I am using FFMPEG to merge 2 or more audios into one audio.
The audio is getting merged properly but the output duration of the audio is wrong.
Eg: Actual merged audio plays for 23 seconds and it shows 25 seconds.
Here is the command I am using for merging the audios.
-i audio1.aac -i audio2.aac -i audio3 -filter_complex "[1:a]adelay=5s:all=1[a1]; [2:a]adelay=10s:all=1[a2]; [0:a] [a1] [a2] amix=inputs=3[a] "-map "[a]" /data/user/0/com.sound.it/cache/mergedAudio1673260887341.aac
Let me know if you have any solutions for the same.
Thanks
Related
Before posting I have searched and found similar questions on stackoverflow (I list some below) - none have helped me towards a solution, hence this post. The duration that each image is shown within the movie file differs from many posts that I have seen thus far.
A camera captures 1 image every 30 seconds. I need stream them, preferably via HLS, thus I wrap 2 images in an MP4. I then convert MP4 to mpegts. Each MP4 and TS file play fine individually (each contain two images, each image transitions after 30seconds, each movie file is 1minute long).
When I reference the two TS files in an M3U8 playlist, only the first TS file gets played. Can anyone advise why it stops and how I can get it to play all the TS files that I expect to create, not just the first TS file? Besides my ffmpeg commands, I also include my VLC log file (though I expect to stream to Firefox/Chrome clients). I am using ffmpeg 4.2.2-static installed on an AWS EC2 with AMI2 Linux.
I have four jpgs named image11.jpg, image12.jpg, image21.jpg, image22.jpg - The images look near identical as only the timestamp in top left changes.
The following command creates 1.mp4, using image11.jpg and image12.jpg, each image displayed for 30 seconds, total duration of the mp4 is 1 minute. It plays like expected.
ffmpeg -y -framerate 1/30 -f image2 -i image1%1d.jpg -c:v libx264 -vf "fps=1,format=yuvj420p" 1.mp4
I then convert 1.mp4 to an mpegts file, creating 1.ts. It plays like expected.
ffmpeg -y -i 1.mp4 -c:v libx264 -vbsf h264_mp4toannexb -flags -global_header -f mpegts 1.ts
I repeat the above steps except specific to image21.jpg and image22.jpg, creating 2.mp4 and 2.ts
ffmpeg -y -framerate 1/30 -f image2 -i image1%1d.jpg -c:v libx264 -vf "fps=1,format=yuvj420p" 2.mp4
ffmpeg -y -i 1.mp4 -c:v libx264 -vbsf h264_mp4toannexb -flags -global_header -f mpegts 2.ts
Thus now I have 1.mp4, 1.ts, 2.mp4, 2.ts and all four play individually just fine.
Using ffprobe I can confirm their duration is 60seconds, for example:
ffprobe -i 1.ts -v quiet -show_entries format=duration -hide_banner -print_format json
My m3u8 playlist follows:
#EXTM3U
#EXT-X-VERSION:4
#EXT-X-PLAYLIST-TYPE:VOD
#EXT-X-MEDIA-SEQUENCE:1
#EXT-X-TARGETDURATION:60.000
#EXTINF:60.0000,
1.ts
#EXTINF:60.000,
2.ts
#EXT-X-ENDLIST
Can anyone advise where I am going wrong?
VLC Error Log (though I expect to play via web browser)
I have researched the process using these (and other pages) as a guide:
How to create a video from images with ffmpeg
convert from jpg to mp4 by ffmpeg
ffmpeg examples page
FFMPEG An Intermediate Guide/image sequence
How to use FFmpeg to convert images to video
Take a look at the start_pts/start_time in the ffprobe -show_streams output, my guess is that they all start at zero/near-zero which will cause playback to fail after your first segment.
You can still produce them independently but you will want to use something like -output_ts_offset to correctly set the timestamps for subsequent segments.
