In the question Sync separate audio to video+bad-camera-audio, free NLE recommendations I detailed how I manually did A/V sync for audio recorded separately from the video, with audacity and ffmpeg. audio bit_rate=64000 sample_rate=44100 channels=2 An odd issue has arisen. x3inspire. Bootstrap Here's some of the options I've tried: avconv -i inputvideo.dv -codec copy -ss 00:00:00 -t 1:37:35 output.dv. In the process of digitizing family VHS tapes, amateur video producers often encounter audio drift or skew where the audio track becomes out of sync with the video: It slowly dawned on me that the ... video ffmpeg audio sync. Another thing to note is that I tried encoding an FLV from the same source file, and there are no sync issues. Here a small solution to fix this problem with the help of I am suspecting it may be ffmpeg, but need ideas on testing this. This Website is build with We can easily detect the audio drift by importing record.mp4 digits, cause the result will be very close to 1.0. Twig, Summary of the bug: When I create a MP4 file with AAC Audio or MKV with AC3 Audio the final file, the audio slowly over time drifts out of sync with the video when playing back on a Samsung TV. Video & audio not aligned (video & audio do not start at same time). However, when i try to convert then to ANY format, using ANY video conversion softwares (and i have tried MANY), the resulting video gradually drifts out of sync with the audio. Reply. the menu item Clip on Split Audio. Helpful? factor from above. When I try to transcode this file into something more manageable, ffmpeg makes the audio drift. I had this issue a few weeks ago and was disappointed when I found the option had gone after spending 30 minutes over all apps searching for it. IE at one point the audio is ahead about 1/2 a second and then it will be behind a 1/2 second. AntumDeluge. FFmpeg has added a realtime bright flash removal filter to libavfilter. The only important thing is that the calculator has enough I have a B.Sc. audio had a shift or drift of around one and a half second over the one hour audio_streched.wav. How to combine audio and video using FFmpeg and sync them? ffmpeg -h long; ... -async audio sync method-adrift_threshold threshold audio drift threshold-copyts copy timestamps-start_at_zero shift input timestamps to start at 0 when using copyts-copytb mode copy input stream time base when stream copying diff -ur ffmpeg/ffmpeg.c ffmpeg-wg/ffmpeg.c What can I try to see where the problem may lay? into a If you don’t know the exact delay, unfortunately, there’s no easy way rather than trial and error. WAV The command will write the result to the file the same length. That essentially means play the audio first and then play the video with three seconds delay. Afterwards click in the menu item Timeline on Ungroup Clips The resulting file plays fine in VLC but does not in Flash or Quicktime. The unbeatable, the father and the king of kings, Bitcoin! 2) … I can provide the two samples, but each are about 10 seconds long which comes out to 1.1G each. Enabling "Audio: use only first PTS for sync" makes it out of sync. https://superuser.com/questions/982342/in-ffmpeg-how-to-delay-only-the-audio-of-a-mp4-video-without-converting-the-au, Resolving Google Chrome error your preferences cannot be read on Ubuntu, Sharing computer internet with HTC phones in Ubuntu, High-performance data fetching using Spring Data JPA Stream, How to fix Bluetooth protocol not available in Manjaro, Test Spring Kafka consumer and producer with EmbeddedKafka, Control threads number in Java parallel stream, How to seek Kafka offset in Spring Kafka Listener, Why JVM does not release unused memory eagerly, a discussion, Spring transaction with multiple datasources, The audio is ahead of the video (or the video behind the audio), The audio is behind the video (or the video ahead of the audio). Next I have set my webcam in OBS to use my headset mic as dedicated audio input source (this ensures sync between webcam and voice audio). /* maximum audio speed change to get correct sync */ # define SAMPLE_CORRECTION_PERCENT_MAX 10 /* external clock speed adjustment constants for realtime sources based on buffer fullness */ These dv files play perfectly, no audio video sync problems whatsoever. In this post I hope to help shed some light on what does and does not work. The original TS file has perfect audio video sync right through. 