Ffmpeg: Unterschied zwischen den Versionen

Version vom 5. April 2024, 10:01 Uhr

ffmpeg bearbeitet und konvertiert Audio- und Videodateien

Das FFmpeg-Projekt besteht aus einer Reihe von freien Computerprogrammen und Programmbibliotheken, die digitales Video- und Audiomaterial aufnehmen, konvertieren, senden (streamen), filtern und in verschiedene Containerformate verpacken können.

Unter anderem enthält es mit libavcodec eine umfangreiche Sammlung von Audio- und Videocodecs.

FFmpeg (bzw. libavcodec als Bestandteil von FFmpeg) enthält Implementierungen von mehr als 100 Codecs, von denen ein Teil von Patentinhabern angefochten werden könnte.
In manchen Gesetzgebungen könnten, aufgrund von vagen Hinweisen, eventuell Patentansprüche gegen verschiedene Standards, die FFmpeg unterstützt, geltend gemacht werden.
Weiterhin sind viele dieser Codecs unter Nutzungsbedingungen veröffentlicht worden, die Reverse Engineering untersagen; selbst zur Sicherstellung der Interoperabilität.
Solche Bedingungen sind in manchen Ländern allerdings unwirksam, so etwa in Deutschland

# apt install ffmpeg

Quelle	Ziel	Befehl
wav	mp3	ffmpeg -i audio.wav -acodec libmp3lame audio.mp3
wav	ogg	ffmpeg -i audio.wav -acodec libvorbis audio.ogg
wav	aac	ffmpeg -i audio.wav -acodec libfaac audio.aac
wav	ac3	ffmpeg -i audio.wav -acodec ac3 audio.mp3
OGG	mp3	ffmpeg -i audio.ogg -acodec libmp3lame audio.mp3
OGG	wav	ffmpeg -i audio.ogg audio.wav
OGG	aac	ffmpeg -i audio.ogg -acodec libfaac audio.aac
OGG	ac3	ffmpeg -i audio.ogg -acodec ac3 audio.ac3
AC3	mp3	ffmpeg -i audio.ac3 -acodec libmp3lame audio.mp3
AC3	wav	ffmpeg -i audio.ac3 audio.wav
AC3	aac	ffmpeg -i audio.ac3 -acodec libfaac audio.aac
AC3	ogg	ffmpeg -i audio.ac3 -acodec libvorbis audio.ogg
AAC	mp3	ffmpeg -i audio.aac -acodec libmp3lame audio.mp3
AAC	wav	ffmpeg -i audio.aac audio.wav
AAC	ac3	ffmpeg -i audio.aac -acodec ac3 audio.ac3
AAC	ogg	ffmpeg -i audio.aac -libvorbis audio.ogg

Aufgabe	Befehl
90 Grad nach rechts	ffmp4 -i input.mp4 -vf "transpose=1" -qscale 0 output.mp4
90 Grad nach links	ffmp4 -i input.mp4 -vf "transpose=2" -qscale 0 output.mp4
180 Grad	ffmp4 -i input.mp4 -vf "hflip,vflip" -qscale 0 output.mp4
Video-Größe reduzieren	ffmp4 -i input.mp4 [FIXME]
Tonspuren entfernen	ffmpeg -i input.mp4 -an -c:v copy output.mp4

Videostrom ohne Ton kopieren

$ ffmpeg -i [input file] -an -c:v copy [output file]

Option	Beschreibung
-an	Tonspur ignorieren
-c:v copy	Kopie ohne Neukodierung

$ ffmpeg -i input.mp4 -an -c:v copy output.mp4

So i'm tried to reduce video filesize by scale down video -vf 640:-2, but nothing changes. Scale down or up doesnt affect video filesize

I've read ffmpeg wiki about Scaling but it dont have any information about scale and filesize.

When i'm scale down images, filesize have big drop but for video, nothing changes

Your question doesn't contain enough information. You need to show all the information about your video both before and after your attempt to reduce its size. Try using ffprobe on both.
i found other answer on website, he's said that resolution and codec are two different things, to reduce file size you must use better codec, in this case i'm using libx265

You can use -crf option to reduce final video size.

The range of the CRF scale is 0–51, where 0 is lossless (for 8 bit only, for 10 bit use -qp 0), 23 is the default, and 51 is worst quality possible.

-crf 23 (for default)

You have to use H.264 encoder. this will help almost all type of video. works batter in mp4 videos.

yes, -c:v libx265 -crf 25 -x265-params profile=main10 -preset fast -pix_fmt yuv420p10le with this, quality is better and file size is lower but encode time is longer, -vf scale is just for visual, not for size/quality
You can use '-preset ultrafast' for decrease conversion time. use that before your add your output path.
ok thank you, i will try that, hope quality is same and encode time is reduce
look like ultrafast = higher size, not reduce size at all, should fast or slow
-crf use for reduce the size of video and -preset is use for decrease conversion time. I personally used that.

Can you do sound and video separately? Like I want perfect sound but the video can be trash. It's for creating subtitles. Then I can add the subtitles to the high-quality video afterwards.

@@ Zeile 116: / Zeile 116: @@
 * i found other answer on website,	he's said that resolution and codec are two different things, to	reduce file size you must use better codec, in this case i'm using	libx265
-== Answer ==
+; Answer
 You can use -crf option to reduce final video size.