The following solution works well for me. I have tested it uninterrupted for more than two hours and believe it ticks all my boxes. (Edited because I forgot the all important -re tag)
ffmpeg will loop continuously, reading test.jpg and stream it to my RTMP server. When my camera posts an image every 30seconds, I copy the new image on top of the existing test.jpg which in effect changes what is streamed out.
Note the command below is all one line, I have put new lines in to assist reading and The order of the parameters are important - the loop and fflags genpts for example must appear before the -i parameter
ffmpeg
-re
-loop 1
-fflags +genpts
-framerate 1/30
-i test.jpg
-c:v libx264
-vf fps=25
-pix_fmt yuvj420p
-crf 30
-f fifo -attempt_recovery 1 -recovery_wait_time 1
-f flv rtmp://localhost:5555/video/test
Some arguments explained:
-re implies play in real time
loop 1 (1 turns the loop on, 0 off)
-fflags +genpts is something I only half understand. PTS I believe is the start/end time of the segment and without this flag, the PTS is reset to zero with every new image. Using this arguement means I avoid EXT-X-DISCONTINUITY when a new image is served.
-framerate 1/30 means one frame for 30seconds
-i test.jpg is my image 'placeholder'. As new images are received via a separate script, it overwrites this image. When combined with loop it means the ffmpeg output will reference the new image.
-c:v libx264 is for H264 video output formating
-vf fps=25 Removing this, or using a different value resulted in my output stream not being 30seconds.
-pix_fmt yuvj420p (sometimes I have seen yuv420p referenced but this did not work on my environment). I believe there are different jpg colour palettes and this switch ensures I can process a wider choice.
-crf 30 implies highest quality image, lowest compression (important for my client)
-f fifo -attempt_recovery 1 -recovery_wait_time 1 -f flv rtmp://localhost:5555/video/test is part of the magic to go with loop. I believe it keeps the connection open with my stream server, reduces the risk of DISCONTINUITY in the play list.
I hope this helps someone going forward.
The following links helped nudge me forward and I share as it might help others to improve upon my solution
Creating a video from a single image for a specific duration in ffmpeg
How can I loop one frame with ffmpeg? All the other frames should point to the first with no changes, maybe like a recusion
Display images on video at specific framerate with loop using FFmpeg
Loop image ffmpeg HLS
https://trac.ffmpeg.org/wiki/Slideshow
https://superuser.com/questions/1699893/generate-ts-stream-from-image-file
https://ffmpeg.org/ffmpeg-formats.html#Examples-3
https://trac.ffmpeg.org/wiki/StreamingGuide
I have just started using ffmpeg for one of my project. I have very limited knowledge of ffmpeg.
I need a help on below problem. Thanks in advance.
I have two files:-
Audio File
Video File
I want to generate single file after performing below operations:-
trim the audio file to custom start and stop point.
merge audio and video file to a single file (video file is of same size)
apply speed filter on the generated file.
I am able to achieve the output but with three different ffmpeg commands due to which it is taking lot of time. I want to achieve the all there tasks in a single ffmpeg command.
Thanks.
Use the setpts and atempo (or rubberband) filters. This example will double the speed:
ffmpeg -i video.mp4 -ss 3 -t 10 -i audio.mp3 -filter_complex "[0:v]setpts=0.5*PTS[v];[1:a]atempo=2[a]" -map "[v]" -map "[a]" -shortest output.mp4
-ss 3 will skip beginning 3 seconds in audio.mp3.
-t 10 will limit audio.mp3 duration to 10 seconds.
-shortest will make output.mp4 duration the same as the shortest output stream duration.
I have tried to speed up a video file (with the audio stream) 8 times with ffmpeg using the script below. All works well that from a 50 hour video I get a 7-hour video with the audio sped up also, yet in the resulting file the audio lasts for just over 2 hours and silences after that, i.e. there video without audio.
ffmpeg -i video.mp4 -filter_complex "[0:v]setpts=0.5*PTS,setpts=0.5*PTS,setpts=0.5*PTS[v];[0:a]atempo=2.0,atempo=2.0,atempo=2.0[a]" -map "[v]" -map "[a]" video_x8.mp4
EDIT:
video.mp4 file
video_x8.mp4 file (naming is different for the clear picture)
EDIT 1.
