Record a Video (MP4)

You can record a video of the DEM calculation and play it back later – a quick way to review the particle flow at close to real-time speed, without re-running a calculation that might take hours. You can also send the video file to people who don't have HelixChute2 installed.

FFmpeg is required. Recording a video needs FFmpeg, a free video encoder, installed on your PC. It is not included with HelixChute2 – see Installing FFmpeg below. Everything else in the program works without it.

To record a video

Build your chute model, complete the inputs, and do a short test run first.
Press Record Video... on the toolbar.
Choose a file name and location for the .mp4 file and press Save.
The Video Recording Settings dialog appears – set the Compression Quality slider (0–100%; higher gives better quality and a larger file) and press OK.
Press Calculate to start the DEM calculation; the drawing is recorded as it runs. The Record Video... button changes to Stop Recording.
You can rotate/pan/zoom the view while recording – the video reflects whatever is currently displayed.
Press Stop Calculation to pause the DEM run, and Stop Recording to end the video and close the file.

Videos are recorded as standard MP4 (H.264) files, so they play in any modern media player without needing a codec to be installed – double-click the file, or use Play Recorded Video... in the program to open the most recently recorded (or any previously saved) video.

Unlike the legacy program's screen-capture based AVI recording, video output here is generated directly from the 3D drawing, so there's no codec list to choose from and no risk of other windows or dialogs appearing in the recording.

Licence watermark. The first five seconds of every video carry a line of text along the bottom: Licensed to followed by the name your licence is issued to, or Evaluation Only for a trial or a copy that hasn't been activated. The rest of the video is unmarked. Copy Image and Save Image pictures carry the same watermark – see Drawing Settings.

Installing FFmpeg

Why it is needed

HelixChute2 draws each frame of the video itself, then hands the frames to FFmpeg to compress them into an MP4 (H.264) file. FFmpeg is the free, open-source video encoder used by a great many video programs. It is a separate program with its own licence, so it is not installed with HelixChute2 – you install it once, and HelixChute2 finds it whenever you record. You only need it for Record Video; Copy Image, Save Image and playing back recordings do not use it.

Option 1 – install with one command (recommended)

Open the Windows Start menu, type PowerShell (or Command Prompt) and open it.
Type the following and press Enter:
```
winget install --id Gyan.FFmpeg -e
```
Accept the agreement prompts if asked. This downloads FFmpeg from its publisher and sets Windows up so other programs can find it.
Close HelixChute2 if it is open, and start it again. A program only picks up a newly installed FFmpeg when it starts.

winget (the Windows Package Manager) is part of Windows 11 and current Windows 10. If Windows says winget is not recognised, use Option 2.

Option 2 – download and install by hand

Go to www.gyan.dev/ffmpeg/builds (the Windows builds linked from the official ffmpeg.org download page) and download ffmpeg-release-essentials.zip.
Extract the zip to a folder such as C:\ffmpeg, so that the program ends up at C:\ffmpeg\bin\ffmpeg.exe. (The zip contains a folder with a long version name – rename it, or move its contents up, so the path matches.)
Tell Windows where it is: open the Start menu, type environment variables and choose Edit environment variables for your account. Select Path, press Edit..., then New, type C:\ffmpeg\bin, and press OK on each window.
Close HelixChute2 if it is open, and start it again.

Checking it is installed

Open a new PowerShell or Command Prompt window and type:

ffmpeg -version

If FFmpeg is installed correctly this prints its version and build details. If Windows says ffmpeg is not recognised, it is not installed, or its folder is not on the Path.

If recording will not start

Message	What to do
Could not start recording: Could not start ffmpeg ('ffmpeg')...	HelixChute2 cannot find FFmpeg. Install it as above, then restart HelixChute2. If you have just installed it, the restart is usually all that is missing.
ffmpeg exited unexpectedly, mentioning libx264 or an unknown encoder	The FFmpeg you have cannot write H.264 video. Some cut-down builds leave that part out. Install one of the builds above, which include it.

Company PCs. If your IT department controls what can be installed, ask them to install FFmpeg for you, giving them this page. It needs to be on the Path for your Windows account (or for all users).