{"id":2060,"date":"2009-11-24T10:01:57","date_gmt":"2009-11-24T08:01:57","guid":{"rendered":"http:\/\/mummila.net\/swirling\/?p=176"},"modified":"2009-11-24T10:01:57","modified_gmt":"2009-11-24T08:01:57","slug":"make-some-noise","status":"publish","type":"post","link":"https:\/\/mummila.net\/nuudelisoppa\/2009\/11\/24\/make-some-noise\/","title":{"rendered":"Make some noise"},"content":{"rendered":"<p>I adapted <a title=\"Geek Thoughts: Making Noise with ImageMagick\" href=\"http:\/\/brunogirin.blogspot.com\/2009\/09\/making-noise-with-imagemagick.html\"><em>Geek Thoughts<\/em>&#8216; &#8220;Making Noise with ImageMagick&#8221;<\/a> in creating video noise \u2014 a video simulating what you used to get when you turned on a television with no signal, back in the analog days. To combine the noise frames created by ImageMagick I used Netpbm, which I had to install separately (that is, it wasn&#8217;t installed by default in Lenny).<\/p>\n<p>Here&#8217;s the Bash multi-liner I used to generate 48 frames worth of noise:<\/p>\n<blockquote>\n<pre><code>(for i in `seq 1 48`; \\\ndo convert -size 640x480 xc: +noise Random \\\n-blur 1x1 -fx intensity -normalize ppm:-; done) \\\n| ppmtompeg kohina.txt<\/code><\/pre>\n<\/blockquote>\n<p>And here&#8217;s <code>kohina.txt<\/code> which specifies how ppmtompeg packs the frames. Note that I just threw this together without too much thought, so it definitely needs <a title=\"Ppmtompeg user manual: Parameter file\" href=\"http:\/\/netpbm.sourceforge.net\/doc\/ppmtompeg.html#parmfile\">tweaking<\/a> depending on what the video is used for and so what (quality, compression, speed) matters. For example, I only used I-frames due to lack of imagination.<\/p>\n<blockquote>\n<pre><code>PATTERN IIIIIIII\nOUTPUT kohina.mpeg\nINPUT_DIR stdin\nBASE_FILE_FORMAT PPM\nINPUT_CONVERT *\nGOP_SIZE 8\nSLICES_PER_FRAME 30\nPIXEL HALF\nRANGE 2\nPSEARCH_ALG LOGARITHMIC\nBSEARCH_ALG SIMPLE\nIQSCALE 1\nPQSCALE 1\nBQSCALE 1\nREFERENCE_FRAME ORIGINAL<\/code><\/pre>\n<\/blockquote>\n<p>And here&#8217;s what it looks like, recompressed with Theora (using Oggconvert): <a title=\"kohina.ogg\" href=\"http:\/\/mummila.net\/nuudelisoppa\/files\/2009\/11\/kohina.ogg\"><code>kohina.ogg<\/code><\/a> (2,8 MB). Generating an accompanyng soundtrack is trivial with Audacity.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>I adapted Geek Thoughts&#8217; ImageMagick noise tutorial in creating video noise \u2014 a video simulating what you used to get when you turned on a television with no signal, back in the analog days.<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[],"tags":[3084],"class_list":["post-2060","post","type-post","status-publish","format-standard","hentry","tag-command-line"],"_links":{"self":[{"href":"https:\/\/mummila.net\/nuudelisoppa\/wp-json\/wp\/v2\/posts\/2060","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mummila.net\/nuudelisoppa\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mummila.net\/nuudelisoppa\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mummila.net\/nuudelisoppa\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/mummila.net\/nuudelisoppa\/wp-json\/wp\/v2\/comments?post=2060"}],"version-history":[{"count":0,"href":"https:\/\/mummila.net\/nuudelisoppa\/wp-json\/wp\/v2\/posts\/2060\/revisions"}],"wp:attachment":[{"href":"https:\/\/mummila.net\/nuudelisoppa\/wp-json\/wp\/v2\/media?parent=2060"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mummila.net\/nuudelisoppa\/wp-json\/wp\/v2\/categories?post=2060"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mummila.net\/nuudelisoppa\/wp-json\/wp\/v2\/tags?post=2060"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}