If you are trying to turn a game recording (demo) into a video:
: Import your .gltf or .glb file into Blender. Set your render engine, then under Output Properties , select "FFmpeg Video" and set the container to MPEG-4 . GL-TF2.mp4
: Use the command startmovie h264 to export directly to a video format, or export as a sequence of TGA images and WAV audio for higher quality. If you are trying to turn a game