I'm trying to use FFmpeg to generate the following from a local mp4 file:
A copy of the original video with no audio
A copy of the original video with audio but without visuals (a black screen instead). This file also needs to be in mp4 format.
After reading through the documentation I am struggling to get the terminal commands right. To remove the audio I have tried this command without any success:
ffmpeg -i file.mp4 -map 0:0 -map 0:2 -acodec copy -vcodec copy
Could anyone guide me towards how to accomplish this?
Create black video and silent audio
Use the color and anullsrc filters. Example to make 10 second output, 1280x720, 25 frame rate, stereo audio, 44100 sample rate:
ffmpeg -f lavfi -i color=size=1280x720:rate=25:color=black -f lavfi -i anullsrc=channel_layout=stereo:sample_rate=44100 -t 10 output.mp4
Remove audio
Only keep video:
ffmpeg -i input.mp4 -map 0:v -c copy output.mp4
Keep everything except audio:
ffmpeg -i input.mp4 -map 0 -map -0:a -c copy output.mp4
See FFmpeg Wiki: Map for more info on -map.
Make video black but keep the audio
Using the drawbox filter.
ffmpeg -i input.mp4 -vf drawbox=color=black:t=fill -c:a copy output.mp4
Generate silent audio
See How to add a new audio (not mixing) into a video using ffmpeg? and refer to the anullsrc example.
To remove the audio you can use this:
ffmpeg -i file.mp4 -c copy -an file-nosound.mp4
notice the -an option
-an (output)
Disable audio recording.
To keep audio but "replace" the video with a black screen, you could do this:
ffmpeg -i file.mp4 -i image.png -filter_complex overlay out.mp4
image.png is a black wallpaper that is placed on top of the video, but there should be better ways of full removing the frames, you could either extract the audio and later create a new video with the audio as a background
Related
I have some DVDs that I would like to encode so that I can play them on a Chromecast, with subtitles. It seems that Chromecast only supports text-based subtitle formats, while DVD subtitles are in a bitmap format, so I need to hardcode the subtitles onto the video stream.
First I use vobcopy to create a VOB file:
vobcopy -I /dev/sr0
Next I want to use ffmpeg to encode it as a video stream in a format that is supported by the Chromecast. This is the closest I've come so far (based on the ffmpeg documentation):
ffmpeg -analyzeduration 100M -probesize 100M -i in.vob \
-filter_complex "[0:v:0][0:s:0]overlay[vid]" -map "[vid]" \
-map 0:3 -codec:v libx264 -crf 20 -codec:a copy out.mkv
The -filter_complex "[0:v:0] [0:s:0]overlay[vid] parameters should overlay the first subtitle stream on the first video stream (-map 0:3 is for the audio). This partially works, but the subtitles are only shown for a fraction of a second (I'm guessing one frame).
How can I make the subtitles display for the correct duration?
I'm using ffmpeg 4.4.1 on Linux, but I've also tried the latest snapshot version, and tried gstreamer and vlc (but didn't get far).
The only solution I found that worked perfectly was a tedious multi-stage process.
Copy the DVD with vobcopy
vobcopy -I /dev/sr0
Extract the subtitles in vobsub format using mencoder. This command will write subs.idx and subs.sub. The idx file can be edited if necessary to tweak the appearance of the subtitles.
mencoder *.vob -nosound -ovc frameno -o /dev/null \
-vobsuboutindex 0 -sid 0 -vobsubout subs
Copy the audio and video from the VOB into an mkv file. ffprobe can be used to identify the relevant video and audio stream numbers.
ffmpeg -fflags genpts -i *vob -map 0:1 -map 0:3 \
-codec:v copy -codec:a copy copied_av.mkv
Merge the subtitles with the audio/video stream.
mkvmerge -o merged.mkv copied_av.mkv subs.sub subs.idx
Then ffmpeg will work reliably with the mkv file to write hardcoded subtitles to the video stream.
ffmpeg -i merged.mkv -filter_complex "[0:v:0][0:s:0]overlay[vid]" \
-map [vid] -map 0:1 -codec:v libx264 -codec:a copy hardcoded.mkv
I have a video file without sound and a stereo audio file. Video is several times longer than audio. I'd like to create a background sound which starts from 2 second silence, then trim silence of the audio at both ends and duplicate trimmed audio several times to the end of the video.
I found how to trim audio:
ffmpeg -y -i audio.wav -af silenceremove=start_periods=1:start_threshold=-75dB,areverse,silenceremove=start_periods=1:start_threshold=-75dB,areverse trimmed_audio.wav
And how to create silence:
ffmpeg -y -f lavfi -i anullsrc=channel_layout=stereo:sample_rate=48000:duration=2 silence.wav
How can I duplicate the audio and combine it with the video?
Basic syntax is
ffmpeg -an -i video -stream_loop -1 -i trimmed_audio.wav -af adelay=2000:all=1 -shortest -fflags +shortest -max_interleave_delta 100M out.mp4
Use ffmpeg 4.1 or newer.
