This command allows you to extract specific frames from a video, which are basically image files that make up the video. Output.mp4 is the output file, you can rename it as you need. 'copy' means you're using the same codec as the input file.

vcodec stands for the video codec to encode the output file. i is the input file, in the above case it's a file called 'input.mp4'.

How to fix out of sync between audio and video usi.Get 3-Month FREE License (Limited Time) >īefore digging into how to use FFmpeg, keep in mind the powerful command: ffmpeg -ss 00:00:05 -t 6 -i input.mp4 -vcodec copy -acodec copy output.mov.

ffmpeg will see the '.flv' and apply the proper codecs for the audio and video to make a '.flv' file.) Since there's no offset applied to the first input file, it will be processed normally.įinally we change the audio sample rate (-ar) to something suitable for a flash movie and output will be a file called 'video.flv'. Then '-map 0:1' tells it to use the second stream from the first input as the audio. Since that's the input that follows the '-itsoffset' switch, that's the stream that will be delayed. Here '-map 1:0' tells ffmpeg to use the second input file (1) and take its first stream (0) as the video source. The command line will be:įfmpeg -i sample.ogg -itsoffset -i sample.ogg -map 1:0 -map 0:1 -ar 22050 video.flv Since I know that a flash movie has two streams: video first and then audio second, (which you can see using 'ffmpeg -i movie.flv'), the first 'map' switch specifies the video, and the second specifies the audio.

The '-map' switches should be listed in the order you want the streams to appear in the output file. Let say that the video we want to convert is: 'sample.ogg' and that the converted (final output) is called: 'video.flv'Ĭonsidere that we want ffmpeg to take the first input file as the audio, and the second as the video, since we need to delay the video and we've applied the delay to the second input file. If this first fix doesn't work for your stream, them use the -itsoffset command the option. Specially handsome while converting video streams like dvb-recordings. No need to use the -itsoffset with separate A/V inputs, no need to calculate the offset. Quick fix for A/V out-of-sync when using ffmpegįfmpeg now has the option called: '-async ' which syncronizes audio and video at the beginnig of the stream when using '-async 1' in the command line of ffmpeg.

Ffmpeg map audio from second video