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View Full Version : question for video codec folks....

SamuraiCatJB
03-28-2005, 08:00 PM
Doing video recording using VFW API from microsoft. (yeah, yeah, I know jack, garbage in, etc....)

I am trying to naturally align video frames to their real-time equivalent timings. The video source when recording off of the OpenGL screen is "variable" based user hardware and scene complexity. Anywhere from 4fps to 15fps, and even running live it will vary from second to second by 1-3fps. I just finished coding the frame count to match the timing of the desired output frame, so it essentially skips frames it couldn't render leading to frame counts of 1,3,5,6,9,11,13 etc. very odd distribution, but it matches the nearest aproximation of live data from the original frames and "looks good". Am I breaking any rules by dropping frames inside of the AVI file or is this the proper way to adjust timing for low-framerate video?
JackAxe
03-28-2005, 08:17 PM
Huh! :confused: :)

You just wanted to brag. :D If it looks good, go with it.

<]=)
zackepceo
03-28-2005, 09:07 PM
Insert meaningless babble about genlock clock here!
SamuraiCatJB
03-28-2005, 09:33 PM
Huh! :confused: :)

You just wanted to brag. :D If it looks good, go with it.

<]=)

actually, I am trying to keep from violating rules, because I will be recording "bad-stuff" that happens for reviews by folks with stars on shoulders.... :)
JackAxe
03-28-2005, 10:04 PM
You mean astronomers? :)

I don't see any issues.

One of my clients is an unamed large aerospace monkey, they do both commercial(Airlines) and military work and the quality of the product demos that they have me work on for their clients is "eh." I get video captures from one of their boxes which runs on DX and anyways I always have to manually cut out frames where the hardware paused. This is after I crop, resize and color correct them so they look purdy.

My rambles seem to pertain to what you're doing, but then again it's probably completely off base and in la la land. :)

<]=)
SamuraiCatJB
03-28-2005, 10:24 PM
well, I tried first to pack the same frame multiple times, but that just slowed it down. I wasn't sure if just skipping a frame in the count would work, but it seems to. I am not a video expert so I don't know if submitting 15 frames, numbered by skipping every other one is legal (or skipping 2 for every one written, etc.).

Next I need to multi-thread the AVI creation, push the frames to another thread where they are encoded and written. Now THAT will be a bit harder. :)
JackAxe
03-29-2005, 03:34 AM
Have work buy you one of thos high-end Sony boxes. Then you'll simply play your OGL creation and record it at the same time. :) Then it will capture it at 29.97 fps. Not need for multi-threading voodoo magic.

<]=)
SamuraiCatJB
03-29-2005, 07:12 AM
Have work buy you one of thos high-end Sony boxes. Then you'll simply play your OGL creation and record it at the same time. :) Then it will capture it at 29.97 fps. Not need for multi-threading voodoo magic.

<]=)

Outside of an SLI box, there is not much higher end from mine at work.
JackAxe
03-29-2005, 05:35 PM
High-end video capture device. Not sure what they're called, but all it does is either record and signal sent into it, or it will take a Hi-rez signal and dynamically resize it for a TV broacast, providing the cleanest image possible in real time.

<]=)
SamuraiCatJB
03-29-2005, 06:19 PM
High-end video capture device. Not sure what they're called, but all it does is either record and signal sent into it, or it will take a Hi-rez signal and dynamically resize it for a TV broacast, providing the cleanest image possible in real time.

