[FFmpeg-user] Command line to show channel label/position

[MrNice]

On 29/01/2025 11:26, Paul B Mahol wrote:
> For your specific case, one would need to look at flac specification, and
> check does ffmpeg follow specification correctly.
>
> On Wed, Jan 29, 2025 at 10:24 AM MrNice <wxcvbn2006 at iol.ie> wrote:
>
>>>> On Jan 28, 2025, at 4:14 PM, MrNice <wxcvbn2006 at iol.ie> wrote:
>>>>
>>>> On 28/01/2025 18:26, Carl Zwanzig wrote:
>>>>> On 1/28/2025 8:18 AM, MrNice wrote:
>>>>>> have an audio file, with MediaInfo I get
>>>>>> Audio
>>>>>> Channel layout                           : L R Ls Rs
>>>>>>    > ffmpeg -v error -layouts | awk '/quad /{print $2}'
>>>>>> FL+FR+BL+BR
>>>>>> What is the correct answer?
>>>>> Both.
>>>>> Left, assumed to be front (L) = Front Left (FL)
>>>>> Left surround/side (Ls) = Back Left (BL)
>>>>> etc
>>>>>
>>>>> (that's part way down the AudioChannelManipulation page, even farther
>> down is a list of the channel names and standard layouts, also in the
>> -layouts output)
>>>>> z!
>>>>>
>>>>> _______________________________________________
>>>> Are you sure for good Carl?
>>>>
>>>> AFAIK, LS is surround and BL is back/Rear
>>>>
>>>> Please look here
>>>>
>>>> https://mediaarea.net/AudioChannelLayout
>>>>
>>>> They say, depending of standardization;
>>>> Left Surround = Ls = CL = SL = Ls (MediaInfo name)
>>>> Right Surround = Rs = CR = SR = Rs (MediaInfo name)
>>>> Left Rear Surround = Lrs = BL = Lsr = SL = Lb (MediaInfo name)
>>>> Right Rear Surround = Rrs = BR = Rsr = Rb (MediaInfo name)
>>>>
>>> I'm not sure I understand the question, but I believe that "back"
>> channels are only involved if there are more than 5 distinct audio signals
>> plus one low frequency signal. By way of explanation, I believe that 5
>> distinct audio signals plus one low frequency signal is the configuration
>> commonly referred to as "5.1" audio (front left, front right, center, side
>> left, side right, and low frequency). I don't believe that the term "5.1"
>> when used to describe an audio standard (summarized as the description of
>> speaker locations listed in my previous sentence) specifies any "back'
>> audio signals at all. If you wish to convert 5.1 audio to an audio format
>> having more distinct signals or sends, then I think it is up to you to
>> determine how you would like to distribute the audio signals to make use of
>> the additional available channels. Did I say anything useful, or have I
>> just confused the issue?
>>> LL
>>>
>>> _______________________________________________
>> Thank you for your answer.
>>
>> The point is that ffmpeg and MediaInfo do not output the same answer for
>> the channels positions. Side is not Back particularly in the last
>> century with quadrophonic.
>>
>> Or the information embedded in the file is confusing or one of the two
>> programs decipher the embedded info in a wrong way. It could be
>> interesting to know what is effectively coded inside the file and as
>> well how the 2 programs decipher and output that data to understand the
>> difference.
>>
>> Moreover, to get an accurate knowledge on ffmpeg, it could be
>> interesting to copy the table https://mediaarea.net/AudioChannelLayout
>> in the ffmpeg documentation and add one column with the corresponding
>> ffmpeg output.
>>
>> MrNice
>>
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> _______________________________________________

Unfortunately, I am not skilled enough in that matter to go this way.

Is there de developer who could complete the table

https://mediaarea.net/AudioChannelLayout

With the ffmpeg/ffprobe output ?