[vlc-devel] [vlc-commits] commit: stream_filter/httplive.c: HTTP Live Streaming (Jean-Paul Saman )
remi at remlab.net
Thu Oct 14 08:50:57 CEST 2010
On Wed, 13 Oct 2010 23:06:22 +0200, David Glaude <david.glaude at gmail.com>
> Le 13 octobre 2010 11:53, Rémi Denis-Courmont <remi at remlab.net> a écrit
>> On Wed, 13 Oct 2010 09:48:16 +0200, Jean-Paul Saman <jpsaman at gmail.com>
>> >> - What is the protocol to detect bw_up and bw_down? Was that not too
>> >> difficult with VLC arch?
>> > It is fairly simple, measure the download speed per segment and base a
>> > decision on that.
>> > Since the stream_filter initiates the download itself it can also
>> > measure how long that takes and
>> > calculate the average download speed in terms of bandwidth of the
>> This assumes that the HTTP server will agree to serve the file at a much
>> larger TCP bandwidth than playback bandwidth of the media.
> I think we are assuming that the HTTP server is tuned or design to serve
> Apple HTTP streaming and/or that a CDN is in use for that.
That's exactly the kind of server I would expect perform rate limiting.
> Why would someone try to do Apple HTTP streaming and limit the bandwidth
> per connection below the highest bitrate offered?
Because bandwidth is expensive on the Internet. Most Flash-based video
sites already do rate limiting. With a fixed bandwidth, less bandwidth per
users means more users for the same price.
Sure, it would be idiotic to serve a high bit rate file at less than the
its native bit rate. But what prevents doing that for a low bit rate file?
>> Thus there is a risk that even the slightest transient congestion
>> might make VLC needless scale down the video.
> With Apple HTTP streaming you are suppose to have a few chunk of advance
> (when the user is not seeking in every direction) and at least for LIVE
> streaming that is what you do.
> So you can detect without problem that the download speed is degrading
My point is that you might not see the download speed improving. Of course
you can see the download speed degrading.
More information about the vlc-devel