[FFmpeg-devel] [PATCH v4] doc/filters: add 4x4 layout example for xstack filter

Limin Wang lance.lmwang at gmail.com
Thu Sep 26 17:38:57 EEST 2019


On Thu, Sep 26, 2019 at 04:07:14PM +0530, Gyan wrote:
> 
> 
> On 26-09-2019 12:22 PM, Limin Wang wrote:
> >On Wed, Sep 25, 2019 at 09:26:58PM +0530, Gyan wrote:
> >>Ok, the formatting is fine except for one. See below.
> >>
> >>On 25-09-2019 03:56 AM, lance.lmwang at gmail.com wrote:
> >>>From: Limin Wang <lance.lmwang at gmail.com>
> >>>
> >>>Reviewed-by: Gyan <ffmpeg at gyani.pro>
> >>>Signed-off-by: Limin Wang <lance.lmwang at gmail.com>
> >>>---
> >>>  doc/filters.texi | 42 +++++++++++++++++++++++++++++++++++++++++-
> >>>  1 file changed, 41 insertions(+), 1 deletion(-)
> >>>
> >>>diff --git a/doc/filters.texi b/doc/filters.texi
> >>>index e41384a..a8342c0 100644
> >>>--- a/doc/filters.texi
> >>>+++ b/doc/filters.texi
> >>>@@ -19057,6 +19057,13 @@ terminates. Default value is 0.
> >>>  @itemize
> >>>  @item
> >>>  Display 4 inputs into 2x2 grid.
> >>>+
> >>>+Below is the 4 inputs position:
> >>>+ at example
> >>>+input1(0, 0)  | input3(w0, 0)
> >>>+input2(0, h0) | input4(w0, h0)
> >>>+ at end example
> >>>+
> >>>  Note that if inputs are of different sizes unused gaps might appear,
> >>>  as not all of output video is used.
> >>>  @example
> >>>@@ -19065,6 +19072,12 @@ xstack=inputs=4:layout=0_0|0_h0|w0_0|w0_h0
> >>>  @item
> >>>  Display 4 inputs into 1x4 grid.
> >>>+
> >>>+Below is the 4 inputs position:
> >>>+ at example
> >>>+input1(0, 0) | input2(0, h0) | input3(0, h0+h1) | input4(0, h0+h1+h2)
> >>Since this is 1 column x 4 rows, these should be different lines
> >>without the separator.
> >>
> >>>+ at end example
> >>>+
> >>>  Note that if inputs are of different sizes unused gaps might appear,
> >>>  as not all of output video is used.
> >>>  @example
> >>>@@ -19073,11 +19086,38 @@ xstack=inputs=4:layout=0_0|0_h0|0_h0+h1|0_h0+h1+h2
> >>>  @item
> >>>  Display 9 inputs into 3x3 grid.
> >>>+
> >>>+Below is the 9 inputs position:
> >>>+ at example
> >>>+input1(0, 0)       | input4(w0, 0)      | input7(w0+w1, 0)
> >>>+input2(0, h0)      | input5(w0, h0)     | input8(w0+w1, h0)
> >>>+input3(0, h0+h1)   | input6(w0, h0+h1)  | input9(w0+w1, h0+h1)
> >>Shouldn't the third column be at x = w0+w3? w1 is width of input2, right?
> >>
> >>>+ at end example
> >>>+
> >>>  Note that if inputs are of different sizes unused gaps might appear,
> >>>  as not all of output video is used.
> >>>  @example
> >>>-xstack=inputs=9:layout=w3_0|w3_h0+h2|w3_h0|0_h4|0_0|w3+w1_0|0_h1+h2|w3+w1_h0|w3+w1_h1+h2
> >>>+xstack=inputs=9:layout=0_0|0_h0|0_h0+h1|w0_0|w0_h0|w0_h0+h1|w0+w1_0|w0+w1_h0|w0+w1_h0+h1
> >>>  @end example
> >>>+
> >>>+ at item
> >>>+Display 16 inputs into 4x4 grid.
> >>>+
> >>>+Below is the 16 inputs position:
> >>>+ at example
> >>>+input1(0, 0)       | input5(w0, 0)       | input9 (w0+w1, 0)       | input13(w0+w1+w2, 0)
> >>>+input2(0, h0)      | input6(w0, h0)      | input10(w0+w1, h0)      | input14(w0+w1+w2, h0)
> >>>+input3(0, h0+h1)   | input7(w0, h0+h1)   | input11(w0+w1, h0+h1)   | input15(w0+w1+w2, h0+h1)
> >>>+input4(0, h0+h1+h2)| input8(w0, h0+h1+h2)| input12(w0+w1, h0+h1+h2)| input16(w0+w1+w2, h0+h1+h2)
> >>Same as above.
> >>
> >>You should also note that when videos are of different sizes, the
> >>videos may overlap e.g. if height of input5 is greater than input1,
> >>then input6 will be overlaid on top of part of input5.
> >I have tested with different width videos, it's better to same width for every column.
> >Please check my last update version, please ignore the first one, it's wrong version.
> That's a user's choice but warn about the possibility of overlapping
> as well.
OK, so it's better to add the note to the document also. I'll try to
update the old note section, please help to check if it's accuate.

> 
> Gyan
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