[FFmpeg-cvslog] doc/filters: make examples a bit more consistent.
Clément Bœsch
git at videolan.org
Tue Mar 5 21:08:30 CET 2013
ffmpeg | branch: master | Clément Bœsch <ubitux at gmail.com> | Tue Mar 5 21:08:16 2013 +0100| [c0bfc2b90d3db55f963e2d559eee8e2ce8a67974] | committer: Clément Bœsch
doc/filters: make examples a bit more consistent.
Create dedicated subsection and itemize. Not done for every filters, but
a large part is done.
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=c0bfc2b90d3db55f963e2d559eee8e2ce8a67974
---
doc/filters.texi | 136 ++++++++++++++++++++++++++++++++++++++----------------
1 file changed, 96 insertions(+), 40 deletions(-)
diff --git a/doc/filters.texi b/doc/filters.texi
index e260216..a1ab365 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -266,7 +266,7 @@ or the corresponding number value defined in @file{libavutil/channel_layout.h}.
The special parameter "auto", signifies that the filter will
automatically select the output format depending on the output filter.
-Some examples follow.
+ at subsection Examples
@itemize
@item
@@ -647,6 +647,7 @@ select cubic root
@end table
@subsection Examples
+
@itemize
@item
Fade in first 15 seconds of audio:
@@ -722,12 +723,17 @@ All inputs must have the same sample rate, and format.
If inputs do not have the same duration, the output will stop with the
shortest.
-Example: merge two mono files into a stereo stream:
+ at subsection Examples
+
+ at itemize
+ at item
+Merge two mono files into a stereo stream:
@example
amovie=left.wav [l] ; amovie=right.mp3 [r] ; [l] [r] amerge
@end example
-Example: multiple merges:
+ at item
+Multiple merges:
@example
ffmpeg -f lavfi -i "
amovie=input.mkv:si=0 [a0];
@@ -738,6 +744,7 @@ amovie=input.mkv:si=4 [a4];
amovie=input.mkv:si=5 [a5];
[a0][a1][a2][a3][a4][a5] amerge=inputs=6" -c:a pcm_s16le output.mkv
@end example
+ at end itemize
@section amix
@@ -803,16 +810,22 @@ expresses a sample rate and @var{resampler_options} is a list of
@var{key}=@var{value} pairs, separated by ":". See the
ffmpeg-resampler manual for the complete list of supported options.
-For example, to resample the input audio to 44100Hz:
+ at subsection Examples
+
+ at itemize
+ at item
+Resample the input audio to 44100Hz:
@example
aresample=44100
@end example
-To stretch/squeeze samples to the given timestamps, with a maximum of 1000
+ at item
+Stretch/squeeze samples to the given timestamps, with a maximum of 1000
samples per second compensation:
@example
aresample=async=1000
@end example
+ at end itemize
@section asetnsamples
@@ -952,15 +965,21 @@ The filter accepts exactly one parameter, the audio tempo. If not
specified then the filter will assume nominal 1.0 tempo. Tempo must
be in the [0.5, 2.0] range.
-For example, to slow down audio to 80% tempo:
+ at subsection Examples
+
+ at itemize
+ at item
+Slow down audio to 80% tempo:
@example
atempo=0.8
@end example
-For example, to speed up audio to 125% tempo:
+ at item
+To speed up audio to 125% tempo:
@example
atempo=1.25
@end example
+ at end itemize
@section earwax
@@ -1082,16 +1101,22 @@ Set noise tolerance. Can be specified in dB (in case "dB" is appended to the
specified value) or amplitude ratio. Default is -60dB, or 0.001.
@end table
+ at subsection Examples
+
+ at itemize
+ at item
Detect 5 seconds of silence with -50dB noise tolerance:
@example
silencedetect=n=-50dB:d=5
@end example
+ at item
Complete example with @command{ffmpeg} to detect silence with 0.0001 noise
tolerance in @file{silence.mp3}:
@example
ffmpeg -f lavfi -i amovie=silence.mp3,silencedetect=noise=0.0001 -f null -
@end example
+ at end itemize
@section asyncts
Synchronize audio data with timestamps by squeezing/stretching it and/or
@@ -1303,6 +1328,8 @@ the samples).
All volumes are in decibels relative to the maximum PCM value.
+ at subsection Examples
+
Here is an excerpt of the output:
@example
[Parsed_volumedetect_0 @ 0xa23120] mean_volume: -27 dB
@@ -1369,7 +1396,8 @@ must be consistent.
@end table
-For example:
+ at subsection Examples
+
@example
abuffer=44100:s16p:stereo
@end example
@@ -1442,7 +1470,6 @@ sample rate
@subsection Examples
@itemize
-
@item
Generate silence:
@example
@@ -1450,7 +1477,6 @@ aevalsrc=0
@end example
@item
-
Generate a sin signal with frequency of 440 Hz, set sample rate to
8000 Hz:
@example
@@ -1516,14 +1542,21 @@ Set the number of samples per requested frames.
@end table
-Follow some examples:
+ at subsection Examples
+
+ at itemize
+ at item
+Set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO.
@example
-# set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO.
anullsrc=r=48000:cl=4
+ at end example
-# same as
+ at item
+Do the same operation with a more obvious syntax:
+ at example
anullsrc=r=48000:cl=mono
@end example
+ at end itemize
@section abuffer
Buffer audio frames, and make them available to the filter chain.
@@ -1871,10 +1904,9 @@ Value of pixel component at current location for second video frame (bottom laye
@end table
@end table
-Some examples follow.
+ at subsection Examples
@itemize
-
@item
Apply transition from bottom layer to top layer in first 10 seconds:
@example
@@ -1941,7 +1973,7 @@ corresponding value set for @option{luma_power}.
