I was recording a game through GeForce Experience when my computer suddenly crashed, the file was saved but I was unable to play it. I used recover_mp4 to save it and it did actually work but some parts of the audio were missing but it's more like it was skipping (about 3 minutes of skipped audio). It's a really large file about 10GB and it did give me two warnings

WARNING: The current max AVC NAL unit (IDR) size 0x3FFFFF.
WARNING: The current max AVC NAL unit (non IDR) size 0xFFFFF.
Try to change it adding parameter --avcidrmax 92566 and/or --avcxmax 7E343
- Thanks in advance