

Justin.tv brings live broadcasting to Linux - kvogt
http://apiwiki.justin.tv/mediawiki/index.php/Linux_Broadcasting_API

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DarkShikari
And this time they're using x264; it seems like they value their bandwidth!

One thing that should be better-documented are Justin.TV-side bitrate
restrictions; I assume that they don't want users broadcasting 1-2 megabit
DVD-quality streams over their network, but nothing of the sort is listed in
the guide.

Additionally, there's the matter of constant bitrate requirements: H.264
streaming works under a leaky buffer model based on two parameters, the rate
and buffer size. For optimal performance Justin.TV should document what buffer
size they set on the viewers' Flash players so that the encoder settings can
be set accordingly. For example, let's say that Justin.TV uses a 2 second
buffer:

I pick a constant bitrate of 500kbps. (bitrate=500)

I set the maxrate to 500. (vbv-maxrate=500)

I set the bufsize to 500x2 = 1000. (vbv-bufsize=1000)

If the buffer in the encoder is _greater_ than that used by Justin.TV, it's
possible for the stream to drop out for viewers during local bitrate spikes,
so getting it right is important, especially at higher bitrates (at 300kbps
you probably don't have to care much).

Another issue to note is latency. Total latency in a connection is as follows:

(Encoder-side latency) + (Network latency) + (Decoder buffer size)

x264's default encoder-side latency is about 40 frames in the latest version;
if anyone's interested in how to lower that for a low-latency stream, I can
give more information.

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kvogt
Actually we don't have any bitrate limitations. I've seen users push 8mb
streams before, but most people chose lower bitrates because very few viewers
have the bandwidth and CPU required to enjoy those streams.

You make a very good point about VBR, thanks for bringing that up!

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ROFISH
Does Justin.tv have a non-Flash way of viewing streams? While creating one
without Flash is awesome, it's still annoying to have Adobe's horrible Flash
implementation crash (and or bloat) watching two-three hour streams.

------
zepolen
Does justin.tv pay for their bandwidth from revenue generated or from funding?

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tumult
Super cool. Can't wait for Mac.

~~~
antonovka
Targeting Linux before Mac OS X seems like a very odd choice.

~~~
kd5bjo
We already had several ways to broadcast from Windows and OS X, but no way to
broadcast from Linux. Given that, it made sense to make this available as soon
as the Linux version was ready, without waiting to work all of the bugs out of
the Mac version.