Here are the full 100MB logs. https://gofile.io/?c=L0Au2e
EDIT 2: Thank you Gyan. But could you please help me write it in 1 command so that it works in 1 go?
As far as I can tell, the atempo (whether due to the chaining or otherwise), is not updating timestamps correctly, so the remedy is to insert asetpts afterwards.
ffmpeg -i video.mp4 -vf "setpts=0.125*PTS" -af "atempo=8.0,asetpts=N/SR/TB" video_x8.mp4
everyone.
I'm trying to use FFmpeg to record video and 3 audio sources and use it to generate 3 different video files - each file should contain the same video stream but the different audio stream. The problem is that I got audio sync issues. The first audio stream is synced perfectly, but the second one has 1 sec lag, and the third one has like 2 sec lag.
I've made a few tests so far and it seems that root cause of the issue is initialization time of video/audio devices. So, one device is already recording something but the second is still being opened and so on. I've tried to change input devices order and after that audio streams still have the same issue BUT if before 2nd and 3rd audio streams were some time ahead of video, after reordering they became to lag after the audio (audio for the same event appears with some delay). So this test confirms my version about device initialization times.
But the question still, why the first audio stream is synchronized properly, while other 2 are not. and also, how could I overcome this issues? Any workarounds and ideas are highly appreciated.
Here is FFmpeg command I'm using and it's output.
ffmpeg.exe -f dshow -video_size 1920x1080 -i video="Logitech HD Webcam
C615" -f dshow -i audio="Microphone (HD Webcam C615)" -f dshow -i
audio="Microphone Array (Realtek High Definition Audio)"
-filter_complex "[1:a]volume=1[a1];[2:a]volume=1[a2]" -vf scale=h=1080:force_original_aspect_ratio=decrease -vcodec libx264
-pix_fmt yuv420p -crf 23 -preset ultrafast -acodec aac -vbr 5 -threads 0 -map v:0 -map [a1] -map [a2] -f tee
"[select=\'v,a:0\']C:/Users/vshevchu/Desktop/123/111/111_jjj1.avi|
[select=\'v,a:1\']C:/Users/vshevchu/Desktop/123/111/111_jjj2.avi"
OUTPUT
PS. Actually, the issue is exactly the same when I'm not using "tee" muxer but writing all the audio streams to one container. So, "tee" isn't a suspect.
I've got a video file, video.mp4. It is 18 minutes 23 seconds in duration. I am looking to extract the audio only from this video, and create an MP3 of the highest possible quality from the audio in the video.
Some googlefu lead me to this command: ffmpeg -i video.mp4 audio.mp3
The problem is that, this command doubles the length of the audio that's outputted (duration is 36 minutes 46 seconds). It loops the audio track once, so the output contains the entire 18 minutes 23 seconds of audio, then immediately starts the 18 minutes and 23 seconds of audio over again.
Some more googlefu lead me to this flag: -write_xing 0 from this SO question, but even with that flag it still loops the audio.
EDIT: Additional googlefu and me seeming to think it has something to do with 2 audio channels (and perhaps looping channel 2 immediately after channel 1, rather than merging the two) lead me to this flag: -ac 1 to force it to merge stereo -> mono. This did not work also, and it still outputs a 38 minute 46 seconds MP3 file.
How can I extract (to MP3) the audio from a video file, without doubling the duration?
Your googlefu must be malfunctioning.
If you have a single audio track:
ffmpeg -i movie.mp4 -map 0:a -c:a mp3 audio.mp3
If you have multiple audio tracks:
Identify the track:
ffprobe -i movie.mp4 and look for an audio Stream #0:x where x is an integer
Use the above command using -map 0:x. Example for x = 2:
ffmpeg -i movie.mp4 -map 0:2 -c:a mp3 audio.mp3
How to use the -map option