When you export a clip as a file sequence (using the Video Options), or when you export it as part of a Sequence Publish where the media is exported as a file sequence, you can use the Link Media options to accelerate the export and minimize used storage space.
Because unedited frames are not recreated but only referenced in the exported sequence, the export takes less time to complete, and saves storage space by avoiding media duplication. The mechanism used to create links is described at How Media Linking Works.
Link Media Export Options
Simple Link Media (Bit Depth) example:
The last 40 files are referenced, and because they were neither created nor moved, the export process was that much faster.
Because media linking uses tools enabled by the operating system (see below), the following conditions must also be met.
Additional requirements for successful media linking:
If the source media is not available, Flame can link to the media cache instead, but on the following conditions:
For the link media mechanism, Flame uses the hard link mechanism found in POSIX-compliant operating systems such as the Linux and the macOS X operating systems.
To understand the hard link, you must first understand how a file is stored on a volume. On a file system, for reasons of efficiency, data and the organization of files on a volume are managed separately.
Consider a .dpx file named original.dpx. When the operating system ask the file system to write this file to disk, the following happens:
For the user a file is the data. But for the file system, file and data are two separate entities. It is the operating system that creates the illusion for the user. But this illusion is quite useful: moving a file between folders changes the path in the file's metadata, without actually moving the data. The file hierarchy displayed by the file system (folders and files) bears little resemblance with how the data is stored on the volume: moving a file around does not change its inode, or address.
Going further, one can create a new file, called linked_file.dpx. This file has its own file name, creation date, file path. But it is assigned the same inode as original.dpx: both files point to the same content. But no actual data is duplicated. The operating system presents both files separately. This is what's called creating hard links.
-rw -rw -rw 1 user users 8.0M Jan 5 09:47 solo_file.dpx -rw -rw -rw 2 user users 8.0M Jan 5 09:49 linked_file.dpx
And that is what happens with the Media Linking. By assigning existing inodes to new files for those frames that have not changed, Flame avoids data duplication. And saves time, since creating a new file is much faster than writing a whole media frame.
Notes about hard links:
For example, you wish to publish DPX content that was modified in Flame. But changes to the files' metadata such as timecode and tape name are not reflected in the hard link media.
Also, managed media created in Flame (renders, caching, etc.) do not contain any timecode nor tape name when created as DPX or OpenEXR. Creating Hard Links to be used in third party applications might need to be used with file name information for timecode since the files will not contain the original media attributes.
Hard links used by Link Media require that the original media file and the hard link are both created on the same volume. This limitation is inherited from the file system: inodes (essential to media link) cannot be shared between file systems. In cases where you absolutely need to create links across file systems, you can use soft links. On macOS, a soft-link is also known as an alias.
A soft link is an indirect link to a file: if file linked_file.dpx is soft linked to file original.dpx, file linked_file.dpx essentially stores the path to file original.dpx. It does not duplicate any inode information! This means that:
In the end, you only want to use soft links because your workflow requires using multiple volumes. And as long as you are aware of the limitations, this workflow can work.
Soft links are disabled by default.
To enable soft links:
/opt/Autodesk/sw/cfg/sw_restart