{"id":2618,"date":"2017-11-27T09:41:00","date_gmt":"2017-11-27T08:41:00","guid":{"rendered":"http:\/\/milchyn.cz\/?page_id=2618"},"modified":"2025-12-07T16:29:27","modified_gmt":"2025-12-07T16:29:27","slug":"ffmpeg-zpracovani-multimedii","status":"publish","type":"page","link":"https:\/\/milchyn.cz\/ffmpeg-zpracovani-multimedii","title":{"rendered":"ffmpeg &#8211; zpracov\u00e1n\u00ed multim\u00e9di\u00ed"},"content":{"rendered":"<p>Jedn\u00e1 se o \u0161ikovn\u00fd komplexn\u00ed n\u00e1stroj z p\u0159\u00edkazov\u00e9 \u0159\u00e1dky pro p\u0159ehr\u00e1v\u00e1n\u00ed <i>(ffplay)<\/i>, \u00fapravu form\u00e1t\u016f audio a video soubor\u016f <em>(\u00faprava rozm\u011bru obrazu, hlasitosti, metadat a dal\u0161\u00edch parametr\u016f)<\/em>. Lze zadat i velice jednodu\u0161e, kdy <mark>podle koncovky c\u00edlov\u00e9ho souboru<\/mark> bude v\u00fdchoz\u00ed form\u00e1t. Aby nedo\u0161lo k po\u0161kozen\u00ed vstupn\u00edho souboru kolizn\u00edm p\u0159eps\u00e1n\u00edm v\u00fdstupem, mus\u00ed se<mark> v\u00fdstup nasm\u011brovat do jin\u00e9ho souboru ne\u017e je soubor vstupn\u00ed<\/mark>.<\/p>\n<p>&nbsp;<\/p>\n<a id=\"instalace_ffmpeg\"><\/a><div class=\"mch-acr\"><div class=\"mch-acr-title\" role=\"button\" tabindex=\"0\" aria-expanded=\"false\" aria-controls=\"mch-acr-content-19\">Instalace ffmpeg<\/div><div id=\"mch-acr-content-19\" class=\"mch-acr-content\" hidden><\/p>\n<p>\ud83d\udcbb <code>sudo apt install ffmpeg x264 x265<\/code><\/p>\n<p><\/div><\/div>\n<a id=\"informace_o_audio_video_souboru\"><\/a><div class=\"mch-acr\"><div class=\"mch-acr-title\" role=\"button\" tabindex=\"0\" aria-expanded=\"false\" aria-controls=\"mch-acr-content-20\">Informace o Audio\/Video souboru<\/div><div id=\"mch-acr-content-20\" class=\"mch-acr-content\" hidden><\/p>\n<p>Zji\u0161t\u011bn\u00ed form\u00e1tu a dal\u0161\u00edch parametr\u016f<\/p>\n<p>\ud83d\udcbb <code>ffprobe zdrojov\u00fd_soubor.mp4<\/code><\/p>\n<p><\/div><\/div>\n<a id=\"jednoduch\u00fd_p\u0159ehr\u00e1va\u010d_ffplay_pro_zkou\u0161en\u00ed_ffmpeg_parametr\u016f\"><\/a><div class=\"mch-acr\"><div class=\"mch-acr-title\" role=\"button\" tabindex=\"0\" aria-expanded=\"false\" aria-controls=\"mch-acr-content-21\">Jednoduch\u00fd p\u0159ehr\u00e1va\u010d \u201effplay\u201c pro zkou\u0161en\u00ed \u201effmpeg\u201c parametr\u016f<\/div><div id=\"mch-acr-content-21\" class=\"mch-acr-content\" hidden><\/p>\n<h5>Popis<\/h5>\n<p>Pro mo\u017enost odzkou\u0161en\u00ed n\u011bkter\u00fdch parametr\u016f p\u0159\u00edkazu ffmpeg je mo\u017eno si jejich \u00fa\u010dinek rovnou zobrazit s pou\u017eit\u00edm ffplay <i>(samoz\u0159ejm\u011b s vynech\u00e1n\u00edm v\u00fdstupn\u00edho souboru)<\/i>.<\/p>\n<h5>P\u0159\u00edklad<\/h5>\n<p>P\u0159ehr\u00e1n\u00ed souboru s upraven\u00fdm rozli\u0161en\u00edm obrazu\u00a0<i>(parametr -i nen\u00ed povinn\u00fd pro jeden soubor bez slo\u017eit\u00fdch filtr\u016f).