From 3b36389af09663cf31637ac22ab85381e94ba1ae Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Mon, 6 Aug 2007 00:19:17 +0000 Subject: [PATCH] vbv related questions Originally committed as revision 9958 to svn://svn.ffmpeg.org/ffmpeg/trunk --- doc/faq.texi | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/doc/faq.texi b/doc/faq.texi index 5d4e5c934a..050e810287 100644 --- a/doc/faq.texi +++ b/doc/faq.texi @@ -315,6 +315,23 @@ yes, (@url{http://dir.gmane.org/gmane.comp.video.ffmpeg.user}) see (@url{http://en.wikipedia.org/wiki/Thread_hijacking}) +@section ffmpeg does not adhere to the -maxrate setting, some frames are bigger than maxrate/fps + +Read the mpeg spec, read about video buffer verifer. + +@section I want CBR but no matter what i do frame sizes differ + +You do not understand what cbr is, please read the mpeg spec. +Read about video buffer verifer and constant bitrate. +The 1 sentence summary is that there is a buffer and the input rate is +constant, the output can vary as needed. + +@section How do i check if a stream is CBR? + +To quote the MPEG-2 spec: +"There is no way to tell that a bitstream is constant bitrate without +examining all of the vbv_delay values and making complicated computations." + @chapter Development