I am looking for a way to convert large number of MP3 files to videos, each using the same image. Efficient processing time is important.
I tried the following:
ffmpeg -i image.jpg -i audio.mp3 -vcodec libx264 video.mp4
VLC media player played the resulting video file with the correct sound, but a blank screen.
Microsoft Media Player played the sound and showed the intended image. I uploaded the video to YouTube and received the message:
"The video has failed to process. Please make sure you are uploading a supported file type."
How can I make this work?
Create video:
ffmpeg -framerate 6 -loop 1 -i input.jpg -c:v libx264 -vf format=yuv420p -t 00:10:00 video.mp4
The duration (-t) should be ≥ the MP3 with the longest duration.
Now stream copy the same video for each MP3:
ffmpeg -i video.mp4 -i audio.mp3 -map 0:v -map 1:a -c copy -movflags +faststart -shortest output.mp4
Some notes regarding compatibility:
MP3 in MP4 does not have universal support, but will be fine in YouTube. If your target players do not like it then add -c:a aac after -c copy to output AAC audio.
If your target player does not like it then increase the -framerate value or add the -r output option with an appropriate value, such as -r 15. Again, YouTube should be able to handle it.
I am using ffmpeg on Ubuntu 14.04 (Jon Severinsson's PPA) and am playing video files out of a folder - one by one.
First question I wasn't able to figure out yet - how can I add a simple overlay - 720p footage with 720p overlay (with partial transparency)? So there is no resize or alignment needed - just the 1:1 overlay. I tried a lot already with -vf and -filter_complex but didn't show up.
Second question - with concatenate, is it possible to have the switches between the files seamless? Best without creating a new file - so, on the fly? I need to reduce the gaps between the file switches or eliminate them completely.
This is my bash right now:
#!/usr/bin/env bash
while :; do
files=(*)
ffmpeg -re -i "${files[$RANDOM % ${#files[#]}]}" -acodec copy -vcodec copy -f flv ServerAddress
done
So I have everything in /vod - the videofiles, as well as the overlay.png
Thanks a bunch in advance,
Tim
For the overlay you need to scale the image to the original source dimensions.
To concat multiple source files that have the same codec use the concat demuxer.
Eg:
Make a playlist.txt with the following format:
file '/path/to/file_1'
file '/path/to/file_2'
file '/path/to/file_3'
[..]
And then:
ffmpeg -f concat -i playlist.txt -i overlay.png -filter_complex "[1:v] scale=1280:720 [ovr];[0:v][ovr] overlay=0:0" ...
If the video and the image are the same size you can just use:
ffmpeg -f concat -i playlist.txt -i overlay.png -filter_complex "[0:v] overlay"
Update:
Full example:
You cannot filter and copy the video stream at the same time!
ffmpeg -re -f concat -i playlist.txt -i overlay.png -filter_complex "[0:v] overlay" -c:v h264 -c:a libfdk_aac -ar 44100 -f flv rtmp://...
If your audio stream is valid and has one of the supported audio rates (44100, 22050, 11025) you can do:
ffmpeg -re -f concat -i playlist.txt -i overlay.png -filter_complex "[0:v] overlay" -c:v h264 -c:a copy -f flv rtmp://...
I am trying to create a video output from multiple video cameras.
Following the example given here Presenting more than 2 videos using FFmpeg
and other similar examples.
but Im getting the error
Output pad "default" for the filter "src" of type "buffer" not connected to any destination
when i run
ffmpeg -i /dev/video1 -i /dev/video0 -filter_complex "[0:0]pad=iw*2:ih[a];[a][1:0]overlay=w[b];[b][2:0]overlay=w:h" -shortest output.mp4
Im not really sure what this means or how to fix it.
Any help would be greatly appreciated!
Thanks.
When using the "padding" option, you have to specify which is the size of the output image and where you want to put the input image
[0:0]pad=iw*2:ih:0:0
tested under windows 7 with file of same size
ffmpeg -i out.avi -i out.avi -filter_complex "[0:0]pad=iw*2:ih:0:0[a];[a][1:0]overlay=w" -shortest output.mp4
and with WebCam Cap (vfwcap) and a still picture (as i have only o=1 WebCam). BTW you can see how to scale one the source to fit in the target (just in case your source have different resolution)
ffmpeg -y -f vfwcap -r 10 -i 0 -loop 1 -i photo.jpg -filter_complex "[0:0]pad=iw*2:ih:0:0[a];[1:0]scale=640:480[b];[a][b]overlay=w" -shortest output.mp4
under Linux:
ffmpeg -i /dev/video1 -i /dev/video0 -filter_complex "[0:0]pad=iw*2:ih:0:0[[a];a][1:0]overlay=w" -shortest output.mp4
if it doesn't work test a simple record of video 1 and after of video 0 and check their properties (type, resolution, fps).
ffmpeg -i /dev/video1 -shortest output1.mp4
ffmpeg -I output1.mp4
If you still have issue, update your question with ffmpeg console output (as text) for video and video 0 capture and also of the call with the overlay