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How are the ads even skippable on YouTube? I have never really had a good answer to that. I mean, why is the ad even a different stream or detectable on the cli

How are the ads even skippable on YouTube? I have never really had a good answer to that. I mean, why is the ad even a different stream or detectable on the client? Shouldn't the ads just be spliced into the videos if you really want to make sure people watch them? Is it because it would be prohibitively expensive to do that kind of live encoding for each viewer?

jack_pp 3y ago
You wouldn't even need live encoding because every YouTube video is normalized and if you have two streams that were encoded with the same parameters you can cut and concatenate without re encoding
meindnoch 3y ago
Because you could just seek over them?
- alkonaut 3y ago
  Yes, but the server knows exactly what frames it has sent you and when. If you don't want to watch the ad frames there's nothing the server can do, but it can make sure to not send you the frame that comes after the ad, until the 10 seconds of the ad has passed since it sent you the last frame before the ad.
  - tux3 3y ago
    That works for pre-roll ads, forcing the client to silence them and wait at best (I believe the Twitch streaming service does this) For mid-stream ads, that doesn't work. You could pre-fetch the ad and surrounding video early, so that you can watch buffered content while the server thinks an ad is playing.
    - alkonaut 3y ago
      The server would need to not allow buffering further than the next ad.
      - ethbr1 3y ago
        Multistream client, continually skipping around, and stitching together buffers?
      - meindnoch 3y ago
        Ok, but now you see, it would be a bit more involved than just splicing together static byte streams that even a dumb CDN can accomplish.
  - meindnoch 3y ago
    So basically you would disallow pre-buffering more than an ad's worth of video? I'm not sure about that...
    - alkonaut 3y ago
      Yes. Or at least not past the next ad. No problem buffering up to the following ad.
vbezhenar 3y ago
Right now (or few months ago, when I tinkered with it) ads are different streams, so to skip them, ublock intercepts and alters API responses, stripping ad info. Why they're not embedded into video stream, that I don't know.

jack_pp 3y ago

You wouldn't even need live encoding because every YouTube video is normalized and if you have two streams that were encoded with the same parameters you can cut and concatenate without re encoding

meindnoch 3y ago

Because you could just seek over them?

alkonaut 3y ago
Yes, but the server knows exactly what frames it has sent you and when. If you don't want to watch the ad frames there's nothing the server can do, but it can make sure to not send you the frame that comes after the ad, until the 10 seconds of the ad has passed since it sent you the last frame before the ad.
- tux3 3y ago
  That works for pre-roll ads, forcing the client to silence them and wait at best (I believe the Twitch streaming service does this) For mid-stream ads, that doesn't work. You could pre-fetch the ad and surrounding video early, so that you can watch buffered content while the server thinks an ad is playing.
  - alkonaut 3y ago
    The server would need to not allow buffering further than the next ad.
    - ethbr1 3y ago
      Multistream client, continually skipping around, and stitching together buffers?
    - meindnoch 3y ago
      Ok, but now you see, it would be a bit more involved than just splicing together static byte streams that even a dumb CDN can accomplish.
- meindnoch 3y ago
  So basically you would disallow pre-buffering more than an ad's worth of video? I'm not sure about that...
  - alkonaut 3y ago
    Yes. Or at least not past the next ad. No problem buffering up to the following ad.

vbezhenar 3y ago

Right now (or few months ago, when I tinkered with it) ads are different streams, so to skip them, ublock intercepts and alters API responses, stripping ad info. Why they're not embedded into video stream, that I don't know.