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How to create a video from images with FFmpeg?
...video filter instead of -r for the output framerate
ffmpeg -r 1/5 -i img%03d.png -c:v libx264 -vf fps=25 -pix_fmt yuv420p out.mp4
Alternatively the format video filter can be added to the filter chain to replace -pix_fmt yuv420p like "fps=25,format=yuv420p". The advantage of this method is th...
Bootstrap carousel multiple frames at once
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20
Can this be done with bootstrap 3's carousel? I'm hoping I won't have
to go hunting for yet...
Java String - See if a string contains only numbers and not letters
...Z]+") == false && text.length() > 2){
to:
if (text.matches("[0-9]+") && text.length() > 2) {
Instead of checking that the string doesn't contain alphabetic characters, check to be sure it contains only numerics.
If you actually want to use the numeric value, use Integer.p...
Is SQL or even TSQL Turing Complete?
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Qantas 94 Heavy
14.4k1616 gold badges6060 silver badges7777 bronze badges
answered Sep 28 '11 at 7:59
Jan de VosJan de Vos
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ValueError: math domain error
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edited Sep 3 '17 at 20:49
answered Apr 8 '13 at 23:06
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Best way of returning a random boolean value
...alse].sample is faster than rand(2) == 1. When I performed each operation 10 million times the rand method was 2.179s. The sample method was 1.645s.
– Mirror318
Jun 27 '16 at 4:47
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Pandas dataframe get first row of each group
...column:
>>> df.groupby('id').first().reset_index()
id value
0 1 first
1 2 first
2 3 first
3 4 second
4 5 first
5 6 first
6 7 fourth
To get n first records, you can use head():
>>> df.groupby('id').head(2).reset_index(drop=True)
id value
0 ...
Insert a row to pandas dataframe
...df.sort_index() # sorting by index
And you get, as desired:
A B C
0 2 3 4
1 5 6 7
2 7 8 9
See in Pandas documentation Indexing: Setting with enlargement.
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C# 5 async CTP: why is internal “state” set to 0 in generated code before EndAwait call?
...t. Many thanks to him - and please visit his blog, which rocks.
The value 0 here is only special because it's not a valid state which you might be in just before the await in a normal case. In particular, it's not a state which the state machine may end up testing for elsewhere. I believe that usin...
What does the constant 0.0039215689 represent?
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0.0039215689 is approximately equal to 1/255.
Seeing that this is OpenGL, performance is probably important. So it's probably safe to guess that this was done for performance reasons.
Multiplying by the reciprocal is faster...