Can you update the systitle field of a media library item?
Coveo seems to index the title of the actual media data, not the item name, or custom Title field if available. I have a Post Processor set to update the systitle (p_Args.CoveoItem.Title) according to custom fields that are filled out by the user. But the media data's title is still showing as the systitle.
I did not find a valid answer nor a way to do this. My solution was to add my own custom Title field and use that for my listings.
Have you tried to only reindex a media item and trace in your postprocessor to make sure it actually sets the Title?
var myTitle = DocumentInfo.GetFieldValue("CustomTitleMetadata");
CustomTitleMetadata is the metadata associated to your Coveo field, not the actual field name.
Then, you can set the Title property of the document like so:
DocumentInfo.Title = myTitle;
You can put those method and property calls inside an
if that detects if you are currently indexing a media item document.