<\/i><\/p>\n<p>\ud83d\udcbb <code>ffplay -i zdrojov\u00fd_soubor.mp4 -vf scale=800:450<\/code><\/p>\n<p><\/div><\/div>\n<a id=\"mo\u017enosti_komprimace_mp4_video_souboru_p\u0159\u00edklad_form\u00e1t_pro_web\"><\/a><div class=\"mch-acr\"><div class=\"mch-acr-title\" role=\"button\" tabindex=\"0\" aria-expanded=\"false\" aria-controls=\"mch-acr-content-22\">Mo\u017enosti komprimace mp4 video souboru <i>(p\u0159\u00edklad form\u00e1t pro web)<\/i><\/div><div id=\"mch-acr-content-22\" class=\"mch-acr-content\" hidden><\/p>\n<h5>Komprima\u010dn\u00ed vztah \u201en\u011bco za n\u011bco\u201c<\/h5>\n<p>Obecn\u011b plat\u00ed:<\/p>\n<table>\n<tbody>\n<tr>\n<td>\ud83d\udd34 n\u00edzk\u00e1 komprimace<\/td>\n<td>\ud83d\udfe2 rychl\u00fd p\u0159evod <i>(n\u00edzk\u00e9 zat\u00ed\u017een\u00ed CPU)<\/i><\/td>\n<td>\ud83d\udd34 velk\u00fd v\u00fdsledn\u00fd soubor<\/td>\n<\/tr>\n<tr>\n<td>\ud83d\udfe2 velk\u00e1 komprimace <i>(\u00faspora m\u00edsta)<\/i><\/td>\n<td>\ud83d\udd34 pomal\u00fd p\u0159evod\u00a0<i>(vysok\u00e9 zat\u00ed\u017een\u00ed CPU)<\/i><\/td>\n<td>\ud83d\udfe2 mal\u00fd v\u00fdsledn\u00fd soubor<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h5>Mo\u017enosti komprimace<\/h5>\n<p>Podstatn\u00e1 je hodnota parametru <samp>-preset<\/samp>\u00a0 ur\u010duj\u00edc\u00ed m\u00edru komprimace:<\/p>\n<table>\n<tbody>\n<tr>\n<td><em><strong>hodnota parametru<\/strong><\/em><\/td>\n<td><em><strong>v\u00fdsledn\u00fd soubor<\/strong><\/em><\/td>\n<td><em><strong>ur\u010den\u00ed<\/strong><\/em><\/td>\n<\/tr>\n<tr>\n<td><samp>ultrafast<\/samp><\/td>\n<td>\ud83d\udd34 velmi velk\u00fd<\/td>\n<td>testy, realtime stream <i>(velmi rychl\u00e1 komprimace)<\/i><\/td>\n<\/tr>\n<tr>\n<td><code data-start=&#8220;506&#8243; data-end=&#8220;517&#8243;>superfast<\/code><\/td>\n<td>\ud83d\udd34 velk\u00fd<\/td>\n<td>rychl\u00fd n\u00e1hled, m\u00e9n\u011b d\u016fle\u017eit\u00e9 video<\/td>\n<\/tr>\n<tr>\n<td><code data-start=&#8220;605&#8243; data-end=&#8220;615&#8243;>veryfast<\/code><\/td>\n<td>\ud83d\udfe0 v\u011bt\u0161\u00ed o 10\u201320 %<\/td>\n<td>\u017eiv\u00e9 streamov\u00e1n\u00ed, rychl\u00fd p\u0159evod<\/td>\n<\/tr>\n<tr>\n<td><code data-start=&#8220;705&#8243; data-end=&#8220;713&#8243;>faster<\/code><\/td>\n<td>\ud83d\udfe0 o n\u011bco v\u011bt\u0161\u00ed<\/td>\n<td>kompromis<\/td>\n<\/tr>\n<tr>\n<td><code data-start=&#8220;773&#8243; data-end=&#8220;779&#8243;>fast<\/code><\/td>\n<td>\ud83d\udfe1 skoro stejn\u00fd<\/td>\n<td>b\u011b\u017en\u00e9 pou\u017eit\u00ed<\/td>\n<\/tr>\n<tr>\n<td><strong><code data-start=&#8220;845&#8243; data-end=&#8220;853&#8243;>medium<\/code><\/strong><\/td>\n<td>\ud83d\udfe1 vyv\u00e1\u017een\u00e9<\/td>\n<td><strong>univerz\u00e1ln\u00ed, doporu\u010den\u00fd standard<\/strong><\/td>\n<\/tr>\n<tr>\n<td><code data-start=&#8220;926&#8243; data-end=&#8220;932&#8243;>slow<\/code><\/td>\n<td>\ud83d\udfe2 men\u0161\u00ed (\u221210\u201320 %)<\/td>\n<td>archivace, web<\/td>\n<\/tr>\n<tr>\n<td><code data-start=&#8220;1044&#8243; data-end=&#8220;1052&#8243;>slower<\/code><\/td>\n<td>\ud83d\udfe2 