Changes between Version 1 and Version 2 of FancyFilteringExamples


Ignore:
Timestamp:
05/30/2012 12:58:58 AM (13 months ago)
Author:
ubitux
Comment:

Add an audio aevalsrc example

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  • FancyFilteringExamples

    v1 v2  
    11= Fancy Filtering Examples = 
    22 
    3 == mandelbrot == 
     3== Video == 
     4 
     5=== mandelbrot === 
    46{{{ 
    57ffplay -f lavfi -i mandelbrot 
    … …  
    79}}} 
    810 
    9 == cellauto == 
     11=== cellauto === 
    1012{{{ 
    1113ffplay -f lavfi -i cellauto 
    … …  
    1315}}} 
    1416 
    15 == life == 
     17=== life === 
    1618{{{ 
    1719ffplay -f lavfi life=s=640x480:mold=10:r=100:ratio=0.1:death_color=blue:life_color=#00ff00,boxblur=2:2 
    1820}}} 
     21 
     22== Audio == 
     23 
     24=== aevalsrc === 
     25 
     26Making some random "musical" keys: 
     27 
     28{{{ 
     29% cat expr 
     30# floor(t): 0 0 0 0 0 ... 1 1 1 1 1 ... 2 2 2 2 2 
     31#  => set a random key when floor(t) changes 
     32if(eq(floor(t),ld(2)), 
     33    st(0,random(4)*3000+1000)); 
     34 
     35# the next value to compare floor(t) with 
     36st(2,floor(t)+1); 
     37 
     38# mod(t,1) makes t always in the range [0;1) for each key 
     39st(1,mod(t,1)); 
     40 
     41# 0.6*... + 0.4*... for "echo" effect 
     42# exp() to mitigate the sound according to the time 
     43(0.6*sin(1*ld(0)*ld(1))+ 
     44 0.4*sin(2*ld(0)*ld(1)))*exp(-4*ld(1)) 
     45}}} 
     46 
     47And to test it: 
     48 
     49{{{ 
     50ffplay -f lavfi -i "aevalsrc=$(grep -v '^#' expr|tr -d '\n'|sed 's/\([,;]\)/\\\1/g')" 
     51}}}