To convert audio mp3 to MP4 by ffmpeg, use the following command
ffmpeg -f lavfi -i color=c=black:s=1280x720:r=5 -i audio.mp3 -crf 0 -c:a copy -shortest output.mp4
This generates mp4 formatted video with blank black background with the color source filter instead of using an image.
Since it is just black video this is one case with lossless mode (-crf 0) will have a smaller file size than the default lossy mode.
I'm buiding a command line tool in Go that has an option to install itself as a service on Windows, which it needs admin rights for. I wanted to be able to have it reliably detect if it was running as admin already and if not, relaunch itself as admin. When the user runs the tool with the specific switch to trigger this functionality (-install or -uninstall in my case) they are prompted by UAC (User Account Control) to run the program as admin, which allows the tool to relaunch itself with the necessary rights.
To detect if I was admin, I tried the method described here first:
https://coolaj86.com/articles/golang-and-windows-and-admins-oh-my/
This wasn't accurately detecting that I was elevated, and was reporting that I was not elevated even when running the tool in CMD prompt started with "Run as Administrator" so I needed a more reliable method.
I didn't want to try writing to an Admin protected area of the filesystem or registry because Windows has the ability to transparently virtualize those writes
| package main | |
| import ( | |
| "log" | |
| "os/exec" | |
| ) | |
| func main() { | |
| path, err := exec.LookPath("ls") | |
| if err != nil { |
| # Gawk version | |
| # Remote | |
| grep -v "rem_address" /proc/net/tcp | awk '{x=strtonum("0x"substr($3,index($3,":")-2,2)); for (i=5; i>0; i-=2) x = x"."strtonum("0x"substr($3,i,2))}{print x":"strtonum("0x"substr($3,index($3,":")+1,4))}' | |
| # Local | |
| grep -v "rem_address" /proc/net/tcp | awk '{x=strtonum("0x"substr($2,index($2,":")-2,2)); for (i=5; i>0; i-=2) x = x"."strtonum("0x"substr($2,i,2))}{print x":"strtonum("0x"substr($2,index($2,":")+1,4))}' | |
| # No Gawk | |
| # Local | |
| grep -v "rem_address" /proc/net/tcp | awk 'function hextodec(str,ret,n,i,k,c){ |
| var mediaJSON = { "categories" : [ { "name" : "Movies", | |
| "videos" : [ | |
| { "description" : "Big Buck Bunny tells the story of a giant rabbit with a heart bigger than himself. When one sunny day three rodents rudely harass him, something snaps... and the rabbit ain't no bunny anymore! In the typical cartoon tradition he prepares the nasty rodents a comical revenge.\n\nLicensed under the Creative Commons Attribution license\nhttp://www.bigbuckbunny.org", | |
| "sources" : [ "http://commondatastorage.googleapis.com/gtv-videos-bucket/sample/BigBuckBunny.mp4" ], | |
| "subtitle" : "By Blender Foundation", | |
| "thumb" : "images/BigBuckBunny.jpg", | |
| "title" : "Big Buck Bunny" | |
| }, | |
| { "description" : "The first Blender Open Movie from 2006", | |
| "sources" : [ "http://commondatastorage.googleapis.com/gtv-videos-bucket/sample/ElephantsDream.mp4" ], |