je\u0161t\u011b men\u0161\u00ed<\/td>\n<td>web, velk\u00e1 komprese <i>(pomal\u00e1 komprimace)<\/i><\/td>\n<\/tr>\n<tr>\n<td><code data-start=&#8220;1140&#8243; data-end=&#8220;1150&#8243;>veryslow<\/code><\/td>\n<td>\ud83d\udfe2\ud83d\udfe2 u\u017e jen o m\u00e1lo men\u0161\u00ed ne\u017e u <code data-start=&#8220;1044&#8243; data-end=&#8220;1052&#8243;>slower<\/code><\/td>\n<td>ji\u017e neefektivn\u00ed \u00faspora v\u016f\u010di velmi pomal\u00e9 komprimaci<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h5>P\u0159\u00edklad komprimace pro Web<\/h5>\n<p>P\u0159evod souboru na \u00fasporn\u00fd form\u00e1t:<\/p>\n<ul>\n<li><samp>taskset -c 0-3<\/samp> &#8211; omezen\u00ed zpracov\u00e1n\u00ed na 4 CPU vl\u00e1kna<\/li>\n<li><samp>-vf scale=800:450<\/samp> &#8211; rozli\u0161en\u00ed 800&#215;450<\/li>\n<li><samp>-crf 30<\/samp> &#8211; kvalita obrazu <i>(vy\u0161\u0161\u00ed \u010d\u00edslo &#8211; ni\u017e\u0161\u00ed kvalita)<\/i><\/li>\n<li><samp>-preset slow<\/samp> &#8211; m\u00edra komprese<\/li>\n<\/ul>\n<p>\ud83d\udcbb <code>taskset -c 0-3 ffmpeg -i zdrojov\u00fd_soubor.mp4 -c:v libx264 -vf scale=800:450 -crf 30 -preset slow c\u00edlov\u00fd_soubor__web.mp4<\/code><\/p>\n<p><\/div><\/div>\n<a id=\"p\u0159evod_mp4_videa_z_prom\u011bnliv\u00e9ho_sn\u00edmkov\u00e1n\u00ed_vfr_na_pevn\u00e9_25_fps\"><\/a><div class=\"mch-acr\"><div class=\"mch-acr-title\" role=\"button\" tabindex=\"0\" aria-expanded=\"false\" aria-controls=\"mch-acr-content-23\">P\u0159evod mp4 videa z prom\u011bnliv\u00e9ho sn\u00edmkov\u00e1n\u00ed <i>(VFR)<\/i> na pevn\u00e9 25 FPS<\/div><div id=\"mch-acr-content-23\" class=\"mch-acr-content\" hidden><\/p>\n<p>Video s pevn\u00fdm sn\u00edmkov\u00e1n\u00edm b\u00fdv\u00e1 po\u017eadov\u00e1no nap\u0159\u00edklad ve st\u0159ihov\u00e9m studiu Kdenlive a lze p\u0159ipravit p\u0159\u00edkazem:<\/p>\n<p>\ud83d\udcbb <code>ffmpeg -i zdrojov\u00fd_soubor.mp4 -vf &quot;fps=25&quot; -c:v libx264 -preset fast -crf 25 -c:a copy c\u00edlov\u00fd_soubor.25fps.mp4<\/code><\/p>\n<p>Pro soubory v dres\u00e1\u0159i dle masky <samp>*.mp4<\/samp> a s dotazov\u00fdm promptem pro p\u0159epis existuj\u00edc\u00edho c\u00edle:<\/p>\n<p>\ud83d\udcbb <code>for x in *.mp4; do ffmpeg -i &quot;$x&quot; -vf &quot;fps=25&quot; -c:v libx264 -preset fast -crf 25 -c:a copy &quot;${x%.mp4}.25fps.mp4&quot; ;done<\/code><\/p>\n<p><\/div><\/div>\n<a id=\"p\u0159evod_form\u00e1tu_z_mp4_video_do_mp3_audio_souboru\"><\/a><div class=\"mch-acr\"><div class=\"mch-acr-title\" role=\"button\" tabindex=\"0\" aria-expanded=\"false\" aria-controls=\"mch-acr-content-24\">P\u0159evod form\u00e1tu z mp4 video do mp3 audio souboru<\/div><div id=\"mch-acr-content-24\" class=\"mch-acr-content\" hidden><\/p>\n<p>\ud83d\udcbb <code>ffmpeg -i zdrojov\u00fd_soubor.mp4 c\u00edlov\u00fd_soubor.mp3<\/code><\/p>\n<p>s \u00fapravou zes\u00edlen\u00ed hlasitosti +8dB a ubr\u00e1n\u00ed v\u00fd\u0161ek -6dB od 8kHz.