Split padding and transcription into separate workflow steps

- Split process_tracks into process_paddings + process_transcriptions
- Create PaddingWorkflow and TranscriptionWorkflow as separate child workflows
- Update dependency: mixdown_tracks now depends on process_paddings (not process_transcriptions)
- Performance: mixdown starts ~295s earlier (after padding completes, not after transcription)

Changes:
- New: padding_workflow.py, transcription_workflow.py
- Modified: daily_multitrack_pipeline.py (new tasks, updated dependencies)
- Modified: models.py (new ProcessPaddingsResult, ProcessTranscriptionsResult, deleted dead ProcessTracksResult)
- Modified: constants.py (new task names)
- Modified: run_workers_cpu.py, run_workers_llm.py (workflow registration)
- Deleted: track_processing.py

Code quality fixes:
- Removed redundant comments and verbose docstrings
- Added language validation in process_transcriptions
- Improved error logging with full context (transcript_id, track_index)
- Fixed log accuracy bugs (use correct counts)
- Updated worker pool documentation

server/reflector/hatchet/constants.py

@@ -8,7 +8,8 @@ from enum import StrEnum
 class TaskName(StrEnum):
     GET_RECORDING = "get_recording"
     GET_PARTICIPANTS = "get_participants"
-    PROCESS_TRACKS = "process_tracks"
+    PROCESS_PADDINGS = "process_paddings"
+    PROCESS_TRANSCRIPTIONS = "process_transcriptions"
     MIXDOWN_TRACKS = "mixdown_tracks"
     GENERATE_WAVEFORM = "generate_waveform"
     DETECT_TOPICS = "detect_topics"

server/reflector/hatchet/run_workers_cpu.py

@@ -1,9 +1,9 @@
 """
 CPU-heavy worker pool for audio processing tasks.
-Handles ONLY: mixdown_tracks
+Handles: mixdown_tracks (serialized), padding workflows (parallel child workflows)
 
 Configuration:
-- slots=1: Only mixdown (already serialized globally with max_runs=1)
+- slots=1: Mixdown serialized globally with max_runs=1
 - Worker affinity: pool=cpu-heavy
 """
 
@@ -11,6 +11,7 @@ from reflector.hatchet.client import HatchetClientManager
 from reflector.hatchet.workflows.daily_multitrack_pipeline import (
     daily_multitrack_pipeline,
 )
+from reflector.hatchet.workflows.padding_workflow import padding_workflow
 from reflector.logger import logger
 from reflector.settings import settings
 
@@ -23,7 +24,7 @@ def main():
     hatchet = HatchetClientManager.get_client()
 
     logger.info(
-        "Starting Hatchet CPU worker pool (mixdown only)",
+        "Starting Hatchet CPU worker pool (mixdown + padding)",
         worker_name="cpu-worker-pool",
         slots=1,
         labels={"pool": "cpu-heavy"},
@@ -31,11 +32,11 @@ def main():
 
     cpu_worker = hatchet.worker(
         "cpu-worker-pool",
-        slots=1,  # Only 1 mixdown at a time (already serialized globally)
+        slots=1,
         labels={
             "pool": "cpu-heavy",
         },
-        workflows=[daily_multitrack_pipeline],
+        workflows=[daily_multitrack_pipeline, padding_workflow],
     )
 
     try:

server/reflector/hatchet/run_workers_llm.py

@@ -9,7 +9,7 @@ from reflector.hatchet.workflows.daily_multitrack_pipeline import (
 )
 from reflector.hatchet.workflows.subject_processing import subject_workflow
 from reflector.hatchet.workflows.topic_chunk_processing import topic_chunk_workflow
-from reflector.hatchet.workflows.track_processing import track_workflow
+from reflector.hatchet.workflows.transcription_workflow import transcription_workflow
 from reflector.logger import logger
 from reflector.settings import settings
 