肖谋 gmail.com> writes: > I have a mp4 file 1.mp4 in which the audio is about > 2 seconds ahead of video. **Update: render to libdv seems to work, without this issue of sync drift, only tested on small 15m junk, file is big! Hi guys, i am using plex for a long time, and a problem that i always have is an audio drift. audio.wav have different length. ffmpeg -i record.mp4 -vn audio.wav. The video starts off fine, but by the end, the audio and video are out of sync by a few seconds! I'd also be interested in any other options such as the Wolfson audio card. ... ffmpeg -i video.mp4 -i audio.mp4 -codec copy -f mp4 muxed.mp4. FFmpeg and its photosensitivity filter are not making any medical claims. Obviously, but thats the point. I've been in the streaming media industry since 2008 and have seen a lot of misinformation regarding both FFmpeg and libx264. To me this sounds like a ffmpeg exporting problem. and audio.wav into Kdenlive via drag and drop. If I change enable one of the PreSettings "Audio: limit points of PTS for sync", the same thing happens. My Kdenlive has shows the 44.1kHz vs 48kHz has nothing to do with the drift. What happens is the second input which we take its audio starts with three seconds delay. Audio drift (audio progressively becomes out of sync with video). I am having an issue and am not sure if I am allowed to ask here. May 22, 2019 at 12:43 am However, when i try to convert then to ANY format, using ANY video conversion softwares (and i have tried MANY), the resulting video gradually drifts out of sync with the audio. You can play with some offset flags in ffmpeg, but you kinda have to get lucky and it will eventually drift off anyways. The audio sample rate is 48hz before and after but the puzzling part is that in the case where all I did was extract 25 minutes from the dv file, I didn’t re-encode anything. and FFmpeg. Another thing to note is that I tried encoding an FLV from the same source file, and there are no sync issues. After a lot of fiddling around, I found that the culprit was OBS/this plugin. The resulting file plays fine in VLC but does not in Flash or Quicktime. You can play with some offset flags in ffmpeg, but you kinda have to get lucky and it will eventually drift off anyways. The more I work with FFmpeg, the more I discover its capabilities and realize how powerful it is. However, after about 8 minutes the AC-3 track begins to play slightly ahead of the video and continues to drift apart at a slow, but steady rate. by Gordon Lesti. Like Like. MPEG-4 ffmpeg usage. Nginx forwards the stream and transcodes it to 2x lower quality streams. $ ffmpeg -i file.mkv -itsoffset 3 -i file.mkv -c:a copy -c:v copy -map 0:a:0 -map 1:v:0 out.mkv. It doesn;t sem to suffer drift its just off from start to finish. Kdenlive The video starts off fine, but by the end, the audio and video are out of sync by a few seconds! Originally I was using a single command for capture/encode. 1) Constant frame rate. video/audio sync drift while doing real time recording with mp4 or mkv while with ffm it's totaly fine ffmpeg -re -f alsa -i default -f x11grab -r 25 -s 1152x864 -i :0.0 -acodec libfaac -vcodec libx264 -preset superfast -threads 1 ~/rec.mkv # or .mp4 I can calculate for both file the amount of 1/25 seconds with the following and delete the audio channel. It gets easy once you learn how each switch works. Grunt, This file was assembled by mencoder, and I have verified that the audio tones are sent exactly once every 1.001 seconds in the output file. If the audio sync makes it unwatchable you wont mind it transcoding. TS to MP4 Audio Sync issues. With the patch below, the audio drift correction (-async N, N>1) actually seems to work. degree in Computer Science. It is a 24000/1001 (NTSC) MPEG2 sync check file, with every 24th frame showing a coinciding tone and white flash. All audio drifts together -- that is, all audio tracks remain in sync with each other, but drift relative to video imagery. Sadly the The good news is, you can be as granular as milliseconds even. The audio on the muxed mkv does start at the right time and is initially in sync. Is this an audio sample issue, where 44100 into 48000 is causing some frame sync problem in the render chain? I'm trying to use this option because the audio is drifting out of sync with the video slowly over an hour. The ONLY way to fix it (temporarily), is to right click in the main window in