Can you come up with an equation

[Wictorian]

So I always stream videos at 2x playback speed. When I watch a livestream for example if I am 10 mins behind the stream it adds 5 mins when I watch it. Can you come up with an equation when I would reach the stream?

[zeusthemoose]

So you are watching a live stream at 2x speed while it is still going on but watching at an earlier part of the stream and you want to figure out how long to reach the point that is live?Then it would just take the amount of time you are behind by to catch up because every 1 second that passes, 1 second is added the video and 2 seconds are watched.

[Wictorian]

6 minutes ago, zeusthemoose said:

So you are watching a live stream at 2x speed while it is still going on but watching at an earlier part of the stream and you want to figure out how long to reach the point that is live?Then it would just take the amount of time you are behind by to catch up because every 1 second that passes, 1 second is added the video and 2 seconds are watched.

Lol thanks 

[Moonzy]

Sum (1/(speed of watching)^x)

x: 1 -> inf

 

(I think)

 

Sum (1/2^x) ~= 1

x: 1 -> inf

 

Minute you intend to catch up to at the start multiply by that formula would be your answer

 

I'm bad at maths, by the way '-' so it might be very wrong

 

edit: -double checks on PC-

1.25x

Spoiler

 

1.5x

Spoiler

 

1.75x

Spoiler

 

and 2x

Spoiler

 

looks right

 

0.75x (you'll never catch up)

Spoiler

 

 

upon fiddling with it, it seems like

length * ( 1 / (x-1) ) also works

it's more elegant but only works for speed of above 1.0

Spoiler

 

[Wictorian]

1 hour ago, Moonzy said:

Sum (1/(speed of watching)^x)

x: 1 -> inf

 

(I think)

 

Sum (1/2^x) ~= 1

x: 1 -> inf

 

Minute you intend to catch up to at the start multiply by that formula would be your answer

 

I'm bad at maths, by the way '-' so it might be very wrong

 

edit: -double checks on PC-

1.25x

  Reveal hidden contents

 

1.5x

  Reveal hidden contents

 

1.75x

  Reveal hidden contents

 

and 2x

  Reveal hidden contents

 

looks right

 

0.75x (you'll never catch up)

  Reveal hidden contents

 

 

upon fiddling with it, it seems like

length * ( 1 / (x-1) ) also works

it's more elegant but only works for speed of above 1.0

  Reveal hidden contents

 

only problem, you will actually catch up at 0.75 after the stream ends.

[Moonzy]

1 minute ago, Wictorian said:

only problem, you will actually catch up at 0.75 after the stream ends.

i'm assuming infinite length

 

if you do have a fixed length then it's a whole other equation

[Wictorian]

2 minutes ago, Moonzy said:

i'm assuming infinite length

 

if you do have a fixed length then it's a whole other equation

so the equation wouldn't work for fixed lenght?

[Moonzy]

2 minutes ago, Wictorian said:

so the equation wouldn't work for fixed lenght?

depends, if you can catch up before the end, then it's still valid (since it's calculating the time to catch up, not to the end)

 

if the stream ended before u catch up, then no, it's not the right equation

[Wictorian]

Just now, Moonzy said:

 

 

if the stream ended before u catch up, then no, it's not the right equation

then I would calculate time to end

[Moonzy]

Just now, Wictorian said:

then I would calculate time to end

-shrug-

i dont think i can come up with a equation without pen and paper like i did for the earlier one as it's more complicated

and

1 hour ago, Moonzy said:

I'm bad at maths, by the way '-'

this is very true, among my peers anyways

[Dash Lambda]

On 1/23/2021 at 9:24 AM, Sakuriru said:

This could probably be described by a differential equation, probably by someone smarter than me.

@Dash Lambda

Indeed it can! Quite a simple one actually, as there are constant rates of change.

 

The gap between your place on the stream and the stream's current time increases when the stream moves forward and decreases when you move forward, meaning the rate of change is the difference between the stream's speed and your playback speed, which we'll say are 1 and r respectively. Thus, the equation becomes:

 

g' = 1 - r

 

Quite simple! To solve, just integrate for:

 

g = (1 - r)*t + g₀

 

In this context, the constant of integration represents the initial gap. To solve for the time to close the gap with respect to the length of the gap and the playback speed, set g=0 and solve for t:

 

t = g₀/(r - 1)

 

Thus, for a stream where you're 300s (5m) behind with a playback speed of 2, the time to catch up is 300/(2 - 1) = 300s.

 

Sorry I'm late, I need to start checking here more often again!