@@ -42,7 +42,7 @@ def main():
             daily_multitrack_pipeline,
             topic_chunk_workflow,
             subject_workflow,
-            track_workflow,
+            transcription_workflow,
         ],
     )
 

server/reflector/hatchet/workflows/__init__.py

@@ -4,6 +4,10 @@ from reflector.hatchet.workflows.daily_multitrack_pipeline import (
     PipelineInput,
     daily_multitrack_pipeline,
 )
+from reflector.hatchet.workflows.padding_workflow import (
+    PaddingInput,
+    padding_workflow,
+)
 from reflector.hatchet.workflows.subject_processing import (
     SubjectInput,
     subject_workflow,
@@ -12,15 +16,20 @@ from reflector.hatchet.workflows.topic_chunk_processing import (
     TopicChunkInput,
     topic_chunk_workflow,
 )
-from reflector.hatchet.workflows.track_processing import TrackInput, track_workflow
+from reflector.hatchet.workflows.transcription_workflow import (
+    TranscriptionInput,
+    transcription_workflow,
+)
 
 __all__ = [
     "daily_multitrack_pipeline",
     "subject_workflow",
     "topic_chunk_workflow",
-    "track_workflow",
+    "padding_workflow",
+    "transcription_workflow",
     "PipelineInput",
     "SubjectInput",
     "TopicChunkInput",
-    "TrackInput",
+    "PaddingInput",
+    "TranscriptionInput",
 ]

server/reflector/hatchet/workflows/daily_multitrack_pipeline.py

@@ -54,8 +54,9 @@ from reflector.hatchet.workflows.models import (
     PadTrackResult,
     ParticipantInfo,
     ParticipantsResult,
+    ProcessPaddingsResult,
     ProcessSubjectsResult,
-    ProcessTracksResult,
+    ProcessTranscriptionsResult,
     RecapResult,
     RecordingResult,
     SubjectsResult,
@@ -68,6 +69,7 @@ from reflector.hatchet.workflows.models import (
     WebhookResult,
     ZulipResult,
 )
+from reflector.hatchet.workflows.padding_workflow import PaddingInput, padding_workflow
 from reflector.hatchet.workflows.subject_processing import (
     SubjectInput,
     subject_workflow,
@@ -76,7 +78,10 @@ from reflector.hatchet.workflows.topic_chunk_processing import (
     TopicChunkInput,
     topic_chunk_workflow,
 )
-from reflector.hatchet.workflows.track_processing import TrackInput, track_workflow
+from reflector.hatchet.workflows.transcription_workflow import (
+    TranscriptionInput,
+    transcription_workflow,
+)
 from reflector.logger import logger
 from reflector.pipelines import topic_processing
 from reflector.processors import AudioFileWriterProcessor
@@ -404,39 +409,29 @@ async def get_participants(input: PipelineInput, ctx: Context) -> ParticipantsRe
     execution_timeout=timedelta(seconds=TIMEOUT_HEAVY),
     retries=3,
 )
-@with_error_handling(TaskName.PROCESS_TRACKS)
+@with_error_handling(TaskName.PROCESS_PADDINGS)
-async def process_tracks(input: PipelineInput, ctx: Context) -> ProcessTracksResult:
+async def process_paddings(input: PipelineInput, ctx: Context) -> ProcessPaddingsResult:
-    """Spawn child workflows for each track (dynamic fan-out)."""
+    """Spawn child workflows for each track to apply padding (dynamic fan-out)."""
-    ctx.log(f"process_tracks: spawning {len(input.tracks)} track workflows")
+    ctx.log(f"process_paddings: spawning {len(input.tracks)} padding workflows")
-
-    participants_result = ctx.task_output(get_participants)
-    source_language = participants_result.source_language
 
     bulk_runs = [
-        track_workflow.create_bulk_run_item(
+        padding_workflow.create_bulk_run_item(
-            input=TrackInput(
+            input=PaddingInput(
                 track_index=i,
                 s3_key=track["s3_key"],
                 bucket_name=input.bucket_name,
                 transcript_id=input.transcript_id,
-                language=source_language,
             )
         )
         for i, track in enumerate(input.tracks)
     ]
 
-    results = await track_workflow.aio_run_many(bulk_runs)
+    results = await padding_workflow.aio_run_many(bulk_runs)
 
