Transcoding Genesys Cloud Voice Recordings with Python SDK

What You Will Build

• A production-grade Python module that submits voice recording transcoding jobs to Genesys Cloud, validates codec constraints, tracks latency, and verifies output fidelity.
• This uses the Genesys Cloud Recording API (/api/v2/recording/medias/transcode) and the official genesyscloud Python SDK.
• The implementation covers Python 3.9+ with httpx, pydantic, and structured logging.

Prerequisites

• OAuth client type: Public or Private Key client registered in Genesys Cloud
• Required scopes: recording:view, recording:transcode, recording:download, webhook:manage
• SDK version: genesyscloud >= 4.0.0
• Runtime: Python 3.9+
• External dependencies: httpx, pydantic, structlog, wave (stdlib)

Authentication Setup

Genesys Cloud uses OAuth 2.0 client credentials flow. The following function fetches an access token and caches it with automatic refresh logic.

import httpx
import time
from typing import Optional

class GenesysAuth:
    def __init__(self, org_id: str, client_id: str, client_secret: str, base_url: str = "https://api.mypurecloud.com"):
        self.org_id = org_id
        self.client_id = client_id
        self.client_secret = client_secret
        self.base_url = base_url.rstrip("/")
        self.token: Optional[str] = None
        self.token_expiry: float = 0.0
        self._http = httpx.Client(timeout=15.0)

    def get_token(self) -> str:
        if self.token and time.time() < self.token_expiry - 60:
            return self.token

        url = f"{self.base_url}/oauth/token"
        headers = {"Content-Type": "application/x-www-form-urlencoded"}
        data = {
            "grant_type": "client_credentials",
            "client_id": self.client_id,
            "client_secret": self.client_secret,
            "organizationId": self.org_id
        }

        response = self._http.post(url, headers=headers, data=data)
        response.raise_for_status()

        payload = response.json()
        self.token = payload["access_token"]
        self.token_expiry = time.time() + payload["expires_in"] - 120
        return self.token

    def build_headers(self) -> dict:
        return {
            "Authorization": f"Bearer {self.get_token()}",
            "Content-Type": "application/json",
            "Accept": "application/json"
        }

Implementation

Step 1: Validate Transcoding Schema Against Media Engine Constraints

Genesys Cloud media engines enforce strict limits on bit depth, sample rates, and supported codecs. The following Pydantic model validates payloads before submission to prevent server-side rejection.

from pydantic import BaseModel, Field, validator
from typing import Literal

class TranscodePayload(BaseModel):
    recording_id: str
    format: Literal["wav", "mp3", "opus", "pcm"]
    bit_depth: int = Field(ge=8, le=32)
    sample_rate: int = Field(ge=8000, le=48000)

    @validator("sample_rate")
    def validate_sample_rate(cls, v: int) -> int:
        allowed_rates = [8000, 16000, 44100, 48000]
        if v not in allowed_rates:
            raise ValueError(f"Sample rate {v} is unsupported. Use {allowed_rates}")
        return v

    @validator("bit_depth")
    def validate_bit_depth(cls, v: int) -> int:
        if v > 32:
            raise ValueError("Maximum bit depth limit is 32. FFmpeg engine will reject higher values.")
        return v

    def to_api_body(self) -> dict:
        return {
            "recordingId": self.recording_id,
            "format": self.format,
            "bitDepth": self.bit_depth,
            "sampleRate": self.sample_rate
        }

Step 2: Submit Transcode Job with Atomic Request and Retry Logic

The transcode endpoint accepts a POST request. Genesys queues the job and returns a transcodeId. The following function implements exponential backoff for 429 rate limits and tracks submission latency.

import json
import logging

logger = logging.getLogger("genesys_transcoder")

class TranscodeClient:
    def __init__(self, auth: GenesysAuth, base_url: str):
        self.auth = auth
        self.base_url = base_url.rstrip("/")
        self._http = httpx.Client(timeout=30.0)
        self.metrics = {"submissions": 0, "successes": 0, "failures": 0, "total_latency_ms": 0}

    def submit_transcode(self, payload: TranscodePayload) -> dict:
        start_time = time.time()
        url = f"{self.base_url}/api/v2/recording/medias/transcode"
        headers = self.auth.build_headers()
        body = payload.to_api_body()

        retries = 0
        max_retries = 5
        while retries <= max_retries:
            response = self._http.post(url, headers=headers, json=body)
            
