First of all check your videos for missing audio at 3:09
In most files I can find the video cuts out at 3:09 when he turns the camera on himself and says "Hello lads".
Now to get into the issue: There are at least 4 different videos that are being passed around as the original. From discussions it is clear that many people who claim to have downloaded the file directly from facebook have files of different sizes, often to their own confusion.
This thread is dedicated to tracking down the best one.
Whether this whole things means there was an error in the file on kikebook's servers for a while, if one download glitched and then this specific file got shared a lot or if it's and issue of some kind of re-encode I don't know. Three of the files seem to have the same video track but different audio tracks so it is really confusing.
The files I am aware of are two with complete sound and two with the gap.
The first is the one I believe is the original video
68.3 MiB
Video: 648x360p VFR (30) , 8 bit Y'UV 4:2:0, AVC L3.0 493 kbps
Audio: 48 kHz / 24 kHz stereo, HE-AAC / LC64 kbps CBR
SHA256: BFF3449B9A48714FED41BEF26F2B4F07DCEB1C85FE3910098F0B432F680C5142
The second is larger but I believe it is a re-encode. Even though it is larger it appears to have less detail.
90.7 MiB
Video: 864x480p30, 8 bit Y'UV 4:2:0, AVC L3.1 645 kbps
Audio: 48 kHz stereo, AAC / LC 96 kbps CBR
The two with bad sound seem to have video streams identical with that of the original so only the audio track is bad.
66.7 MiB: 48 kHz stereo, AAC LC 48 kbps CBR
64.8 MiB: 48 kHz stereo, AAC LC 32 kbps CBR
If anyone has any other varint claimed to be directly saved from kikebook I would love to take a look at it.
Links for the one I believe is the original. I have one link in reserve so holler if the kike takes these down.
dbr.ee
anonfile.com
Also note that in all videos the recording is mono (identical data on both tracks) so if you are making a webm with stereo tracks you are just wasting space unless you've added your own music or something.
As for sampling you need something above 32 kHz for every sound to come through, but that's basically only when he hits the camera (unpleasant anyway) or fires a gun (where it will be masked). If you need to squeeze the size I would go for 22,050 Hz as there is basically nothing above 10.5 kHz. For those who don't know you need a sampling frequency at least twice the frequency of the sounds you want to preserve. For practical purposes a bit higher. Make sure your software runs a low pass filter as the track is downsampled. Otherwise you should to do that manually before you downsample.