-    target_language = participants_result.target_language
-
-    track_words: list[list[Word]] = []
     padded_tracks = []
     created_padded_files = set()
 
     for result in results:
-        transcribe_result = TranscribeTrackResult(**result[TaskName.TRANSCRIBE_TRACK])
-        track_words.append(transcribe_result.words)
-
         pad_result = PadTrackResult(**result[TaskName.PAD_TRACK])
 
         # Store S3 key info (not presigned URL) - consumer tasks presign on demand
@@ -451,25 +446,75 @@ async def process_tracks(input: PipelineInput, ctx: Context) -> ProcessTracksRes
             storage_path = f"file_pipeline_hatchet/{input.transcript_id}/tracks/padded_{pad_result.track_index}.webm"
             created_padded_files.add(storage_path)
 
-    all_words = [word for words in track_words for word in words]
+    ctx.log(f"process_paddings complete: {len(padded_tracks)} padded tracks")
-    all_words.sort(key=lambda w: w.start)
 
-    ctx.log(
+    return ProcessPaddingsResult(
-        f"process_tracks complete: {len(all_words)} words from {len(input.tracks)} tracks"
-    )
-
-    return ProcessTracksResult(
-        all_words=all_words,
         padded_tracks=padded_tracks,
-        word_count=len(all_words),
         num_tracks=len(input.tracks),
-        target_language=target_language,
         created_padded_files=list(created_padded_files),
     )
 
 
 @daily_multitrack_pipeline.task(
-    parents=[process_tracks],
+    parents=[process_paddings],
+    execution_timeout=timedelta(seconds=TIMEOUT_HEAVY),
+    retries=3,
+)
+@with_error_handling(TaskName.PROCESS_TRANSCRIPTIONS)
+async def process_transcriptions(
+    input: PipelineInput, ctx: Context
+) -> ProcessTranscriptionsResult:
+    """Spawn child workflows for each padded track to transcribe (dynamic fan-out)."""
+    participants_result = ctx.task_output(get_participants)
+    paddings_result = ctx.task_output(process_paddings)
+
+    source_language = participants_result.source_language
+    if not source_language:
+        raise ValueError("source_language is required for transcription")
+
+    target_language = participants_result.target_language
+    padded_tracks = paddings_result.padded_tracks
+
+    ctx.log(
+        f"process_transcriptions: spawning {len(padded_tracks)} transcription workflows"
+    )
+
+    bulk_runs = [
+        transcription_workflow.create_bulk_run_item(
+            input=TranscriptionInput(
+                track_index=i,
+                padded_key=padded_track.key,
+                bucket_name=padded_track.bucket_name,
+                language=source_language,
+            )
+        )
+        for i, padded_track in enumerate(padded_tracks)
+    ]
+
+    results = await transcription_workflow.aio_run_many(bulk_runs)
+
+    track_words: list[list[Word]] = []
+    for result in results:
+        transcribe_result = TranscribeTrackResult(**result[TaskName.TRANSCRIBE_TRACK])
+        track_words.append(transcribe_result.words)
+
+    all_words = [word for words in track_words for word in words]
+    all_words.sort(key=lambda w: w.start)
+
+    ctx.log(
+        f"process_transcriptions complete: {len(all_words)} words from {len(padded_tracks)} tracks"
+    )
+
+    return ProcessTranscriptionsResult(
+        all_words=all_words,
+        word_count=len(all_words),
+        num_tracks=len(input.tracks),
+        target_language=target_language,
+    )
+
+
+@daily_multitrack_pipeline.task(
+    parents=[process_paddings],
     execution_timeout=timedelta(seconds=TIMEOUT_AUDIO),
     retries=3,
     desired_worker_labels={
@@ -489,12 +534,12 @@ async def process_tracks(input: PipelineInput, ctx: Context) -> ProcessTracksRes
 )
 @with_error_handling(TaskName.MIXDOWN_TRACKS)
 async def mixdown_tracks(input: PipelineInput, ctx: Context) -> MixdownResult:
-    """Mix all padded tracks into single audio file using PyAV (same as Celery)."""
+    """Mix all padded tracks into single audio file using PyAV."""
     ctx.log("mixdown_tracks: mixing padded tracks into single audio file")
 