<\/p>\n<p>\ud83d\udcbb <code>ffmpeg -i zdrojov\u00fd_soubor.mp4 -filter:a &quot;volume=+8dB,treble=gain=-6dB:frequency=8000&quot; c\u00edlov\u00fd_soubor.mp3<\/code><\/p>\n<p><\/div><\/div>\n<a id=\"p\u0159evod_form\u00e1tu_videa_z_avi_souboru_do_mp4_souboru\"><\/a><div class=\"mch-acr\"><div class=\"mch-acr-title\" role=\"button\" tabindex=\"0\" aria-expanded=\"false\" aria-controls=\"mch-acr-content-25\">P\u0159evod form\u00e1tu videa z avi souboru do mp4 souboru<\/div><div id=\"mch-acr-content-25\" class=\"mch-acr-content\" hidden><\/p>\n<p>\ud83d\udcbb <code>ffmpeg -i zdrojov\u00fd_soubor.avi c\u00edlov\u00fd_soubor.mp4<\/code><\/p>\n<p>P\u0159evod s vymaz\u00e1n\u00edm metadat<\/p>\n<p>\ud83d\udcbb <code>ffmpeg -i zdrojov\u00fd_soubor.avi -metadata title=&quot;&quot; c\u00edlov\u00fd_soubor.mp4<\/code><\/p>\n<p><\/div><\/div>\n<a id=\"p\u0159evod_audio_form\u00e1tu_mp4_videa_z_6_kan\u00e1lov\u00e9ho_verze_5_1_na_stereo_do_mp4_souboru\"><\/a><div class=\"mch-acr\"><div class=\"mch-acr-title\" role=\"button\" tabindex=\"0\" aria-expanded=\"false\" aria-controls=\"mch-acr-content-26\">P\u0159evod audio form\u00e1tu MP4 videa z 6 kan\u00e1lov\u00e9ho<em> (verze 5.1)<\/em> na stereo do mp4 souboru<\/div><div id=\"mch-acr-content-26\" class=\"mch-acr-content\" hidden><\/p>\n<p>\ud83d\udcbb <code>ffmpeg -i zdrojov\u00fd_soubor.mp4 -ac 2 -c:v copy c\u00edlov\u00fd_soubor.mp4<\/code><\/p>\n<p>P\u0159evod s procentu\u00e1ln\u00edm poskl\u00e1d\u00e1n\u00edm stereo kan\u00e1l\u016f <code>lev\u00fd = st\u0159edov\u00fd + 30% lev\u00fd p\u0159edn\u00ed + 30% lev\u00fd zadn\u00ed<\/code> a <code>prav\u00fd = st\u0159edov\u00fd + 30% prav\u00fd p\u0159edn\u00ed + 30% prav\u00fd zadn\u00ed<\/code><\/p>\n<p>\ud83d\udcbb <code>ffmpeg -i zdrojov\u00fd_soubor.mp4 -filter_complex &quot;[0:a]pan=stereo|FL=FC+0.30*FL+0.30*BL|FR=FC+0.30*FR+0.30*BR&quot; -c:v copy c\u00edlov\u00fd_soubor.mp4<\/code><\/p>\n<p><\/div><\/div>\n<a id=\"vytvo\u0159en\u00ed_gif_z_video_souboru\"><\/a><div class=\"mch-acr\"><div class=\"mch-acr-title\" role=\"button\" tabindex=\"0\" aria-expanded=\"false\" aria-controls=\"mch-acr-content-27\">Vytvo\u0159en\u00ed GIF z  video souboru<\/div><div id=\"mch-acr-content-27\" class=\"mch-acr-content\" hidden><\/p>\n<p>Nastaven\u00ed na 8 fps a rozli\u0161en\u00ed 160&#215;120 px<\/p>\n<p>\ud83d\udcbb <code>ffmpeg -i zdrojov\u00fd_soubor.gif -r 8 -vf &quot;scale=160x120&quot; c\u00edlov\u00fd_soubor.gif<\/code><\/p>\n<p>P\u0159evod s vymaz\u00e1n\u00edm metadat<\/p>\n<p>\ud83d\udcbb <code>ffmpeg -i zdrojov\u00fd_soubor.gif -metadata title=&quot;&quot;\u00a0 c\u00edlov\u00fd_soubor.mp4<\/code><\/p>\n<p>P\u0159evod s p\u0159edvolen\u00fdm video\/audio kodekem a kvalitou<\/p>\n<p>\ud83d\udcbb <code>ffmpeg -i zdrojov\u00fd_soubor.avi -vcodec libx264 -crf 24 -acodec libmp3lame -b:a 128k -ac 2 c\u00edlov\u00fd_soubor.mp4<\/code><\/p>\n<p><\/div><\/div>\n<a id=\"filtr_pro_zm\u011bnu_rozm\u011br\u016f_a_o\u0159\u00edznut\u00ed_okraj\u016f_z_video_souboru\"><\/a><div