Error on programmatically Start call Recording with own blob storage

Question

Error on programmatically Start call Recording with own blob storage

Agarwal, Ansh 50

Hi, I was using following piece of azure code to start recording with my own blob storage, but it is not able to start the recording

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same when i try removing this last param recording_storage it is working fine. so what is the issue, and for <container_url> i am passing it by generating it from azure portal from container from shared access token, and by drilling down the below error is returned

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kindly assist quickly, i am in middle of Prod Issue. thanks

Bhargavi Naragani 5,270 Reputation points Microsoft External Staff Moderator

2025-06-20T14:51:00.92+00:00
Hi @Agarwal, Ansh,

It seems like the problem stems from the way the container_url is being supplied. Azure Communication Services does not accept SAS tokens or any query parameters in the blob container URL. It expects a clean URL in the form:

https://<storage_account>.blob.core.windows.net/<container_name>

Instead of using a SAS token, please make sure to assign the appropriate Storage Blob Data Contributor role to your Azure Communication Services resource via RBAC. This will securely grant access without the need for SAS.

https://learn.microsoft.com/en-us/azure/storage/blobs/assign-azure-role-data-access?tabs=portal
https://learn.microsoft.com/en-us/python/api/azure-communication-callautomation/azure.communication.callautomation.callautomationclient?view=azure-python#start-recording

Hope this helps, if you have any further concerns or queries, please feel free to reach out to us.
Agarwal, Ansh 50 Reputation points

2025-06-23T07:53:17.8133333+00:00

hi @Bhargavi Naragani , when i call the start_recording with the blob container, will on completion the event will return me location of the blob or acs location??

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Bhargavi Naragani 5,270 Reputation points Microsoft External Staff Moderator

2025-06-20T14:51:00.92+00:00

Hi @Agarwal, Ansh,

It seems like the problem stems from the way the container_url is being supplied. Azure Communication Services does not accept SAS tokens or any query parameters in the blob container URL. It expects a clean URL in the form:

https://<storage_account>.blob.core.windows.net/<container_name>

Instead of using a SAS token, please make sure to assign the appropriate Storage Blob Data Contributor role to your Azure Communication Services resource via RBAC. This will securely grant access without the need for SAS.

https://learn.microsoft.com/en-us/azure/storage/blobs/assign-azure-role-data-access?tabs=portal
https://learn.microsoft.com/en-us/python/api/azure-communication-callautomation/azure.communication.callautomation.callautomationclient?view=azure-python#start-recording

Hope this helps, if you have any further concerns or queries, please feel free to reach out to us.
Agarwal, Ansh 50 Reputation points

2025-06-23T07:53:17.8133333+00:00

hi @Bhargavi Naragani , when i call the start_recording with the blob container, will on completion the event will return me location of the blob or acs location??

Answer 1

Bhargavi Naragani 5,270 Microsoft External Staff Moderator

Hi @Agarwal, Ansh,

Even when using your own Blob container (BYOS), ACS still emits a RecordingFileStatusUpdated event containing ACS-hosted download URLs:

contentLocation
metadataLocation
deleteLocation

These are temporary ACS URLs (valid for about 24 hours) meant for convenience and API consistency. Meanwhile, the recording file itself has already persisted in your Blob storage container.

So, you have two options after recording finishes:

Download directly from your Blob container anytime.
Use the temporary ACS URLs to download or delete the file within the time window.

You can verify this behavior in the Microsoft docs:
Call Recording Event Schema with contentLocation & metadataLocation https://learn.microsoft.com/en-us/azure/communication-services/concepts/voice-video-calling/call-recording#event-grid-notifications
Bring Your Own Storage Overview (noting ACS keeps files 24 hrs)
https://learn.microsoft.com/en-us/azure/communication-services/quickstarts/call-automation/call-recording/bring-your-own-storage?pivots=programming-language-java

If the answer is helpful, please click Accept Answer and kindly upvote it so that other people who faces similar issue may get benefitted from it.

Let me know if you have any further Queries.

Agarwal, Ansh 50 Reputation points

2025-06-23T08:58:26.15+00:00

hi @Bhargavi Naragani , got it. and here content location and metadata location is in recording chunk so i have two queries.

first, does it multiple recording chunks??, if yes, then when it will multiple chunks?? and if there are multiple, then if i use below code provided in documentation to download recording, will it download complete recording on a specific chunk ?

response = recording_data = call_automation_client.download_recording(content_location) with open("<file_name>", "wb") as binary_file: binary_file.write(recording_data.read())
Bhargavi Naragani 5,270 Reputation points Microsoft External Staff Moderator

2025-06-23T09:22:56.81+00:00
Hi @Agarwal, Ansh,

Yes, recording may be split into multiple chunks when it's large or long.

Each webhook includes a recordingChunks array, with separate download URLs for each chunk (contentLocation).

Your current code downloads just one chunk. To retrieve the full recording:

Loop through recordingChunks,

Download each chunk by URL,

Concatenate them in order.

https://learn.microsoft.com/azure/event-grid/communication-services-voice-video-events#microsoftcommunicationrecordingfilestatusupdated

If this answer was helpful and pointed you in the right direction, please consider clicking "Accept Answer"—it may benefit other community members reading this thread. If you have any further questions, feel free to let us know.
Agarwal, Ansh 50 Reputation points

2025-06-23T10:24:07.9366667+00:00

hi @Bhargavi Naragani, just wanted to know what duration is max to have one recording chunk
Bhargavi Naragani 5,270 Reputation points Microsoft External Staff Moderator

2025-06-23T13:49:47.01+00:00

Hi @Agarwal, Ansh,

Each recording chunk can last up to a maximum of 4 hours. Once this duration or ACS’s internal size limit is reached, ACS automatically finalizes the chunk and starts a new one, so if your call goes beyond 4 hours, you'll see multiple chunks, each up to 4 hours long.
Bhargavi Naragani 5,270 Reputation points Microsoft External Staff Moderator

2025-06-24T08:06:33.6966667+00:00

Hi @Agarwal, Ansh,

If this answer was helpful and pointed you in the right direction, please consider clicking "Accept Answer"—it may benefit other community members reading this thread. If you have any further questions, feel free to let us know.

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Error on programmatically Start call Recording with own blob storage

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