-    track_result = ctx.task_output(process_tracks)
+    paddings_result = ctx.task_output(process_paddings)
     recording_result = ctx.task_output(get_recording)
-    padded_tracks = track_result.padded_tracks
+    padded_tracks = paddings_result.padded_tracks
 
     # Dynamic timeout: scales with track count and recording duration
     # Base 300s + 60s per track + 1s per 10s of recording
@@ -648,7 +693,7 @@ async def generate_waveform(input: PipelineInput, ctx: Context) -> WaveformResul
 
 
 @daily_multitrack_pipeline.task(
-    parents=[process_tracks],
+    parents=[process_transcriptions],
     execution_timeout=timedelta(seconds=TIMEOUT_HEAVY),
     retries=3,
 )
@@ -657,8 +702,8 @@ async def detect_topics(input: PipelineInput, ctx: Context) -> TopicsResult:
     """Detect topics using parallel child workflows (one per chunk)."""
     ctx.log("detect_topics: analyzing transcript for topics")
 
-    track_result = ctx.task_output(process_tracks)
+    transcriptions_result = ctx.task_output(process_transcriptions)
-    words = track_result.all_words
+    words = transcriptions_result.all_words
 
     if not words:
         ctx.log("detect_topics: no words, returning empty topics")
@@ -1109,13 +1154,14 @@ async def finalize(input: PipelineInput, ctx: Context) -> FinalizeResult:
     ctx.log("finalize: saving transcript and setting status to 'ended'")
 
     mixdown_result = ctx.task_output(mixdown_tracks)
-    track_result = ctx.task_output(process_tracks)
+    transcriptions_result = ctx.task_output(process_transcriptions)
+    paddings_result = ctx.task_output(process_paddings)
 
     duration = mixdown_result.duration
-    all_words = track_result.all_words
+    all_words = transcriptions_result.all_words
 
     # Cleanup temporary padded S3 files (deferred until finalize for semantic parity with Celery)
-    created_padded_files = track_result.created_padded_files
+    created_padded_files = paddings_result.created_padded_files
     if created_padded_files:
         ctx.log(f"Cleaning up {len(created_padded_files)} temporary S3 files")
         storage = _spawn_storage()

server/reflector/hatchet/workflows/models.py

@@ -23,10 +23,8 @@ class ParticipantInfo(BaseModel):
 class PadTrackResult(BaseModel):
     """Result from pad_track task."""
 
-    padded_key: NonEmptyString  # S3 key (not presigned URL) - presign on demand to avoid stale URLs on replay
+    padded_key: NonEmptyString
-    bucket_name: (
+    bucket_name: NonEmptyString | None
-        NonEmptyString | None
-    )  # None means use default transcript storage bucket
     size: int
     track_index: int
 
@@ -59,18 +57,24 @@ class PaddedTrackInfo(BaseModel):
     """Info for a padded track - S3 key + bucket for on-demand presigning."""
 
     key: NonEmptyString
-    bucket_name: NonEmptyString | None  # None = use default storage bucket
+    bucket_name: NonEmptyString | None
 
 
-class ProcessTracksResult(BaseModel):
+class ProcessPaddingsResult(BaseModel):
-    """Result from process_tracks task."""
+    """Result from process_paddings task."""
+
+    padded_tracks: list[PaddedTrackInfo]
+    num_tracks: int
+    created_padded_files: list[NonEmptyString]
+
+
+class ProcessTranscriptionsResult(BaseModel):
+    """Result from process_transcriptions task."""
 
     all_words: list[Word]
-    padded_tracks: list[PaddedTrackInfo]  # S3 keys, not presigned URLs
     word_count: int
     num_tracks: int
     target_language: NonEmptyString
-    created_padded_files: list[NonEmptyString]
 
 
 class MixdownResult(BaseModel):

