On 8/27/18, Michael Koch <astroelectro...@t-online.de> wrote: > In the first example I have two identical 1kHz sine sources. The first > source is delayed by 0.5ms (which means 180DEG phase shift), and then both > channels are mixed. This works as expected, the result is silence. > > ffmpeg -f lavfi -i sine=f=1000:d=5 -f lavfi -i sine=f=1000:d=5 > -filter_complex "adelay=0.5,amix" -y test1.mp3 > > In the second example the only difference is that the other channel is > delayed. The result should be the same. But it doesn't work, the result > isn't silence. Why doesn't it work? > > ffmpeg -f lavfi -i sine=f=1000:d=5 -f lavfi -i sine=f=1000:d=5 > -filter_complex "adelay=0|0.5,amix" -y test2.mp3
sine audio source filter gives mono output, but you give adelay options like it is gonna use stereo input. > > Uncut console outputs for both examples are below. > > Thanks, > Michael > > > c:/ffmpeg/ffmpeg -f lavfi -i sine=f=1000:d= > 5 -f lavfi -i sine=f=1000:d=5 -filter_complex "adelay=0.5,amix" -y test1.mp3 > ffmpeg version N-91565-g1940c27c82 Copyright (c) 2000-2018 the FFmpeg > developers > > built with gcc 7.3.1 (GCC) 20180722 > configuration: --enable-gpl --enable-version3 --enable-sdl2 > --enable-bzlib --e > nable-fontconfig --enable-gnutls --enable-iconv --enable-libass > --enable-libblur > ay --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb > --enable- > libopencore-amrwb --enable-libopenjpeg --enable-libopus > --enable-libshine --enab > le-libsnappy --enable-libsoxr --enable-libtheora --enable-libtwolame > --enable-li > bvpx --enable-libwavpack --enable-libwebp --enable-libx264 > --enable-libx265 --en > able-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp > --enable- > libvidstab --enable-libvorbis --enable-libvo-amrwbenc --enable-libmysofa > --enabl > e-libspeex --enable-libxvid --enable-libaom --enable-libmfx --enable-amf > --enabl > e-ffnvcodec --enable-cuvid --enable-d3d11va --enable-nvenc > --enable-nvdec --enab > le-dxva2 --enable-avisynth > libavutil 56. 18.102 / 56. 18.102 > libavcodec 58. 22.100 / 58. 22.100 > libavformat 58. 17.101 / 58. 17.101 > libavdevice 58. 4.101 / 58. 4.101 > libavfilter 7. 26.100 / 7. 26.100 > libswscale 5. 2.100 / 5. 2.100 > libswresample 3. 2.100 / 3. 2.100 > libpostproc 55. 2.100 / 55. 2.100 > Input #0, lavfi, from 'sine=f=1000:d=5': > Duration: N/A, start: 0.000000, bitrate: 705 kb/s > Stream #0:0: Audio: pcm_s16le, 44100 Hz, mono, s16, 705 kb/s > Input #1, lavfi, from 'sine=f=1000:d=5': > Duration: N/A, start: 0.000000, bitrate: 705 kb/s > Stream #1:0: Audio: pcm_s16le, 44100 Hz, mono, s16, 705 kb/s > Stream mapping: > Stream #0:0 (pcm_s16le) -> adelay > Stream #1:0 (pcm_s16le) -> amix:input1 > amix -> Stream #0:0 (libmp3lame) > Press [q] to stop, [?] for help > Output #0, mp3, to 'test1.mp3': > Metadata: > TSSE : Lavf58.17.101 > Stream #0:0: Audio: mp3 (libmp3lame), 44100 Hz, mono, fltp (default) > Metadata: > encoder : Lavc58.22.100 libmp3lame > [Parsed_sine_0 @ 0000000000512840] EOF timestamp not reliable > [Parsed_sine_0 @ 0000000000514c00] EOF timestamp not reliable > size= 40kB time=00:00:05.01 bitrate= 64.7kbits/s speed=32.2x > video:0kB audio:39kB subtitle:0kB other streams:0kB global headers:0kB > muxing ov > erhead: 0.562815% > > > > > c:/ffmpeg/ffmpeg -f lavfi -i sine=f=1000:d= > 5 -f lavfi -i sine=f=1000:d=5 -filter_complex "adelay=0|0.5,amix" -y > test2.mp3 > ffmpeg version N-91565-g1940c27c82 Copyright (c) 2000-2018 the FFmpeg > developers > > built with gcc 7.3.1 (GCC) 20180722 > configuration: --enable-gpl --enable-version3 --enable-sdl2 > --enable-bzlib --e > nable-fontconfig --enable-gnutls --enable-iconv --enable-libass > --enable-libblur > ay --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb > --enable- > libopencore-amrwb --enable-libopenjpeg --enable-libopus > --enable-libshine --enab > le-libsnappy --enable-libsoxr --enable-libtheora --enable-libtwolame > --enable-li > bvpx --enable-libwavpack --enable-libwebp --enable-libx264 > --enable-libx265 --en > able-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp > --enable- > libvidstab --enable-libvorbis --enable-libvo-amrwbenc --enable-libmysofa > --enabl > e-libspeex --enable-libxvid --enable-libaom --enable-libmfx --enable-amf > --enabl > e-ffnvcodec --enable-cuvid --enable-d3d11va --enable-nvenc > --enable-nvdec --enab > le-dxva2 --enable-avisynth > libavutil 56. 18.102 / 56. 18.102 > libavcodec 58. 22.100 / 58. 22.100 > libavformat 58. 17.101 / 58. 17.101 > libavdevice 58. 4.101 / 58. 4.101 > libavfilter 7. 26.100 / 7. 26.100 > libswscale 5. 2.100 / 5. 2.100 > libswresample 3. 2.100 / 3. 2.100 > libpostproc 55. 2.100 / 55. 2.100 > Input #0, lavfi, from 'sine=f=1000:d=5': > Duration: N/A, start: 0.000000, bitrate: 705 kb/s > Stream #0:0: Audio: pcm_s16le, 44100 Hz, mono, s16, 705 kb/s > Input #1, lavfi, from 'sine=f=1000:d=5': > Duration: N/A, start: 0.000000, bitrate: 705 kb/s > Stream #1:0: Audio: pcm_s16le, 44100 Hz, mono, s16, 705 kb/s > Stream mapping: > Stream #0:0 (pcm_s16le) -> adelay > Stream #1:0 (pcm_s16le) -> amix:input1 > amix -> Stream #0:0 (libmp3lame) > Press [q] to stop, [?] for help > Output #0, mp3, to 'test2.mp3': > Metadata: > TSSE : Lavf58.17.101 > Stream #0:0: Audio: mp3 (libmp3lame), 44100 Hz, mono, fltp (default) > Metadata: > encoder : Lavc58.22.100 libmp3lame > [Parsed_sine_0 @ 00000000003f4c80] EOF timestamp not reliable > [Parsed_sine_0 @ 00000000003f2880] EOF timestamp not reliable > size= 40kB time=00:00:05.01 bitrate= 64.7kbits/s speed=45.9x > video:0kB audio:39kB subtitle:0kB other streams:0kB global headers:0kB > muxing ov > erhead: 0.562815% > > 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