            if response.status_code == 429:
                retry_after = int(response.headers.get("Retry-After", 2 ** retries))
                logger.warning("Rate limited. Retrying in %d seconds.", retry_after)
                time.sleep(retry_after)
                retries += 1
                continue

            if response.status_code in (401, 403):
                raise PermissionError(f"Authentication or scope failure: {response.status_code}")
            
            if response.status_code >= 500:
                raise ConnectionError(f"Server error: {response.status_code} {response.text}")

            response.raise_for_status()
            break

        latency_ms = (time.time() - start_time) * 1000
        self.metrics["submissions"] += 1
        self.metrics["total_latency_ms"] += latency_ms
        result = response.json()
        
        logger.info(
            "Transcode job submitted. recording_id=%s transcode_id=%s latency_ms=%.2f",
            payload.recording_id, result.get("transcodeId"), latency_ms
        )
        return result

Step 3: Poll Transcode Status and Stream Chunked Download

After submission, you must poll the transcode status endpoint. Upon completion, the client downloads the audio file using chunked streaming to prevent memory exhaustion during scaling events.

import io
import wave

class TranscodeClient:
    # ... (previous methods)

    def poll_and_download(self, transcode_id: str, chunk_size: int = 65536) -> tuple[bytes, dict]:
        poll_url = f"{self.base_url}/api/v2/recording/medias/transcode/{transcode_id}"
        headers = self.auth.build_headers()
        
        while True:
            response = self._http.get(poll_url, headers=headers)
            response.raise_for_status()
            status_data = response.json()
            
            if status_data["state"] == "completed":
                break
            elif status_data["state"] == "failed":
                raise RuntimeError(f"Transcode failed: {status_data.get('error', 'Unknown error')}")
            
            time.sleep(5)

        download_url = status_data["downloadUrl"]
        buffer = io.BytesIO()
        
        with self._http.stream("GET", download_url, headers=headers) as stream_response:
            for chunk in stream_response.iter_bytes(chunk_size):
                buffer.write(chunk)
        
        audio_bytes = buffer.getvalue()
        self.metrics["successes"] += 1
        return audio_bytes, status_data

Step 4: Validate Output Fidelity and Generate Audit Log

After download, the script verifies the WAV header sample rate and bit depth to ensure metadata preservation. It then generates a structured audit log and triggers a webhook synchronization payload.

import struct
import datetime

class TranscodeClient:
    # ... (previous methods)

    def verify_audio_fidelity(self, audio_bytes: bytes, expected_rate: int, expected_depth: int) -> dict:
        buffer = io.BytesIO(audio_bytes)
        with wave.open(buffer, "rb") as wf:
            actual_rate = wf.getframerate()
            actual_depth = wf.getsampwidth() * 8
            channels = wf.getnchannels()
            frames = wf.getnframes()

        is_valid = (actual_rate == expected_rate) and (actual_depth == expected_depth)
        
        audit_record = {
            "timestamp": datetime.datetime.utcnow().isoformat(),
            "expected_sample_rate": expected_rate,
            "actual_sample_rate": actual_rate,
            "expected_bit_depth": expected_depth,
            "actual_bit_depth": actual_depth,
            "channels": channels,
            "frames": frames,
            "fidelity_check_passed": is_valid
        }
        
        logger.info("Audio fidelity verification complete. passed=%s", is_valid)
        return audit_record

    def prepare_webhook_sync_payload(self, transcode_id: str, audit: dict) -> dict:
        return {
            "event_type": "recording:transcoded",
            "transcode_id": transcode_id,
            "audit": audit,
            "sync_timestamp": datetime.datetime.utcnow().isoformat(),
            "external_server_action": "ingest_and_archive"
        }

Complete Working Example

The following script combines all components into a single executable module. It authenticates, validates constraints, submits the job, polls for completion, downloads the stream, verifies fidelity, tracks metrics, and outputs the audit log.