class=\"mch-acr\"><div class=\"mch-acr-title\" role=\"button\" tabindex=\"0\" aria-expanded=\"false\" aria-controls=\"mch-acr-content-28\">Filtr pro zm\u011bnu rozm\u011br\u016f a o\u0159\u00edznut\u00ed okraj\u016f z video souboru<\/div><div id=\"mch-acr-content-28\" class=\"mch-acr-content\" hidden><\/p>\n<p>Princip o\u0159\u00edznut\u00ed a posun obrazu, \u201escale\u201c pro v\u00fdslednou velikost obrazu<\/p>\n<p><samp>&#8230; -vf &#8222;crop={o\u0159ez_X}:{o\u0159ez_Y}[:{posun_zleva_X}[:{posun_shora_Y}]][,scale={rozm\u011br_X}x{rozm\u011br_Y}]&#8220; &#8230;<\/samp><\/p>\n<p>P\u0159\u00edklad o\u0159\u00edznut\u00ed s vycentrov\u00e1n\u00edm a zm\u011bnou rozm\u011bru<\/p>\n<p><samp>&#8230; -vf &#8222;crop=in_w-0:in_h-148:(in_w-out_w)\/2+0:(in_h-out_h)\/2+1,scale=1024&#215;576&#8220; &#8230;<\/samp><\/p>\n<p><\/div><\/div>\n<a id=\"oto\u010den\u00ed_videa\"><\/a><div class=\"mch-acr\"><div class=\"mch-acr-title\" role=\"button\" tabindex=\"0\" aria-expanded=\"false\" aria-controls=\"mch-acr-content-29\">Oto\u010den\u00ed videa<\/div><div id=\"mch-acr-content-29\" class=\"mch-acr-content\" hidden><\/p>\n<p>Bez p\u0159ek\u00f3dov\u00e1n\u00ed a ve stupn\u00edch 90, 180, 270:<\/p>\n<p>\ud83d\udcbb <code>ffmpeg -i zdrojov\u00fd_soubor.mp4 -metadata:s:v rotate=&quot;90&quot; -codec copy c\u00edlov\u00fd_soubor.mp4<\/code><\/p>\n<p>&nbsp;<\/p>\n<p>P\u0159ek\u00f3dov\u00e1n\u00edm dle parametru transpose 1=90\u00b0, 2=180\u00b0, 3=270\u00b0 :<\/p>\n<p>\ud83d\udcbb <code>ffmpeg -noautorotate -i zdrojov\u00fd_soubor.mp4 -vf &quot;transpose=1,scale=-1:720,pad=1280:720:(ow-iw)\/2:(oh-ih)\/2&quot; -c:v libx264 -crf 25 -preset slow -c:a copy -map_metadata 0 -metadata:s:v:0 rotate=0 c\u00edlov\u00fd_soubor.mp4<\/code><\/p>\n<p>nebo<\/p>\n<p>\ud83d\udcbb <code>ffmpeg -noautorotate -i zdrojov\u00fd_soubor.mp4 -vf &quot;transpose=1,scale=-1:720,pad=1280:720:(ow-iw)\/2:(oh-ih)\/2&quot; -c:v libx264 -crf 25 -preset slow -c:a copy -map_metadata -1 -movflags +faststart c\u00edlov\u00fd_soubor.mp4<\/code><\/p>\n<p><\/div><\/div>\n<a id=\"p\u0159evod_videa_z_dvd_vob_do_souboru\"><\/a><div class=\"mch-acr\"><div class=\"mch-acr-title\" role=\"button\" tabindex=\"0\" aria-expanded=\"false\" aria-controls=\"mch-acr-content-30\">P\u0159evod videa z DVD <em>(VOB)<\/em> do souboru<\/div><div id=\"mch-acr-content-30\" class=\"mch-acr-content\" hidden><\/p>\n<p>P\u0159ipojen\u00ed DVD, zji\u0161t\u011bn\u00ed soubor\u016f a form\u00e1tu pot\u0159ebn\u00e9ho videa. Reklamy, bonusy a pauzy jsou nejmen\u0161\u00ed soubory<\/p>\n<p>\ud83d\udcbb <code>sudo mount \/dev\/sr0 \/mnt<\/code><\/p>\n<p>\ud83d\udcbb <code>ll \/mnt\/VIDEO_TS\/<\/code><\/p>\n<p>\ud83d\udcbb <code>ls -l \/mnt\/VIDEO_TS\/VTS_*<\/code><\/p>\n<p>\ud83d\udcbb <code>ffprobe \/mnt\/VIDEO_TS\/VTS_...