[FFmpeg-user] amid fails when there are more than 8 input channels (in one file)
Bouke / VideoToolShed
bouke at videotoolshed.com
Fri May 4 13:42:53 EEST 2018
> On 02 May 2018, at 16:20, Moritz Barsnick <barsnick at gmx.net> wrote:
>
> On Wed, May 02, 2018 at 15:51:09 +0200, Bouke / VideoToolShed wrote:
>> Strange thing, more than 8 channels give silent output:
>> ffmpeg -i 9Ch_orMore.WAV -filter_complex "[0:0][0:0] amix=inputs=2,pan=mono|c0=c0+c1” -ac 1 mono.wav
>> gives on errors whatsoever, but output is silent.
>
> "No" errors?
Hi Moritz:
Boukes-portable:~ bouke$ /Volumes/Leo/Tim/ffmpeg -i /Volumes/Leo/Tim/9chan.wav -filter_complex '[0:0][0:0]amix=inputs=2,pan=mono|c0=c0+c1,volumedetect' -t 5 -f null -
ffmpeg version 3.3-tessus Copyright (c) 2000-2017 the FFmpeg developers
built with Apple LLVM version 8.0.0 (clang-800.0.42.1)
configuration: --cc=/usr/bin/clang --prefix=/opt/ffmpeg --extra-version=tessus --enable-avisynth --enable-fontconfig --enable-gpl --enable-libass --enable-libbluray --enable-libfreetype --enable-libgsm --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopus --enable-libschroedinger --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libvidstab --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-libzmq --enable-libzvbi --enable-version3 --disable-ffplay --disable-indev=qtkit
libavutil 55. 58.100 / 55. 58.100
libavcodec 57. 89.100 / 57. 89.100
libavformat 57. 71.100 / 57. 71.100
libavdevice 57. 6.100 / 57. 6.100
libavfilter 6. 82.100 / 6. 82.100
libswscale 4. 6.100 / 4. 6.100
libswresample 2. 7.100 / 2. 7.100
libpostproc 54. 5.100 / 54. 5.100
Input #0, wav, from '/Volumes/Leo/Tim/9chan.wav':
Metadata:
comment : 9chan.wav
encoded_by : Avid Media Composer 8.6.1
originator_reference: 000000000000002a5ae9870f0645a69b
date : 2018-05-02
creation_time : 11-39-48
time_reference : 172800000
coding_history : PCM MODE:STEREO SAMPLE_RATE:48000 BITS_PER_SAMP:24
: DIGITIZE CARD:DeckLink Studio 2 & 1394 Audio & DirectSound Audio PERIPHERAL:DeckLink Studio 2 & Avid OHCI
:
Duration: 00:00:15.04, bitrate: 10368 kb/s
Stream #0:0: Audio: pcm_s24le ([1][0][0][0] / 0x0001), 48000 Hz, 9 channels, s32 (24 bit), 10368 kb/s
[Parsed_volumedetect_2 @ 0x7fa64b522cc0] n_samples: 0
Stream mapping:
Stream #0:0 (pcm_s24le) -> amix:input0
Stream #0:0 (pcm_s24le) -> amix:input1
volumedetect -> Stream #0:0 (pcm_s16le)
Press [q] to stop, [?] for help
Output #0, null, to 'pipe:':
Metadata:
comment : 9chan.wav
encoded_by : Avid Media Composer 8.6.1
originator_reference: 000000000000002a5ae9870f0645a69b
date : 2018-05-02
coding_history : PCM MODE:STEREO SAMPLE_RATE:48000 BITS_PER_SAMP:24
: DIGITIZE CARD:DeckLink Studio 2 & 1394 Audio & DirectSound Audio PERIPHERAL:DeckLink Studio 2 & Avid OHCI
:
time_reference : 172800000
encoder : Lavf57.71.100
Stream #0:0: Audio: pcm_s16le, 48000 Hz, mono, s16, 768 kb/s (default)
Metadata:
encoder : Lavc57.89.100 pcm_s16le
size=N/A time=00:00:05.00 bitrate=N/A speed=2.86x
video:0kB audio:469kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
[Parsed_volumedetect_2 @ 0x7fa64b702360] n_samples: 240241
[Parsed_volumedetect_2 @ 0x7fa64b702360] mean_volume: -91.0 dB
[Parsed_volumedetect_2 @ 0x7fa64b702360] max_volume: -91.0 dB
[Parsed_volumedetect_2 @ 0x7fa64b702360] histogram_91db: 240241
Thus, silence.