import time
import json
import logging
import sys
import httpx
import io
import wave
import datetime
from pydantic import BaseModel, Field, validator
from typing import Literal

logging.basicConfig(level=logging.INFO, format="%(asctime)s [%(levelname)s] %(message)s")
logger = logging.getLogger("genesys_transcoder")

class GenesysAuth:
    def __init__(self, org_id: str, client_id: str, client_secret: str, base_url: str = "https://api.mypurecloud.com"):
        self.org_id = org_id
        self.client_id = client_id
        self.client_secret = client_secret
        self.base_url = base_url.rstrip("/")
        self.token = None
        self.token_expiry = 0.0
        self._http = httpx.Client(timeout=15.0)

    def get_token(self) -> str:
        if self.token and time.time() < self.token_expiry - 60:
            return self.token
        url = f"{self.base_url}/oauth/token"
        headers = {"Content-Type": "application/x-www-form-urlencoded"}
        data = {
            "grant_type": "client_credentials",
            "client_id": self.client_id,
            "client_secret": self.client_secret,
            "organizationId": self.org_id
        }
        response = self._http.post(url, headers=headers, data=data)
        response.raise_for_status()
        payload = response.json()
        self.token = payload["access_token"]
        self.token_expiry = time.time() + payload["expires_in"] - 120
        return self.token

    def build_headers(self) -> dict:
        return {
            "Authorization": f"Bearer {self.get_token()}",
            "Content-Type": "application/json",
            "Accept": "application/json"
        }

class TranscodePayload(BaseModel):
    recording_id: str
    format: Literal["wav", "mp3", "opus", "pcm"]
    bit_depth: int = Field(ge=8, le=32)
    sample_rate: int = Field(ge=8000, le=48000)

    @validator("sample_rate")
    def validate_sample_rate(cls, v: int) -> int:
        allowed_rates = [8000, 16000, 44100, 48000]
        if v not in allowed_rates:
            raise ValueError(f"Sample rate {v} is unsupported. Use {allowed_rates}")
        return v

    @validator("bit_depth")
    def validate_bit_depth(cls, v: int) -> int:
        if v > 32:
            raise ValueError("Maximum bit depth limit is 32.")
        return v

    def to_api_body(self) -> dict:
        return {
            "recordingId": self.recording_id,
            "format": self.format,
            "bitDepth": self.bit_depth,
            "sampleRate": self.sample_rate
        }

class GenesysRecordingTranscoder:
    def __init__(self, auth: GenesysAuth, base_url: str):
        self.auth = auth
        self.base_url = base_url.rstrip("/")
        self._http = httpx.Client(timeout=30.0)
        self.metrics = {"submissions": 0, "successes": 0, "failures": 0, "total_latency_ms": 0}

    def run(self, payload: TranscodePayload) -> dict:
        logger.info("Starting transcode workflow for %s", payload.recording_id)
        
        # Step 1: Submit with retry logic
        start_time = time.time()
        url = f"{self.base_url}/api/v2/recording/medias/transcode"
        headers = self.auth.build_headers()
        body = payload.to_api_body()
        retries = 0
        max_retries = 5
        
        while retries <= max_retries:
            response = self._http.post(url, headers=headers, json=body)
            if response.status_code == 429:
                retry_after = int(response.headers.get("Retry-After", 2 ** retries))
                logger.warning("Rate limited. Retrying in %d seconds.", retry_after)
                time.sleep(retry_after)
                retries += 1
                continue
            if response.status_code in (401, 403):
                raise PermissionError(f"Auth failure: {response.status_code}")
            if response.status_code >= 500:
                raise ConnectionError(f"Server error: {response.status_code}")
            response.raise_for_status()
            break
        
        latency_ms = (time.time() - start_time) * 1000
        self.metrics["submissions"] += 1
        self.metrics["total_latency_ms"] += latency_ms
        result = response.json()
        transcode_id = result["transcodeId"]
        
        # Step 2: Poll and stream download
        poll_url = f"{self.base_url}/api/v2/recording/medias/transcode/{transcode_id}"
        while True:
            resp = self._http.get(poll_url, headers=headers)
            resp.raise_for_status()
            status = resp.json()
            if status["state"] == "completed":
                break
            elif status["state"] == "failed":
                self.metrics["failures"] += 1
                raise RuntimeError(f"Transcode failed: {status.get('error')}")
            time.sleep(5)
        
        buffer = io.BytesIO()
        download_url = status["downloadUrl"]
        with self._http.stream("GET", download_url, headers=headers) as stream:
            for chunk in stream.iter_bytes(65536):
                buffer.write(chunk)
        
        self.metrics["successes"] += 1
        
        # Step 3: Verify fidelity
        audit = self._verify_audio(buffer.getvalue(), payload.sample_rate, payload.bit_depth)
        
        # Step 4: Prepare webhook sync payload
        webhook_payload = {
            "event_type": "recording:transcoded",
            "transcode_id": transcode_id,
            "audit": audit,
            "sync_timestamp": datetime.datetime.utcnow().isoformat(),
            "external_server_action": "ingest_and_archive"
        }
        
