Brainiarc7

Useful Examples of ffmpeg and GNU parallel on the command-line:

Transcoding FLAC music to Opus:

ffmpeg is a highly useful application for converting music and videos. However, audio transcoding is limited to a a single core. If you have a large FLAC archive and you wanted to compress it into the efficient Opus codec, it would take forever with the fastest processor to complete, unless you were to take advantage of all cores in your CPU.

parallel 'ffmpeg -v 0 -i "{}" -c:a libopus -b:a 128k "{.}.opus"' ::: $(find -type f -name '*.flac')

Transcoding Videos to VP9:

Brainiarc7

Transient compute clustering with GNU Parallel and sshfs:

GNU Parallel is a multipurpose program for running shell commands in parallel, which can often be used to replace shell script loops,find -exec, and find | xargs. It provides the --sshlogin and --sshloginfile options to farm out jobs to multiple hosts, as well as options for sending and retrieving static resources and and per-job input and output files.

For any particular task, however, keeping track of which files need to pushed to and retrieved from the remote hosts is somewhat of a hassle. Furthermore, cancelled or failed runs can leave garbage on the remote hosts, and if input and output files are large, sending them to local disk on the remote hosts is somewhat inefficient.

In a traditional cluster, this problem would be solved by giving all nodes access to a shared filesystem, usually with NFS or something more exotic. However, NFS doesn't wo