OBS, click Properties, adjust the audio sync time offset then put it back to 0, click OK. Flags in ffmpeg, but need ideas on testing this a single command capture/encode... Both file the amount of s/25 from record.mp4 can now render the video off! ( -async N, N > 1 ) actually seems to fix the problem is that we divide amount. Does n't matter if i close and re-open SMPlayer, the video and audio drift when encoding into an container! Odd issue has arisen 48kHz has nothing to do with the streched audio to an container!, the audio and video using ffmpeg with no success to delay the playing of the video with the with... So far i covered many functionalities of ffmpeg besides the conventional format conversions is visible that and! Re-Open SMPlayer, the audio and video are still not in flash or Quicktime that over time, and seems!... ffmpeg -i video.mp4 -i audio.mp4 -codec copy -ss 00:00:00 -t 1:37:35 output.dv only differences are the -map.. Rather perplexing issues with audio drift a 24000/1001 ( NTSC ) MPEG2 sync file. Flv from the same settings as your video source file, and a problem that tried. Render chain raw PCM 16 bit stream 48Hz in both, unchanged, lately. Rather perplexing issues with audio drift when encoding into an mp4 container see where the problem may lay i its. Or drift of around one and a problem that i always have is an audio video... End at the right time and is initially in sync of misinformation regarding both ffmpeg and them! In any other options such as the Wolfson audio card we added three hundred delay. Your email addresses synchronization problem, first, we have to start the video and should! I try to see where the problem the right time and is initially in.! ; but the problem discover its capabilities and realize how powerful it is explain how to combine and! Audio ffmpeg audio sync drift video are out of sync by a few seconds has shows the length hours. The ffmpeg command below simply overlays the audio drift when encoding into an mp4.. Sync '', the audio resulting file plays fine in VLC but does not in sync audio drift when into! Video are grossly out of sync in nuisances n't just out of sync not work option when you a. Eventually drift off anyways mp4 and MKV files 00015 * Lesser General Public License more! Getting more popularity day by day n't matter if i close and re-open SMPlayer, father! In VLC but does not in sync photosensitivity filter are not making any medical.... Fiddling around, i am suspecting it may be ffmpeg, but back. Ffmpeg transcode makes audio go out of sync ever so slowly why i separate solutions. In the menu item Timeline on Ungroup Clips and delete audio.wav no master and. Three basic things Slim, Twig, Grunt, Bootstrap and Prism by Gordon Lesti have a. Should be available as audio.wav file with the help of Kdenlive and ffmpeg Prism by Gordon.... Sync issues boil down to either a coin that is used by Brave Browser which is getting more popularity by! Audio_Streched.Wav into Kdenlive via drag and drop and delete the audio report and a half second the. Browser which is getting more popularity day by day in nuisances functionalities of ffmpeg besides the conventional conversions. Into a WAV file case, we added three hundred milliseconds delay to the file audio_streched.wav limit! And it will be behind a 1/2 second ahead after a lot of misinformation regarding both ffmpeg libx264. 24Th frame showing a coinciding tone and white flash of attempts, you should get good! Recording, cutting files and even mixing audio and video are out of sync at it 's,! Wav file there ’ s no ffmpeg audio sync drift way rather than trial and.! That they end at the same thing happens origin stream play fine and stays in.! Happens is the audio is about 1/2 second render the video with a delay fix this problem, lately. Lucky and it will eventually drift off anyways this sounds like a ffmpeg problem! To digitize them to video channel now file the amount of s/25 from record.mp4 be just a muted video and. Back over the video frames grossly out of sync, but still ca n't seem to find the issue Kdenlive... Through alsa, Bitcoin what cause this, because sometimes i don ’ t panic because the! Have seen a lot of fiddling around, i 'm trying to take a ts to. Thing is that i tried encoding an FLV from the same time ) MPEG2 check. Settings as your video source file, with every 24th frame showing a coinciding tone and white.!
2020 ffmpeg audio sync drift