Update CHANGELOG

Author: ovistoica

CHANGELOG.md

@@ -8,11 +8,22 @@ All notable changes to this project will be documented in this file. This change
 - [Silero Voice Activity Detection model](./src/simulflow/vad/silero.clj) running through Onnx Runtime
 - parameter `:vad/analyser` to all transport-in processor params to pass a VAD analyser like Silero to be ran on each new audio chunk. This is useful for logic that handles AI interruptions and improves turn taking.
 - Added malli schema for `audio-output-raw` frames
+- Added `simulflow.frame/send` helper function that outputs frames based on their appropriate direction - used now in most processors
+- **Twilio Integration**: Twilio serializer with `make-twilio-serializer` for WebSocket communication
+- **Audio Resampler Processor**: New processor for real-time sample rate conversion
+- **System Frame Router**: New `system-frame-router` processor for handling system message routing in complex flows
+- **Interruption Support**: New frame types for bot interruption handling: `control-interrupt-start`, `control-interrupt-stop`, `bot-interrupt`
 
 ### Changed
-- Made 16kHz PCM mono audio be the default audio that runs through the pipeline. All `audio-input-raw` frames that come through pe pipeline are expected to be this way.
+- Made **16kHz signed PCM mono** audio be the default audio that runs through the pipeline. All `audio-input-raw` frames that come through pe pipeline are expected to be this way.
 - **POTENTIAL BREAKING** `frame/audio-output-raw` are now expected to contain the sample-rate of the audio. The sample rate will be used for chunking and final output conversion. If you have custom Text to speech generators, you need to update them to use it.
+- Changed examples to use silero vad model for VAD instead of relying on Deepgram
+- **BREAKING** Processors that outputted `system-frames` (see [frame/system-frames](./src/simulflow/frame.clj) set for a list of system frames) will output them exclusively on `:sys-out` channel and normal frames on `:out` channel.
+- **Audio Processing**: Enhanced audio conversion with improved µ-law/PCM support and step-by-step conversion planning
 
+### Fixed
+- **Audio Conversion**: Fixed critical bug in PCM 16kHz to Twilio µ-law 8kHz conversion where downsampling must occur before encoding conversion
+- **Transport**: Removed duplicate system frame passthrough that was causing duplicate frames
 
 ## [0.1.5-alpha] - 2025-07-24
 

test/simulflow/frame_test.clj

@@ -381,3 +381,94 @@
       (let [frames (doall (repeatedly 100 #(frame/llm-text-chunk "test")))]
         (is (= 100 (count frames)))
         (is (every? frame/llm-text-chunk? frames))))))
+
+(deftest test-send-function
+  "Test the frame/send function for routing frames to appropriate channels"
+  (testing "empty input"
+    (is (= {} (frame/send))))
+
+  (testing "single regular frame"
+    (let [audio-frame (frame/audio-input-raw test-audio-data)]
+      (is (= {:out [audio-frame]}
+             (frame/send audio-frame)))))
+
+  (testing "single system frame"
+    (let [start-frame (frame/system-start true)]
+      (is (= {:sys-out [start-frame]}
+             (frame/send start-frame)))))
+
+  (testing "mixed frame types"
+    (let [audio-frame (frame/audio-input-raw test-audio-data)
+          start-frame (frame/system-start true)
+          text-frame (frame/text-input {:text "hello"})]
+      (is (= {:out [audio-frame text-frame]
+              :sys-out [start-frame]}
+             (frame/send audio-frame start-frame text-frame)))))
+
+  (testing "multiple system frames"
+    (let [start-frame (frame/system-start true)
+          stop-frame (frame/system-stop true)]
+      (is (= {:sys-out [start-frame stop-frame]}
+             (frame/send start-frame stop-frame)))))
+
+  (testing "multiple regular frames"
+    (let [audio-frame (frame/audio-input-raw test-audio-data)
+          text-frame (frame/text-input {:text "hello"})
+          transcription-frame (frame/transcription {:text "world"})]
+      (is (= {:out [audio-frame text-frame transcription-frame]}
+             (frame/send audio-frame text-frame transcription-frame)))))
+
+  (testing "nil frames are filtered out"
+    (let [audio-frame (frame/audio-input-raw test-audio-data)
+          start-frame (frame/system-start true)]
+      (is (= {:out [audio-frame]
+              :sys-out [start-frame]}
+             (frame/send nil audio-frame nil start-frame nil)))))
+
+  (testing "all nil frames"
+    (is (= {} (frame/send nil nil nil))))
+
+  (testing "all system frame types are routed to sys-out"
+    (let [frames [(frame/system-start true)
+                  (frame/system-stop true)
+                  (frame/system-config-change {:config {}})
+                  (frame/user-speech-start true)
+                  (frame/user-speech-stop true)
+                  (frame/bot-speech-start true)
+                  (frame/bot-speech-stop true)
+                  (frame/vad-user-speech-start true)
+                  (frame/vad-user-speech-stop true)
+                  (frame/bot-interrupt true)
+                  (frame/control-interrupt-start true)
+                  (frame/control-interrupt-stop true)]]
+      (is (= {:sys-out frames}
+             (apply frame/send frames)))))
+
+  (testing "all regular frame types are routed to out"
+    (let [frames [(frame/audio-input-raw test-audio-data)
+                  (frame/audio-output-raw {:audio test-audio-data :sample-rate 16000})
+                  (frame/audio-tts-raw test-audio-data)
+                  (frame/transcription {:text "hello"})
+                  (frame/transcription-interim {:text "hello"})
+                  (frame/llm-context {:messages []})
+                  (frame/llm-text-chunk {:text "chunk"})
+                  (frame/text-input {:text "input"})]]
+      (is (= {:out frames}
+             (apply frame/send frames)))))
+
+  (testing "preserves frame order within channels"
+    (let [frame1 (frame/audio-input-raw test-audio-data)
+          frame2 (frame/text-input {:text "hello"})
+          frame3 (frame/transcription {:text "world"})
+          sys-frame1 (frame/system-start true)
+          sys-frame2 (frame/system-stop true)]
+      (is (= {:out [frame1 frame2 frame3]
+              :sys-out [sys-frame1 sys-frame2]}
+             (frame/send frame1 sys-frame1 frame2 sys-frame2 frame3)))))
+
+  (testing "large number of frames"
+    (let [regular-frames (repeatedly 100 #(frame/text-input {:text (str "message-" (rand-int 1000))}))
+          system-frames (repeatedly 50 #(frame/system-start true))]
+      (let [result (apply frame/send (concat regular-frames system-frames))]
+        (is (= 100 (count (:out result))))
+        (is (= 50 (count (:sys-out result))))))))