1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
|
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<!-- Created by GNU Texinfo 6.8, https://www.gnu.org/software/texinfo/ -->
<head>
<meta charset="utf-8">
<title>
FFmpeg Scaler Documentation
</title>
<meta name="viewport" content="width=device-width,initial-scale=1.0">
<link rel="stylesheet" type="text/css" href="bootstrap.min.css">
<link rel="stylesheet" type="text/css" href="style.min.css">
</head>
<body>
<div class="container">
<h1>
FFmpeg Scaler Documentation
</h1>
<div align="center">
</div>
<a name="SEC_Top"></a>
<div class="Contents_element" id="SEC_Contents">
<h2 class="contents-heading">Table of Contents</h2>
<div class="contents">
<ul class="no-bullet">
<li><a id="toc-Description" href="#Description">1 Description</a></li>
<li><a id="toc-Scaler-Options" href="#Scaler-Options">2 Scaler Options</a></li>
<li><a id="toc-See-Also" href="#See-Also">3 See Also</a></li>
<li><a id="toc-Authors" href="#Authors">4 Authors</a></li>
</ul>
</div>
</div>
<a name="Description"></a>
<h2 class="chapter">1 Description<span class="pull-right"><a class="anchor hidden-xs" href="#Description" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Description" aria-hidden="true">TOC</a></span></h2>
<p>The FFmpeg rescaler provides a high-level interface to the libswscale
library image conversion utilities. In particular it allows one to perform
image rescaling and pixel format conversion.
</p>
<span id="scaler_005foptions"></span><a name="Scaler-Options"></a>
<h2 class="chapter">2 Scaler Options<span class="pull-right"><a class="anchor hidden-xs" href="#Scaler-Options" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Scaler-Options" aria-hidden="true">TOC</a></span></h2>
<p>The video scaler supports the following named options.
</p>
<p>Options may be set by specifying -<var>option</var> <var>value</var> in the
FFmpeg tools, with a few API-only exceptions noted below.
For programmatic use, they can be set explicitly in the
<code>SwsContext</code> options or through the <samp>libavutil/opt.h</samp> API.
</p>
<dl compact="compact">
<dd>
<span id="sws_005fflags"></span></dd>
<dt><span><samp>sws_flags</samp></span></dt>
<dd><p>Set the scaler flags. This is also used to set the scaling
algorithm. Only a single algorithm should be selected. Default
value is ‘<samp>bicubic</samp>’.
</p>
<p>It accepts the following values:
</p><dl compact="compact">
<dt><span>‘<samp>fast_bilinear</samp>’</span></dt>
<dd><p>Select fast bilinear scaling algorithm.
</p>
</dd>
<dt><span>‘<samp>bilinear</samp>’</span></dt>
<dd><p>Select bilinear scaling algorithm.
</p>
</dd>
<dt><span>‘<samp>bicubic</samp>’</span></dt>
<dd><p>Select bicubic scaling algorithm.
</p>
</dd>
<dt><span>‘<samp>experimental</samp>’</span></dt>
<dd><p>Select experimental scaling algorithm.
</p>
</dd>
<dt><span>‘<samp>neighbor</samp>’</span></dt>
<dd><p>Select nearest neighbor rescaling algorithm.
</p>
</dd>
<dt><span>‘<samp>area</samp>’</span></dt>
<dd><p>Select averaging area rescaling algorithm.
</p>
</dd>
<dt><span>‘<samp>bicublin</samp>’</span></dt>
<dd><p>Select bicubic scaling algorithm for the luma component, bilinear for
chroma components.
</p>
</dd>
<dt><span>‘<samp>gauss</samp>’</span></dt>
<dd><p>Select Gaussian rescaling algorithm.
</p>
</dd>
<dt><span>‘<samp>sinc</samp>’</span></dt>
<dd><p>Select sinc rescaling algorithm.
</p>
</dd>
<dt><span>‘<samp>lanczos</samp>’</span></dt>
<dd><p>Select Lanczos rescaling algorithm. The default width (alpha) is 3 and can be
changed by setting <code>param0</code>.
</p>
</dd>
<dt><span>‘<samp>spline</samp>’</span></dt>
<dd><p>Select natural bicubic spline rescaling algorithm.
</p>
</dd>
<dt><span>‘<samp>print_info</samp>’</span></dt>
<dd><p>Enable printing/debug logging.
</p>
</dd>
<dt><span>‘<samp>accurate_rnd</samp>’</span></dt>
<dd><p>Enable accurate rounding.
</p>
</dd>
<dt><span>‘<samp>full_chroma_int</samp>’</span></dt>
<dd><p>Enable full chroma interpolation.
</p>
</dd>
<dt><span>‘<samp>full_chroma_inp</samp>’</span></dt>
<dd><p>Select full chroma input.
