I'm trying to use ffmpeg to convert my video files to H.264 encoded MPEG4 files. The command I'm using looks like this:



The problem is, I specify the bitrate to be 768 and the outputted file's bitrate always seems to be higher than this. I've tried a couple other free video converters, and it's the same thing... the bitrate always reads higher than what I specified.

I'm pretty new to the video conversion world, so is there something I just don't understand about video bitrates?

how do you determine the bit rate is higher? and how much is it?

Mainly Quicktime's "Movie Info" menu, but ffmpeg tells me the same thing.

Well, for instance, I encode an mpeg file 1.13mbit/sec, but specifying 768kbit/sec the resulting file is actually 1.02mbit/sec. ffmpeg seems to just be totally ignoring the bitrate parameter, even though it says in the console:



So it clearly receives my parameters fine.

Also, can someone explain to me what "bitrate tolerance" is?

hmmm... well I don't know what can cause that behaviour.

Personally I just use x264cli to encode h264 video and if the files are not too short even in 1-pass mode i get accurate results.

Maybe some weirdness in ffmpeg... wouldn't be the only thing...

I'll look up this x264cli thing you speak of.

Thanks.