server/reflector/hatchet/workflows/padding_workflow.py

@@ -0,0 +1,145 @@
+"""
+Hatchet child workflow: PaddingWorkflow
+Handles individual audio track padding only.
+"""
+
+import tempfile
+from datetime import timedelta
+from pathlib import Path
+
+import av
+from hatchet_sdk import Context
+from pydantic import BaseModel
+
+from reflector.hatchet.client import HatchetClientManager
+from reflector.hatchet.constants import TIMEOUT_AUDIO
+from reflector.hatchet.workflows.models import PadTrackResult
+from reflector.logger import logger
+from reflector.utils.audio_constants import PRESIGNED_URL_EXPIRATION_SECONDS
+from reflector.utils.audio_padding import (
+    apply_audio_padding_to_file,
+    extract_stream_start_time_from_container,
+)
+
+
+class PaddingInput(BaseModel):
+    """Input for individual track padding."""
+
+    track_index: int
+    s3_key: str
+    bucket_name: str
+    transcript_id: str
+
+
+hatchet = HatchetClientManager.get_client()
+
+padding_workflow = hatchet.workflow(
+    name="PaddingWorkflow", input_validator=PaddingInput
+)
+
+
+@padding_workflow.task(execution_timeout=timedelta(seconds=TIMEOUT_AUDIO), retries=3)
+async def pad_track(input: PaddingInput, ctx: Context) -> PadTrackResult:
+    """Pad audio track with silence based on WebM container start_time."""
+    ctx.log(f"pad_track: track {input.track_index}, s3_key={input.s3_key}")
+    logger.info(
+        "[Hatchet] pad_track",
+        track_index=input.track_index,
+        s3_key=input.s3_key,
+        transcript_id=input.transcript_id,
+    )
+
+    try:
+        # Create fresh storage instance to avoid aioboto3 fork issues
+        from reflector.settings import settings  # noqa: PLC0415
+        from reflector.storage.storage_aws import AwsStorage  # noqa: PLC0415
+
+        storage = AwsStorage(
+            aws_bucket_name=settings.TRANSCRIPT_STORAGE_AWS_BUCKET_NAME,
+            aws_region=settings.TRANSCRIPT_STORAGE_AWS_REGION,
+            aws_access_key_id=settings.TRANSCRIPT_STORAGE_AWS_ACCESS_KEY_ID,
+            aws_secret_access_key=settings.TRANSCRIPT_STORAGE_AWS_SECRET_ACCESS_KEY,
+        )
+
+        source_url = await storage.get_file_url(
+            input.s3_key,
+            operation="get_object",
+            expires_in=PRESIGNED_URL_EXPIRATION_SECONDS,
+            bucket=input.bucket_name,
+        )
+
+        with av.open(source_url) as in_container:
+            if in_container.duration:
+                try:
+                    duration = timedelta(seconds=in_container.duration // 1_000_000)
+                    ctx.log(
+                        f"pad_track: track {input.track_index}, duration={duration}"
+                    )
+                except Exception:
+                    ctx.log(f"pad_track: track {input.track_index}, duration=ERROR")
+
+            start_time_seconds = extract_stream_start_time_from_container(
+                in_container, input.track_index, logger=logger
+            )
+
+            if start_time_seconds <= 0:
+                logger.info(
+                    f"Track {input.track_index} requires no padding",
+                    track_index=input.track_index,
+                )
+                return PadTrackResult(
+                    padded_key=input.s3_key,
+                    bucket_name=input.bucket_name,
+                    size=0,
+                    track_index=input.track_index,
+                )
+
+            with tempfile.NamedTemporaryFile(suffix=".webm", delete=False) as temp_file:
+                temp_path = temp_file.name
+
+            try:
+                apply_audio_padding_to_file(
+                    in_container,
+                    temp_path,
+                    start_time_seconds,
+                    input.track_index,
+                    logger=logger,
+                )
+
+                file_size = Path(temp_path).stat().st_size
+                storage_path = f"file_pipeline_hatchet/{input.transcript_id}/tracks/padded_{input.track_index}.webm"
+
+                with open(temp_path, "rb") as padded_file:
+                    await storage.put_file(storage_path, padded_file)
+
+                logger.info(
+                    f"Uploaded padded track to S3",
+                    key=storage_path,
+                    size=file_size,
+                )
+            finally:
+                Path(temp_path).unlink(missing_ok=True)
+
+        ctx.log(f"pad_track complete: track {input.track_index} -> {storage_path}")
+        logger.info(
+            "[Hatchet] pad_track complete",
+            track_index=input.track_index,
+            padded_key=storage_path,
+        )
+
+        return PadTrackResult(
+            padded_key=storage_path,
+            bucket_name=None,  # None = use default transcript storage bucket
+            size=file_size,
+            track_index=input.track_index,
+        )
+
+    except Exception as e:
+        logger.error(
+            "[Hatchet] pad_track failed",
+            transcript_id=input.transcript_id,
+            track_index=input.track_index,
+            error=str(e),
+            exc_info=True,
+        )
+        raise

