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Diffstat (limited to 'DOCS/xml/en/encoding-guide.xml')
| -rw-r--r-- | DOCS/xml/en/encoding-guide.xml | 13 |
1 files changed, 13 insertions, 0 deletions
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). </para> +<para> + 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. +</para> + <note><title>Note:</title> <para> Most codecs which support ABR encode only support two pass encode |