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Ask HN: Share your FFmpeg settings for video hosting

72 points indulona | 1 comments | 20 Jul 24 17:30 UTC | HN request time: 0.228s | source

I am working on a website that has video hosting capability. Users can upload video files and i will generate multiple versions with different qualities or just audio, thumbnails and things like that.

I have chosen the mp4 container because of how widely supported it is. To prevent users having to fetch whole files, i use the fast start option, where the container's metadata is written at the beginning of the file, instead of at the end.

Next, I have picked h264 codec because of how widely supported it is. VP8/VP9/AV1/x265/x266 are certainly better but the h264 software encoding is often beating hardware encoding due to highly optimized and time-proven code and supported hardware. And the uploaded videos are already compressed, users won't be uploading some 8k raw videos where most advanced codes would be useful for preserving "quality".

For audio, i have picked opus codec. Seems like good value over others. Not much else to add.

I run the ffmpeg to convert video with command like this:

ffmpeg -hide_banner -loglevel error -i input.mp4 -g 52 -c:v h264 -maxrate:v vbr -bufsize vbr -s HxW -c:a libopus -af aformat=channel_layouts=7.1|5.1|stereo -maxrate:a abr -ar 48000 -ac 2 -f mp4 -movflags faststart -map 0:v:0 -map 0:a:0 output.mp4

where vbr is video bitrate like 1024k(1mbps), abr is audio bitrate like 190k and HxW is video dimensions in case of resizing.

I wonder how are folks that handle video encoding process and generate their videos?

How did you pick your settings, what issues have you encountered and any tips you can share are certainly appreciated.

Quite a niche segment when it comes to operations and not being merely consumer/customer.

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Apreche ◴[24 Jul 24 12:45 UTC] No.41056486[source]▶
Generally when you are hosting videos you don’t pick one set of transcoding settings and stick with that. You transcode many many renditions and then serve up the appropriate one depending on the client. It’s quite difficult and expensive in terms of both processing and storage. This is why it is so difficult to unseat the incumbent platforms like YouTube. It’s also why so few people do this on their own.
replies(2): >>41056733 #>>41056842 #
1. turkishmonky ◴[24 Jul 24 13:24 UTC] No.41056842[source]▶
While not at the same level as any large service, I typically spin off a 720p copy of any media as a background process nightly. 720p is pretty small in comparison to 1080p or 4k source files. This way I have an immediate mobile friendly version I can stream from my phone or load up on an ipad without emptying it's storage, even if the quality is markedly lower.