[Ffmpeg-devel] h263+: size of encoded frames after opening ffmpeg

Michael Niedermayer michaelni
Tue Jan 16 15:57:47 CET 2007


On Mon, Jan 15, 2007 at 02:05:12PM +0100, Martin wrote:
> Hi,
> I'm using ffmpeg to encode and decode h263+ video. While encoding, I
> want to change the bitrate of the encoded stream. Therefore, I close
> ffmpeg, change the bitrate in the codec context and reopen ffmpeg again.
> I noticed that the first frame encoded is a key frame and the next 4
> frames encoded after the first one are all no key frames. These 4 frames
> are much bigger than other frames in the stream, that are no key frames.
> Is it possible to stop ffmpeg from creating frames (that are not key
> frames) with such a big size after opening?

try AVCodecContext.rc_initial_cplx

> Even better, is there a
> possibility to change the bitrate without closing and reopening ffmpeg?

you can set the quality of frames which affects the bitrate,
closing and reopening within the same stream is generally not allowed
doing so means you are on your own


Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

I count him braver who overcomes his desires than him who conquers his
enemies for the hardest victory is over self. -- Aristotle
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