flv file sizes

[Bret Williams]

What data rate did you set? it’s only going to be as large as you tell it to be. Oh, you can alternatively encode an h.264 qt and change the .mov to .flv.

[Josh Olenslager]

While file size can turn into an issue, as Bret mentions data rate is more important in this case. Ultimately, if you’re delivering on a streaming server, or a progressive download, keeping the data rate in a range that the end viewer can utilize. For flash (not h264 with f4v extension) I shoot for a data rate between 400-700 kb/s or so. Using h264 with f4v extension I usually run the data rate a bit hotter than that. But if you can get away with something even lower, go for it. It’ll save you serious file size. Personally my motto is if you don’t need a hot data rate, don’t force a hot data rate. If you’re really concerned with file size (and also high data rates) check your keyframes. More = bigger sizes and data rates, you’ll just need to find a balance for your content.

good luck

Josh

[John Fishback]

I constantly hear from people, “our flv file size can’t exceed x MB,” as if the file size affects anything. It’s all about the data rate as Josh says. The question to be asked is what data rate can most of the audience play. If everyone has cable modems, a higher data rate is fine. If they’re on a corporate network where they don’t want to crash the network and so spec a 200kbps data rate you have to work with that. With low data rates a trick you can use is to encode your video at 12 or 15fps rather than 24 or 30. That way the encoder can apply twice the data for each frame, thereby, improving the look. Except for very fast-moving footage this approach is a good compromise.

John

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[Josh Olenslager]

Good point, John, about the playback rates. There’s a huge advantage to playing back at lower speeds whenever it doesn’t interrupt the quality. I generally use 15 fps for web delivery (although 24 for more demanding stuff), but have been able to drop to 5 on some internal review materials. It’s been a big help on our server stresses, and in general it’s been pretty easy to recognize the media that needs higher data rates and stuff that works at much lower speeds.

Josh