Growing files and LOADBG / AUTO

[martastain]

In older versions, it was possible to use LOADBG AUTO with growing files (for example during ingest or transfer to the playout storage). Since ~7.3 it is no longer possible.

You can simulate growing MXF file using following command:

ffmpeg -y -re -f lavfi -i "testsrc=duration=60:size=1920x1080" -pix_fmt yuv422p -c:v dnxhd -b:v 36M -an media.dir/growing.mxf

and then execute the following AMCP commands:

PLAY 1-1 growing
LOADBG 1-1 #cccccc AUTO

With 7.0a, the growing file plays to the end (although started during its creation) and then the server correctly switches to the color producer. In later versions (tested 7.3a - I do not have any builds in between), Caspar switches to the color producer right after LOADBG command is executed.

I believe it has again something to do with duration reporting - 7.0a does not give you duration information of the growing file's duration until it's finished (which is expected).