In answer to the question \"How-to make a silent mp3 or wav-file\" on ubuntuforums.org FakeOutdoorsman provided the following recipe:
Another method b
That's an outdated method. You can now use the anullsrc filter instead, and it will work on any OS:
ffmpeg -f lavfi -i anullsrc -t 5 -c:a libvorbis output.ogg
Default sample rate is 44100, and default channel layout is stereo. If you want something different you can do something like: anullsrc=r=48000:cl=mono
(or use cl=1
for mono).
For Vorbis in general, avoid the native encoder vorbis
if possible; libvorbis
will provide a better output (although it doesn't really matter with a silent output).
An annoying tone or beeping tone can be made with sine filter. Generate a 220 Hz sine wave with a 880 Hz beep each second, for 5 seconds:
ffmpeg -f lavfi -i sine=f=220:b=4:d=5 -c:a libvorbis output.oga
Using the color filter.
ffmpeg -f lavfi -i color=d=5 -c:v libtheora output.ogv
Default frame rate is 25 and default video size is 320x240. To change it: color=r=24:s=1280x720:d=5
.
But who uses Theora anymore? A more modern alternative that likely fills its niche is VP8/VP9 + Vorbis in WebM: -c:v libvpx output.webm
.
Using testsrc and sine
filters:
ffmpeg -f lavfi -i testsrc -f lavfi -i sine -t 10 -c:v libtheora -c:a libvorbis \
-q:v 5 -q:a 5 output.ogv
Change frame rate and video size the same way as shown above for the color
filter.
See FFmpeg Filter Documentation: Video Sources for a list of many other video source filters such as smptehdbars
.