ffmpeg commandline crossfade-looped video

crossfadevideo.sh

#!/bin/bash
[[ ! -n $3 ]] && { echo "Usage: crossfadevideo <input.mp4> <fade in seconds> <output.mp4> [looptimes]"; exit; }
input="$1"
fade="$2"
duration="$(ffprobe -v error -select_streams v:0 -show_entries stream=duration -of default=noprint_wrappers=1:nokey=1 "$input")"
duration=$(echo "$duration-($fade)" | bc | sed 's/\..*//g')
[[ ${duration:0:1} == "." ]] && duration="0$duration"
output="$3"
[[ -n $4 ]] && loop=$4 && output="${output}.mkv"
set -x
ffmpeg -y -i "$input" -filter_complex '
[0]split[body][pre];
[pre]trim=duration='$fade',format=yuva420p,fade=d='$fade':alpha=1,setpts=PTS+('$(($duration-$fade))'/TB)[jt];
[body]trim='$fade',setpts=PTS-STARTPTS[main];
[main][jt]overlay' "$output"
# we use mkv for looping since ffmpeg loops mp4 badly
[[ -n $loop ]] && ffmpeg -y -stream_loop $loop -i $output -c copy ${output/\.mkv/}

Awesome ! Thank you for your reply

Fixed a typo in my fork. Should work now.

My man, this is absolutely beautiful. Thanks for taking the time to take the oneliner into this very usable script.

Duration always returned empty for me so (thanks to this post) I replaced line 5 with

duration=$(ffmpeg -i cut.mp4 2>&1 | grep "Duration"| cut -d ' ' -f 4 | sed s/,// | sed 's@\..*@@g' | awk '{ split($1, A, ":"); split(A[3], B, "."); print 3600*A[1] + 60*A[2] + B[1] }')

Also final loop length was fade seconds longer than needed, so my setpts bit looks like setpts=PTS+('$(($duration-$fade))'/TB)[jt]

With that, everything works perfect for me

@mexomagno thank you for the fix, I've integrated it (and added a looptimes param too)

Version of this script that supports transparent videos: https://gist.github.com/api-haus/e4845156845ce07de1744a5fa45db5be

The last command of the last line deleted all the mkv files in my folder. Luckily I didn't need any of them. But maybe it would be better to fix this

Hi. Can you be so kind to explain me what variables should be changed in the code to make it work for me? Which parts?
When I try to execute it, returns only echo and nothing happens

@weweb1 sure! Please copy/paste the command you typed in your terminal.

Thanks a lot! @coderofsalvation

I directly copied your code from above, making sure that I run it in the folder with the video, and with the video name called input.mp4:

im getting a freeze for fade seconds at the end of the video (if i do not provide looptimes), and also between every loop when i do provide looptimes. any idea how i can fix this?

this is my ffmpeg version

ffmpeg version 6.0 Copyright (c) 2000-2023 the FFmpeg developers
built with Apple clang version 14.0.3 (clang-1403.0.22.14.1)
configuration: --prefix=/opt/homebrew/Cellar/ffmpeg/6.0_1 --enable-shared --enable-pthreads --enable-version3 --cc=clang --host-cflags= --host-ldflags= --enable-ffplay --enable-gnutls --enable-gpl --enable-libaom --enable-libaribb24 --enable-libbluray --enable-libdav1d --enable-libjxl --enable-libmp3lame --enable-libopus --enable-librav1e --enable-librist --enable-librubberband --enable-libsnappy --enable-libsrt --enable-libsvtav1 --enable-libtesseract --enable-libtheora --enable-libvidstab --enable-libvmaf --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libxvid --enable-lzma --enable-libfontconfig --enable-libfreetype --enable-frei0r --enable-libass --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libspeex --enable-libsoxr --enable-libzmq --enable-libzimg --disable-libjack --disable-indev=jack --enable-videotoolbox --enable-audiotoolbox --enable-neon
libavutil      58.  2.100 / 58.  2.100
libavcodec     60.  3.100 / 60.  3.100
libavformat    60.  3.100 / 60.  3.100
libavdevice    60.  1.100 / 60.  1.100
libavfilter     9.  3.100 /  9.  3.100
libswscale      7.  1.100 /  7.  1.100
libswresample   4. 10.100 /  4. 10.100
libpostproc    57.  1.100 / 57.  1.100

EDIT: i think this is because im using a file with two streams. removing the audio stream fixes the problem. would be great if we can detect and handle such files in the script

Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'input.mp4':
  Metadata:
    major_brand     : mp42
    minor_version   : 0
    compatible_brands: mp42mp41
    creation_time   : 2021-12-11T19:25:10.000000Z
  Duration: 00:00:10.00, start: 0.000000, bitrate: 100323 kb/s
  Stream #0:0[0x1](eng): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709, progressive), 3840x2160, 99986 kb/s, 30 fps, 30 tbr, 30k tbn (default)
    Metadata:
      creation_time   : 2021-12-11T19:25:10.000000Z
      handler_name    : ?Mainconcept Video Media Handler
      vendor_id       : [0][0][0][0]
      encoder         : AVC Coding
  Stream #0:1[0x2](eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 316 kb/s (default)
    Metadata:
      creation_time   : 2021-12-11T19:25:10.000000Z
      handler_name    : #Mainconcept MP4 Sound Media Handler
      vendor_id       : [0][0][0][0]