3

Sorry if my question is dumb, but I'm new to FFmpeg.

I have some videos. They all have the same video codec, resolution and framerate. Audio streams also have the same format. For example, MP4 files, H264, AAC.

I want to merge some of them into one file with smooth transitions between them. I just want the simplest one - when videos overlaps for 2-3 seconds. The first one fades out and the second fades in.

I read the docs and some other questions and found out that I need some set of concat filter with something like blend or overlay or fade.

Please help.

Update:

ffmpeg \
 -i input0.mp4 \
 -i input1.mp4 \
 -filter_complex \
 "[0:v]setpts=PTS-STARTPTS[v0];[1:v]setpts=PTS-STARTPTS+4/TB,format=yuva444p,fade=st=4:d=1:t=in:alpha=1[v1];[v0][v1]overlay,format=yuv420p[v];[0:a]asetpts=PTS-STARTPTS[a0];[1:a]asetpts=PTS-STARTPTS[a1];[a0][a1]acrossfade=d=1[a]" \
 -map "[v]" -map "[a]" output.mp4

Log:

ffmpeg version 3.4.6-0ubuntu0.18.04.1 Copyright (c) 2000-2019 the FFmpeg developers
  built with gcc 7 (Ubuntu 7.3.0-16ubuntu3)
  configuration: --prefix=/usr --extra-version=0ubuntu0.18.04.1 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --enable-gpl --disable-stripping --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librubberband --enable-librsvg --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-omx --enable-openal --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libopencv --enable-libx264 --enable-shared
  libavutil      55. 78.100 / 55. 78.100
  libavcodec     57.107.100 / 57.107.100
  libavformat    57. 83.100 / 57. 83.100
  libavdevice    57. 10.100 / 57. 10.100
  libavfilter     6.107.100 /  6.107.100
  libavresample   3.  7.  0 /  3.  7.  0
  libswscale      4.  8.100 /  4.  8.100
  libswresample   2.  9.100 /  2.  9.100
  libpostproc    54.  7.100 / 54.  7.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'input0.mp4':
  Metadata:
    major_brand     : mp42
    minor_version   : 0
    compatible_brands: isommp42
    creation_time   : 2019-10-20T09:15:30.000000Z
    com.android.version: 8.0.0
  Duration: 00:00:23.81, start: 0.000000, bitrate: 17280 kb/s
    Stream #0:0(eng): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709), 1920x1080, 17023 kb/s, SAR 1:1 DAR 16:9, 30.04 fps, 30 tbr, 90k tbn, 180k tbc (default)
    Metadata:
      creation_time   : 2019-10-20T09:15:30.000000Z
      handler_name    : VideoHandle
    Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 256 kb/s (default)
    Metadata:
      creation_time   : 2019-10-20T09:15:30.000000Z
      handler_name    : SoundHandle
Input #1, mov,mp4,m4a,3gp,3g2,mj2, from 'input1.mp4':
  Metadata:
    major_brand     : mp42
    minor_version   : 0
    compatible_brands: isommp42
    creation_time   : 2019-10-20T09:16:05.000000Z
    com.android.version: 8.0.0
  Duration: 00:00:28.76, start: 0.000000, bitrate: 17282 kb/s
    Stream #1:0(eng): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709), 1920x1080, 17019 kb/s, SAR 1:1 DAR 16:9, 30.04 fps, 30 tbr, 90k tbn, 180k tbc (default)
    Metadata:
      creation_time   : 2019-10-20T09:16:05.000000Z
      handler_name    : VideoHandle
    Stream #1:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 256 kb/s (default)
    Metadata:
      creation_time   : 2019-10-20T09:16:05.000000Z
      handler_name    : SoundHandle
Stream mapping:
  Stream #0:0 (h264) -> setpts
  Stream #0:1 (aac) -> asetpts
  Stream #1:0 (h264) -> setpts
  Stream #1:1 (aac) -> asetpts
  format -> Stream #0:0 (libx264)
  acrossfade -> Stream #0:1 (aac)
Press [q] to stop, [?] for help
[libx264 @ 0x55dd4a513aa0] using SAR=1/1
[libx264 @ 0x55dd4a513aa0] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2
[libx264 @ 0x55dd4a513aa0] profile High, level 4.0
[libx264 @ 0x55dd4a513aa0] 264 - core 152 r2854 e9a5903 - H.264/MPEG-4 AVC codec - Copyleft 2003-2017 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=6 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
Output #0, mp4, to 'output.mp4':
  Metadata:
    major_brand     : mp42
    minor_version   : 0
    compatible_brands: isommp42
    com.android.version: 8.0.0
    encoder         : Lavf57.83.100
    Stream #0:0: Video: h264 (libx264) (avc1 / 0x31637661), yuv420p(progressive), 1920x1080 [SAR 1:1 DAR 16:9], q=-1--1, 30 fps, 15360 tbn, 30 tbc (default)
    Metadata:
      encoder         : Lavc57.107.100 libx264
    Side data:
      cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
    Stream #0:1: Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 128 kb/s (default)
    Metadata:
      encoder         : Lavc57.107.100 aac
Past duration 0.600319 too large   24832kB time=00:00:27.11 bitrate=7502.4kbits/s speed=0.792x    
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    Last message repeated 1 times
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    Last message repeated 1 times
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Past duration 0.913322 too large
frame=  985 fps= 13 q=-1.0 Lsize=   60323kB time=00:00:51.58 bitrate=9579.9kbits/s speed=0.695x    
video:59484kB audio:810kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.048264%
[libx264 @ 0x55dd4a513aa0] frame I:5     Avg QP:22.90  size:206885
[libx264 @ 0x55dd4a513aa0] frame P:303   Avg QP:25.09  size:100886
[libx264 @ 0x55dd4a513aa0] frame B:677   Avg QP:27.85  size: 43292
[libx264 @ 0x55dd4a513aa0] consecutive B-frames:  6.3%  4.3%  5.8% 83.7%
[libx264 @ 0x55dd4a513aa0] mb I  I16..4: 11.1% 49.1% 39.8%
[libx264 @ 0x55dd4a513aa0] mb P  I16..4:  6.5% 14.1%  9.5%  P16..4: 37.5% 16.2%  8.2%  0.0%  0.0%    skip: 8.0%
[libx264 @ 0x55dd4a513aa0] mb B  I16..4:  1.5%  1.6%  3.3%  B16..8: 48.1%  8.4%  2.2%  direct: 4.6%  skip:30.3%  L0:52.3% L1:34.9% BI:12.8%
[libx264 @ 0x55dd4a513aa0] 8x8 transform intra:40.2% inter:46.8%
[libx264 @ 0x55dd4a513aa0] coded y,uvDC,uvAC intra: 63.8% 25.9% 2.2% inter: 27.2% 7.1% 0.0%
[libx264 @ 0x55dd4a513aa0] i16 v,h,dc,p: 20% 25% 25% 30%
[libx264 @ 0x55dd4a513aa0] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 19% 26% 25%  4%  4%  4%  6%  3%  8%
[libx264 @ 0x55dd4a513aa0] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 12% 27% 18%  6%  6%  4% 10%  4% 13%
[libx264 @ 0x55dd4a513aa0] i8c dc,h,v,p: 73% 14% 11%  2%
[libx264 @ 0x55dd4a513aa0] Weighted P-Frames: Y:18.8% UV:5.9%
[libx264 @ 0x55dd4a513aa0] ref P L0: 67.5% 18.8% 10.3%  3.0%  0.5%
[libx264 @ 0x55dd4a513aa0] ref B L0: 96.9%  2.4%  0.7%
[libx264 @ 0x55dd4a513aa0] ref B L1: 98.4%  1.6%
[libx264 @ 0x55dd4a513aa0] kb/s:14841.31
[aac @ 0x55dd4a4b21c0] Qavg: 496.588

