Merge commit '811bd0784679dfcb4ed02043a37c92f9df10500e'

* commit '811bd0784679dfcb4ed02043a37c92f9df10500e':
  avconv: make input -ss accurate when transcoding

Conflicts:
	Changelog
	doc/ffmpeg.texi
	ffmpeg.h
	ffmpeg_filter.c

Merged-by: Michael Niedermayer <michaelni@gmx.at>

1 files changed, 15 insertions, 3 deletions

diff --git a/doc/ffmpeg.texi b/doc/ffmpeg.texi
index 50b2c8b8f0..a923f97867 100644
--- a/doc/ffmpeg.texi
+++ b/doc/ffmpeg.texi
@@ -272,9 +272,15 @@ Set the file size limit, expressed in bytes.
 
 @item -ss @var{position} (@emph{input/output})
 When used as an input option (before @code{-i}), seeks in this input file to
-@var{position}. When used as an output option (before an output filename),
-decodes but discards input until the timestamps reach @var{position}. This is
-slower, but more accurate.
+@var{position}. Note the in most formats it is not possible to seek exactly, so
+@command{ffmpeg} will seek to the closest seek point before @var{position}.
+When transcoding and @option{-accurate_seek} is enabled (the default), this
+extra segment between the seek point and @var{position} will be decoded and
+discarded. When doing stream copy or when @option{-noaccurate_seek} is used, it
+will be preserved.
+
+When used as an output option (before an output filename), decodes but discards
+input until the timestamps reach @var{position}.
 
 @var{position} may be either in seconds or in @code{hh:mm:ss[.xxx]} form.
 
@@ -1060,6 +1066,12 @@ This option is similar to @option{-filter_complex}, the only difference is that
 its argument is the name of the file from which a complex filtergraph
 description is to be read.
 
+@item -accurate_seek (@emph{input})
+This option enables or disables accurate seeking in input files with the
+@option{-ss} option. It is enabled by default, so seeking is accurate when
+transcoding. Use @option{-noaccurate_seek} to disable it, which may be useful
+e.g. when copying some streams and transcoding the others.
+
 @item -override_ffserver (@emph{global})
 Overrides the input specifications from ffserver. Using this option you can
 map any input stream to ffserver and control many aspects of the encoding from