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