If you can print other PDFs but not a particular one it is very likely that the PDF size is A4 (the longer, skinnier Asian paper size) instead of the North American letter size ( 8.5" x 11"). This breaks printing in most cases. Or it may print if you find a program that ignores the size issue.
Here is an example of an A4 being rejected by a printer in Ubuntu Linux via CUPS
Cannot print PDF CUPS Samsung C460:
When things go wrong your video is basically unplayable or the first video plays fine and then freezes when moving on to the next. Generally if both videos weren't produced with the exact 100% same settings you will have issues. You can try the basic concat but it often won't work right.
Solution for me:
My example uses 3 videos in total so "n=3" and a=1 to include audio.
ffmpeg -threads 12 -i file1.mp4 -........
I believe from what I've read that this card's driver doesn't support the features after trying all known troubleshooting methods.
ffmpeg -i uservideoRendered.mp4 -filter:v hwupload_cuda,scale_npp=w=1920:h=1080:format=nv12:interp_algo=lanczos,hwdownload -c:v hevc_nvenc -profile main -preset slow -rc vbr_hq -c:a copy uservideoRendered.mp4-test
ffmpeg -i uservideoRendered.mp4 -filter:v hwupload_cuda,scale_npp=w=1920:h=1080:format=nv12:interp_algo=lanczos,hwdownload........
If you have this problem: http://realtechtalk.com/mencoder_bmovl_error_vf_bmovl_Unknown_command_Ignoring_-1860-articles
Then ffmpeg is for you. Go here if you are using Linux Mint and cannot find or install it to use an external PPA........
Mencoder is great, you can throw anything at it, including video files from your camera and have it encode into xvid or almost any other format.
In my case I took 640x480 video from my Canon and reduced the size by 1/3 with the options below (there are many other options that you can read about in the manual but I like to keep it simple).
mencoder -ovc xvid -oac mp3lame -xvidencopts fixed_quant=4 -o ........