server/reflector/hatchet/workflows/track_processing.py

@@ -1,229 +0,0 @@
-"""
-Hatchet child workflow: TrackProcessing
-
-Handles individual audio track processing: padding and transcription.
-Spawned dynamically by the main diarization pipeline for each track.
-
-Architecture note: This is a separate workflow (not inline tasks in DailyMultitrackPipeline)
-because Hatchet workflow DAGs are defined statically, but the number of tracks varies
-at runtime. Child workflow spawning via `aio_run()` + `asyncio.gather()` is the
-standard pattern for dynamic fan-out. See `process_tracks` in daily_multitrack_pipeline.py.
-
-Note: This file uses deferred imports (inside tasks) intentionally.
-Hatchet workers run in forked processes; fresh imports per task ensure
-storage/DB connections are not shared across forks.
-"""
-
-import tempfile
-from datetime import timedelta
-from pathlib import Path
-
-import av
-from hatchet_sdk import Context
-from pydantic import BaseModel
-
-from reflector.hatchet.client import HatchetClientManager
-from reflector.hatchet.constants import TIMEOUT_AUDIO, TIMEOUT_HEAVY
-from reflector.hatchet.workflows.models import PadTrackResult, TranscribeTrackResult
-from reflector.logger import logger
-from reflector.utils.audio_constants import PRESIGNED_URL_EXPIRATION_SECONDS
-from reflector.utils.audio_padding import (
-    apply_audio_padding_to_file,
-    extract_stream_start_time_from_container,
-)
-
-
-class TrackInput(BaseModel):
-    """Input for individual track processing."""
-
-    track_index: int
-    s3_key: str
-    bucket_name: str
-    transcript_id: str
-    language: str = "en"
-
-
-hatchet = HatchetClientManager.get_client()
-
-track_workflow = hatchet.workflow(name="TrackProcessing", input_validator=TrackInput)
-
-
-@track_workflow.task(execution_timeout=timedelta(seconds=TIMEOUT_AUDIO), retries=3)
-async def pad_track(input: TrackInput, ctx: Context) -> PadTrackResult:
-    """Pad single audio track with silence for alignment.
-
-    Extracts stream.start_time from WebM container metadata and applies
-    silence padding using PyAV filter graph (adelay).
-    """
-    ctx.log(f"pad_track: track {input.track_index}, s3_key={input.s3_key}")
-    logger.info(
-        "[Hatchet] pad_track",
-        track_index=input.track_index,
-        s3_key=input.s3_key,
-        transcript_id=input.transcript_id,
-    )
-
-    try:
-        # Create fresh storage instance to avoid aioboto3 fork issues
-        from reflector.settings import settings  # noqa: PLC0415
-        from reflector.storage.storage_aws import AwsStorage  # noqa: PLC0415
-
-        storage = AwsStorage(
-            aws_bucket_name=settings.TRANSCRIPT_STORAGE_AWS_BUCKET_NAME,
-            aws_region=settings.TRANSCRIPT_STORAGE_AWS_REGION,
-            aws_access_key_id=settings.TRANSCRIPT_STORAGE_AWS_ACCESS_KEY_ID,
-            aws_secret_access_key=settings.TRANSCRIPT_STORAGE_AWS_SECRET_ACCESS_KEY,
-        )
-
-        source_url = await storage.get_file_url(
-            input.s3_key,
-            operation="get_object",
-            expires_in=PRESIGNED_URL_EXPIRATION_SECONDS,
-            bucket=input.bucket_name,
-        )
-
-        with av.open(source_url) as in_container:
-            if in_container.duration:
-                try:
-                    duration = timedelta(seconds=in_container.duration // 1_000_000)
-                    ctx.log(
-                        f"pad_track: track {input.track_index}, duration={duration}"
-                    )
-                except Exception:
-                    ctx.log(f"pad_track: track {input.track_index}, duration=ERROR")
-
-            start_time_seconds = extract_stream_start_time_from_container(
-                in_container, input.track_index, logger=logger
-            )
-
-            # If no padding needed, return original S3 key
-            if start_time_seconds <= 0:
-                logger.info(
-                    f"Track {input.track_index} requires no padding",
-                    track_index=input.track_index,
-                )
-                return PadTrackResult(
-                    padded_key=input.s3_key,
-                    bucket_name=input.bucket_name,
-                    size=0,
-                    track_index=input.track_index,
-                )
-
