concate audio amix

[StevenG]

concat of audios doesn't work

ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT

ffmpeg -i m:\temp\a1.wav -i m:\temp\a2.wav -filter_complex "amix=inputs=2" m:\temp\a3.wav
ffmpeg version N-42939-g236ecc3 Copyright (c) 2000-2012 the FFmpeg developers

built on Jul 26 2012 20:50:57 with gcc 4.7.1 (GCC)

[StevenG]

Output:
Stream mapping:

Stream #0:0 (pcm_s16le) -> amix:input0
Stream #1:0 (pcm_s16le) -> amix:input1
amix -> Stream #0:0 (pcm_s16le)

I got resulting files containing only first file,
no concat.

[Nicolas George]

amix is supported only for compatibility with the fork named "libav"; to mix several audio streams, first merge them using amerge and then mix the channels using pan.

Your bug report has "concat" in the subject but does nothing to concatenate the streams. It does not make sense.

Please explain what you are trying to do and copy-paste the complete and unedited command line and console output.

[StevenG]

I try to merge[concat] two audio into one.

d:\2.Prog\All\myTools\xMp4\tools>ffmpeg -i m:\temp\a1.wav -i m:\temp\a2.wav -fil
ter_complex "amix=inputs=2" m:\temp\a3.wav
ffmpeg version N-42939-g236ecc3 Copyright (c) 2000-2012 the FFmpeg developers
  built on Jul 26 2012 20:50:57 with gcc 4.7.1 (GCC)
  configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-ru
ntime-cpudetect --enable-avisynth --enable-bzlib --enable-frei0r --enable-libass
 --enable-libcelt --enable-libopencore-amrnb --enable-libopencore-amrwb --enable
-libfreetype --enable-libgsm --enable-libmp3lame --enable-libnut --enable-libope
njpeg --enable-librtmp --enable-libschroedinger --enable-libspeex --enable-libth
eora --enable-libutvideo --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-
libvorbis --enable-libvpx --enable-libx264 --enable-libxavs --enable-libxvid --e
nable-zlib
  libavutil      51. 65.100 / 51. 65.100
  libavcodec     54. 45.100 / 54. 45.100
  libavformat    54. 21.100 / 54. 21.100
  libavdevice    54.  2.100 / 54.  2.100
  libavfilter     3.  3.100 /  3.  3.100
  libswscale      2.  1.100 /  2.  1.100
  libswresample   0. 15.100 /  0. 15.100
  libpostproc    52.  0.100 / 52.  0.100
[wav @ 0234cfe0] max_analyze_duration 5000000 reached at 5001333
Input #0, wav, from 'm:\temp\a1.wav':
  Duration: 00:05:00.03, bitrate: 4608 kb/s
    Stream #0:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 48000 Hz, 5.1, s16, 4
608 kb/s
[wav @ 02343a20] max_analyze_duration 5000000 reached at 5001333
Input #1, wav, from 'm:\temp\a2.wav':
  Duration: 00:05:00.03, bitrate: 4608 kb/s
    Stream #1:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 48000 Hz, 5.1, s16, 4
608 kb/s
File 'm:\temp\a3.wav' already exists. Overwrite ? [y/N] y
Output #0, wav, to 'm:\temp\a3.wav':
  Metadata:
    encoder         : Lavf54.21.100
    Stream #0:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 48000 Hz, 5.1, s16, 4
608 kb/s
Stream mapping:
  Stream #0:0 (pcm_s16le) -> amix:input0
  Stream #1:0 (pcm_s16le) -> amix:input1
  amix -> Stream #0:0 (pcm_s16le)
Press [q] to stop, [?] for help
size=  168767kB time=00:05:00.03 bitrate=4608.0kbits/s
video:0kB audio:168767kB subtitle:0 global headers:0kB muxing overhead 0.000039%

[Nicolas George]

amix does not concatenate. Please see the FAQ:
​http://www.ffmpeg.org/faq.html#How-can-I-join-video-files_003f

[StevenG]

​http://ffmpeg.org/ffmpeg.html#concat-1

[Nicolas George]

Yes, concat, not amix. You wrote amix.