How can I achieve the best overall FLV quality with FFMPEG?

video ffmpeg flv video-encoding
dcolumbus picture dcolumbus · Jul 7, 2010 · Viewed 33.5k times · Source

I'm looking to accomplish the best quality FLV with the lowest file size. After all, isn't that everyone's goal? These videos will be streamed if that makes any difference.

For now, my video(s) are no wider than 320px, and some are widescreen, so their heights are a little smaller than 240px. As it stands, the quality of the converted FLVs is quite poor.

Current command:

> ffmpeg -i video.mov -ar 22050 -ab 32 -f flv -s 320x240 -aspect 4:3 video.flv

Answer

Russ picture Russ · Jul 7, 2010

By default flv defaults to 200Kb and with the qmax being as high as 30 (since you're not overriding it) it'll probably be producing output near that. You can fix this by either:

  • Setting qmax to a lower value forcing the quality control to up the birate to meet the requirement.
  • Upping the bitrate with -vb 400k

On the test video I just tried -qmax 10 gave acceptable output. Using qmax and qmin to set the lower and upper acceptable quality is the preferred way.

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