ffmpeg split audio channels

[Selur]

I got a 7.1 audio file (single audio stream) and I want to create a single output file which contains the 8 channels as mono stream.

I thought that:

ffmpeg -y -i "f:\TestClips&Co\audio\Audio channel test files\DTS Master Audio, 7.1 channels, 24 bits, 96kHz.dtsma" -filter channelsplit=channel_layout=7.1 -acodec pcm_s32le "f:\TestClips&Co\audio\Audio channel test files\split_7.1.mka

should do this, but I'm missing something (probably obvious), since I get:

Simple filtergraph 'channelsplit=channel_layout=7.1' was expected to have exactly 1 input and 1 output. However, it had 1 input(s) and >1 output(s). Please adjust, or use a complex filtergraph (-filter_complex) instead.
Error opening filters!

-> How to do it properly?

Cu Selur

[sneaker]

Change "-filter" to "-filter_complex" like error message says?

[Selur]

doh, I thought it wanted to tell me to do some more complex processing,.. thanks!

[pandy]

Why splitting channels? Just decode channels to PCM and write in container supporting multiple audio tracks (such as wav).
And audio filter is '-af' not '-filter' .

[Selur]

I split the channels because I want to test some stuff and need some test samples.

[pandy]

I split the channels because I want to test some stuff and need some test samples.

But splitting channels means that you create multiple outputs - that's why you have complains from ffmpeg - by decoding multiple tracks format to another multiple track container you not splitting channels and wav keeps channel structure.

@ffmpeg -y -i %1 -vn -sn -dn -c:a pcm_f32le -f wav "%~n1_pcm.wav"

Above works for me perfectly.

[Selur]

But splitting channels means that you create multiple outputs

No it doesn't it just means to you create multiple mono streams, which can still be placed in one container.
The call I posted works fine, after adjusting '-filter' to '-filter_complex' like sneaker suggested.
-> I got a nice container with the 8 channels I wanted.

Cu Selur

[pandy]

But splitting channels means that you create multiple outputs

No it doesn't it just means to you create multiple mono streams, which can still be placed in one container.
The call I posted works fine, after adjusting '-filter' to '-filter_complex' like sneaker suggested.
-> I got a nice container with the 8 channels I wanted.

Cu Selur

Same above - tested with 7.1 source DTS sample and ffmpeg created single wav containing all 8 channels created correctly.

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

Split each channel from an input audio stream into a separate output stream.

[Selur]

Your call converts the 7.1 audio to a single wav file which contains one audio stream with 8 channels and a 7.1 channel mapping.
My call converts the 7.1 audio to a single output file with 8 separate audio stream (order by wav channel mapping).
Those are two different things and my call does what I needed.

About 'channelsplit': you might want to read up on what the channel_layout sub-option does, before blindly quoting stuff and not properly looking at the used call.

-> my problem was solved by sneaker and you seem to be trying to invent problems which never existed in the first place.

Cu Selur

[pandy]

Your call converts the 7.1 audio to a single wav file which contains one audio stream with 8 channels and a 7.1 channel mapping.
My call converts the 7.1 audio to a single output file with 8 separate audio stream (order by wav channel mapping).
Those are two different things and my call does what I needed.

About 'channelsplit': you might want to read up on what the channel_layout sub-option does, before blindly quoting stuff and not properly looking at the used call.

-> my problem was solved by sneaker and you seem to be trying to invent problems which never existed in the first place.

Cu Selur

lol - you are unbelievable