</p>
</dd>
<dt><span>‘<samp>bitexact</samp>’</span></dt>
<dd><p>Enable bitexact output.
</p></dd>
</dl>
</dd>
<dt><span><samp>srcw <var>(API only)</var></samp></span></dt>
<dd><p>Set source width.
</p>
</dd>
<dt><span><samp>srch <var>(API only)</var></samp></span></dt>
<dd><p>Set source height.
</p>
</dd>
<dt><span><samp>dstw <var>(API only)</var></samp></span></dt>
<dd><p>Set destination width.
</p>
</dd>
<dt><span><samp>dsth <var>(API only)</var></samp></span></dt>
<dd><p>Set destination height.
</p>
</dd>
<dt><span><samp>src_format <var>(API only)</var></samp></span></dt>
<dd><p>Set source pixel format (must be expressed as an integer).
</p>
</dd>
<dt><span><samp>dst_format <var>(API only)</var></samp></span></dt>
<dd><p>Set destination pixel format (must be expressed as an integer).
</p>
</dd>
<dt><span><samp>src_range <var>(boolean)</var></samp></span></dt>
<dd><p>If value is set to <code>1</code>, indicates source is full range. Default value is
<code>0</code>, which indicates source is limited range.
</p>
</dd>
<dt><span><samp>dst_range <var>(boolean)</var></samp></span></dt>
<dd><p>If value is set to <code>1</code>, enable full range for destination. Default value
is <code>0</code>, which enables limited range.
</p>
<span id="sws_005fparams"></span></dd>
<dt><span><samp>param0, param1</samp></span></dt>
<dd><p>Set scaling algorithm parameters. The specified values are specific of
some scaling algorithms and ignored by others. The specified values
are floating point number values.
</p>
</dd>
<dt><span><samp>sws_dither</samp></span></dt>
<dd><p>Set the dithering algorithm. Accepts one of the following
values. Default value is ‘<samp>auto</samp>’.
</p>
<dl compact="compact">
<dt><span>‘<samp>auto</samp>’</span></dt>
<dd><p>automatic choice
</p>
</dd>
<dt><span>‘<samp>none</samp>’</span></dt>
<dd><p>no dithering
</p>
</dd>
<dt><span>‘<samp>bayer</samp>’</span></dt>
<dd><p>bayer dither
</p>
</dd>
<dt><span>‘<samp>ed</samp>’</span></dt>
<dd><p>error diffusion dither
</p>
</dd>
<dt><span>‘<samp>a_dither</samp>’</span></dt>
<dd><p>arithmetic dither, based using addition
</p>
</dd>
<dt><span>‘<samp>x_dither</samp>’</span></dt>
<dd><p>arithmetic dither, based using xor (more random/less apparent patterning that
a_dither).
</p>
</dd>
</dl>
</dd>
<dt><span><samp>alphablend</samp></span></dt>
<dd><p>Set the alpha blending to use when the input has alpha but the output does not.
Default value is ‘<samp>none</samp>’.
</p>
<dl compact="compact">
<dt><span>‘<samp>uniform_color</samp>’</span></dt>
<dd><p>Blend onto a uniform background color
</p>
</dd>
<dt><span>‘<samp>checkerboard</samp>’</span></dt>
<dd><p>Blend onto a checkerboard
</p>
</dd>
<dt><span>‘<samp>none</samp>’</span></dt>
<dd><p>No blending
</p>
</dd>
</dl>
</dd>
</dl>
<a name="See-Also"></a>
<h2 class="chapter">3 See Also<span class="pull-right"><a class="anchor hidden-xs" href="#See-Also" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-See-Also" aria-hidden="true">TOC</a></span></h2>
<p><a href="ffmpeg.html">ffmpeg</a>, <a href="ffplay.html">ffplay</a>, <a href="ffprobe.html">ffprobe</a>,
<a href="libswscale.html">libswscale</a>
</p>
<a name="Authors"></a>
<h2 class="chapter">4 Authors<span class="pull-right"><a class="anchor hidden-xs" href="#Authors" aria-hidden="true">#</a> <a class="anchor hidden-xs"href="#toc-Authors" aria-hidden="true">TOC</a></span></h2>
<p>The FFmpeg developers.
</p>
<p>For details about the authorship, see the Git history of the project
(git://source.ffmpeg.org/ffmpeg), e.g. by typing the command
<code>git log</code> in the FFmpeg source directory, or browsing the
online repository at <a href="http://source.ffmpeg.org">http://source.ffmpeg.org</a>.
</p>
<p>Maintainers for the specific components are listed in the file
<samp>MAINTAINERS</samp> in the source code tree.
</p>
<p style="font-size: small;">
This document was generated using <a href="https://www.gnu.org/software/texinfo/"><em>makeinfo</em></a>.
</p>
</div>
</body>
</html>
|
