[FFmpeg-devel] [PATCH] Add documentation for the image2 muxer.

[Janne Grunau]

On Wed, Jan 26, 2011 at 11:03:54PM +0100, Stefano Sabatini wrote:

some suggestions inline

> ---
>  doc/muxers.texi |   50 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 files changed, 50 insertions(+), 0 deletions(-)
> 
> diff --git a/doc/muxers.texi b/doc/muxers.texi
> index 2257669..8d82edf 100644
> --- a/doc/muxers.texi
> +++ b/doc/muxers.texi
> @@ -18,4 +18,54 @@ enabled muxers.
>  
>  The description of some of the currently available muxers follows.
>  
> + at section image2
> +
> +Image file muxer.
> +
> +This muxer allows to write the input video to a list of image files
> +specified by a pattern.

... muxer writes video frames to multiple image ...

> +The pattern may contain the string "%d" or "%0 at var{N}d", which
> +specifies the position of the characters representing a sequential
> +number in each filename specified by the pattern. If the form

... sequential
numbering in the filenames. If ..

> +"%d0 at var{N}d" is used, the string representing the number in each
> +filename is 0-padded and @var{N} is the total number of 0-padded
> +digits representing the number. The literal character '%' can be
> +specified in the pattern with the string "%%".
> +
> +If the pattern contains "%d" or "%0 at var{N}d", the first filename of
> +the file list specified will contain the number 1, all the following
> +numbers will be sequential.
> +
> +The pattern may contain a suffix which is used to automatically
> +determine the format of the image files to write.
> +
> +For example the pattern "img-%03d.bmp" will specify a sequence of
> +filenames of the form @file{img-001.bmp}, @file{img-002.bmp}, ...,
> + at file{img-010.bmp}, etc.; the pattern "i%%m%%g-%d.jpg" will specify a

no need to make the example more complicated than necessary, one '%%' is
enough. A newline after the first example might also be in order.

> +sequence of filenames of the form @file{i%m%g-1.jpg},
> + at file{i%m%g-2.jpg}, ..., @file{i%m%g-10.jpg}, etc.
> +
> +The following example shows how to use @file{ffmpeg} for creating a
> +sequence of files @file{img-001.jpeg}, @file{img-002.jpeg}, ...,
> +taking one image every second from the input video:
> + at example
> +ffmpeg -i in.avi -r 1 -f image2 'img-%03d.jpeg'
> + at end example
> +
> +Note that with @file{ffmpeg}, if the format is not specified with the
> + at code{-f} option and the output filename specifies an image file
> +format, the image2 muxer is automatically selected, so the previous
> +command can be written as:
> + at example
> +ffmpeg -i in.avi -r 1 'img-%03d.jpeg'
> + at end example
> +
> +Note also that the pattern must not necessarily contain "%d" or
> +"%0 at var{N}d", for example to create a single image file
> + at file{img.jpeg} from the input video you can employ the command:
> + at example
> +ffmpeg in.avi -f image2 -vframes 1 img.jpeg
> + at end example
> +
>  @c man end MUXERS

otherwise ok

Janne