To create a video from images with FFmpeg, fit every image into one fixed canvas before it reaches the encoder: scale with force_original_aspect_ratio=decrease and force_divisible_by=2 , then pad (or a blurred fill) to exactly 1920×1080, convert to limited-range yuv420p , hold each still with -loop 1 plus trim , and join the stills with xfade . Then check the result with ffprobe: frame count, size, SAR, pixel format and a duration of n × hold − (n − 1) × fade .

The usual one-liner skips the fitting step. With a folder of mixed photos it either refuses to start or, worse, exits 0 and quietly stretches every portrait photo.…