[FFmpeg-user] 回复: How to control the bitrate between a min and maxin VBR encoding

Francois Visagie francois.visagie at gmail.com
Tue Apr 2 12:17:23 CEST 2013


> -----Original Message-----
> From: ffmpeg-user-bounces at ffmpeg.org [mailto:ffmpeg-user-
> bounces at ffmpeg.org] On Behalf Of ???
> Sent: 02 April 2013 08:01
> To: FFmpeg user questions
> Subject: [FFmpeg-user] 回复: How to control the bitrate between a min
> and maxin VBR encoding
> 
> Thank you for answer first.
> 
> 
> Now I use command below:
>     ffmpeg -y -i input.mp4 -analyzeduration 2G -pass 1 -vcodec libx264
-vpre
> fastfirstpass -b 1024k -s 1056x576 -aspect 1056:576 -r 25 -psnr -an -f flv
-
> map_chapters -1:-1 -g 50 /dev/null
>     ffmpeg -y -i input.mp4 -analyzeduration 2G -pass 2 -vcodec libx264
-vpre
> normal -b 1024k -s 1056x576 -aspect 1056:576 -r 25 -psnr -acodec copy -f
flv -
> map_chapters -1:-1 -g 50 output.flv
> 
> 
> The output.flv is a video with VBR,The part of maxbitrate is bigger than
1024k
> ,I want to control the bitrate between 1500k because of my poor
> boundwidth.
> 
> 
> I searchd more on google .There are some options can be used.Such as -
> minrate -maxrate -bufsize.
> I used them,but the quality of the output is not satisfactory.
> 
> 
> Someone said that this command only effective in CBR mode.
> 
> 
> Is there any other options can make me control the bitrate?

If you haven't already, have a look at

http://ffmpeg.org/trac/ffmpeg/wiki/x264EncodingGuide
http://mewiki.project357.com/wiki/X264_Settings#Ratecontrol
http://git.videolan.org/?p=x264.git;a=blob_plain;f=doc/ratecontrol.txt;hb=HE
AD
http://www-ee.uta.edu/dip/courses/ee5351/h.264spic.pdf (although somewhat
technical, explains some of the concepts)

> 
> 
> 
> 
> 
> 
> 
> 
> ------------------ 原始邮件 ------------------
> 发件人: "Carl Eugen Hoyos"<cehoyos at ag.or.at>;
> 发送时间: 2013年4月2日(星期二) 中午1:37
> 收件人: "ffmpeg-user"<ffmpeg-user at ffmpeg.org>;
> 
> 主题: Re: [FFmpeg-user] How to control the bitrate between a min and
> maxin VBR encoding
> 
> 
> 
> 韩瑞松 <550399108 <at> qq.com> writes:
> 
> > How can I make the bitrate under control?
> 
> -vb allows to control the bitrate.
> 
> > Which version of ffmpeg can be useful?
> 
> On this mailing list, only current git head is supported.
> 
> Carl Eugen
> 
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