On Fri, Nov 28, 2003 at 03:18:05PM +1300, Simon Byrnand said:
At 13:41 28/11/2003 +1300, Craig Whitmore wrote:
>Fast-Forward nope., but a lot more jerkier than the original streaming
>MJPG streaming from Wellington. Still about the same amount of Bandwidth
>used (about 1Mbit viewing it) but its loosing a lot of the pictures
>randomly. All these problems I guess they are still working on fixing.
Yup. There's a jpeg frame corruption problem somewhere in the stream
FTP from the master server (webcam.citylink.co.nz) out to the anycast
servers. We've bodged the copy so that it drops the bung frames, which
eases the nasty grey flashing in IE, but it does make the motion jerky.
I'm pretty confidant that the race will be sorted out today, and we'll
be back to full frame rates soon (at least in Akld and Wgtn - out of NZ
users will almost certainly still have a reduced frame rate).
I see the same thing too. Seems to be rather slow and jerky considering its
using nearly 1Mbit, at a guess I'd say I'm seeing 2 to 4 frames per second
with quite a few dropped or incomplete frames like the one in Craig's
snapshot, despite local measuring showing its downloading at nearly
1Mbit... the 300Kbit/sec streams from xtra's "broadband" site by
comparision play smoothly and look pretty good despite using 1/3 of the
Yup. That's joy of Axis webcams using motion jpeg versus proper mpeg.
Motion jpeg is horribly inefficient, as it's basically standard jpeg
frames mashed together with some mime glue, so it can't do frame to
frame compression tricks. On the upside, it's supported directly by
most any browser, and is pretty easy to implement (all you need is an
FTP server and gob loads of bandwidth).
There'll be MMS streams of the host broadcast on the day, they'll be a
lot smoother than the cameras. They do require a significantly more
backend infrastructure to get going (think van loads of encoding PC's
and generators :-).