[ptarasiewiczNV]

Summary

Change the default realtime ASR example from Voxtral to Qwen/Qwen3-ASR-0.6B, which boots and serves realtime transcription. Previously Qwen/Qwen3-ASR-0.6B had no realtime support in vLLM, but it has been added and since it's one of the most popular ASR models it's better suited to be the default in the example. This also avoids the Voxtral startup failure reported in DYN-4860 for the default example.

• Automatically select Qwen3ASRRealtimeGeneration when using the default model without --hf-overrides.
• Preserve explicit overrides and require an explicit realtime architecture for other models.
• Update the voice overview link label to match the new default.
• Clarify that --hf-overrides is optional for the default Qwen3-ASR model and required for other models; remove the version number from the recipe support description.

vLLM 0.31.0 can repeat earlier segments and expose raw ASR markers. The same behavior reproduces on native vLLM; it remains an upstream limitation. This change does not fix Voxtral's startup failure or replace coverage that requires a model without text-generation support.

Upstream tracking:

• Repetition: vllm-project/vllm#51374 is open. Proposed context-reset fix: vllm-project/vllm#56218 (open, unmerged).
• Raw ASR markers: vllm-project/vllm#35767 reports both marker leakage and repetition; it was auto-closed for inactivity. Proposed marker post-processing fix: vllm-project/vllm#55786 (open, unmerged).

Validation

• GPU-tested on an RTX A6000 in nvcr.io/nvstaging/ai-dynamo/vllm-runtime:1.6.0-rc.2 (Dynamo 1.6.0, vLLM 0.31.0), with the image's packages unchanged and only the example scripts/test assets mounted.
• Launched without --model or --hf-overrides, using --max-model-len 4096 --max-num-seqs 2 --kv-cache-memory-bytes 1073741824. The worker booted, registered the model, and remained healthy after three audio requests.
• A paced 6.72-second clip produced its first delta at 5.48 seconds, before commit at 6.83 seconds, and completed at 7.11 seconds. The documented client passed --require-incremental; residual-only audio also completed. No startup or inference crash.
• Separately, 79 existing realtime connection/handler tests passed in the earlier vLLM 0.31.0 validation environment.
• Invalid-argument checks passed for a custom model without an override and for explicitly empty overrides.
• On current main: pre-commit checks, bash -n, and git diff --check passed. Scoped docs lint passed with zero errors and five existing navigation warnings for untouched pages.

Related Issues

Refs DYN-4860 (Linear).

Summary by CodeRabbit

• New Features
  • The realtime transcription launcher now defaults to Qwen3-ASR and applies the matching architecture setting when no model overrides are provided.
  • Custom model overrides remain supported in either command-line format.
• Documentation
  • Speech-worker setup instructions now point to the Qwen3-ASR realtime transcription launcher.

[github-actions]

🌿 Fern Docs Preview: https://nvidia-preview-01a1395c-515f-7375-b048-ed8ba859dc09.docs.buildwithfern.com/dynamo/dev

[devin-ai-integration]

✅ Dynamo PR CI passed — run 38529564817 (attempt 1) on 17edfa32ec

Gate checks: ✅ backend-status-check · ✅ deploy-status-check · ✅ dynamo-status-check

_{Posted automatically by Devin for run 38529564817. Updated on every full-CI run of this PR.}

[coderabbitai]

Walkthrough

The realtime transcription launcher now defaults to Qwen3-ASR and supplies its realtime architecture override when no override is provided. The voice documentation names the Qwen3-ASR launcher. The launcher URL is unchanged.

Changes

Qwen3-ASR launcher configuration

Layer / File(s)	Summary
Launcher defaults and override handling examples/backends/vllm/launch/agg_realtime_transcription.sh, docs/fern/pages/use-cases/multimodal-serving/voice.md	The script defaults to Qwen/Qwen3-ASR-0.6B and tracks whether either supported --hf-overrides form was supplied. If no override was supplied and the default model is selected, it sets the Qwen realtime architecture override. The documentation names the Qwen3-ASR launcher; its URL is unchanged.

Priority: ➖ Normal

Estimated code review effort: 2 (Simple) | ~10 minutes

Merge Risk: 🔵 Low · up to e9f21

The launcher works as intended, but the recipe should be corrected so users do not provide an unnecessary override.

Pre-merge checks · 5

Passed checks (5 passed)

Check name	Status	Explanation
Docstring Coverage		No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 1…
Linked Issues check		Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check		Check skipped because no linked issues were found for this pull request.
Title check		The title clearly and concisely identifies the primary change: changing the default realtime ASR model to Qwen3-ASR.
Description check		The description is detailed and covers the change, implementation details, validation, limitations, and related issue. It does not use every template heading, and it uses “Refs DYN-4860” instead of th…

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[coderabbitai]

Actionable comments posted: 1

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• 🪄 Fix CodeRabbit comments on this PR

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Inline comments:
Review comments at @examples/backends/vllm/launch/agg_realtime_transcription.sh:
- Line 50: Update the vLLM CLI template recipe text associated with the launcher
usage so it states that --hf-overrides is optional for the default Qwen3-ASR
model and required for other models; keep the launcher’s usage line unchanged.

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📥 Commits

Reviewing files that changed from the base of the PR and between 2210b07 and e9f2117.

📒 Files selected for processing (2)

• docs/fern/pages/use-cases/multimodal-serving/voice.md
• examples/backends/vllm/launch/agg_realtime_transcription.sh

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[JulienDarve]

Approved.

[harryskim]

Docs-only review. voice.md link-label change looks good. A few notes on the vllm.mdx accordion inline, plus two that fall outside the diff hunks:

Known limitations not documented. The PR description notes vLLM 0.31.0 can repeat earlier segments and leak raw ASR markers. Since that's the first thing a user of this example will hit, consider a short note after the delta before commit: True paragraph:

<Note>
With vLLM 0.31.0, transcripts can repeat earlier segments or include raw ASR markers.
These are upstream vLLM issues ([#51374](https://github.com/vllm-project/vllm/issues/51374),
[#35767](https://github.com/vllm-project/vllm/issues/35767)).
</Note>

Nit (pre-existing): this accordion is the only one without a Configuration table / Command-line flags line. The script reads DYN_HTTP_PORT, DYN_SYSTEM_PORT, and GPU-memory env vars, and now has a defaulted --model and optional --hf-overrides, which would fit there.

[harryskim]

approved