doc/avconv: elaborate on basic functionality.

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Anton Khirnov 2011-11-05 16:23:23 +01:00
parent 2b56db5869
commit d9b49e72a6

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@ -26,6 +26,23 @@ avconv is a very fast video and audio converter that can also grab from
a live audio/video source. It can also convert between arbitrary sample
rates and resize video on the fly with a high quality polyphase filter.
avconv reads from an arbitrary number of input "files" (which can be regular
files, pipes, network streams, grabbing devices, etc.), specified by the
@code{-i} option, and writes to an arbitrary number of output "files", which are
specified by a plain output filename. Anything found on the commandline which
cannot be interpreted as an option is considered to be an output filename.
Each input or output file can in principle contain any number of streams of
different types (video/audio/subtitle/attachment/data). Allowed number and/or
types of streams can be limited by the container format. Selecting, which
streams from which inputs go into output, is done either automatically or with
the @code{-map} option (see the Stream selection chapter).
To refer to input files in options, you must use their indices (0-based). E.g.
the first input file is @code{0}, the second is @code{1} etc. Similarly, streams
within a file are referred to by their indices. E.g. @code{2:3} refers to the
fourth stream in the third input file. See also the Stream specifiers chapter.
As a general rule, options are applied to the next specified
file. Therefore, order is important, and you can have the same
option on the command line multiple times. Each occurrence is
@ -33,6 +50,10 @@ then applied to the next input or output file.
Exceptions from this rule are the global options (e.g. verbosity level),
which should be specified first.
Do not mix input and output files -- first specify all input files, then all
output files. Also do not mix options which belong to different files. All
options apply ONLY to the next input or output file and are reset between files.
@itemize
@item
To set the video bitrate of the output file to 64kbit/s: