From 740f19c59ff9dcb08a3eaea9cf161f7b30fd6ca5 Mon Sep 17 00:00:00 2001 From: gpoirier Date: Fri, 12 Aug 2005 13:27:26 +0000 Subject: Why multipass is better in a nutshell. Taken from Rich's encoding guide. git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@16203 b3059339-0415-0410-9bf9-f77b7e298cf2 --- DOCS/xml/en/encoding-guide.xml | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'DOCS') diff --git a/DOCS/xml/en/encoding-guide.xml b/DOCS/xml/en/encoding-guide.xml index 9a01a59730..cdc93edf5c 100644 --- a/DOCS/xml/en/encoding-guide.xml +++ b/DOCS/xml/en/encoding-guide.xml @@ -289,6 +289,19 @@ (CBR), constant quantizer, and multipass (ABR, or average bitrate). + + The complexity (and thus the number of bits) required to compress the + frames of a movie can vary greatly from one scene to another. + Modern video encoders can adjust to these needs as they go and vary + the bitrate. + However, in simple modes such CBR, they cannot exceed the requested + average bitrate for long stretches of time, because they do not know + the bitrate needs of future scenes. + Wiser modes, such as multipass encode can take into account the + statistics from previous passes, which fixes the problem mentioned + above. + + Note: Most codecs which support ABR encode only support two pass encode -- cgit v1.2.3