Encountered *filter* with multiple outgoing edges with same upstream label None; a `split` filter is probably required

[AzazelHD]

I get this error when I try to overlay 2 videos and then merge their audios.

input_video = ffmpeg.input(input_path)
overlay_video = ffmpeg.input(overlay_path)

overlay_video = overlay_video.filter('scale', size='600x600')

overlay = input_video.overlay(
    overlay_video,
    x=200,
    y=100,
    eof_action='pass',
)

audio = ffmpeg.filter([input_video.audio, overlay_video.audio], 'amerge')

output = ffmpeg.output(
    overlay,
    audio,
    'output1.mp4',
    vcodec='libx264',
    acodec='aac',
    crf=23,
    preset='veryfast',
    format='mp4',
)

output.run(overwrite_output=True)

This is my script.

I know on normal ffmpeg the command is:

ffmpeg -i v1.mp4 -i v2.mkv -filter_complex "[1:v]scale=size=300x300[s0];[0:v][s0]overlay=eof_action=pass:x=100:y=100[s1];[1:a][0:a]amerge=inputs=2[a]" -map [s1] -map [a] -vcodec libx264 -acodec aac -strict -2 -pix_fmt yuv420p -crf 23 test.mp4

I've also noticed overlay and audio labels are "None", but idk if this is the issue. Can you please help me?

PD: If i set

output = ffmpeg.output(
    overlay,
    input_video.audio,

Works perfectly, but only with input video audio

[abingham]

I get the same error when I try to 'concat' multiple identical lavfi streams:

# bug.py
import ffmpeg

BLACK_1 = ffmpeg.input(
    "color=black:s=800x600",
    format="lavfi",
)

BLACK_2 = ffmpeg.input(
    "color=black:s=800x600",
    format="lavfi",
)

ffmpeg.concat(
    BLACK_1.trim(duration=1),
    BLACK_2.trim(duration=1)
).output("black.mov").compile()

which produces this output:

$ python bug.py
Traceback (most recent call last):
  File "/Users/austin/sandbox/bug/bug.py", line 17, in <module>
    ).output("black.mov").compile()
  File "/Users/austin/sandbox/bug/venv/lib/python3.10/site-packages/ffmpeg/_run.py", line 190, in compile
    return cmd + get_args(stream_spec, overwrite_output=overwrite_output)
  File "/Users/austin/sandbox/bug/venv/lib/python3.10/site-packages/ffmpeg/_run.py", line 161, in get_args
    filter_arg = _get_filter_arg(filter_nodes, outgoing_edge_maps, stream_name_map)
  File "/Users/austin/sandbox/bug/venv/lib/python3.10/site-packages/ffmpeg/_run.py", line 101, in _get_filter_arg
    _allocate_filter_stream_names(filter_nodes, outgoing_edge_maps, stream_name_map)
  File "/Users/austin/sandbox/bug/venv/lib/python3.10/site-packages/ffmpeg/_run.py", line 90, in _allocate_filter_stream_names
    raise ValueError(
ValueError: Encountered trim(duration=1) <1da8cb401eff> with multiple outgoing edges with same upstream label None; a `split` filter is probably required

My initial guess is that the stream naming scheme it's using is incorrectly producing identical names for identical - but conceptually distinct - streams.

[abingham]

And FWIW, I was able to make this problem go away but putting labels on my inputs:

BLACK_1 = ffmpeg.input(
    "color=black:s=800x600",
    format="lavfi",
    label='black_1',
)

BLACK_2 = ffmpeg.input(
    "color=black:s=800x600",
    format="lavfi",
    label='black_2',
)

Well...almost. The error goes away when I'm just running compile(), but when I actually try to execute the ffmpeg command with run(), I see that ffmpeg-python actually inserts the "-label' into the command, resulting in an invalid ffmpeg command:

ffmpeg -f lavfi -label black_1 -i color=black:s=800x600 -f lavfi -label black_2 -i color=black:s=800x600 -filter_complex [0]trim=duration=1[s0];[1]trim=duration=1[s1];[s0][s1]concat=n=2[s2] -map [s2] black.mov

So this is not the solution I was hoping for :(