Problems with ffmpeg & video bitrate

[Yansky]

Hi, I'm having some problems converting an xvid avi file to a dvd compliant mpeg-2 file using ffmpeg.

The problem I'm having is that ffmpeg isn't using the bitrate I specify. I've tried

ffmpeg -i video.avi -vcodec mpeg2video -acodec mp2 -b 7000k output.mpg

but the bitrate hovers at around 2500K when it's converting.

I also tried

ffmpeg -i video.avi -sameq -target dvd output.mpg

but the bitrate hovers at around 6500K when it's converting. Which isn't the same bitrate as the original video.

Anybody know why it's doing this?

[Bjs]

https://www.videohelp.com/tools?tool=gui4ffmpeg

Up above there is "options" ... uncheck preset , unlocks to generator down below

[Yansky]

https://www.videohelp.com/tools?tool=gui4ffmpeg

Up above there is "options" ... uncheck preset , unlocks to generator down below

Thanks, but gui4ffmpeg is also not using the bitrate I specify. As you can see from the screenshot, the bitrate is around 4680kbits/s, not 6000kbits/s - which is what I specified.

[GTRBudda]

I believe what you're seeing is because the output mpeg is VBR and the numbers are what's going on at that moment during the encode. The -b is average bitrate but moment by moment the actual can move around quite a bit. If it's any help, this is a script I use fairly often. The padding is to beat overscan:

"C:\Program Files\ffmpeg.exe" -i "C:\path\to\file.avi" -target ntsc-dvd -b 6500 -maxrate 8000 -aspect 4:3 -s 656x448 -g 15 -padright 32 -padleft 32 -padtop 16 -padbottom 16 -acodec ac3 -ab 192 -ac 2 -mbd 2 -qmin 2 -async 1 -y "C:\path\to\file.mpg"