I am converting a sample .mkv file to a .mp4 file. The problem I run into is that the sound is out of sync. As you can see in the log, the longer the movie plays, the closer in sync audio and video get.
Now, my question is, is there any way to avoid this from happening?
➜ ~ ffmpeg -i mkv.mkv -vcodec copy -acodec copy mkv.mp4
ffmpeg version 3.2.2 Copyright (c) 2000-2016 the FFmpeg developers
built with Apple LLVM version 8.0.0 (clang-800.0.42.1)
configuration: --prefix=/usr/local/Cellar/ffmpeg/3.2.2 --enable-shared --enable-pthreads --enable-gpl --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-libmp3lame --enable-libx264 --enable-libxvid --enable-opencl --disable-lzma --enable-vda
libavutil 55. 34.100 / 55. 34.100
libavcodec 57. 64.101 / 57. 64.101
libavformat 57. 56.100 / 57. 56.100
libavdevice 57. 1.100 / 57. 1.100
libavfilter 6. 65.100 / 6. 65.100
libavresample 3. 1. 0 / 3. 1. 0
libswscale 4. 2.100 / 4. 2.100
libswresample 2. 3.100 / 2. 3.100
libpostproc 54. 1.100 / 54. 1.100
Input #0, matroska,webm, from 'mkv.mkv':
Metadata:
ENCODER : Lavf53.24.2
Duration: 00:00:34.08, start: -1.400000, bitrate: 1232 kb/s
Stream #0:0: Video: mpeg4 (Simple Profile), yuv420p, 720x480 [SAR 1:1 DAR 3:2], 25 fps, 25 tbr, 1k tbn, 25 tbc (default)
Stream #0:1: Audio: aac (LC), 48000 Hz, 5.1, fltp (default)
Output #0, mp4, to 'mkv.mp4':
Metadata:
encoder : Lavf57.56.100
Stream #0:0: Video: mpeg4 (Simple Profile) ( [0][0][0] / 0x0020), yuv420p, 720x480 [SAR 1:1 DAR 3:2], q=2-31, 25 fps, 25 tbr, 16k tbn, 1k tbc (default)
Stream #0:1: Audio: aac (LC) ([64][0][0][0] / 0x0040), 48000 Hz, 5.1 (default)
Stream mapping:
Stream #0:0 -> #0:0 (copy)
Stream #0:1 -> #0:1 (copy)
Press [q] to stop, [?] for help
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132736, current: 67440; changing to 132737. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132737, current: 68472; changing to 132738. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132738, current: 69496; changing to 132739. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132739, current: 70520; changing to 132740. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132740, current: 71544; changing to 132741. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132741, current: 72568; changing to 132742. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132742, current: 73592; changing to 132743. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132743, current: 74616; changing to 132744. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132744, current: 75640; changing to 132745. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132745, current: 76664; changing to 132746. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132746, current: 77688; changing to 132747. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132747, current: 78712; changing to 132748. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132748, current: 79736; changing to 132749. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132749, current: 80760; changing to 132750. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132750, current: 81784; changing to 132751. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132751, current: 82808; changing to 132752. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132752, current: 83832; changing to 132753. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132753, current: 84856; changing to 132754. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132754, current: 85880; changing to 132755. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132755, current: 86904; changing to 132756. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132756, current: 87928; changing to 132757. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132757, current: 88952; changing to 132758. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132758, current: 89976; changing to 132759. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132759, current: 91000; changing to 132760. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132760, current: 92024; changing to 132761. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132761, current: 93048; changing to 132762. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132762, current: 94072; changing to 132763. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132763, current: 95096; changing to 132764. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132764, current: 96120; changing to 132765. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132765, current: 97144; changing to 132766. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132766, current: 98168; changing to 132767. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132767, current: 99192; changing to 132768. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132768, current: 100216; changing to 132769. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132769, current: 101240; changing to 132770. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132770, current: 102264; changing to 132771. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132771, current: 103288; changing to 132772. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132772, current: 104312; changing to 132773. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132773, current: 105336; changing to 132774. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132774, current: 106360; changing to 132775. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132775, current: 107384; changing to 132776. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132776, current: 108408; changing to 132777. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132777, current: 109432; changing to 132778. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132778, current: 110456; changing to 132779. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132779, current: 111480; changing to 132780. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132780, current: 112504; changing to 132781. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132781, current: 113528; changing to 132782. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132782, current: 114552; changing to 132783. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132783, current: 115576; changing to 132784. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132784, current: 116600; changing to 132785. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132785, current: 117624; changing to 132786. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132786, current: 118648; changing to 132787. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132787, current: 119672; changing to 132788. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132788, current: 120696; changing to 132789. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132789, current: 121720; changing to 132790. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132790, current: 122744; changing to 132791. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132791, current: 123768; changing to 132792. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132792, current: 124792; changing to 132793. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132793, current: 125816; changing to 132794. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132794, current: 126840; changing to 132795. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132795, current: 127864; changing to 132796. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132796, current: 128888; changing to 132797. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132797, current: 129912; changing to 132798. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132798, current: 130936; changing to 132799. This may result in incorrect timestamps in the output file.
[mp4 @ 0x7fd7b1003200] Non-monotonous DTS in output stream 0:1; previous: 132799, current: 131960; changing to 132800. This may result in incorrect timestamps in the output file.
frame= 887 fps=0.0 q=-1.0 Lsize= 5130kB time=00:00:35.45 bitrate=1185.4kbits/s speed= 668x
video:3447kB audio:1663kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.401607%
Thanks for all the help already. I cant seem to find an answer...
sstfor your case. You may have to re-encode audio. Will provide command if so.ffmpeg -y -i mkv.mkv -movflags faststart -c:v libx264 -avoid_negative_ts mkv.mp4I receive this error:At least one output file must be specified. Thanks for your help Mulvya!make_zeromake_zero, I still receive the out of sync audio andNon-monotonous DTS in output stream.