Merge commit '22f4d9c303ede1a240538fd105c97047db40dc86'

[ffmpeg] / doc / writing_filters.txt

diff --git a/doc/writing_filters.txt b/doc/writing_filters.txt
index eb16d424806a8ef21dc5bfb67cfd6c51ee8fa52d..66ebb532433d824ec3f8caaf8105e1477206600c 100644 (file)
--- a/doc/writing_filters.txt
+++ b/doc/writing_filters.txt
@@ -3,8 +3,8 @@ libavfilter.
 
 Foreword: just like everything else in FFmpeg, libavfilter is monolithic, which
 means that it is highly recommended that you submit your filters to the FFmpeg
 
 Foreword: just like everything else in FFmpeg, libavfilter is monolithic, which
 means that it is highly recommended that you submit your filters to the FFmpeg

-development mailing-list and make sure it is applied. Otherwise, your filter is
-likely to have a very short lifetime due to more a less regular internal API
+development mailing-list and make sure that they are applied. Otherwise, your filters
+are likely to have a very short lifetime due to more or less regular internal API

 changes, and a limited distribution, review, and testing.
 
 Bootstrap
 changes, and a limited distribution, review, and testing.
 
 Bootstrap


@@ -64,7 +64,7 @@ filter, so you can update the boilerplate with your credits.
 Doxy
 ----
 
 Doxy
 ----
 

-Next chunk is the Doxygen about the file. See http://ffmpeg.org/doxygen/trunk/.
+Next chunk is the Doxygen about the file. See https://ffmpeg.org/doxygen/trunk/.

 Detail here what the filter is, does, and add some references if you feel like
 it.
 
 Detail here what the filter is, does, and add some references if you feel like
 it.
 


@@ -73,11 +73,11 @@ Context
 
 Skip the headers and scroll down to the definition of FoobarContext. This is
 your local state context. It is already filled with 0 when you get it so do not
 
 Skip the headers and scroll down to the definition of FoobarContext. This is
 your local state context. It is already filled with 0 when you get it so do not

-worry about uninitialized read into this context. This is where you put every
-"global" information you need, typically the variable storing the user options.
+worry about uninitialized reads into this context. This is where you put all
+"global" information that you need; typically the variables storing the user options.

 You'll notice the first field "const AVClass *class"; it's the only field you
 You'll notice the first field "const AVClass *class"; it's the only field you

-need to keep assuming you have a context. There are some magic you don't care
-about around this field, just let it be (in first position) for now.
+need to keep assuming you have a context. There is some magic you don't need to
+care about around this field, just let it be (in the first position) for now.

 
 Options
 -------
 
 Options
 -------


@@ -87,7 +87,7 @@ options. For example, -vf foobar=mode=colormix:high=0.4:low=0.1. Most options
 have the following pattern:
   name, description, offset, type, default value, minimum value, maximum value, flags
 
 have the following pattern:
   name, description, offset, type, default value, minimum value, maximum value, flags
 

- - name is the option name, keep it simple, lowercase
+ - name is the option name, keep it simple and lowercase

  - description are short, in lowercase, without period, and describe what they
    do, for example "set the foo of the bar"
  - offset is the offset of the field in your local context, see the OFFSET()
  - description are short, in lowercase, without period, and describe what they
    do, for example "set the foo of the bar"
  - offset is the offset of the field in your local context, see the OFFSET()


@@ -99,7 +99,7 @@ have the following pattern:
  - min and max values define the range of available values, inclusive
  - flags are AVOption generic flags. See AV_OPT_FLAG_* definitions
 
  - min and max values define the range of available values, inclusive
  - flags are AVOption generic flags. See AV_OPT_FLAG_* definitions
 

-In doubt, just look at the other AVOption definitions all around the codebase,
+When in doubt, just look at the other AVOption definitions all around the codebase,

 there are tons of examples.
 
 Class
 there are tons of examples.
 
 Class


@@ -146,14 +146,14 @@ we won't cover this here since vf_foobar is just a simple 1:1 filter.
 uninit()
 ~~~~~~~~
 
 uninit()
 ~~~~~~~~
 

-Similarly, there is the uninit() callback, doing what the name suggest. Free
+Similarly, there is the uninit() callback, doing what the name suggests. Free

 everything you allocated here.
 
 query_formats()
 ~~~~~~~~~~~~~~~
 
 everything you allocated here.
 
 query_formats()
 ~~~~~~~~~~~~~~~
 

-This is following the init() and is used for the format negotiation, basically
-where you say what pixel format(s) (gray, rgb 32, yuv 4:2:0, ...) you accept
+This follows the init() and is used for the format negotiation. Basically
+you specify here what pixel format(s) (gray, rgb 32, yuv 4:2:0, ...) you accept

 for your inputs, and what you can output. All pixel formats are defined in
 libavutil/pixfmt.h. If you don't change the pixel format between the input and
 the output, you just have to define a pixel formats array and call
 for your inputs, and what you can output. All pixel formats are defined in
 libavutil/pixfmt.h. If you don't change the pixel format between the input and
 the output, you just have to define a pixel formats array and call


@@ -182,7 +182,7 @@ will update outlink->w and outlink->h.
 filter_frame()
 ~~~~~~~~~~~~~~
 
 filter_frame()
 ~~~~~~~~~~~~~~
 

-This is the callback you are waiting from the beginning: it is where you
+This is the callback you are waiting for from the beginning: it is where you

 process the received frames. Along with the frame, you get the input link from
 where the frame comes from.
 
 process the received frames. Along with the frame, you get the input link from
 where the frame comes from.
 


@@ -317,7 +317,7 @@ Adding timeline support
 feature to add. In the most simple case, you just have to add
 AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC to the AVFilter.flags. You can typically
 do this when your filter does not need to save the previous context frames, or
 feature to add. In the most simple case, you just have to add
 AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC to the AVFilter.flags. You can typically
 do this when your filter does not need to save the previous context frames, or

-basically if your filter just alter whatever goes in and doesn't need
+basically if your filter just alters whatever goes in and doesn't need

 previous/future information. See for instance commit 86cb986ce that adds
 timeline support to the fieldorder filter.
 
 previous/future information. See for instance commit 86cb986ce that adds
 timeline support to the fieldorder filter.