Update 2: As I was told, the effect I was searching for is Crossfade. I've found these:

After some experiments I've finally got the working command for my purpose:

[0:v]setpts=PTS-STARTPTS[v0];
[1:v]setpts=PTS-STARTPTS+(23/TB),format=yuva444p,fade=st=23:d=1:t=in:alpha=1[v1];[v0][v1]overlay,format=yuv420p[v];
[0:a]asetpts=PTS-STARTPTS[a0];
[1:a]asetpts=PTS-STARTPTS[a1];
[a0][a1]acrossfade=d=1[a]

It works, but I have to set times for crossfade for every pair of videos manually

So what I want to ask again:

  • Is there any way to automate position for crossfade (last second of the video)? Is there any use for PREV_OUTPTS or PREV_INPTS? I didn't manage to get them work.
  • Can this effect be done with stream copy? There is no use for encoding the stream again.
Improve this question
4
  • Adapt the examples in superuser.com/a/834035
    – llogan
    Jan 10, 2020 at 20:30
  • I used an example for crossfade with the complex filter like this for video: [0:v]setpts=PTS-STARTPTS[v0];[1:v]setpts=PTS-STARTPTS+4/TB,format=yuva444p,fade=st=4:d=1:t=in:alpha=1[v1];. But this results in output with 4 seconds from the first video then crossfade and complete second video. I suppose something should be done with this [1:v]setpts=PTS-STARTPTS+4/TB and this fade=st=4: but didn't figure out the correct result
    – Alexander Y.
    Jan 13, 2020 at 21:32
  • Edit your question to include your full command and the complete log.
    – llogan
    Jan 13, 2020 at 21:32
  • @llogan, I've updated my question
    – Alexander Y.
    Jan 26, 2020 at 19:05

1 Answer 1

Reset to default
1

Is there any way to automate position for crossfade (last second of the video)?

Not with ffmpeg alone (yet at least–there is a patch that never got applied that would simplify this). You can use ffprobe to get the duration of each input and use that to determine the values for setpts and fade.

Example ffprobe command:

ffprobe -v error -show_entries format=duration -of csv=p=0 input.mp4

Is there any use for PREV_OUTPTS or PREV_INPTS? I didn't manage to get them work.

No. These do not refer to previous input/output streams or files.

Can this effect be done with stream copy? There is no use for encoding the stream again.

No. You can't filter and stream copy the same stream.

Improve this answer
3
  • Thank you for answer and noting the use of ffprobe. Maybe in some time I'll manage to write script to automate this for me. By the way - will complex filters setpts and fade work with float numbers, for example 442.224 seconds?
    – Alexander Y.
    Jan 27, 2020 at 21:30
  • @AlexanderY. Yes, but such accuracy can become moot due to the frame rate.
    – llogan
    Jan 28, 2020 at 19:04
  • Thanks. Will experiment more.
    – Alexander Y.
    Jan 28, 2020 at 19:44

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