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Plus my understanding is that most streaming video works with a playlist of video segments, each video segment is independent and self contained, so not sure ho

by cm2187 2y ago

Plus my understanding is that most streaming video works with a playlist of video segments, each video segment is independent and self contained, so not sure how an adblocker could tell an ad segment from a content segment, ie you wouldn’t need to reencode anything, just serve different segments dynamically.

iforgotpassword 2y ago
Yep, the video is split up in many tiny chunks, for example so the client can seamlessly change quality during playback in "auto"-mode. So they'd just have to find a good spot between those chunks and start injecting different chunks (i.e. the ad) there before continuing with the actual video. This doesn't require any re-encode or other shenanigans on the server side.
rented_mule 2y ago
If it's done that way, then something like SponsorBlock could upload a hash for every segment that is played by everyone with the extension. After a few hundred views, personalization will make clear which segments are the ads (because they are targeted, each ad segment will appear in far less of the segment playlists). Modify the segment playlist on the fly to only include the segments sent to everyone. If SponsorBlock is still used by YouTube Premium users (to avoid content creator ads), this is even easier, as those users will have the "golden" set of segments.
- joegibbs 2y ago
  But then couldn’t YouTube modify each ad segment very slightly - by a few bytes - so that the hash is different every time?
  - cm2187 2y ago
    I imagine that wouldn’t play well with CDNs
  - rented_mule 2y ago
    That would work against them because you exclude the segments served up the least, and those modified versions would only be served up once. That approach could work better for YouTube if you did it to the segments of the actual video rather than the ads. But then you could get into things like audio fingerprinting of the segments - only show fingerprints that were also shown to YouTube Premium members. I'm no expert at this stuff, but people who build blockers will brainstorm every time they have to sit through a YouTube ad.

by cm2187 2y ago

iforgotpassword 2y ago

Yep, the video is split up in many tiny chunks, for example so the client can seamlessly change quality during playback in "auto"-mode. So they'd just have to find a good spot between those chunks and start injecting different chunks (i.e. the ad) there before continuing with the actual video. This doesn't require any re-encode or other shenanigans on the server side.

rented_mule 2y ago

If it's done that way, then something like SponsorBlock could upload a hash for every segment that is played by everyone with the extension. After a few hundred views, personalization will make clear which segments are the ads (because they are targeted, each ad segment will appear in far less of the segment playlists). Modify the segment playlist on the fly to only include the segments sent to everyone. If SponsorBlock is still used by YouTube Premium users (to avoid content creator ads), this is even easier, as those users will have the "golden" set of segments.

joegibbs 2y ago
But then couldn’t YouTube modify each ad segment very slightly - by a few bytes - so that the hash is different every time?
- cm2187 2y ago
  I imagine that wouldn’t play well with CDNs
- rented_mule 2y ago
  That would work against them because you exclude the segments served up the least, and those modified versions would only be served up once. That approach could work better for YouTube if you did it to the segments of the actual video rather than the ads. But then you could get into things like audio fingerprinting of the segments - only show fingerprints that were also shown to YouTube Premium members. I'm no expert at this stuff, but people who build blockers will brainstorm every time they have to sit through a YouTube ad.