<\/code><\/p>\n<p>P\u0159\u00edklad: \u201e720&#215;576 &#8211; 5:4\u201c video soubor =&gt; o\u0159\u00edznut\u00ed svisl\u00fdch okraj\u016f =&gt; p\u0159evod na \u201e1024&#215;768 &#8211; 4:3\u201c<\/p>\n<p>\ud83d\udcbb <code>cat \/mnt\/VIDEO_TS\/VTS_01_[1-9].VOB | ffmpeg -y -i - -metadata title=&quot;&quot; -vcodec libx264 -vf &quot;crop=in_w-24:in_h:(in_w-out_w)\/2-4,scale=1024x768&quot; -crf 26 -deinterlace -preset veryfast -acodec libmp3lame -b:a 128k -ac 2 c\u00edlov\u00fd_soubor.mp4<\/code><\/p>\n<p>P\u0159\u00edklad: \u201e720&#215;576 &#8211; 5:4\u201c video soubor =&gt; o\u0159\u00edznut\u00ed vodorovn\u00fdch okraj\u016f =&gt; p\u0159evod na \u201e1024&#215;576 &#8211; 16:9\u201c<\/p>\n<p>\ud83d\udcbb <code>cat \/mnt\/VIDEO_TS\/VTS_01_[1-9].VOB | ffmpeg -y -i - -metadata title=&quot;&quot; -vcodec libx264 -vf &quot;crop=in_w-0:in_h-146:(in_w-out_w)\/2+0:(in_h-out_h)\/2+1,scale=1024x576&quot; -crf 26 -deinterlace -preset veryfast -acodec libmp3lame -b:a 128k -ac 2 c\u00edlov\u00fd_soubor.mp4<\/code><\/p>\n<p><\/div><\/div>\n<a id=\"p\u0159evod_videa_z_dvd_vob_do_souboru_s_volbou_jazyka\"><\/a><div class=\"mch-acr\"><div class=\"mch-acr-title\" role=\"button\" tabindex=\"0\" aria-expanded=\"false\" aria-controls=\"mch-acr-content-31\">P\u0159evod videa z DVD<em> (VOB)<\/em> do souboru s volbou jazyka<\/div><div id=\"mch-acr-content-31\" class=\"mch-acr-content\" hidden><\/p>\n<p>P\u0159\u00edklad: P\u0159emapov\u00e1n\u00ed audio kan\u00e1lu -map 0:1 =&gt; -map 0:3<\/p>\n<p>\ud83d\udcbb <code>cat \/mnt\/VIDEO_TS\/VTS_01_[1-9].VOB | ffmpeg -y -i - -metadata title=&quot;&quot; -map 0:1 -vcodec libx264 -crf 26 -deinterlace -preset veryfast -acodec libmp3lame -map 0:3 -b:a 128k -ac 2 c\u00edlov\u00fd_soubor.mp4<\/code><\/p>\n<p><\/div><\/div>\n<a id=\"zobrazen\u00ed_ze_dvou_webkamer_s_p\u0159idanou_lupou\"><\/a><div class=\"mch-acr\"><div class=\"mch-acr-title\" role=\"button\" tabindex=\"0\" aria-expanded=\"false\" aria-controls=\"mch-acr-content-32\">Zobrazen\u00ed ze dvou webkamer s p\u0159idanou \u201elupou\u201c<\/div><div id=\"mch-acr-content-32\" class=\"mch-acr-content\" hidden><span class=\"nadpis-kapitola\"><br \/>\n<\/span><\/p>\n<p>P\u0159\u00edklad: Poskl\u00e1d\u00e1n\u00ed obrazu ze dvou webkamer <em>(s p\u0159edem nastaven\u00fdm rozli\u0161en\u00edm 640&#215;480)<\/em> do t\u0159\u00ed sekc\u00ed.<br \/>\nhorn\u00ed:<br \/>\n<code class=&#8220;code-line&#8220; style=&#8220;display: inline; margin: 0px; border-style: none;&#8220;>\/dev\/video0 [0:v](640x480)<\/code> -&gt; [horni]<em>(640&#215;200)<\/em>,<br \/>\ndoln\u00ed + lupa:<br \/>\n<code class=&#8220;code-line&#8220; style=&#8220;display: inline; margin: 0px; border-style: none;&#8220;>\/dev\/video1 [1:v](640x480)<\/code> -&gt; [dolni]<em>(640&#215;280)<\/em> + [lupa]<em>(140&#215;280)<\/em><\/p>\n<p>\ud83d\udcbb <code>ffmpeg -f video4linux2 -r 15 -input_format mjpeg -i \/dev\/video0 -f video4linux2 -r 15 -input_format mjpeg -i \/dev\/video1 -filter_complex &quot;[0:v]setpts=PTS-STARTPTS,crop=in_w:200:0:0[horni]; [1:v][horni]overlay=0:0[dolni]; [1:v]setpts=PTS-STARTPTS,crop=70:250:70:230,scale=140:280[lupa]; [dolni][lupa]overlay=0:200&quot; -an -c:v h264 -bufsize 2M -maxrate 512K -f asf - | mplayer -<\/code><\/p>\n<p><\/div><\/div>\n<a id=\"separace_\u010d\u00e1sti_audia_z_videa_s_korekc\u00ed_bas\u016f_a_v\u00fd\u0161ek\"><\/a><div class=\"mch-acr\"><div class=\"mch-acr-title\" role=\"button\" tabindex=\"0\" aria-expanded=\"false\" aria-controls=\"mch-acr-content-33\">Separace \u010d\u00e1sti Audia z Videa s korekc\u00ed Bas\u016f a V\u00fd\u0161ek<\/div><div id=\"mch-acr-content-33\" class=\"mch-acr-content\" hidden><\/p>\n<p>P\u0159\u00edklad separace \u00faseku zvuku <em>(od 12,5 sec. po dobu 180 sec)<\/em> do mp3 souboru s korekc\u00ed bas\u016f a v\u00fd\u0161ek<\/p>\n<p>\ud83d\udcbb <code>ffmpeg -y -ss 12.5 -t 180 -i videosoubor_zdroj.mp4 -vcodec copy -preset veryfast -acodec libmp3lame -af &quot;bass=gain=3,treble=gain=-10:frequency=8000&quot; -b:a 128k -ac 2 c\u00edlov\u00fd_soubor.mp3<\/code><\/p>\n<p><\/div><\/div>\n<a id=\"\u00daprava_hlasitosti_videa\"><\/a><div class=\"mch-acr\"><div class=\"mch-acr-title\" role=\"button\" tabindex=\"0\" aria-expanded=\"false\" aria-controls=\"mch-acr-content-34\">\u00daprava hlasitosti videa<\/div><div id=\"mch-acr-content-34\" class=\"mch-acr-content\" hidden><\/p>\n<p>P\u0159\u00edklad zeslaben\u00ed hlasitosti ve video souboru o 12dB<\/p>\n<p>\ud83d\udcbb <code>ffmpeg -y -i videosoubor_zdroj.mp4 -vcodec copy -filter:a &quot;volume=-12dB&quot; c\u00edlov\u00fd_soubor.mp4<\/code><\/p>\n<p><\/div><\/div>\n<a id=\"kl\u00ed\u010dov\u00e1n\u00ed_webkamery_do_obr\u00e1zku_s_v\u00fdstupem_do_virtu\u00e1ln\u00ed_kamery\"><\/a><div class=\"mch-acr\"><div class=\"mch-acr-title\" role=\"button\" tabindex=\"0\" aria-expanded=\"false\" aria-controls=\"mch-acr-content-35\">Kl\u00ed\u010dov\u00e1n\u00ed webkamery do obr\u00e1zku s v\u00fdstupem do virtu\u00e1ln\u00ed kamery<\/div><div id=\"mch-acr-content-35\" class=\"mch-acr-content\" hidden><\/p>\n<p>prvn\u011b, <a href=\"https:\/\/milchyn.cz\/v4l-podpora-webkamer?open=1&amp;accordion_id=virtualni-kamera#virtualni-kamera\" rel=\"noopener\"><strong>vytvo\u0159it si virtu\u00e1ln\u00ed webkameru<\/strong><\/a>\u00a0 <code class=&#8220;code-line&#8220; style=&#8220;display: inline; margin: 0px; border-style: none;&#8220;>\/dev\/video10<\/code> a do t\u00e9to pos\u00edlat kl\u00ed\u010dovan\u00e9 video z fyzick\u00e9 webkamery <code class=&#8220;code-line&#8220; style=&#8220;display: inline; margin: 0px; border-style: none;&#8220;>\/dev\/video0<\/code> na pozad\u00ed tvo\u0159en\u00e9 obr\u00e1zkem <code class=&#8220;code-line&#8220; style=&#8220;display: inline; margin: 0px; border-style: none;&#8220;>Picture.jpg<\/code> .