When the battery dies during recording XAVC-S video on the Sony A7S the camera does not have time to write the associated XML file that is needed to access that file.The video is saved as a corrupt file. The video is there but it cant be read without its XML twin.
Does anyone have a way of recovering these video files and making them readable ?
There is one online company I have found that will recover these "corrupt" files but it costs a lot.
As this must be a common problem surely there is a piece of software I can get that is cheap or free.
 

Look inside the XML file (with a text editor) of a good recording, and see if you can modify it to work with your corrupted files. That is all a cheap or free software would do ... I guess.

Ok so following replies I took a look at the video files and the XML files with a text editor and compared the playable video files to the "corrupt" one. **(First of all dont use text editor on a mac - these files are too big for it - I used Hex Fiend)**

Technically the XML file that the A7S lays down at the end of recording is just a copy of the instructions that the camera writes at the end of the video file to make it playable. All my good video files had their XML file text in their file content at the end. The XML files seem to be just confirmation that the instructions have been written in the video file.

My "corrupt" file has all the video content intact but because the battery died suddenly during recording the access instructions were not written at the end of the video file and hence no XML file showing these instructions.

I tried copy and pasting the instructions from a good video file to the one that wouldn't play but unfortunately this didn't work.