FFmpeg Lands CLI Multi-Threading As Its "Most Complex Refactoring" In Decades

starman@programming.dev to Programming@programming.dev – 194 points –
FFmpeg Lands CLI Multi-Threading As Its "Most Complex Refactoring" In Decades
phoronix.com
8

I'm not sure I understand. I've already been running ffmpeg from the command line and it's been using multiple cores but default. What's the difference, what's the new behavior?

before you could tell an encoder to run multiple threads, but everything outside of the encoder would run effectively single threaded.

now you (should) be able to have all the ffmpeg components, decoder, encoder, filters, audio, video, everything all run parallel

Oooo. Will it be automatic? Or do you need to pass a flag?

This is the best summary I could come up with:


The long-in-development work for a fully-functional multi-threaded FFmpeg command line has been merged!

FFmpeg is widely-used throughout many industries for video transcoding and in today's many-core world this is a terrific improvement for this key open-source project.

The patches include adding the thread-aware transcode scheduling infrastructure, moving encoding to a separate thread, and various other low-level changes.

Change the main loop and every component (demuxers, decoders, filters, encoders, muxers) to use the previously added transcode scheduler.

There's a recent presentation on this work by developer Anton Khirnov.

It's terrific seeing this merged and will be interesting to see the performance impact in practice.


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I was using gnu parallel before with ffmpeg. Is this any different and better?

GNU Parallel allows multi-process, which generally tends to be less efficient than multi-threading. I can't speak to the specifics of your use vs. FFmpeg's refactoring, though.