Streaming Speeds

I was messing with the TBB Meter and noticed the speed of a Youtube vid, so decided to measure the various vid speeds. Also included a random Beeb vid (2 mins viewtime).

http://www.camieabz.co.uk/streams.jpg

It's interesting that the youtube default speed (usually 360p/240p) is around 500kbps and the Beeb's vids have no set speed. That probably explains why the Beeb's streaming can be choppy at peak times. It's obviously doing a burst...allowing the next few seconds to be watched then it repeats the process.

Youtube on the other hand rarely stalls for me (once started...the initial start can be hit or miss in busy times...you can see the initial download is high), as long as the view quality isn't too high. Also with the Plusnet Extra limits (here) of 2.5 Meg from 6pm to 10pm, one can sometimes notice a bit of a lag. Most likely Youtube is responding to demand. However, the Beeb site is frequently choppy, although it probably comes under the 'streaming' column which claims to be at 'line speed'.

Do the Beeb need to change their streaming methods, or is it geared for unexpected demand, and thus more suited for a first come, first serve?

Edited by camieabz (Tue 02-Nov-10 16:31:41)

Dangers in how both systems deliver the data, the 240/360/480p you tube would appear to require a more constant speed, question was how long after data stopping did the video stop playing, i.e. how big was its buffer to cope with glitches. The initial burst may have been this.

iPlayer if the desktop is Adobe Air, the stream in web is just Flash, so should be similar to YouTube, but perhaps they can use different settings.

The 720p and 1080p may simply be that you are just about fast enough to cope with the data, i.e. a similar pattern the lower bit rates may be seen if you had a fast enough connection.

The newer version will tell you a little more about the actual traffic, i.e. what ports are used, and even what exe is doing the transfer.

In all of the Youtube vids the buffer (wishy-washy pink colour) stayed at least a minute ahead of the stream, while the faster steams (720 & 1080) finished streaming the buffer early.

The Beeb video format doesn't include a buffer indicator, so it's very difficult to tell. You know there's a problem when the video stalls though.

Will have a look at the new version.

Have watched hour long shows on PS3 via iPlayer and had no buffering issues on a line that is a little slower than yours.

The PS3 iPlayer may be tuned to work better perhaps.

Lots of factors at play though, so hard to say with certainty. The real test of any streaming is when its live and you cannot buffer it.

Might be worth popping a 'coming soon' edit into your post about the new version of the speed test. I didn't spot that.

Think you will find that YouTube videos are VBR H.264 encoded. It often seems that at busy times the allocated bandwidth matches the variable bit rate of the video. Buffering will remain steadily and sufficiently ahead of the playback point in sync with the video content and its associated VBR in order not to over consume bandwidth.

At off peak times I find the videos simply buffer/load at line speed.

Similar thing may be happening with "live" non-buffered streaming on the iPlayer?

I've been having real problems streaming iplayer for some time now.
I get lots of buffering on PS3, and a number of different computers through wired and wireless.

I've tried two routers and still get the issue after changing to an LLU service.
I am currently syncing around 17Mbps and can achieve over 10Mbps on the TBB speed tester.

However when running the Iplayer test it confirms a download speed of around 10Mbps but the 3 streaming tests all come out around 700Kbps.

Never have any slowdowns for other types of trafic on my exchange as far as I can tell.
Another clue may be I only get around 700kbps when I use the TBB speed test on it's standard port. Maybe a firewall issue but as far as I can tell the router is open to outgoing conections.

Anyone any ideas?

Gary

Which ISP?

In reply to a post by MrSaffron:

Which ISP?

Originally with AAISP but just moved to Vivaciti Opal network.
Same problem on both.

Given the wide variation in ISP's then a firewall issue does sound likely

In reply to a post by MrSaffron:

Given the wide variation in ISP's then a firewall issue does sound likely

Just been playing around and admit I am completely baffled by this!

With my Zxyel router...

Plugged it directly into my laptop using dhcp and nat. Tested.
Then...
Switched off nat and dhcp and assigned external IP's to the router lan address and laptop. This should have removed any firewalling and given as direct a connection as possible. Tested.

Switched to another bridged modem and PPPoe on my clearOS gateway. Tested.

All three tests gave similar results.
Around 15000Kb/s download and between 600 and 1000Kb/s streaming speed.

Even tried using my HTC desire on wireless to rule out the laptop which gave the same results.

I'm sure I had the same problem when with AAISP before switching who I know give a completely clean connection to the net so I'm assuming it isn't traffic shaping.

Bit stuck now?? I might give it a go very early in the morning to maybe rule out congestion somewhere on the network...


Gary

Took a snapshot of the tbb meter. Link

From the right is a tbb test file (port 8080), then a tbb speedtest, then the iplayer streaming test. Another iplayer test to the left.
Streaming around 500kb/s, the same as the tbb speedtest. Coincidence?
This is half as fast as last night.

Looks to me like port throttling - does our test improve if you select the port 80 option?

Also as you have tbbmeter try its 20MB file on the three ports offered, and the multiple thread test using 3 or more threads.

In reply to a post by MrSaffron:

Looks to me like port throttling - does our test improve if you select the port 80 option?

Also as you have tbbmeter try its 20MB file on the three ports offered, and the multiple thread test using 3 or more threads.

Thanks for the help on this.
Link to port test

In order

tbb speedtest port 80
20mb file port 80
20mb file port 81
20mb file port 8080
20mb multithread
tbb speedtest standard port
tbb speedtest port 80

The fact the multi thread is faster points to traffic management and it is based on packet inspection at a guess.

Since all the HTTP traffic was slow - odd as usually HTTP is left alone.

Our speedtest does not use HTTP even when using port 80

OK thanks.
I'll give Vivaciti a call and see what they have to say.

Gary

OK. I'll hold my hand up. Looks like this was my fault for not asking enough questions before signing up

I've already forgotten the exact times mentioned but there is throttling in office hours between around 9ish and 7.30pm.
Doesn't explain the slow streaming speeds in the evening but I will be sent more detail on how this works.

The solution is to pay an extra £19 a month for the "file sharing add on" which should remove any and all traffic management.

I've ordered this to see how it works out.

Hopefully it will also resolve the slow evening streaming speed even though that isn't supposed to be throttled.

Kind of puts me back to what I was paying BT and AAISP except on the faster LLU speed and a lot more available daytime usage.
I won't mind this too much if the service is truly unmanaged as I realise that generally performance costs and my options are somewhat limited

Only thing left now is finding out why my latency has doubled since Monday evening!

Thanks for your help with this MrSaffron.

I'll add an update to my Vivaciti review to mention the throttling and upgrade option.