[FFmpeg-user] filter_complex: concat an image to a video, but ALSO xfade

[Arif Driessen]

Hi guys,

What I have:
    [0:0] = thumbnail.png
    [1:0] = aevalsrc="-2+random(0)" (white noise)
    [2:0][2:1] = IN_VIDEO.avi (mono audio track)

What I want:
    - [0:0] and [1:0] to play/loop unmodified for
${FADE_IN_DURATION_SECONDS}
    - THEN [0:0] will xfade into [2:0]
    - (however this is achieved, [2:1] must stay in sync with [2:0])

This is what I have:

ffmpeg \
  -loop 1 -framerate ${FPS} -t ${FADE_IN_DURATION_SECONDS} -i ${THUMBNAIL}
`# [file 0]` \
  -t ${FADE_IN_DURATION_SECONDS} -f lavfi -i aevalsrc="-2+random(0)" `#
white noise track` `# [file 1]` \
  -ss ${TRIM_START_SECONDS} \
  -i ${IN_VIDEO} `# [file 2]` \
  -to ${TRIM_END_SECONDS} \
  -filter_complex \
  "
    `# match thumbnail to IN_VIDEO specs`
    [0:0]
      scale=${VIDEO_RESOLUTION}
    [scaled];
    [scaled]
      format=pix_fmts=${PIXEL_FORMAT}
    [formatted];
    [formatted]
      setsar=${DAR}
    [sar_matched];
    [sar_matched]
      settb=expr=${TIME_BASE}
    [thumbnail];
    `# make a copy for later concat`
    [thumbnail]
      split
    [thumbnail_a][thumbnail_b];
    `# xfade thumbnail with video`
    [thumbnail_a][2:0]
      xfade=
        transition=fade
    [xfaded];
    `# concat thumbnail with xfaded`
    [thumbnail_b][1:0][xfaded][2:1]
    concat=n=2:v=1:a=1
  " \
  -vcodec libx264 \
  -preset veryfast \
  -crf 18 \
  -pix_fmt yuv420p \
  -acodec aac \
  -b:a 192k \
  ${OUT_VIDEO}

--

If I don't do the concating, the xfading works fine. Once I split and
concat, then the concating works perfectly, but I've lost the xfade.

Any ideas?

Many thanks,
Arif Driessen