How to convert mp4 videos into flv ones with ffmpeg?

How to convert mp4 videos into flv ones with ffmpeg?

I'm late, but if this can help somebody, it's time well spent.

If I understand correctly, you want to convert MP4 to FLV using FFMPEG. Here are two command lines to help you do that; I'm currently using them myself (you can adjust them to your needs too) :

ffmpeg -i source.mp4 -c:v libx264 -crf 19 destinationfile.flv

and if the first one doesn't work :

ffmpeg -i source.mp4 -c:v libx264 -ar 22050 -crf 28 destinationfile.flv

Please note that -crf XX is the quality of the video you will create. It's between 0 and 51 (but between 17 and 23 is a reasonable range and the lower the number is, the better quality the video is going to be).

The -ar 22050 is for adjusting the audio sample range (audio quality). You can choose 11025, 22050 or 44100.

I suggest you read this Tutorial for FFMPEG . It's really complete and has many useful tips.

Hope this will help you or somebody in the same situation.