Jon,
I'm interested in the data you have below about transparent borders +
AIR. Are you expressing a general truth - using your own border
graphics will have THAT much of a performance hit on any AIR app? First
I've heard of this and I've got something in the wild using a
transparent border in a similar fashion to Christope's Sales Builder
app.
Jeff
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Jon Bradley
Sent: Wednesday, March 11, 2009 12:12 PM
To: [email protected]
Subject: Re: [flexcoders] Best practices for full screen video
in AIR? What's the best HD performance we can?
On Mar 11, 2009, at 10:56 AM, George wrote:
What I'm doing on video:
Use an standalone Window component to contain a
FLVPlayback (CS4
version), run full screen display mode on its stage
alone. (Didn't set
'fullScreenSourceRect', as I tried, it cause worse
performance
significantly)
Write your own. I'd stay away from FLVPlayback. Roll your own
video player using NetStream and/or video classes along with scripts to
control it.
Instead of using fullScreenSourceRect you can just try simple
full screen mode and set up your controls properly. Flash has a pretty
efficient full screen model now and also takes into consideration
vertical blank (VBL) for smoother playback. I'm not so sure hardware
scaling does that.
Video encode settings:
960x540, Field Oder - none (no interlace), profile -
high, level - 4.1,
frame rate - should be 30 or 29.97 fps, target bitrate -
1.5 mbps, max
bitrate - 2 mbps.
That sounds good.
Ensure no smoothing is on the video. Try to set the profile to
"main." High is more processor intensive. Drop the data rate in half as
a test - though I'm guessing the results you get will be similar. It
just might be your processor.
My question is:
- Does each AIR nativeWindow run its own thread, or the
whole AIR
application running a single thread?
Certain things within Flash are multithreaded and will take
advantage of multiple cores (bitmap filters, some vector ops, H.264
decoding and hardware scaling).
Flash itself runs in one thread (i think?). The only other thing
with AIR that's unique is WebKit ... don't know much about that.
- What's the best practices for full screen high quality
video in AIR?
Anything I can improve?
On an intel core 2 duo chip you should be able to do full screen
720p (1280x720) video at the least - and barely 1080p. Should being the
operative word. Best practices here is all in the encoding and bit rate.
Check out the Adobe HD Gallery and see if you can run those
videos on your test case. If you can't, you need a faster machine.
You can try FFMPEG to encode the H.264 video (x264 or mencoder).
It does a great job and you get some nice additional encoding features
that might give you a one-up on performance. That said, I think the
latest Flash Media Encoder is pretty well tuned.
- How to GC after video played? I used
videoplayer.clear(), but cannot
run videoplayer.close(), as I test when try to load a
new video quickly,
it throw an error.
Not sure there's enough information to help here. What error are
you getting? GC is automatic and you don't have much control with
FLVPlayback.
- What's the best HD video performance we can get in
multiple windows
Flex/AIR application?
One stream of H.264 encoded 1080p video for best performance on
a dual core processor. More windows with more streams is possible but
from a performance standpoint, you might need 2x as many cores as you
have streams to play. I'm not sure how smart the multithreading is on
the video decoding in Flash.
Some other thoughts:
1. I'd recommend trying WinXP Pro as a test case
2. Do not use any transparent border skin for the AIR Window.
The custom border skin will kill the performance of your application
anywhere from 10-20%
cheers,
Jon
