[FFmpeg-devel] [PATCH] Add detail to the documentation for ffmpeg -map.

[Stefano Sabatini]

On date Wednesday 2011-03-02 14:53:35 +0100, Diego Biurrun encoded:
> On Mon, Feb 28, 2011 at 03:35:40PM +0100, Stefano Sabatini wrote:
[...]
> > +Specify an input stream to be a source for the output file. An input
> > +stream is identified by two numbers: an input file index, specified by
> > + at var{input_file_id}, and an input stream index within that file,
> > +specified by @var{input_stream_id}. Both start counting from 0.  If
> > +used, @var{sync_file_id}. at var{sync_stream_id} specifies which input
> > +stream is used as a presentation sync reference.
> 
> Designate an input stream as a source for the output file. Each input
> stream is identified by the input file index @var{input_file_id} and the
> input stream index @var{input_stream_id} within the input file. Both
> indexes start at 0.

Changed.

> > +For example, if you have two streams in the first input file, these
> > +streams are identified by "0.0" and "0.1". You can use @code{-map} to
> > +select which one to map to the single stream of an output file.
> 
> Let's not overuse the verb map too much here: 
> 
>   You can use @code{-map} to select which stream to place in an output file.

Changed.

> > For example:
> > + at example
> > +ffmpeg -i INPUT OUTPUT -map 0.1
> > + at end example
> > +will map the input stream identified by "0.1" to the (single) output
> > +stream.
> 
> will mark the input stream identified by "0.1" as (single) output stream.

I'm not happy about this, as "marking" is not denoting precisely the
operation done, because it doesn't imply the mapping operation, so I
kept "map".

> > +For example, to select stream 2 from input file @file{A.mov}
> > +(specified by the identifier "0.2"), and stream 6 from input
> > + at file{B.mov} (specified by the identifier "1.6"), and copy them to
> > +output file @file{out.mov}:
> 
> Didn't you say above that counting starts at 0?

I admit this is a bit confusing, "stream 2" in this case means "stream
with index 2" rather than "the second stream". Replaced with "to select
stream with index 2 from ...".
-- 
FFmpeg = Fantastic and Fascinating Merciless Puristic ExchanGer