[Ffmpeg-devel] Ratecontrol problem

Thomas Parmegiani thomasp
Thu Oct 12 14:51:36 CEST 2006

Hi all !

I have some problems to reencode a MPEG2 file (IBP, 1920x1080, 30 Mbs) to a
15 Mbs I only

file (I only is important as I need it).

At the moment my main problem is not the quality but the target bitrate. I
get too many rc buffer underflow warnings ! Can anyone help me about my
problem ?

Here is the command line I use : ./ffmpeg -i /e/test.ts -b 15000000 -minrate
15000000 -maxrate 15000000 -bt 1 -bufsize 1500000 -intra /e/test2.ts

Changing bufsize value does not change anything. If target bitrate is bigger
than source bitrate It works but not if I want a lower bitrate.

Please note I have the same problem if I work with a lower bitrate files. I
have uploaded a small low bitrated file (8 Mbs) for testing :

./ffmpeg -i /e/Film V44.mpg -b 3000000 -minrate 3000000 -maxrate 3000000 -bt
1 -bufsize 300000 -intra /e/test2.ts

I tried to have a 3Mbs without any success. Please help !



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