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Home > Archive > Macromedia Flash Server > April 2005 > Camera bandwidth
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| Simon Skrødal 2005-04-15, 2:45 am |
| Just a quickie:=20
I'm playing around with streaming live video atm. and, as you all know, =
the MM licensing makes you feel really greedy on bandwidth... Well, I am =
on a developer's edition and can't complain too much, but I have learnt =
to love every single one of my 250000bps' equally much, and would hate =
to see any of them go to waste - which leads to my question:
I have read the Camera/Microphone docs, and it doesn't really say =
anywhere if the Camera.setQuality(bandwidth... ) includes the audio as =
well. In fact, since it only refers to the outgoing video feed, I am =
left to assume that audio comes on top of this. However, the Microphone =
object does not let you set/monitor its bandwidth, which swings me back =
to believe that the Camera.bandwidth is a combined value/limit of both =
video and audio.=20
So, knowing that default max bandwidth value for outgoing video feed is =
16384 BYTES per second, does this also include the audio overhead, if a =
mic is detected and attached to the stream?
Thanks for your time,=20
Simon Skr=F8dal
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| Dario De Agostini 2005-04-15, 2:45 am |
| Dear Simon,
>I have read the Camera/Microphone docs, and it doesn't really say anywhere
>if the Camera.setQuality(bandwidth... )
>includes the audio as well. In fact, since it only refers to the outgoing
>video feed, I am left to assume that audio comes
>on top of this. However, the Microphone object does not let you set/monitor
>its bandwidth, which swings me back to
>believe that the Camera.bandwidth is a combined value/limit of both video
>and audio.
from what i understood camera.setquality (obviously) will try to keep the
VIDEO STREAM bandwidth "around" the value you specify (you will need to play
with FPS and QUALITY), remember that it's not an upper limit... flash
encoder may not be able to keep used bw below that value.
Audio is a different league... you will have a "fixed" bw usage... which is
directly proportional to audio sample rate.
Your effective used bw will be video stream bw + audio stream bw + a very
small overhead.
You can control bandwidth upper limit on server side with
client.setBandwidthLimit.
Remember that setting a limit which is lower than the actual stream bw will
provide bad results both is upload and download (i'm talking about real time
a/v)
Dario De Agostini
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| Bill Sanders 2005-04-15, 7:45 am |
| Simon,
This is a rough way of finding out what amount of BW, but one way is to=20=
set your microphone to mute, measure the BW, then, turn your mic back=20
on and measure it again. The difference should tell you the amount of=20
BW used by your microphone.
You can play around with this app:
http://poobah.hartford.edu/flashcom...il/vid2004.html
to see the amount of BW your camera uses with different settings as=20
well. (However it goes up to 10mb, but you can keep it lower.)
If you use the setSilenceLevel() you can make sure that when someone is=20=
not talking, that they audio will not use BW by streaming when you=20
don't want it to.
Finally, I'd convert your BYTES to bits by multiplying them by 8 so=20
that you can clearly see what portion of your 250kbps is being used.
HTH,
Bill
On Apr 15, 2005, at 3:16 AM, Simon Skr=F8dal wrote:
> Just a quickie:
>
> I'm playing around with streaming live video atm. and, as you all=20
> know, the MM licensing makes you feel really greedy on bandwidth...=20
> Well, I am on a developer's edition and can't complain too much, but I=20=
> have learnt to love every single one of my 250000bps' equally much,=20
> and would hate to see any of them go to waste - which leads to my=20
> question:
>
> I have read the Camera/Microphone docs, and it doesn't really say=20
> anywhere if the Camera.setQuality(bandwidth... ) includes the audio as=20=
> well. In fact, since it only refers to the outgoing video feed, I am=20=
> left to assume that audio comes on top of this. However, the=20
> Microphone object does not let you set/monitor its bandwidth, which=20
> swings me back to believe that the Camera.bandwidth is a combined=20
> value/limit of both video and audio.
