Sadly the audio had a shift or drift of around one and a half second over the one hour video. The initial sync is still a problem. The audio sync 'drifts' - in a 1 hour video the audio can be off by up to 15 seconds of more, and around 30 minutes it syncs up correctly. You can leave either video or audio unchanged and sync the remaining stream(s) to the unchanged one. Video sync method. After rendering your video in Video Enhance AI as an mp4 file, if your audio is out of sync, this indicates that your source video is running at a variable framerate. 5. … We tried to do some ffmpeg audio/video sync features but it did not fix the problem. MPlayer or MEncoder as Source = possible out of sync A/V FFmpeg as source = OK However actual can't use correctly FFmpeg as source - no problem in older MediaCoder builds. 1. Here a small solution to fix this problem with the help of Kdenlive and FFmpeg. Note: this will work for all video formats, not just mkv/mp4/avi – they’re just common formats (and the 3 that I’ve found most often have sync issues). But sometimes during a conversion to another file format (such as mp4), the audio and video will not remain in sync and the itsoffset switch can be used to adjust them. Output file has -fixed appended to it. Some .mov files work and others have a huge (1 second or more) lag in video w/re to audio. With -map you can select from which stream the timestamps should be taken. ... below 0.01%) on the newest firmware. Video will be stretched/squeezed to match the timestamps, it is done by duplicating and dropping frames. The audio and video sometimes end up out of sync by a small difference (less than 1 second I'd say, although it might be worse with longer recordings). `-async samples_per_second' Audio sync method. It occurs because the sync during the actual render follows different rules than vse playback. Here there is no audio-video sync issue Receive RTMP in ffmoeg and write audio and video as mpegts files seperately. Any help appreciated. Video synchronization works in a similar way. My example is a record.mp4 file. Tried writing to an mkv file instead of the stream URL, the problem still appeared. Before continuing, under the ‘Video Output‘ and ‘Audio Output‘ options, make sure it says ‘Copy’. Play the project in the editor and notice that the audio & video remain in sync for the entire duration. Save the result to a new MPEG file. I tried two invocations: ffmpeg -f alsa -i hw:1,0 -f v4l2 -i /dev/video0 -acodec mp2 -b:a 384k -vcodec mpeg2video -b:v 8000k -f mpegts badsync-av.mpg -report Please help me Thanks in advenced. we faced problem in live stream. Active 1 year, 4 months ago. Extract audio with FFmpeg. It's free to sign up and bid on jobs. By default, ffmpeg will try to perform re-encoding on both the video and audio streams of the input media before exporting the final result, which is a time consuming task. problam is that after encode livestream on rtmp server than after one hour audio and video out of sync in live stream . Thank you! At this point, the Raw DV file is perfectly in sync and great quality, but I'm trying to remove the blank space at the end so I can burn it to DVD. I can fix it temporarily using the -itsoffset option of ffmpeg, but after a while it just goes out of sync again. Here’s the script. Bonus Skip Re-Encoding. Both of those should play. There are a few ways to circumvent this issue. If you have a video with audio sync issues, you can easily fix it using ffmpeg. Specifically this is an issue experienced after successfully lining-up and playing everything properly on vse playback. It’s fast. Oldest first Newest first. The problem is the audio is out of sync right from the start (sound comes after the video). 4. 1. A variable framerate causes some video editors to experience some minor hiccups in performance. 2. When I encode the frames I add the PTS in the following way (which I took from the muxing.c example): For the video frames I increment the PTS one by one (starting at 0). The separate video (.mpv) and audio (.mpa) will automatically be imported onto timeline after finishing the demuxing process. [ I don't have enough reputation to comment on the ... Something wrong with recording video and merging audio and video by using FFmpeg. [CTRL]+[F12] to "Render Animation" (or just use the big button in Render properties). Both devices work separately but i cannot seem to get the audio & video to sync up. Search for jobs related to Ffmpeg android ndk audio video sync or hire on the world's largest freelancing marketplace with 15m+ jobs. Adjust the relative offset between audio and video, by moving either the video clip or the audio clip, till they are in sync. To verify whether the problem is with ffmpeg or with input stream I have verified the below: Receive RTMP in ffmpeg and directly write to mp4 file. ... FFmpeg, encode video for 720p @ 4mbps playback. This covers an audio sync issue you may unknowingly experience in blender at some point if you render using audio+video settings. I am currently evaluating using Premiere Pro. Add a video file and an audio file that are to remain in sync, together, for the duration (~1min.) With Premiere, opening "problematic" .mov files launches a dialog asking if I want to sync the audio and video so Premiere Pro seems to have solved the problem. Downlod MPEG Video … ffmpeg -i record.mp4 -vn audio.wav After removal, the finshed file has synced audio at the start, but by the end (an hour or two later), it can be as much as 3 to 5 seconds off, it's a gradual drift. Like Like I have tried Handbrake, multiple different settings, same results. At this moment transcoding FLV with variable frame rate, it's not … -> Out of sync! If they do then do the following. Sir we are broadcast live stream on rtmp server using ffmpeg. Log: Re: audio/video recordings out of sync: ... To reduce the risk of sync issues, i modified the videoroom plugin in order to start recording audio & video at the same time (on a key frame). Comments only. It takes 2 inputs: the filename and delay: 0.100 is 100 ms or 0.1 seconds. ffmpeg -i inputfile.ext -vcodec copy -an -f mp4 video.mp4 ffmpeg -i inputfile.ext -acodec aac -b:a 192k -ac 2 -ar 48000 -f mp4 audio.mp4. I am having similar issues, our mp4 files have serious audio sync issues. FFMPEG is hanging on a single frame. Audio and video recorded from the device using ffmpeg are out of sync. Only takes 2-3 seconds to process a 1.5 hour recording. The following command will extract the audio of the MPEG-4 into a WAV file. The itsoffset switch is nearly always used in conjunction with the “map” switch, since this tells ffmpeg which stream you want to affect, and what streams you wish to merge into a new output file. I have a Raspberry Pi camera & a USB microphone. Just choose the video stream mapping of the offset media file and you are good to go. This can help to reduce audio and video sync issues when delivering a live feed or creating VOD content. Problem with audio sync when concatenating multiple mp4(s) Ask Question Asked 1 year, 5 months ago. Open the video with the out of sync audio in VLC and then select Tools -> Track Synchronization (Mac users: select Window -> Track Synchronization ) However, they are out of sync differently depending on the order in which you specify the inputs on the command line. ffmpeg -i video.mp4 -i audio.mp4 -codec copy -f mp4 muxed.mp4. 0. ffmpeg audio sync issue when using hstack filter. Video remain in sync, together, for the entire duration will be. 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