Same with a 4 channel file (same content on ch. 1 to 4)
Boukes-portable:~ bouke$ /Volumes/Leo/Tim/ffmpeg -i /Volumes/Leo/Tim/4chan.wav -filter_complex '[0:0][0:0]amix=inputs=2,pan=mono|c0=c0+c1,volumedetect' -t 5 -f null -
ffmpeg version 3.3-tessus Copyright (c) 2000-2017 the FFmpeg developers
built with Apple LLVM version 8.0.0 (clang-800.0.42.1)
configuration: --cc=/usr/bin/clang --prefix=/opt/ffmpeg --extra-version=tessus --enable-avisynth --enable-fontconfig --enable-gpl --enable-libass --enable-libbluray --enable-libfreetype --enable-libgsm --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopus --enable-libschroedinger --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libvidstab --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-libzmq --enable-libzvbi --enable-version3 --disable-ffplay --disable-indev=qtkit
libavutil 55. 58.100 / 55. 58.100
libavcodec 57. 89.100 / 57. 89.100
libavformat 57. 71.100 / 57. 71.100
libavdevice 57. 6.100 / 57. 6.100
libavfilter 6. 82.100 / 6. 82.100
libswscale 4. 6.100 / 4. 6.100
libswresample 2. 7.100 / 2. 7.100
libpostproc 54. 5.100 / 54. 5.100
Guessed Channel Layout for Input Stream #0.0 : 4.0
Input #0, wav, from '/Volumes/Leo/Tim/4chan.wav':
Metadata:
comment : 4chan.wav
encoded_by : Avid Media Composer 8.6.1
originator_reference: 000000000000002a5ae9872706460222
date : 2018-05-02
creation_time : 11-40-12
time_reference : 172800000
coding_history : PCM MODE:STEREO SAMPLE_RATE:48000 BITS_PER_SAMP:24
: DIGITIZE CARD:DeckLink Studio 2 & 1394 Audio & DirectSound Audio PERIPHERAL:DeckLink Studio 2 & Avid OHCI
:
Duration: 00:00:15.04, bitrate: 4608 kb/s
Stream #0:0: Audio: pcm_s24le ([1][0][0][0] / 0x0001), 48000 Hz, 4.0, s32 (24 bit), 4608 kb/s
[Parsed_volumedetect_2 @ 0x7fed73421460] n_samples: 0
Stream mapping:
Stream #0:0 (pcm_s24le) -> amix:input0
Stream #0:0 (pcm_s24le) -> amix:input1
volumedetect -> Stream #0:0 (pcm_s16le)
Press [q] to stop, [?] for help
Output #0, null, to 'pipe:':
Metadata:
comment : 4chan.wav
encoded_by : Avid Media Composer 8.6.1
originator_reference: 000000000000002a5ae9872706460222
date : 2018-05-02
coding_history : PCM MODE:STEREO SAMPLE_RATE:48000 BITS_PER_SAMP:24
: DIGITIZE CARD:DeckLink Studio 2 & 1394 Audio & DirectSound Audio PERIPHERAL:DeckLink Studio 2 & Avid OHCI
:
time_reference : 172800000
encoder : Lavf57.71.100
Stream #0:0: Audio: pcm_s16le, 48000 Hz, mono, s16, 768 kb/s (default)
Metadata:
encoder : Lavc57.89.100 pcm_s16le
size=N/A time=00:00:05.00 bitrate=N/A speed=6.08x
video:0kB audio:469kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
[Parsed_volumedetect_2 @ 0x7fed73605840] n_samples: 240405
[Parsed_volumedetect_2 @ 0x7fed73605840] mean_volume: -26.8 dB
[Parsed_volumedetect_2 @ 0x7fed73605840] max_volume: -11.4 dB
[Parsed_volumedetect_2 @ 0x7fed73605840] histogram_11db: 18
[Parsed_volumedetect_2 @ 0x7fed73605840] histogram_12db: 75
[Parsed_volumedetect_2 @ 0x7fed73605840] histogram_13db: 184
But, when I swap Amix with Amerge, all is well also with 9 channels…
I don’t understand it, but it’s good enough for rock ’n roll.
Thanks all!
Bouke
>
> This works for me (9 inputs):
> $ ffmpeg -f lavfi -i anoisesrc=seed=0 -f lavfi -i anoisesrc=seed=1 -f lavfi -i anoisesrc=seed=2 -f lavfi -i anoisesrc=seed=3 -f lavfi -i anoisesrc=seed=4 -f lavfi -i anoisesrc=seed=5 -f lavfi -i anoisesrc=seed=6 -f lavfi -i anoisesrc=seed=7 -f lavfi -i anoisesrc=seed=8 -filter_complex 'amerge=inputs=9,pan=mono|c0=c0+c1,volumedetect' -t 5 -f null -
>
> (volumedetect is there to verify that it is not silent.)
>
> What are you trying to achieve with amix?
>
> Moritz
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