I concatenate 3 videos as below:
Video 1 - 13 seconds with audio Video 2 - 4 seconds without audio (I generated this video using xfade transition Video 3 - 4 seconds with audio If I concatenate video 1 and 3 everything works fine; audio synchronization is correct from start to end. However, when I concatenate all 3 of them, the audio from video 3 starts playing a little bit before the end of video 2. As video 3 is a person talking, you clearly see that the audio doesn't match the mouth movements. I use the following to concatenate: Ffmpeg -safe 0 -f concat -i D:\99_FFMpeg\file_list.txt -c copy concatenated.mp4 Why is this happening and how can I fix it? Console output is below: EXE: -safe 0 -f concat -i D:\99_FFMpeg\file_list.txt -c copy concatenated.mp4 ffmpeg version 2021-03-14-git-1d61a31497-essentials_build-www.gyan.dev Copyright (c) 2000-2021 the FFmpeg developers built with gcc 10.2.0 (Rev6, Built by MSYS2 project) configuration: --enable-gpl --enable-version3 --enable-static --disable-w32threads --disable-autodetect --enable-fontconfig --enable-iconv --enable-gnutls --enable-libxml2 --enable-gmp --enable-lzma --enable-zlib --enable-libsrt --enable-libssh --enable-libzmq --enable-avisynth --enable-sdl2 --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxvid --enable-libaom --enable-libopenjpeg --enable-libvpx --enable-libass --enable-libfreetype --enable-libfribidi --enable-libvidstab --enable-libvmaf --enable-libzimg --enable-amf --enable-cuda-llvm --enable-cuvid --enable-ffnvcodec --enable-nvdec --enable-nvenc --enable-d3d11va --enable-dxva2 --enable-libmfx --enable-libgme --enable-libopenmpt --enable-libopencore-amrwb --enable-libmp3lame --enable-libtheora --enable-libvo-amrwbenc --enable-libgsm --enable-libopencore-amrnb --enable-libopus --enable-libspeex --enable-libvorbis --enable-librubberband libavutil 56. 68.100 / 56. 68.100 libavcodec 58.131.100 / 58.131.100 libavformat 58. 74.100 / 58. 74.100 libavdevice 58. 12.100 / 58. 12.100 libavfilter 7.109.100 / 7.109.100 libswscale 5. 8.100 / 5. 8.100 libswresample 3. 8.100 / 3. 8.100 libpostproc 55. 8.100 / 55. 8.100 [mov,mp4,m4a,3gp,3g2,mj2 @ 0000029fff0972c0] Auto-inserting h264_mp4toannexb bitstream filter Input #0, concat, from 'D:\99_FFMpeg\file_list.txt': Duration: N/A, start: -0.021333, bitrate: 2623 kb/s Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], 2494 kb/s, 60 fps, 60 tbr, 15360 tbn, 120 tbc Metadata: handler_name : VideoHandler vendor_id : [0][0][0][0] Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 129 kb/s Metadata: handler_name : SoundHandler vendor_id : [0][0][0][0] Output #0, mp4, to 'concatenated.mp4': Metadata: encoder : Lavf58.74.100 Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], q=2-31, 2494 kb/s, 60 fps, 60 tbr, 15360 tbn, 15360 tbc Metadata: handler_name : VideoHandler vendor_id : [0][0][0][0] Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 129 kb/s Metadata: handler_name : SoundHandler vendor_id : [0][0][0][0] Stream mapping: Stream #0:0 -> #0:0 (copy) Stream #0:1 -> #0:1 (copy) Press [q] to stop, [?] for help frame= 1 fps=0.0 q=-1.0 size= 0kB time=00:00:00.00 bitrate=N/A speed= 0x [mov,mp4,m4a,3gp,3g2,mj2 @ 0000029fff0ac6c0] Auto-inserting h264_mp4toannexb bitstream filter [mov,mp4,m4a,3gp,3g2,mj2 @ 0000029fff098dc0] Auto-inserting h264_mp4toannexb bitstream filter frame= 1266 fps=0.0 q=-1.0 Lsize= 6209kB time=00:00:21.11 bitrate=2409.4kbits/s speed= 638x video:5906kB audio:268kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.566926% Thanks _______________________________________________ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".