-            with tempfile.NamedTemporaryFile(suffix=".webm", delete=False) as temp_file:
-                temp_path = temp_file.name
-
-            try:
-                apply_audio_padding_to_file(
-                    in_container,
-                    temp_path,
-                    start_time_seconds,
-                    input.track_index,
-                    logger=logger,
-                )
-
-                file_size = Path(temp_path).stat().st_size
-                storage_path = f"file_pipeline_hatchet/{input.transcript_id}/tracks/padded_{input.track_index}.webm"
-
-                logger.info(
-                    f"About to upload padded track",
-                    key=storage_path,
-                    size=file_size,
-                )
-
-                with open(temp_path, "rb") as padded_file:
-                    await storage.put_file(storage_path, padded_file)
-
-                logger.info(
-                    f"Uploaded padded track to S3",
-                    key=storage_path,
-                    size=file_size,
-                )
-            finally:
-                Path(temp_path).unlink(missing_ok=True)
-
-        ctx.log(f"pad_track complete: track {input.track_index} -> {storage_path}")
-        logger.info(
-            "[Hatchet] pad_track complete",
-            track_index=input.track_index,
-            padded_key=storage_path,
-        )
-
-        # Return S3 key (not presigned URL) - consumer tasks presign on demand
-        # This avoids stale URLs when workflow is replayed
-        return PadTrackResult(
-            padded_key=storage_path,
-            bucket_name=None,  # None = use default transcript storage bucket
-            size=file_size,
-            track_index=input.track_index,
-        )
-
-    except Exception as e:
-        logger.error("[Hatchet] pad_track failed", error=str(e), exc_info=True)
-        raise
-
-
-@track_workflow.task(
-    parents=[pad_track], execution_timeout=timedelta(seconds=TIMEOUT_HEAVY), retries=3
-)
-async def transcribe_track(input: TrackInput, ctx: Context) -> TranscribeTrackResult:
-    """Transcribe audio track using GPU (Modal.com) or local Whisper."""
-    ctx.log(f"transcribe_track: track {input.track_index}, language={input.language}")
-    logger.info(
-        "[Hatchet] transcribe_track",
-        track_index=input.track_index,
-        language=input.language,
-    )
-
-    try:
-        pad_result = ctx.task_output(pad_track)
-        padded_key = pad_result.padded_key
-        bucket_name = pad_result.bucket_name
-
-        if not padded_key:
-            raise ValueError("Missing padded_key from pad_track")
-
-        # Presign URL on demand (avoids stale URLs on workflow replay)
-        from reflector.settings import settings  # noqa: PLC0415
-        from reflector.storage.storage_aws import AwsStorage  # noqa: PLC0415
-
-        storage = AwsStorage(
-            aws_bucket_name=settings.TRANSCRIPT_STORAGE_AWS_BUCKET_NAME,
-            aws_region=settings.TRANSCRIPT_STORAGE_AWS_REGION,
-            aws_access_key_id=settings.TRANSCRIPT_STORAGE_AWS_ACCESS_KEY_ID,
-            aws_secret_access_key=settings.TRANSCRIPT_STORAGE_AWS_SECRET_ACCESS_KEY,
-        )
-
-        audio_url = await storage.get_file_url(
-            padded_key,
-            operation="get_object",
-            expires_in=PRESIGNED_URL_EXPIRATION_SECONDS,
-            bucket=bucket_name,
-        )
-
-        from reflector.pipelines.transcription_helpers import (  # noqa: PLC0415
-            transcribe_file_with_processor,
-        )
-
-        transcript = await transcribe_file_with_processor(audio_url, input.language)
-
-        # Tag all words with speaker index
-        for word in transcript.words:
-            word.speaker = input.track_index
-
-        ctx.log(
-            f"transcribe_track complete: track {input.track_index}, {len(transcript.words)} words"
-        )
-        logger.info(
-            "[Hatchet] transcribe_track complete",
-            track_index=input.track_index,
-            word_count=len(transcript.words),
-        )
-
-        return TranscribeTrackResult(
-            words=transcript.words,
-            track_index=input.track_index,
-        )
-
-    except Exception as e:
-        logger.error("[Hatchet] transcribe_track failed", error=str(e), exc_info=True)
-        raise

