[FFmpeg-user] Help with syntax using lv2 filter plugin

[David Ing]

Hi I am wondering about the exact syntax for using ffmpeg with an LV2
filter.

The command I'm using is:

    ffmpeg -i $INPUT -af lv2=plugin=https\\\\://
github.com/lucianodato/speech-denoiser $OUTPUT

But I get an "Error initializing filter 'lv2'" error:

ffmpeg version 4.1.3-0ubuntu1 Copyright (c) 2000-2019 the FFmpeg developers
  built with gcc 8 (Ubuntu 8.3.0-6ubuntu1)
  configuration: --prefix=/usr --extra-version=0ubuntu1
--toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu
--incdir=/usr/include/x86_64-linux-gnu --arch=amd64 --enable-gpl
--disable-stripping --enable-avresample --disable-filter=resample
--enable-avisynth --enable-gnutls --enable-ladspa --enable-libaom
--enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca
--enable-libcdio --enable-libcodec2 --enable-libflite
--enable-libfontconfig --enable-libfreetype --enable-libfribidi
--enable-libgme --enable-libgsm --enable-libjack --enable-libmp3lame
--enable-libmysofa --enable-libopenjpeg --enable-libopenmpt
--enable-libopus --enable-libpulse --enable-librsvg --enable-librubberband
--enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex
--enable-libssh --enable-libtheora --enable-libtwolame --enable-libvidstab
--enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp
--enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq
--enable-libzvbi --enable-lv2 --enable-omx --enable-openal --enable-opengl
--enable-sdl2 --enable-libdc1394 --enable-libdrm --enable-libiec61883
--enable-chromaprint --enable-frei0r --enable-libx264 --enable-shared
  libavutil      56. 22.100 / 56. 22.100
  libavcodec     58. 35.100 / 58. 35.100
  libavformat    58. 20.100 / 58. 20.100
  libavdevice    58.  5.100 / 58.  5.100
  libavfilter     7. 40.101 /  7. 40.101
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  3.100 /  5.  3.100
  libswresample   3.  3.100 /  3.  3.100
  libpostproc    55.  3.100 / 55.  3.100
Guessed Channel Layout for Input Stream #0.0 : stereo
Input #0, wav, from '/data/sample_car.wav':
  Metadata:
    encoder         : Lavf58.12.100
  Duration: 00:01:05.02, bitrate: 1411 kb/s
    Stream #0:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 44100 Hz,
stereo, s16, 1411 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (pcm_s16le (native) -> pcm_s16le (native))
Press [q] to stop, [?] for help
error: attempt to map invalid URI `https'
[lv2 @ 0x561771d961c0] Invalid plugin URI <https>
[AVFilterGraph @ 0x561771d4ebc0] Error initializing filter 'lv2' with args
'plugin=https://github.com/lucianodato/speech-denoiser'
Error reinitializing filters!
Failed to inject frame into filter network: Invalid argument
Error while processing the decoded data for stream #0:0
Conversion failed!


I tried to follow the documentation but it was a bit vague.

    https://ffmpeg.org/ffmpeg-filters.html#lv2

For more specific details about reproducing this problem exactly, see here:

    https://github.com/lucianodato/speech-denoiser/issues/16