A value of 0 will disable the effect.
@end table
-Some examples follow.
+ at subsection Examples
@itemize
@item
@@ -2076,6 +2108,7 @@ The expression for @var{x} may depend on @var{y}, and the expression
for @var{y} may depend on @var{x}.
@subsection Examples
+
@itemize
@item
Crop area with size 100x100 at position (12,34).
@@ -2263,10 +2296,9 @@ finding the right @var{x}, @var{y}, @var{w}, @var{h} parameters, and
@end table
-Some examples follow.
+ at subsection Examples
@itemize
-
@item
Set a rectangle covering the area with top left corner coordinates 0,0
and size 100x77, setting a band of size 10:
@@ -2382,7 +2414,8 @@ video with inverted luma.
Set the thickness of the box edge. Default value is @code{4}.
@end table
-Some examples follow:
+ at subsection Examples
+
@itemize
@item
Draw a black box around the edge of the input image:
@@ -2680,10 +2713,7 @@ The timestamp of the current frame, in seconds, with microsecond accuracy.
@subsection Examples
-Some examples follow.
-
@itemize
-
@item
Draw "Test Text" with font FreeSerif, using the default values for the
optional parameters.
@@ -2818,6 +2848,7 @@ Default value is 0.
@end table
@subsection Examples
+
@itemize
@item
Fade in first 30 frames of video:
@@ -2931,14 +2962,20 @@ the next filter.
The filter accepts a list of pixel format names, separated by ":",
for example "yuv420p:monow:rgb24".
-Some examples follow:
+ at subsection Examples
+
+ at itemize
+ at item
+Convert the input video to the format @var{yuv420p}
@example
-# convert the input video to the format "yuv420p"
format=yuv420p
+ at end example
-# convert the input video to any of the formats in the list
+Convert the input video to any of the formats in the list
+ at example
format=yuv420p:yuv444p:yuv410p
@end example
+ at end itemize
@section fps
@@ -3017,7 +3054,7 @@ description), a position (specified by the syntax @var{X}/@var{Y},
The number and kind of parameters depend on the loaded effect. If an
effect parameter is not specified the default value is set.
-Some examples follow:
+ at subsection Examples
@itemize
@item
@@ -3114,7 +3151,7 @@ plane. Returns 0 if there is no such plane.
For functions, if @var{x} and @var{y} are outside the area, the value will be
automatically clipped to the closer edge.
-Some examples follow:
+ at subsection Examples
@itemize
@item
@@ -3421,7 +3458,8 @@ The options can also be set using the syntax: @var{hue}:@var{saturation}
In this case @var{hue} is expressed in degrees.
-Some examples follow:
+ at subsection Examples
+
@itemize
@item
Set the hue to 90 degrees and the saturation to 1.0:
@@ -3788,7 +3826,8 @@ The parameter syntax and behavior for the listed filters are the same
of the corresponding MPlayer filters. For detailed instructions check
the "VIDEO FILTERS" section in the MPlayer manual.
-Some examples follow:
+ at subsection Examples
+
@itemize
@item
Adjust gamma, brightness, contrast:
@@ -3814,15 +3853,22 @@ input to the next filter.
The filter accepts a list of pixel format names, separated by ":",
for example "yuv420p:monow:rgb24".
-Some examples follow:
+ at subsection Examples
+
+ at itemize
+ at item
+Force libavfilter to use a format different from @var{yuv420p} for the
+input to the vflip filter:
@example
-# force libavfilter to use a format different from "yuv420p" for the
-# input to the vflip filter
noformat=yuv420p,vflip
+ at end example
-# convert the input video to any of the formats not contained in the list
+ at item
+Convert the input video to any of the formats not contained in the list:
+ at example
noformat=yuv420p:yuv444p:yuv410p
@end example
+ at end itemize
@section noise
@@ -3869,9 +3915,10 @@ uniform noise (gaussian otherwise)
@end table
@end table
-Some examples follow:
- at example
+ at subsection Examples
+
Add temporal and uniform noise to input video:
+ at example
noise=alls=20:allf=t+u
@end example
@@ -5288,7 +5335,8 @@ Default value is 1.0 for @option{luma_amount}, 0.0 for
@option{chroma_amount}.
@end table
-Some examples follow:
+ at subsection Examples
+
@itemize
@item
Apply strong luma sharpen effect:
@@ -6400,15 +6448,21 @@ other integer value between this range is allowed.
@end table
-Example of real-time graph using @command{ffplay}, with a EBU scale meter +18:
+ at subsection Examples
+
+ at itemize
+ at item
+Real-time graph using @command{ffplay}, with a EBU scale meter +18:
@example
ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]"
@end example
+ at item
Run an analysis with @command{ffmpeg}:
@example
ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
@end example
+ at end itemize
@section settb, asettb
@@ -6509,7 +6563,8 @@ explicitly by the user.
Different frame rates are acceptable but will result in variable frame rate
at output; be sure to configure the output file to handle it.
-Examples:
+ at subsection Examples
+
@itemize
@item
Concatenate an opening, an episode and an ending, all in bilingual version
@@ -6652,7 +6707,8 @@ option @var{n}. Default value is "25".
Specify the video size for the output. Default value is "600x240".
@end table
-Some examples follow.
+ at subsection Examples
+
@itemize
@item
Output the input file audio and the corresponding video representation
@@ -6739,7 +6795,7 @@ input -----------> deltapts0 --> overlay --> output
movie --> scale--> deltapts1 -------+
@end example
-Some examples follow.
+ at subsection Examples
@itemize
@item
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