<p>The first warning means one of the WAV inputs has no channel layout defined i.e. channel 1 is Front Left, channel 2 is Front Center..etc. <code>amerge</code> decides the channel layout of the output stream based on the input, but since that designation is missing for one of the inputs, amerge will assign a channel layout which is default for the number of channels present in the output.</p>

<p>One thing you could try is rewrap all of the audio inputs i.e.</p>

<pre><code>ffmpeg -i audio1.wav -c copy audio1-new.wav
</code></pre>

<hr>

<p>The 2nd warning is displayed whenever VBR mode is invoked. Unless you get the error: <code>Unable to set the VBR bitrate mode</code>, you should be fine.</p>

CC BY-SA 4.0
2024-01-13T05:37:24.767Z
That channel layout. Can we do it with any filter instead? I just don't want to make second file
Trương Quốc Khánh
CC BY-SA 3.0
2016-07-25T17:03:19.847Z
2016-07-25T17:03:19.847Z
Gyan
<p>I'm trying to merge 8 audio (.wav) files with a video (.mp4) file. I have the following command:</p>

<pre><code>ffmpeg -i video.mp4 -i audio1.wav -i audio2.wav -i audio3.wav -i audio4.wav -i audio5.wav -i audio6.wav -i audio7.wav -i audio8.wav -filter_complex "[1:a][2:a]amerge=inputs=2[a0]" -filter_complex "[3:a][4:a]amerge=inputs=2[a90]" -filter_complex "[5:a][6:a]amerge=inputs=2[a180]" -filter_complex "[7:a][8:a]amerge=inputs=2[a270]" -map 0:0 -map "[a0]" -map "[a90]" -map "[a180]" -map "[a270]" -c:v copy -c:a:0 libfdk_aac -vbr:0 5 -c:a:1 libfdk_aac -vbr:1 5 -c:a:2 libfdk_aac -vbr:2 5 -c:a:3 libfdk_aac -vbr:3 5 -movflags +faststart output.mp4
</code></pre>

<p>I can successfully run the command and the output is good, but i get the following warnings displayed (3 times each):</p>

<blockquote>
  <p>[Parsed_amerge_0 @ 0x7fcaca708da0] No channel layout for input 1
  [Parsed_amerge_0 @ 0x7fcaca708da0] Input channel layouts overlap:
  output layout will be determined by the number of distinct input
  channels</p>
</blockquote>

<p>And:</p>

<blockquote>
  <p>[libfdk_aac @ 0x7fcacc87c800] Note, the VBR setting is unsupported and
  only works with some parameter combinations</p>
</blockquote>

<p>What do they mean and how can i "get rid of them"?</p>

<p>Thanks!</p>

<ffmpeg>
ffmpeg - warnings when i try to merge several audio files with an .mp4 file
YaronGh
# ffmpeg - warnings when i try to merge several audio files with an .mp4 file

(Asked by: username_0 on 2016-07-25)

I'm trying to merge 8 audio (.wav) files with a video (.mp4) file. I have the following command:
ffmpeg -i video.mp4 -i audio1.wav -i audio2.wav -i audio3.wav -i audio4.wav -i audio5.wav -i audio6.wav -i audio7.wav -i audio8.wav -filter_complex "[1:a][2:a]amerge=inputs=2[a0]" -filter_complex "[3:a][4:a]amerge=inputs=2[a90]" -filter_complex "[5:a][6:a]amerge=inputs=2[a180]" -filter_complex "[7:a][8:a]amerge=inputs=2[a270]" -map 0:0 -map "[a0]" -map "[a90]" -map "[a180]" -map "[a270]" -c:v copy -c:a:0 libfdk_aac -vbr:0 5 -c:a:1 libfdk_aac -vbr:1 5 -c:a:2 libfdk_aac -vbr:2 5 -c:a:3 libfdk_aac -vbr:3 5 -movflags +faststart output.mp4

I can successfully run the command and the output is good, but i get the following warnings displayed (3 times each):

[Parsed_amerge_0 @ 0x7fcaca708da0] No channel layout for input 1
  [Parsed_amerge_0 @ 0x7fcaca708da0] Input channel layouts overlap:
  output layout will be determined by the number of distinct input
  channels

And:

[libfdk_aac @ 0x7fcacc87c800] Note, the VBR setting is unsupported and
  only works with some parameter combinations

What do they mean and how can i "get rid of them"?
Thanks!

**Tags:** ffmpeg


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## 1 answers

### Answer by username_1 on 2016-07-25. Score: 0 | Accepted answer

The first warning means one of the WAV inputs has no channel layout defined i.e. channel 1 is Front Left, channel 2 is Front Center..etc. amerge decides the channel layout of the output stream based on the input, but since that designation is missing for one of the inputs, amerge will assign a channel layout which is default for the number of channels present in the output.
One thing you could try is rewrap all of the audio inputs i.e.
ffmpeg -i audio1.wav -c copy audio1-new.wav


The 2nd warning is displayed whenever VBR mode is invoked. Unless you get the error: Unable to set the VBR bitrate mode, you should be fine.

> **Comments:**
> **username_2**: That channel layout. Can we do it with any filter instead? I just don't want to make second file  

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