<\/p>\n<p>\ud83d\udcbb <code>ffmpeg -nostdin -i &#039;Picture.jpg&#039; -f v4l2 -input_format mjpeg -video_size 1280x720 -i \/dev\/video0 -filter_complex &quot; [0:v]scale=1280x720[bg]; [1:v]scale=1280x720,chromakey=color=#326964:0.07:0.02,fps=30[fg]; [bg][fg]overlay&quot; -crf 28 -deinterlace -preset ultrafast -f v4l2 -pix_fmt yuv420p \/dev\/video10<\/code><\/p>\n<p><strong>Zobrazen\u00ed<\/strong> virtu\u00e1ln\u00ed kamery <code class=&#8220;code-line&#8220; style=&#8220;display: inline; margin: 0px; border-style: none;&#8220;>\/dev\/video10<\/code><\/p>\n<p>\ud83d\udcbb <code>ffplay \/dev\/video10 -loglevel quiet -x 960 -y 540 -window_title &quot;Zobrazen\u00ed virtu\u00e1ln\u00ed kamery \/dev\/video10&quot;<\/code><\/p>\n<p><\/div><\/div>\n<a id=\"v\u0161echna_j\u00e1dra_procesoru_jsou_vyt\u00ed\u017eena_jak_z\u00e1t\u011b\u017e_omezit\"><\/a><div class=\"mch-acr\"><div class=\"mch-acr-title\" role=\"button\" tabindex=\"0\" aria-expanded=\"false\" aria-controls=\"mch-acr-content-36\">V\u0161echna j\u00e1dra procesoru jsou vyt\u00ed\u017eena <i>(jak z\u00e1t\u011b\u017e omezit)<\/i> \ud83c\udd98<\/div><div id=\"mch-acr-content-36\" class=\"mch-acr-content\" hidden><\/p>\n<h5>Popis<\/h5>\n<p>ffmpeg je schopen pln\u011b vyu\u017e\u00edt procesor. Lze ale procesu p\u0159id\u011blit jen ur\u010dit\u00fd po\u010det vl\u00e1ken jader pomoc\u00ed p\u0159ed\u0159azen\u00e9ho p\u0159\u00edkazu <samp>taskset<\/samp> s parametrem rozsahu vl\u00e1ken.<\/p>\n<h5>P\u0159\u00edklad<\/h5>\n<p>Omezen\u00ed b\u011bhu procesu s ffmpeg jen na 4 vl\u00e1kna jader procesoru:<\/p>\n<p>\ud83d\udcbb <code>taskset -c 0-3 ffmpeg ...<\/code><\/p>\n<p><\/div><\/div>\n","protected":false},"excerpt":{"rendered":"<p>Jedn\u00e1 se o \u0161ikovn\u00fd komplexn\u00ed n\u00e1stroj z p\u0159\u00edkazov\u00e9 \u0159\u00e1dky pro p\u0159ehr\u00e1v\u00e1n\u00ed (ffplay), \u00fapravu form\u00e1t\u016f audio a video soubor\u016f (\u00faprava rozm\u011bru obrazu, hlasitosti, metadat a dal\u0161\u00edch parametr\u016f). Lze zadat i velice jednodu\u0161e, kdy podle koncovky c\u00edlov\u00e9ho souboru bude v\u00fdchoz\u00ed form\u00e1t. Aby nedo\u0161lo k po\u0161kozen\u00ed vstupn\u00edho souboru kolizn\u00edm p\u0159eps\u00e1n\u00edm v\u00fdstupem, mus\u00ed se v\u00fdstup nasm\u011brovat do jin\u00e9ho souboru [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":8997,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-2618","page","type-page","status-publish","hentry"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v26.1.1 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>ffmpeg - zpracov\u00e1n\u00ed multim\u00e9di\u00ed - milchyn.cz<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/milchyn.cz\/ffmpeg-zpracovani-multimedii\" \/>\n<meta property=\"og:locale\" content=\"cs_CZ\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"ffmpeg - zpracov\u00e1n\u00ed multim\u00e9di\u00ed - milchyn.cz\" \/>\n<meta property=\"og:description\" content=\"Jedn\u00e1 se o \u0161ikovn\u00fd komplexn\u00ed n\u00e1stroj z p\u0159\u00edkazov\u00e9 \u0159\u00e1dky pro p\u0159ehr\u00e1v\u00e1n\u00ed (ffplay), \u00fapravu form\u00e1t\u016f audio a video soubor\u016f (\u00faprava rozm\u011bru obrazu, hlasitosti, metadat a dal\u0161\u00edch parametr\u016f). 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