<]=)


ahhh, well, we have digital recorder boxes here that could take the input, but I am trying to avoid that and do "some" level of capability internally. The other group here does video capture at absolutely insane rates. But that is extra cost. :)
SamuraiCatJB
03-29-2005, 08:04 PM
Now here is a perplexing situation.... I changed my code to run (optionally) by recording the AVI in background. There is still overhead in reading the screen and transferring it to the thread, but now dropping frames causes a fail in writing to the file. Yet it does not when called from the main thread. bizarre.

anyhow, I am now back to approximating the fps as a static number rather than just dropping frames. :(
JackAxe
03-30-2005, 04:51 AM
I don't have a clue. Request a quad XEON to handle the extra threads. :)

<]=)
SamuraiCatJB
03-30-2005, 07:50 AM
show me a motherboard with single or dual 16x PCIe graphics slots and I would get it.
zackepceo
03-30-2005, 05:44 PM
Xeons are poo. $1,395 a processor poo.
SamuraiCatJB
03-30-2005, 06:15 PM
Xeons are poo. $1,395 a processor poo.

Dual processor $2750
Rackmount chassis $750
6800 ultra PCIe $700
5 Ultra 320 SCSI Drives $4000

recording and rendering on the fly at full speed, priceless. :)

But I only have them at work.
JackAxe
03-30-2005, 06:16 PM
You think that's bad, a Quado mobo is over $2K. :)

<]=)
SamuraiCatJB
03-30-2005, 06:21 PM
I will go dual PCIe when they have one compatible with our software... hopefully dual core.... dual processor, dual core, dual GPU (possibly even dual GPU on each board in a dual board SLI through the motherboard). nVidia has said that SLI will work with more than one GPU, and they already have several dual GPU single board SLI, so why not link them together and see? :)

Quad CPU, Quad GPU, hear me roar! :D
http://img56.exs.cx/img56/3032/phm1pk.gif
zackepceo
03-30-2005, 07:37 PM
Get a quad G5 when they come out!
SamuraiCatJB
03-30-2005, 07:45 PM
Get a quad G5 when they come out!

still only one gpu. :)
zackepceo
03-30-2005, 09:11 PM
You just KNOW apple's going to get Nvidia to customize them a dual video card.
JackAxe
03-30-2005, 09:36 PM
I'm thinking that will be announced with Tiger.

Did you see that blurb that Apple is hiring new OGL programmers to work on resolving any performance issues? You should go work for them SC. :)

<]=)
SamuraiCatJB
03-30-2005, 09:46 PM
I'm thinking that will be announced with Tiger.

Did you see that blurb that Apple is hiring new OGL programmers to work on resolving any performance issues? You should go work for them SC. :)

<]=)

oh you want your desktop to give the instantaneous impact prediction of your checkbook? :) you want your desktop windows to move with the live GPS and transponder locations of FAA aircraft? :D
SamuraiCatJB
03-30-2005, 09:51 PM
You just KNOW apple's going to get Nvidia to customize them a dual video card.

oh I am sure they will, the problem is that although Apple now gets current generation hardware, they still get second thought support. Things are still designed for Windows PCs (like SLI) and then offered to Linux and Apple as an "afterthought."

That is what has to change to get me to fully support apple. Or at least, I have to finish the OSG port such that I can test Apple at home as I test Athlon performance at home.
JackAxe
03-30-2005, 10:38 PM
Funny how the one company that influences so many others is an afterthought for the GPU monkeys. :)

Yes, please set my Mac up for airplane transponder monkey stuff. I've been modeling airplanes for the past 4 months, so I welcome it. :)

<]=)
SamuraiCatJB
03-30-2005, 11:11 PM
Funny how the one company that influences so many others is an afterthought for the GPU monkeys. :)

Yes, please set my Mac up for airplane transponder monkey stuff. I've been modeling airplanes for the past 4 months, so I welcome it. :)

<]=)

marketshare. :)
JackAxe
03-31-2005, 04:44 AM
Marketshare. I don't know this word you speak of. :p Remember, marketshare doesn't necessarily mean quality, after all "cheap" sells. :D

<]=)
SamuraiCatJB
03-31-2005, 07:59 AM
Marketshare. I don't know this word you speak of. :p Remember, marketshare doesn't necessarily mean quality, after all "cheap" sells. :D

<]=)

true, which is exactly why Apple still innovates. But to innovate FOR Apple from a 3rd party usually requires an incentive. And that inncentive is marketshare.