Recording
Instructions for recording and making your own video.
Recording
You will need to record two files: Video and MIDI. In order to record these files, you will need a MIDI keyboard, a camera, and a computer.
Video
Find a setup with a camera looking down vertically onto the keyboard. Some things to consider:
Safety: Make sure the camera won’t fall down.
Stability: Try to reduce shaking, e.g. from vibrations from the keyboard.
Focus: Make sure you focus the camera onto the keyboard before recording. It is very disappointing to find that the video is ruined because the keyboard recording is blurry (speaking from experience).
Background: If you desire, place a dark tarp under the keyboard so you can create the “hands floating over nothing” effect. There are some settings in PianoRay to dim the background and achieve this effect.
Privacy: If you plan to release the video to the public, make sure it doesn’t contain any private information.
MIDI
Connect the MIDI keyboard to the computer. Use MIDI recording software to record the MIDI. I use MidiEditor, which has worked great.
Processing
Audio
Create an audio file from the MIDI.
Download a soundfont. SoundFonts4U has great piano soundfonts.
Install software that can render a MIDI file. I use FluidSynth, and the rest of these instructions assume you have FluidSynth.
Run this command, which uses FluidSynth to render and FFmpeg to write the audio file:
fluidsynth -a alsa -T raw -g GAIN -F - SOUNDFONT.sf2 MIDI.mid | ffmpeg -y -f s32le -i - -filter:a "volume=2" AUDIO.mp3
. Replace the uppercase words with the respective values. A value of0.5
for GAIN works usually.
Video
Make sure the video is right side up. That is, your hands come from the bottom of the screen and play the keyboard.
If you need to rotate it, see this page for rotating with FFmpeg.
Offsets
Find the offsets for respective media. PianoRay uses these offsets. It may be beneficial to write down these offsets somewhere so you don’t forget them later.
Audio
Open the audio in an audio player and find the timestamp, in seconds, when the audio starts. I use Audacity.
Video
Find the timestamp in seconds you play the first note and when you play the last note in the video. I use Blender’s video editor.
Video Crop
Find the pixel coordinates of the four corners of the keyboard in the video, starting from the top left and going clockwise. If you use Blender’s video editor, keep in mind that Blender’s image viewer has the Y coordinates reversed.
Rendering
Follow instructions in this page for rendering instructions.