I have two videos of the same length that I'd like to combine. Video A has audio, video B does not. I'd like to take the audio from video A and put it onto Video B. I'd like to do this with FFMPEG, but I can't figure out the arguments I need? Should I use map?
There's a lot of questions about combining a video with audio, but not two videos.
Do I maybe need an intermediate step of converting my original video to audio?
I have tried using this FFMPEG command, and a couple of variations. All of the resulted in just Video A (the one with audio) being the output.
ffmpeg -i videoB.mp4 -i video A.mp4 -c:v copy -c:a aac output.mp4
Try this as a starter
ffmpeg -i videoB.mp4 -i video A.mp4
-filter_complex [0:v][1:a][1:v][1:a]concat=n=2:v=1:a=1[vout][aout]
-map [vout] -map [aout] -c:v h264 -c:a aac output.mp4
You must reencode though.
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
It might be a duplicate question but didn't find any helpful answer.
I have 2 audio files and 1 mp4 video file. Want to add the 2 audio files to mp4 videoat specific time.
For example:
Video file:
input.mp4 (2 minutes video)
Audio files:
Audio File 1:
test_0:01.mp3 (15 seconds audio file) I want to insert this file at position 0:01 in the mp4 video
Audio File 2:
test_0:20.mp3(15 seconds audio file) I want to insert this file at position 0:20 in the mp4 video
I tried the following command with offset
It's only inserting test_0:01.mp3 at 0:01 position in the video file
But test_0:20.mp3 is not getting inserted at 0:020 position getting mute for this file no audio.
ffmpeg -i input.mp4 -itsoffset 01 -i test_0:01.mp3 -itsoffset 20 -i test_0:20.mp3 -c:v copy -map 0:v:0 -map 1:a -map 2:a -c:a aac -b:a 192k output.mp4
Any help will be appreciated!
Your command creates two audio tracks in the MP4 file. If you have a look in your video player you can choose between two audio tracks (usually used to choose different audio languages).
Why
This is because every -map parameter creates a new stream. In your example one video with two audio tracks.
Solution
Use the audio filter amix instead. Use also the filter adelay for the delay in the same filter chain to achieve the best result.
ffmpeg -i input.mp4 -i test_0:01.mp3 -i test_0:20.mp3 -filter_complex "[1:a]adelay=1s:all=1[a1];[2:a]adelay=20s:all=1[a2];[a1][a2]amix=inputs=2[amixout]" -map 0:v:0 -map "[amixout]" -c:v copy -c:a aac -b:a 192k output.mp4
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 have a MKV file with a H264 video track, FLAC audio track and ASS subtitle track. I want to convert the file to a MP4 but keep the video track and re-encode the audio and subtitle tracks. How do I do that?
Use the -c/-codec and -map options.
ffmpeg -i input.mkv -map 0 -c:v copy -c:a aac -c:s mov_text output.mp4
copy enables stream copy mode which only re-muxes and does not re-encode (the video in this example).
See the ffmpeg documentation for more info.
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