[FFmpeg-devel] [PATCH 2/2] doc/filters: Reformat scale filter doc

Stefano Sabatini stefasab at gmail.com
Sat Aug 3 12:16:54 CEST 2013


On date Friday 2013-08-02 18:42:08 -0700, Timothy Gu encoded:
> ---
>  doc/filters.texi | 74 +++++++++++++++++++++++++++++++-------------------------
>  1 file changed, 41 insertions(+), 33 deletions(-)
> 
> diff --git a/doc/filters.texi b/doc/filters.texi
> index d78c4ca..26ee19f 100644
> --- a/doc/filters.texi
> +++ b/doc/filters.texi
> @@ -6294,33 +6294,45 @@ Scale (resize) the input video, using the libswscale library.
>  The scale filter forces the output display aspect ratio to be the same
>  of the input, by changing the output sample aspect ratio.
>  
> +If the input image format is different from the format requested by
> +the next filter, the scale filter will convert the input to the
> +requested format.
> +
> + at subsection Options
>  The filter accepts the following options:
>  
>  @table @option
>  @item width, w
> -Set the output video width expression. Default value is @code{iw}. See
> -below for the list of accepted constants.
> -
>  @item height, h
> -Set the output video height expression. Default value is @code{ih}.
> -See below for the list of accepted constants.
> +Set the output video dimension expression. Default value is the input
> +dimension.
> +
> +If the value is 0, the input width is used for the output.
> +
> +If one of the values is -1, the scale filter will use a value that
> +maintains the aspect ratio of the input image, calculated from the
> +other specified dimension. If both of them are -1, the input size is
> +used
> +
> +See the next subsection for the list of accepted constants for use
> +in the dimension expression.
>  
>  @item interl
> -Set the interlacing. It accepts the following values:
> +Set the interlacing mode. It accepts the following values:
>  
> - at table @option
> + at table @samp
>  @item 1
> -force interlaced aware scaling
> +Force interlaced aware scaling

Add ending point while at it, here and below.

>  
>  @item 0
> -do not apply interlaced scaling
> +Do not apply interlaced scaling
>  
>  @item -1
> -select interlaced aware scaling depending on whether the source frames
> +Select interlaced aware scaling depending on whether the source frames
>  are flagged as interlaced or not
>  @end table
>  
> -Default value is @code{0}.
> +Default value is @samp{0}.
>  
>  @item flags
>  Set libswscale scaling flags. If not explictly specified the filter
> @@ -6333,9 +6345,14 @@ form @var{width}x at var{height}.
>  @item in_color_matrix
>  @item out_color_matrix
>  Set in/output YCbCr colorspace type.
> +
>  This allows the autodetected value to be overridden as well as allows forcing
>  a specific value used for the output and encoder.
> +
>  If not specified, the colorspace type depends on the pixel format.
> +
> +Possible values;
> +
>  @table @samp
>  @item auto
>  Choose automatically
> @@ -6370,7 +6387,7 @@ Choose automatically
>  Full range (0-255 in case of 8bit luma)
>  
>  @item mpeg/tv
> -"Mpeg" range (16-235 in case of 8bit luma)
> +"MPEG" range (16-235 in case of 8bit luma)
>  @end table
>  
>  @item force_original_aspect_ratio
> @@ -6390,52 +6407,43 @@ to work.
>  
>  @end table
>  
> -The values of the @var{w} and @var{h} options are expressions

> + at subsection Available constants
> +

I'd prefer to avoid a dedicated subsection, especially given that
"Available constants" is too generic as a subsection name.

> +The values of the @option{w} and @option{h} options are expressions
>  containing the following constants:
>  
> - at table @option
> + at table @var

>  @item in_w
>  @item in_h
> -the input width and height
> +The input width and height
>  
>  @item iw
>  @item ih
> -same as @var{in_w} and @var{in_h}
> +Same as @var{in_w} and @var{in_h}
>  
>  @item out_w
>  @item out_h
> -the output (cropped) width and height
> +The output (scaled) width and height
>  
>  @item ow
>  @item oh
> -same as @var{out_w} and @var{out_h}
> +Same as @var{out_w} and @var{out_h}
>  
>  @item a
> -same as @var{iw} / @var{ih}
> +Same as @var{iw} / @var{ih}
>  
>  @item sar
> -input sample aspect ratio
> +Input sample aspect ratio
>  
>  @item dar
> -input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
> +Input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
>  
>  @item hsub
>  @item vsub
> -horizontal and vertical chroma subsample values. For example for the
> +Horizontal and vertical chroma subsample values. For example for the
>  pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
>  @end table

These are incomplete statements (no verb) that's the way I kept the
first character lowcase.

[...]

Looks fine otherwise.
-- 
FFmpeg = Faithless & Formidable Monstrous Programmable Ecstatic Gigant


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