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Comment by chopsueyar | Hacker News Reader

Anyone have any recommended ffmpeg CLI examples for encoding to h.264 or links?

Theyre not too difficult to find. Good stuff on Doom9 and flowplayer forums. I realize that the appeal of zencoder is that you don't need to understand ffmpeg's elaborate settings, but its sorta fun to dig around and see what each one can do. Lots of technical algorithmic challenges in encoding.

For a good practical guide, I suggest reading this: http://www.amazon.com/H-264-MPEG-4-Video-Compression-Generat...

It'll give you an idea of where all the settings come from.

Hmmmm....

The Doom9 stuff seems to be more oriented toward ripping and encoding for personal use, not taking a source file and encoding several versions for streaming from a Wowza Media Server, Red5 server, or Flash Media Server...unless I am not looking in the appropriate place.

I haven't yet looked through the flowplayer forums. That seems like a good idea.

That book you linked to has a newer version, but it is over $100.

IF not CLI examples, would you have any recommended settings for encoding to stream for multiple devices and connection speeds (iDevices, Android phones, flash video)? What bitrates and resolutions from a 1280x720 60fps source file?

its really up to you in terms of what looks good in tradeoff for space and speed of encoding. zencoder had some settings that made its way to HN in a blog post not too long ago. theres also some settings on iocannon posts. just dig around, and they'll come up. i forget the exact formula that i use. i use presets where possible.

ffmpeg has presets for ipod ( which btw also work just as well for Blackberry ) and dvds. Go tweak and select a preset that works for you and go with you. My advise is to use existing ffpresets presets.

I think you will find preset in the ffmpeg source/ffpresets

Very important : once you get ffmpeg to work just the way you want, back up the source that you used to build your binary and backup all sources of libs . This is important as sometimes refreshing code from repositories breaks the features you depend on . And if you are extremely paranoid like me and your business had a critical dependency on video transcoding, create a Virtual box guest OS, build ffmpeg and tweek till it works and then save that image for emergencies. Its about a Days work in all.

I have a shell script that scans my "input folder"(an ftp dir) once it finds a file , it invokes ffmpeg process. On a quad core box, I max my cpu utilization at 8 ~10 concurrent instances of ffmpeg. Your mileage would depend on factors like bitrate etc.

Here's a decent example: ffmpeg -i "C:\input.mov" -fpre "presets\libx264-normal.ffpreset" -y -threads 0 -f mp4 -vcodec libx264 -b 1600k "C:\output.mp4"

By the way, this will give crappy audio quality due to ffmpeg's garbage aac encoder. What I did was shut off audio in ffmpeg (-an) then I used Nero AAC encoder to encode the audio. Then mp4box stitched them together.

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