Alien Swarm / ASRD ingame Render Demos

AS / ASRD ingame Render Demos is an technique for old computers which cannot run screen recorder efficiently and can render super high-quality videos with smooth fps.

While rendering it will spawn bunch of files. (maybe 20 ~ 30GB) Make sure you have enough space for these, tho you can delete them after it finish.

There was a man published this guide in very very old time, but got deleted in the last few years. I still remember the steps cuz it helps me alot; the original author cannot be found now.

To use this technique, you need to use Auto Demos Recording (that man is also the original author of it, got deleted too) https://steamcommunity.com/sharedfiles/filedetails/?id=1539057575

Preparation

Tools you will need to use:
1. Any Text Editor
2. MeGui
3. MP4Muxer

Create movie.cfg in Alien Swarm Reactive Drop\reactivedrop\cfg\ folder.

// movie.cfg
host_framerate 30
startmovie "movie\test" raw

And you may need to bind a key to run this cfg file, here is an example:

// put it in console or autoexec.cfg
bind "F10" "exec movie.cfg"

Then create a file called swarm.avs and open it as a text file, put these in it:

ImageSource("E:\Steam\steamapps\common\Alien Swarm Reactive Drop\reactivedrop\movie\test%04d.tga", start=0, end=10000, fps=30, pixel_type = "rgb24")
ConvertToYV12()

The path in this file should be your AS \ RD path, you will need to use swarm.avs in Step 2.

Step 1 - Generate tga Files

Select an AS / ASRD Demo you want to record and start to play it, press F10 (bind key) to run movie.cfg. Then wait for the rendering, it will take double time of your demo length.
You need to quit the game manually to end generation.

These tga files will be spawned in Alien Swarm Reactive Drop\reactivedrop\movie\ folder, it should contain a test.wav file as well.

Step 2 - Render your Video and Audio

First check your Alien Swarm Reactive Drop\reactivedrop\movie\ folder, see the last file name and modify swarm.avs.
For example, test12345.tga is the last one, then you need to change swarm.avs

end=12345

If called test1234.tga, you need to change into

end=1234

and change

test%04d.tga

into

test%03d.tga

Open MeGUI, click AviSynth Script and select your swarm.avs
Set File format to MP4.

Click Audio Input and select test.wav in Alien Swarm Reactive Drop\reactivedrop\movie\ folder. Then click Audio Output to choose your output audio file path, save as test.ac3

If you need to change start point / end point of your video, remember do not change in MeGUI
You should change it via editing swarm.avs or your video will get fuzzy.

Click Queue to generate.

Step 3 - Combine your Video and Audio

Now you can delete that .wav file and bunch of .tga files as they occupy too much space.

Open MP4Muxer
Click Add to add your test.ac3 audio file and click Browse to add your video
Click Multiplex to generate your full video, done.

Videos used with this technique

Current issue: This technique used in new version RD will cause marine has dual animation. This only appears in multiplayer game and it's not a big deal.

If you want your demo to be original Alien Swarm spectating mode, add these in your movie.cfg

hidehud 256
asw_cam_marine_shift_enable 0
asw_cam_marine_dist 430