server/reflector/hatchet/workflows/transcription_workflow.py

@@ -0,0 +1,98 @@
+"""
+Hatchet child workflow: TranscriptionWorkflow
+Handles individual audio track transcription only.
+"""
+
+from datetime import timedelta
+
+from hatchet_sdk import Context
+from pydantic import BaseModel
+
+from reflector.hatchet.client import HatchetClientManager
+from reflector.hatchet.constants import TIMEOUT_HEAVY
+from reflector.hatchet.workflows.models import TranscribeTrackResult
+from reflector.logger import logger
+from reflector.utils.audio_constants import PRESIGNED_URL_EXPIRATION_SECONDS
+
+
+class TranscriptionInput(BaseModel):
+    """Input for individual track transcription."""
+
+    track_index: int
+    padded_key: str  # S3 key from padding step
+    bucket_name: str | None  # None = use default bucket
+    language: str = "en"
+
+
+hatchet = HatchetClientManager.get_client()
+
+transcription_workflow = hatchet.workflow(
+    name="TranscriptionWorkflow", input_validator=TranscriptionInput
+)
+
+
+@transcription_workflow.task(
+    execution_timeout=timedelta(seconds=TIMEOUT_HEAVY), retries=3
+)
+async def transcribe_track(
+    input: TranscriptionInput, ctx: Context
+) -> TranscribeTrackResult:
+    """Transcribe audio track using GPU (Modal.com) or local Whisper."""
+    ctx.log(f"transcribe_track: track {input.track_index}, language={input.language}")
+    logger.info(
+        "[Hatchet] transcribe_track",
+        track_index=input.track_index,
+        language=input.language,
+    )
+
+    try:
+        from reflector.settings import settings  # noqa: PLC0415
+        from reflector.storage.storage_aws import AwsStorage  # noqa: PLC0415
+
+        storage = AwsStorage(
+            aws_bucket_name=settings.TRANSCRIPT_STORAGE_AWS_BUCKET_NAME,
+            aws_region=settings.TRANSCRIPT_STORAGE_AWS_REGION,
+            aws_access_key_id=settings.TRANSCRIPT_STORAGE_AWS_ACCESS_KEY_ID,
+            aws_secret_access_key=settings.TRANSCRIPT_STORAGE_AWS_SECRET_ACCESS_KEY,
+        )
+
+        audio_url = await storage.get_file_url(
+            input.padded_key,
+            operation="get_object",
+            expires_in=PRESIGNED_URL_EXPIRATION_SECONDS,
+            bucket=input.bucket_name,
+        )
+
+        from reflector.pipelines.transcription_helpers import (  # noqa: PLC0415
+            transcribe_file_with_processor,
+        )
+
+        transcript = await transcribe_file_with_processor(audio_url, input.language)
+
+        for word in transcript.words:
+            word.speaker = input.track_index
+
+        ctx.log(
+            f"transcribe_track complete: track {input.track_index}, {len(transcript.words)} words"
+        )
+        logger.info(
+            "[Hatchet] transcribe_track complete",
+            track_index=input.track_index,
+            word_count=len(transcript.words),
+        )
+
+        return TranscribeTrackResult(
+            words=transcript.words,
+            track_index=input.track_index,
+        )
+
+    except Exception as e:
+        logger.error(
+            "[Hatchet] transcribe_track failed",
+            track_index=input.track_index,
+            padded_key=input.padded_key,
+            language=input.language,
+            error=str(e),
+            exc_info=True,
+        )
+        raise