I'm guessing it does have a picture, but something is funny about the decoders you're using to play the recordings, that sometimes results in no picture.
That is particularly true if you're using the TS Mux multiplexer. ie, if you have sound, then it'll definitely also have video in the recording.
So is there a suggestion of how to get the picture? I think I am using TS multiplexer (whatever that is). I get no picture in GBPVR nor with Media Player classic.