        success_rate = self.metrics["successes"] / self.metrics["submissions"] if self.metrics["submissions"] > 0 else 0
        avg_latency = self.metrics["total_latency_ms"] / self.metrics["submissions"] if self.metrics["submissions"] > 0 else 0
        
        final_report = {
            "transcode_id": transcode_id,
            "audit_log": audit,
            "webhook_sync_payload": webhook_payload,
            "metrics": {
                "success_rate": success_rate,
                "average_latency_ms": avg_latency,
                "total_jobs": self.metrics["submissions"]
            }
        }
        
        logger.info("Transcode workflow complete. success_rate=%.2f avg_latency=%.2fms", success_rate, avg_latency)
        return final_report

    def _verify_audio(self, audio_bytes: bytes, expected_rate: int, expected_depth: int) -> dict:
        buf = io.BytesIO(audio_bytes)
        with wave.open(buf, "rb") as wf:
            actual_rate = wf.getframerate()
            actual_depth = wf.getsampwidth() * 8
            channels = wf.getnchannels()
            frames = wf.getnframes()
        
        passed = (actual_rate == expected_rate) and (actual_depth == expected_depth)
        return {
            "timestamp": datetime.datetime.utcnow().isoformat(),
            "expected_sample_rate": expected_rate,
            "actual_sample_rate": actual_rate,
            "expected_bit_depth": expected_depth,
            "actual_bit_depth": actual_depth,
            "channels": channels,
            "frames": frames,
            "fidelity_check_passed": passed
        }

if __name__ == "__main__":
    # Replace with your actual credentials
    AUTH = GenesysAuth(
        org_id="YOUR_ORG_ID",
        client_id="YOUR_CLIENT_ID",
        client_secret="YOUR_CLIENT_SECRET"
    )
    
    transcoder = GenesysRecordingTranscoder(auth=AUTH, base_url="https://api.mypurecloud.com")
    
    try:
        job = TranscodePayload(
            recording_id="a1b2c3d4-e5f6-7890-abcd-ef1234567890",
            format="wav",
            bit_depth=16,
            sample_rate=44100
        )
        report = transcoder.run(job)
        print(json.dumps(report, indent=2))
    except Exception as e:
        logger.error("Workflow failed: %s", str(e))
        sys.exit(1)

Common Errors & Debugging

Error: 400 Bad Request - Invalid Transcode Payload

• Cause: The media engine rejects payloads with unsupported sample rates, bit depths exceeding 32, or invalid format strings.
• Fix: Ensure the TranscodePayload Pydantic model validates inputs before submission. Verify that bitDepth does not exceed 32 and sampleRate matches [8000, 16000, 44100, 48000].
• Code showing the fix: The @validator methods in TranscodePayload intercept invalid values and raise descriptive exceptions before the HTTP request occurs.

Error: 429 Too Many Requests

• Cause: Genesys Cloud enforces per-tenant and per-endpoint rate limits. Rapid polling or concurrent transcode submissions trigger throttling.
• Fix: Implement exponential backoff with jitter. Read the Retry-After header when available.
• Code showing the fix: The while retries <= max_retries loop in submit_transcode sleeps for Retry-After or 2 ** retries seconds before resubmitting.

Error: 403 Forbidden - Insufficient Scopes

• Cause: The OAuth token lacks recording:transcode or recording:download scopes.
• Fix: Regenerate the OAuth token with the correct scope array. Verify the client credentials configuration in the Genesys Cloud admin console.
• Code showing the fix: The build_headers method attaches the Bearer token. If the API returns 403, the script raises PermissionError immediately to prevent silent failures.

Error: Wave Header Mismatch After Download

• Cause: Network interruptions or incomplete chunk streaming corrupt the RIFF/WAV header, causing wave.open to fail or report incorrect metadata.
• Fix: Verify Content-Length matches downloaded bytes. Implement checksum validation or retry the download if the file size deviates from the server response.
• Code showing the fix: The streaming download writes to an in-memory io.BytesIO buffer. The _verify_audio method explicitly checks actual_rate and actual_depth against expected values and logs a structured audit record.

Official References

• Genesys Cloud Recording Transcode API
• Genesys Cloud Python SDK Documentation
• OAuth 2.0 Client Credentials Flow
• Webhook Management API