>
> So, knowing that default max bandwidth value for outgoing video feed=20=
> is 16384 BYTES per second, does this also include the audio overhead,=20=
> if a mic is detected and attached to the stream?
>
> Thanks for your time,
> Simon Skr=F8dal
>
>
> =3D-----------------------------------------------------------
> Supported by Fig Leaf Software - http://www.figleaf.com
> =3D-----------------------------------------------------------
>
> To change your subscription options or search the archive:
> http://chattyfig.figleaf.com/mailman/listinfo/flashcomm
>
>
bill sanders | www.sandlight.com | bloomfield, ct | 860-242-2260
=-----------------------------------------------------------
Supported by Fig Leaf Software - http://www.figleaf.com
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To change your subscription options or search the archive:
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| |
| Simon Skrødal 2005-04-19, 2:45 am |
| Dear Dario and Bill (Sanders),
Thanks for your insights w/regards to camera/audio bandwidth, it makes
complete sense, although I still recon the docs on the matter are a littl=
e
fuzzy.
I have another question related to bandwidth. Playing with live video
streams, I have experienced the following (using the developers ed. of FC=
S
1.5.):
- I have two video applications; One that broadcasts a video stream and o=
ne
that receives it (all happening live)
- The broadcast video quality is set to stream at 26250Bps, or 210kbps. T=
his
is confirmed when retrieving bandwidth usage from camera at runtime.
One would (or at least I would) expect that running the broadcaster and t=
he
receiver at the same time would result in a bandwidth usage of at least
210kbps*2 =3D 420kbps. This is excluding audio and other overheads. Knowi=
ng
that the developers edition limits the stream to 250kbps, how is this
possible?
Question is: Am I wrong in assuming that broadcasting a video stream coun=
ts
towards the FCS bandwidth limit?
Sincerely,
Simon Skr=F8dal
PS! On a sidenote, with regards to the merging of Adobe and MM: Adobe als=
o
bought out Syntrillium, who made great audio software, such as CoolEdit.
Adobe rebranded CoolEdit, and discontinued all the other Syntrillium
products 
----- Original Message -----
From: "Dario De Agostini" <dario-GCN6p6BpY0//wltNWqQaag@public.gmane.org>
To: "FlashComm Mailing List" <flashcomm-1Ss2GqJETD3yZ38Mhd3e/9ZfFG6BLHNm@public.gmane.org>
Sent: Friday, April 15, 2005 5:23 PM
Subject: Re: [FlashComm] Camera bandwidth
> Dear Simon,
>
>
anywhere[vbcol=seagreen]
ing[vbcol=seagreen]
set/monitor[vbcol=seagreen]
deo[vbcol=seagreen]
>
>
> from what i understood camera.setquality (obviously) will try to keep t=
he
> VIDEO STREAM bandwidth "around" the value you specify (you will need to
play
> with FPS and QUALITY), remember that it's not an upper limit... flash
> encoder may not be able to keep used bw below that value.
>
> Audio is a different league... you will have a "fixed" bw usage... whic=
h
is
> directly proportional to audio sample rate.
>
> Your effective used bw will be video stream bw + audio stream bw + a ve=
ry
> small overhead.
>
> You can control bandwidth upper limit on server side with
> client.setBandwidthLimit.
>
> Remember that setting a limit which is lower than the actual stream bw
will
> provide bad results both is upload and download (i'm talking about real
time
> a/v)
>
> Dario De Agostini
>
>
> =3D-----------------------------------------------------------
> Supported by Fig Leaf Software - http://www.figleaf.com
> =3D-----------------------------------------------------------
>
> To change your subscription options or search the archive:
> http://chattyfig.figleaf.com/mailman/listinfo/flashcomm
>
=3D-----------------------------------------------------------
Supported by Fig Leaf Software - http://www.figleaf.com
=3D-----------------------------------------------------------
To change your subscription options or search the archive:
http://chattyfig.figleaf.com/mailman/listinfo/flashcomm
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