This article dives deep into what it means to have a verified MJPEG video sample, why you need it, how verification works, and the tools you can use to achieve it.
ffmpeg -v error -i sample.avi -f null - >error.log 2>&1
-q:v 2 sets a fixed, high-quality quantization factor (scale of 1-31, where 2 is excellent quality with minimal compression artifacts).