FORUMS: list search recent posts

horizontal lines apperaring after compression

COW Forums : Compression Techniques

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
vid osredkar
horizontal lines apperaring after compression
on Apr 16, 2010 at 5:38:05 pm

Hi everybody, have a problem thats been bothering me for a long time, and your help would be very welcome.
(original is uncompressed from AE, when played, no artifacts appear)When i export this file from Sorensen Squezze as a flash flv, I get strange lines across certain parts when there is camera movement.I have tried a bunch of different settings, and cant seem to find what the problem is.
I use on2vp6 codec, and have tried cbr and vbr (2 -pass) with different bit rates.
here is an example of my problem

http://www.flotaskydive.com/

the first video on top
the footage is made out of jpgs with some basic camera movmement.
any suggestions?
i thank you in advance
best regards
Vid


Return to posts index

Chris Blair
Re: horizontal lines apperaring after compression
on Apr 18, 2010 at 5:07:32 pm

Looks like interlace artifacts to me. We need to know how the original uncompressed file was created. Pixel resolution (1920x1080; 1280x720; 720x486 etc.), frame rate, pulldown or no pulldown; was it rendered with fields or frames etc.

My guess is you rendered fields. With such a simple animation and such slow movement, and considering your final output is displayed on a computer, I'd render using frames and turn on motion blur. It'll take a little longer to render, but that should eliminate what you're seeing. I don't know of anything in compressing to an flv that would cause what you're seeing.

Chris Blair
Magnetic Image, Inc.
Evansville, IN
http://www.videomi.com


Return to posts index

vid osredkar
Re: horizontal lines apperaring after compression
on Apr 20, 2010 at 9:48:37 am

Hi Chris, first of all, thank you for your reply.
Here is a link to the video in question
http://www.flotaskydive.com/content/view/15/17/
the video i posted above is an old project but with the same problem. Original cello is rendered from AE:
uncompressed
pixel resolution is 650×260 (requested flv size is the same),
25fps,
no fields rendered and
no pull down.
sample videos are a bit smaller cause they dont fit on my test page.
have in mind that its work in progress and color correction and other fixes have not yet been done.
any comments are welcome
vid


Return to posts index


Daniel Low
Re: horizontal lines apperaring after compression
on Apr 20, 2010 at 2:41:29 pm

[vid osredkar] "pixel resolution is 650×260"

Your encoded frame size needs to be equally divisible by 16 or 8:
http://www.adobe.com/devnet/flash/apps/flv_bitrate_calculator/video_sizes.h...

The player on the webpage needs to have exactly those dimensions, do not let the player rescale the video.


__________________________________________________________________
Sent from my iPad Nano.


Return to posts index

vid osredkar
Re: horizontal lines apperaring after compression
on Apr 21, 2010 at 9:27:45 am

Thanks Daniel!
I followed the tip, made a new test comp in AE, size 448×336, exported it without compressing(picture looks great no lines),i put it in sorenson,encoded the same size to flv,what i ended up with, is on the site
http://www.flotaskydive.com/content/view/15/17/
video on top
no rescaling was done by the player, neither now or in the previous examples.
as you can see my problem did not go away.
i have the same resolution from the start in AE comp till the end encoded as flv (and it is divisible by 16).
I must be doing something wrong i guess
this compression thing is amazing
vid





Return to posts index

vid osredkar
Re: horizontal lines apperaring after compression
on Apr 24, 2010 at 9:42:37 am

Hi
i finally came to an end with my problem.The flv player on our sight its the one to blame, because when i put the same flv file on youtube the picture is good, and no lines appear.
thanks again for all the help
best regards
vid


Return to posts index

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
© 2017 CreativeCOW.net All Rights Reserved
[TOP]