141 MiB | 4-speaker. **Default for streaming diarization.** AOSC anchors speaker slots across silence/re-entry; auto-detected via GGUF metadata tag `parakeet.model_variant`. |
 

packages/transcription-parakeet/addon/src/model-interface/ParakeetTypes.hpp

@@ -17,7 +17,7 @@ struct Transcript {
   float end;
   size_t id;
   // True when this segment ends on a recognised end-of-utterance boundary
-  // (EOU streaming: `<EOU>` token; CTC/TDT/Sortformer always leave this
+  // (EOU streaming: `<EOU>` token; CTC/TDT/RNNT/Sortformer always leave this
   // false). The text field still carries any speech tokens decoded in the
   // same chunk; consumers that want a turn-end signal independent of the
   // transcript should test this flag.
@@ -60,6 +60,7 @@ struct Transcript {
 enum class ModelType : std::uint8_t {
   CTC,        // English-only, fast transcription with punctuation/capitalization
   TDT,        // Multilingual (~25 languages) with auto-detection
+  RNNT,       // Plain RNN-T (Transducer); e.g. the Georgian hybrid transducer head
   EOU,        // Real-time streaming with end-of-utterance detection
   SORTFORMER  // Speaker diarization (up to 4 speakers)
 };

packages/transcription-parakeet/addon/src/model-interface/parakeet/ParakeetModel.cpp

@@ -371,7 +371,7 @@ void ParakeetModel::load() {
   is_loaded_ = true;
 
   // Auto-detect modelType from the loaded GGUF's metadata. The engine
-  // returns "ctc" / "tdt" / "eou" / "sortformer" reflecting the
+  // returns "ctc" / "tdt" / "rnnt" / "eou" / "sortformer" reflecting the
   // `parakeet.model.type` GGUF metadata field, so JS callers don't
   // need to pass `modelType` themselves -- the binding picks the
   // right dispatch (ASR vs Sortformer) automatically. We only fall
@@ -381,6 +381,7 @@ void ParakeetModel::load() {
     const std::string detected = engine_->model_type();
     if (detected == "ctc")        cfg_.modelType = ModelType::CTC;
     else if (detected == "tdt")   cfg_.modelType = ModelType::TDT;
+    else if (detected == "rnnt")  cfg_.modelType = ModelType::RNNT;
     else if (detected == "eou")   cfg_.modelType = ModelType::EOU;
     else if (detected == "sortformer") cfg_.modelType = ModelType::SORTFORMER;
 

packages/transcription-parakeet/index.d.ts

@@ -7,7 +7,7 @@ import { Readable } from 'stream'
  * loaded GGUF's `parakeet.model.type` metadata field; this type is
  * only here for callers that want to surface it in their own UI.
  */
-declare type ModelType = 'tdt' | 'ctc' | 'eou' | 'sortformer'
+declare type ModelType = 'tdt' | 'ctc' | 'rnnt' | 'eou' | 'sortformer'
 
 /**
  * Parakeet-specific configuration options. The model type itself is

packages/transcription-parakeet/index.js

@@ -10,7 +10,7 @@ const { END_OF_INPUT, ERR_CODES, QvacErrorAddonParakeet } = require('./lib/error
 /**
  * High-level Parakeet speech-to-text client backed by the ggml engine
  * sourced from qvac-parakeet.cpp. Takes a single `.gguf` checkpoint
- * (CTC, TDT, EOU, or Sortformer); the model type is auto-detected
+ * (CTC, TDT, RNNT, EOU, or Sortformer); the model type is auto-detected
  * from GGUF metadata, so the same class transcribes or diarizes
  * depending on the file you load.
  */

packages/transcription-parakeet/parakeet.js

@@ -33,7 +33,7 @@ function createParakeetError (code, message, cause = undefined) {
  * runtime. Wraps the ggml-backed Parakeet engine sourced from
  * qvac-parakeet.cpp. The model type is auto-detected from the
  * loaded GGUF's metadata, so there's no `modelType` field on the
- * config -- pass any of CTC / TDT / EOU / Sortformer .gguf files
+ * config -- pass any of CTC / TDT / RNNT / EOU / Sortformer .gguf files
  * to `loadWeights()` and the right pipeline is chosen automatically.
  */
 class ParakeetInterface {