[FFmpeg-user] The parameter of bit_rate in video encoding does not work

James Darnley james.darnley at gmail.com
Thu Nov 14 13:13:13 CET 2013

On 2013-11-14 08:41, Li wrote:
> inVStruct.inCodecContext->bit_rate

Does this contain the value you expect? I mean does it contain 7974000
(or something close) that you say is the input bitrate.

> The file is too big for me.

What are the other encoding settings you are using?  Last I knew,
ffmpeg's defaults were bad.  If you tried to use libx264 as the encoder
it should spit an error message at you.

> If I use the ffmpeg command to do fps processing (actually the original fps
> is 30 too. So this command is only for test purpose):
> ffmpeg -i VID_2013_output.mp4 -r  30 VID_2013_output_fps30.mp4
> The file size is 1.9MB!  Bitrate: 584 kbps
> Since the ffmpeg command can achieve the purpose (lower the video encoding
> bit rate), where is wrong with my ffmpeg C++ code?

ffmpeg prints a very useful log when encoding.  Where is it?  Where is
the log from your code?

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