More options for file input mode and/or qc mode

I use vrecord file input mode as part of my QC process for files received from batch digitization vendors. Making an issue here as a space to remind myself to investigate adding some added features/functionality here around using vrecord for QC. Some possible thoughts include:
* adding some options to better support integrating vrecord into QC loop scripts, such as:
* Allow specified length to play input file for (e.g. 60 seconds) - potentially could leverage existing variable for setting transfer length
* Allow randomized start time for chunk of file to play from file input (so not all files start playing at beginning)
* Use `drawtext` to display file name and some technical metadata (bit depth, codec etc)