When it comes to movie playback, our experience is that using video files with many different codecs, resolutions, and frame rates in a single project can lead to performance problems.
Our recommended "best practice" is to decide on a single codec, resolution, and frame rate for all the movie files in your project. See "Recompressing Your Files Using a New Codec, Resolution, or Frame Rate" below to learn about software that can help you do this.
If that's not possible, then you should at least try to use movie files with a frame rate that matches the "Target Frame Rate" set in Isadora Preferences. (See also: "Setting the Target Frame Rate to Match the Refresh Rates of your Displays/Projectors" below.)
In theory, you can use many codecs in Isadora but our experience has taught us that limiting the number of codecs used in an Isadora file produces a more stable project.
HAP or HAPQ (usually in a .mov or .avi file) is your best choice for any media playback that is using modified playback settings (i.e., a speed other than 1.0, reverse playback, looping, scrubbing, etc). On macOS, the Apple ProRes codec also works well with modified playback; however, this means you can't move your show to a Windows machine without converting the media files to a different codec because Windows can't play Apple ProRes. The downside to using these codecs is that they produce large file sizes.
H264 (usually in a .mov, .mp4, .wmv) file is your best choice if playing the video from start to finish at regular (1x) speed. The H264 codec provides much smaller file sizes so it is also preferred for very long movie files.
Recompressing Your Files Using a New Codec, Resolution, or Frame Rate
You can recompress your video files to a specific codec, wrapper, and frame rate using Adobe Media Encoder (Paid, cross-platform), Shutter Encoder (Free, Windows), AVF Batch Exporter/Converter (Free, macOS), or similar software.
Once the file has been recompressed, you'll want to replace the media files in your Isadora document. To do that, double-click the file in Isadora's Media View (or right-click it and select "Replace Media" from the contextual menu),hen use the resulting file dialog to select the recompressed media file.
Setting the Target Frame Rate to Match the Refresh Rates of your Displays/Projectors
For the best performance, you'll want to set the "Target Frame Rate" in the Isadora Preferences to an even multiple of the "refresh rate" of the projectors or displays you'll use for video output.
Additionally, you should be sure that all of the projectors or displays used by your project share the same refresh rate; if the refresh rates don't match then performance may suffer.
In North America, the refresh rate is often 60 Hz, so you'd want a Target Frame Rate of 30 or 60 fps.
In Europe and many other countries, it is often 50Hz, so you'd want a Target Frame Rate of 25 or 50 fps.
We use the word "often" above because it is entirely possible to force a display to 50Hz in North America. If you want to be 100% sure about the refresh rates of your projectors and displays you can use the procedure below to find out what they are.
- Hold down the OPTION key then click the Apple menu.
- Choose “System Information”.
- In the window that appears, choose choose “Graphics / Displays” from the sidebar.
- Locate the refresh rate information for the active displays used by the displays connected to your computer.
- Windows 10 or 11:
- Right-click any blank area on your desktop.
- Then select Display Settings from the pop-up menu. (You can also access this by going to Start > Settings > System > Display.)
- If you have more than one display, click the display you wish to examine under "Select a display below to change its settings".
- Scroll down to the bottom and click "Advanced Display Settings".
- The refresh rate will be shown under "Display Information"
If the refresh rates don't match, then please consult the documentation for your operating system to find out how to change the refresh rate of a display.