From 1460719153e5eba1eac8de0510766cf7397740bf Mon Sep 17 00:00:00 2001 From: Ganesh Ajjanagadde Date: Thu, 8 Oct 2015 09:00:44 -0400 Subject: [PATCH] doc/writing_filters: miscellaneous grammar and typo fixes Signed-off-by: Ganesh Ajjanagadde --- doc/writing_filters.txt | 28 ++++++++++++++-------------- 1 file changed, 14 insertions(+), 14 deletions(-) diff --git a/doc/writing_filters.txt b/doc/writing_filters.txt index eb16d42480..66ebb53243 100644 --- 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 -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 @@ -64,7 +64,7 @@ filter, so you can update the boilerplate with your credits. 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. @@ -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 -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 -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 ------- @@ -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 - - 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() @@ -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 -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 @@ -146,14 +146,14 @@ we won't cover this here since vf_foobar is just a simple 1:1 filter. 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() ~~~~~~~~~~~~~~~ -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 @@ -182,7 +182,7 @@ will update outlink->w and outlink->h. 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. @@ -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 -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.