Video Rendering Experiment

by **noisy** » 21 Feb 2010, 19:52

Currently I'm experimenting with a possible new feature for FS Recorder, which would allow to render perfectly smooth videos from recorded flights. It does not capture the video in real-time, like e.g. Fraps, but more like a 3D rendering application.

The problem with real-time video capturing is, that everything - the simulation, screen grabbing and video encoding - has to be done in real-time, which requires a lot of processing power. Even if you have a fast computer you probably can't capture smooth videos in very high resolution with high frame rates in real-time.

Therefore I tried a different approach:
Normally, when FS runs in real-time, it measures the time between two simulation frames and calculates aircraft movement etc. from that time interval. I overwrite the measured value on every frame with a fixed time interval corresponding to the output video frame rate. This makes FS 'think' it's running with this fixed frame rate, although the real frame rate can be much slower; in other words, FS is running in slow motion (some of you already had the idea to do the video capturing at half or quarter speed, and afterwards increasing the speed of the video for smoother results, which is a similar idea).
Then I grab the video frames and use the Windows Media SDK to encode them as WMV file. At least on my system so far this works perfectly. I tried to render a video in FSX at full HD resolution (1920x1080) at 60fps and watched it on my full HD projector, it really looks great!

However, there's also a downside: As FS is no longer running in real-time, the FS sound output cannot be recorded with the video, as it's speed doesn't match the speed of the video. And of course this 'video rendering' mode is not useful during live flight, but only for making a video from a recorded flight (except if you want to fly FS in slow motion ;-)

).

For demonstration I made a video of the beautiful PMDG 747-8i in full HD resolution at 30fps and uploaded it on YouTube:
http://www.youtube.com/watch?v=xMhevhN4S0g

If you want to see the original video in full quality you can download it here:
http://www.megaupload.com/?d=9W3E3L2Q

This video is perfectly smooth, if you should see any stutters it's the video playback!

I don't want to promise too much, for now I can only say it works great on my own system. I'll probably release an experimental alpha version of this feature soon after the first beta release of v2.1, to find out how it performs on various systems. If all goes well I'll integrate this feature in v2.2.

by **KenTel** » 22 Feb 2010, 00:07

That is superb. Looking forward for a chance to try it myself.

Thanks for sharing your efforts.

Try to make a Donation shortly.

Regards

KenTel.

by **ukvoodoo** » 22 Feb 2010, 17:40

Brilliant announcement Matthias

Dont worry about the sound either because fraps records the sound well even with stuttering in the recording so its not noticeable =D>

by **noisy** » 22 Feb 2010, 21:32

ukvoodoo wrote:Dont worry about the sound either because fraps records the sound well even with stuttering in the recording so its not noticeable

I don't really understand that sentence.

by **KenTel** » 25 Feb 2010, 00:52

noisy wrote:
ukvoodoo wrote:Dont worry about the sound either because fraps records the sound well even with stuttering in the recording so its not noticeable

I don't really understand that sentence.

I think maybe UKVoodoo means to record a frc normal speed playback with Fraps, then transfer/copy the Fraps sound track over.

Sounds possible, I use a digital Tascam Recorder for live sound recording, the sound track can be played and the speed changed without changing the sound pitch, so I think that could be a way for me to try the idea. Using my Video editing software should be possible.

Looking forward to trying your in developement software, please!

Thanks Matthias..

by **X_eidos2** » 26 Feb 2010, 22:31

Actually I think it's a good thing your rendering method doesn't provide sound directly. According to the terms of Microsoft's game use rules for using video captured from FS to make videos, you're not suppose use their sounds anyway. Having folks re-mix their own sound is a good thing in a lot of ways.

I think this process is going to be a huge step forward in flight sim video production. I am very much in favor of it.

John MacKay
aka X_eidos2

by **noisy** » 27 Feb 2010, 09:33

Recording sound separately during real-time playback using an external sound recorder and then merging the sound with the video is of course possible, I recently tried that myself. It just can mean quite some extra work, especially if you frequently switch views.

X_eidos2 wrote:Actually I think it's a good thing your rendering method doesn't provide sound directly. According to the terms of Microsoft's game use rules for using video captured from FS to make videos, you're not suppose use their sounds anyway.

Thanks for that info, I wasn't aware of that.

by **noisy** » 27 Feb 2010, 13:28

The video quality suffered quite a lot from the YouTube processing, if you want to see the original video you can download it here (~432MB):

http://www.megaupload.com/?d=9W3E3L2Q