Some tips on downloading and uploading DCPs and large files

Downloading and uploading tips

-Turn off automatic updates temporarily if you are uploading or downloading overnight.
-Use a fast internet connection. (50/50 mbit/s can upload and download 100 GB overnight).
-I recommend using a verification method like MD5 hash checksums to make sure files are not corrupted.

Different services I use to send and receive large files (100 GB-1000 GB)

For DCPs and Prores files I use Filemail, SFTP, Amazon S3, Signiant, and IBM Aspera

IBM Aspera Cloud and Signiant

IBM Aspera Cloud and Signiant are used on many large Prores or DCP transfers because they are fast and reliable.  They are used by many film festivals, sales agents, and post-production services. They are fast and reliable because they use a special software client. They are both more expensive than filemail


Filemail costs 18 USD per month for a Filemail multi user Business account with 1000 GB. More storage can be added. I often get good upload and download speed with the Filemail desktop app which supports resume and uses UDP acceleration. If the files are sent to my registered email the sender can send large files. 

Amazon S3

Amazon S3 can be used to deliver and receive big files on the internet. S3 storage is very reliable and scalable.

Price and Storage
You pay for each GB of data transfer and storage so it can be more expensive than Filemail when uploading and downloading large files (100 GB). But you only pay when you are using the service and you can store unlimited data.

Amazon S3 storage is very fast.

Ease of use
You can use the s3 web uploader. After uploading you can make the link accessible (public) and give the clients the S3 download link.

I normally make a user in the IAM Management with a policy to access a bucket. The bucket, access, and secret key can be used in Cyberduck and similar programs like an FTP server that can only access a folder.

Example Policy:

    "Version": "2012-10-17",
    "Statement": [
            "Effect": "Allow",
            "Action": [
            "Resource": "arn:aws:s3:::yourbucket231*"
            "Effect": "Allow",
            "Action": [
            "Resource": "arn:aws:s3:::yourbucket231*"

In Cyberduck, you need to choose the amazon s3
and your access key and secret key
more options
Path: yourbucket231

Dedicated root Server

I have a dedicated Ubuntu root server running SFTPGO with SFTP enabled. Having a dedicated 1000 Mbit server that you can remote control via SSH is great because you have complete control. You can download directly to the server via SFTP/FTP, and compress and uncompress files.

A dedicated server with unlimited data running SFTP/webDAV at Hetzner can be set up on the cheapest action servers that cost around 30 euros a month. 

Hetzner auction servers can have 30 TB of storage and more. In this post, I install Ubuntu on a server with 14 TB of storage.

Max speed for all transfers is 1000 Mbit. The speed for each SFTP will vary with location.

Ease of Use
Using Cyberduck to upload and download from the SFTP server is easy.
You choose SFTP, or WebDAV, and write in the name of the server and port, user name, and password.

Compression Tools

7z or RAR archive utilities 

-If you want to send an uncompressed QuickTime file, TIFF or DPX image sequences, or wav files I recommend using RAR or 7z with normal compression. An uncompressed QuickTime file and wav file will be reduced to half the size after RAR or 7z compression. Archives can be split into parts, encrypted, and have a built-in hash-check. But it can be time-consuming to make a compressed archive.
-I recommend Keka on Mac and WinRAR on Windows to make 7z or RAR archives.

Verification tools

MD5 checksum

You can enable MD5 on Filemail download pages.

Filemail md5 checksum

To check the MD5 hash you can use “md5sum” in a terminal in Linux or in Ubuntu on Windows.

You can use use the command md5 “file” in a terminal on a Mac.

You can use the command certutil -hashfile "file" md5 on a Windows 7, 8, 10, and 11 computer in a command prompt (CMD)

DCP and QuickTime-specific advice

-DCPs have the checksums for the files of the DCP in the XML files that can be verified with the trial version of EasyDCP Player

-Drag the DCP to Easydcp player

-Choose Asset – Hash Checker
-In Hash Checker
-Choose start

This image has an empty alt attribute; its file name is hash-checker-1024x757.png

-When sending a DCP to cinemas in Norway I use my account at the DCP transfer service Movie Transit. The DCP is normally uploaded some weeks before the screening. 

-When downloading a DCP folder in Filezilla from an FTP server it is important to change Transfer – transfer type – binary. It should not be ASCII or auto, this way the XML files will pass the checksum test on servers.

I have a DCP quality checklist when checking downloaded DCPs:
-Does it pass the hash check?
-Is the DCP named correctly?
-Is it in the correct scope or flat format? The DCP should have a correct digital naming convention name. Example: The DCP is called Dcpname_SHR_S but is actually Dcpname_SHR_F because the resolution is wrong and the subtitles are burned in too low and will be cropped at a scope preset in your cinema.
-Is the subtitles burned in too low?
-Is the DCP in the correct language/subtitle language?
-Is the sound OK?

Other tips

-If you get an error message extracting a zip file in Keka that says error code 2 using p7zip, you probably need to extract the zip file with mac os archive utility.

3 thoughts on “Some tips on downloading and uploading DCPs and large files”

  1. Hi Knut.
    Great work! Just the info I needed to solve my problems transporting DCP files over the net.
    Thank you.
    Best Regards Ulrik Lyhne, Aarhus Film Workshop

  2. Hi Knut, thanks for the tips.
    Quick question.. Do you know if there is a site out there with limits as high as say,, which allow you to upload via an FTP program like filezilla?
    Alternatively, a site which has a desktop uploader which you can use with a free account?
    – I seem to have trouble sending larger files over my internet connection using a web-browser; it often fails and I have to start again.

  3. Knut Erik Evensen

    An alternative is Amazon S3. You can use CrossFtp and similar programs to upload to S3. And the link you give clients will be very reliable.

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