I have gotten many calls and emails over the years from users everywhere asking why they are losing metadata on clips while editing or generating lists. I ask; “did you import an ALE and relink?” The answer is always “yes.”
Because of this, my recommendation has always been to merge an ALE into an existing master clip and this will not happen. And yes, productions have gotten away with no issues, but it is far better to have peace of mind than one day run into not having it when you need it. I don’t have a explanation as to why other than it has something to do with MOB’s or whatever. Maybe one of these days I will get an actual explanation but in the meantime, I can show you what actually happens between an ALE relink, and an ALE merge.
The native MXF DNxHD file (OPAtom) was made in DaVinci Resolve. I copied the MXF files to the Avid MediaFiles/MXF folder structure and launched Media Composer. In a bin, I import the ALE and as expected, it does not automatically relink. Highlight the clip(s) and do relink. Make sure to select all drives and uncheck “Relink only to media from current project”. (click for full size image)
The clip comes online and you can play picture and sound and all the columns have the metadata from the from the ALE file. All would seem well and fine.
But if we take a look at the media in the MediaTool for the same clip you will notice that the same MediaFile is missing a lot of the metadata - especially audio related metadata, but AuxiliaryTC as well. The clip metadata is only pointing to the essence and not a part of it. (click for full size image)
The better method is to create a master clip via one of these three methods:
- Import an AAF
- Open the MediaTool and drag the clips to the bin
- Import the msmMMOB.mdb file from the Avid MediaFiles/MXF numbered folder in which the media exists
Once the master clips exist, they can be highlighted and then do a file/import of the ALE file. This process is described in the blog “The Many Uses of ALE.” Once the ALE file has been merged, you can see that the clip in the MediaTool now has this same information on the file itself. It is now part of the MXF file ensuring it sticks with the clip. If this media was moved to another editing system with no bins or ALE, that metadata would still be available to use. (click for full size image)
So while I don’t have an official engineering explanation as to why, I know that I feel much better when I see the clips in the MediaTool and the clips in the bin having the same metadata. So for all those productions transcoding in third party applications and getting media and ALE, create the master clip first and merge. You’ll sleep better for it.