feat(transcription): add the self-hosted ratio backend

scripts/ratio-transcribe runs whisper plus speaker diarization on my own transcription host over an ssh job queue, with a local worker as the fallback when the host is unreachable. It needs no API key, so its descriptor carries nil for the auth host and the env var. The process environment passes through untouched. SPEAKERS=N in the environment pins the diarizer's speaker count.

The interactive switcher used to carry its own copy of the backend list, so a backend added to the descriptors was reachable only by setq. It now derives its choices from the descriptor alist, and a test pins the two to each other.

The script's own behavior (argument validation, the job-id hash, the remote and local branches) is tested in the repo it came from. A bats mirror of those cases is tracked separately.

1 files changed, 16 insertions, 6 deletions

diff --git a/modules/transcription-config.el b/modules/transcription-config.el
index 944063b8..6d7e39b9 100644
--- a/modules/transcription-config.el
+++ b/modules/transcription-config.el
@@ -33,6 +33,11 @@
 ;;   - 'assemblyai: Cloud transcription with speaker diarization
 ;;     API key retrieved from authinfo.gpg (machine api.assemblyai.com)
 ;;   - 'local-whisper: Local transcription (requires whisper installed)
+;;   - 'ratio: Self-hosted whisper plus speaker diarization on my transcription
+;;     host, via scripts/ratio-transcribe (ssh queue; falls back to a local
+;;     worker when the host is unreachable).  No API key.  SPEAKERS=N in the
+;;     environment pins the diarizer's speaker count; 1 is right for a
+;;     recording that holds only one side of a call.
 ;;
 ;; NOTIFICATIONS:
 ;;   - "Transcription started on <file>"
@@ -56,7 +61,8 @@
   "Transcription backend to use.
 - `openai-api': Fast cloud transcription via OpenAI API
 - `assemblyai': Cloud transcription with speaker diarization via AssemblyAI
-- `local-whisper': Local transcription using installed Whisper")
+- `local-whisper': Local transcription using installed Whisper
+- `ratio': Self-hosted whisper plus diarization on my transcription host")
 
 (defvar cj/transcription-keep-log-when-done nil
   "Whether to keep log files after successful transcription.
@@ -74,9 +80,11 @@ Status: running, complete, error")
 (defconst cj/--transcription-backends
   '((openai-api    :script "oai-transcribe"        :auth-host "api.openai.com"     :env-var "OPENAI_API_KEY")
     (assemblyai    :script "assemblyai-transcribe" :auth-host "api.assemblyai.com" :env-var "ASSEMBLYAI_API_KEY")
-    (local-whisper :script "local-whisper"         :auth-host nil                  :env-var nil))
+    (local-whisper :script "local-whisper"         :auth-host nil                  :env-var nil)
+    (ratio         :script "ratio-transcribe"      :auth-host nil                  :env-var nil))
   "Per-backend descriptors. Each entry: (SYMBOL :script S :auth-host H :env-var V).
-`:auth-host' and `:env-var' are nil for local backends that need no API key.")
+`:auth-host' and `:env-var' are nil for backends that need no API key: the
+local whisper install, and the self-hosted ratio queue reached over ssh.")
 
 (defun cj/--backend-plist (backend)
   "Return the descriptor plist for BACKEND, or signal if unknown."
@@ -470,9 +478,11 @@ duration is computed from START-TIME."
   "Switch transcription backend.
 Prompts with completing-read to select from available backends."
   (interactive)
-  (let* ((backends '(("assemblyai" . assemblyai)
-                     ("openai-api" . openai-api)
-                     ("local-whisper" . local-whisper)))
+  ;; Offer exactly the descriptor set.  This used to carry its own list, so
+  ;; a backend added to the descriptors was reachable only by setq.
+  (let* ((backends (mapcar (lambda (entry)
+                             (cons (symbol-name (car entry)) (car entry)))
+                           cj/--transcription-backends))
          (current (symbol-name cj/transcribe-backend))
          (prompt (format "Transcription backend (current: %s): " current))
          (choice (completing-read prompt backends nil t))