Hi Panos,
Thanks for trying!
My personal choice is to use the WavPack codec; it was proposed for the
ambiX format:
https://ambisonics-symposium.org/Members/zotter/copy_of_publications/publications/2011_NachbarZotterSontacchiDeleflie_ambix.pdf
I think it's still a valid choice (even if professionals use WAV or AIFF).
Marc (also an Ambisonics hobbyist).
Le 2023-04-30 à 18 h 27, Panos Kouvelis a écrit :
Hi Marc,
You're right, I thought that this would be easy but I passed the last
hour trying like you and also with flac.exe command line tool using
the -ogg flag.
I used a 16 channel file and the error from the flac utility was that
it wasn't a wavefile extensible and couldn't mark channels, so I
opened my test file using Audition and defined the wavefile extensible
as higher order ambisonics, after that the error I got from the flac
encoder was unsupported number of channels.
I don't really know how this can be done :-(
If you have any news please let me know.
Cheers!
*Pan Athen*
SoundFellas <https://soundfellas.com/>, *MediaFlake Ltd
<http://mediaflake.com/>**
*
Digital Media Services, Content, and Tools
On Sun, Apr 30, 2023 at 10:00 PM Marc Lavallée <m...@hacklava.net> wrote:
Hi Panos,
The Ogg FLAC documentation does not mention that more than 8
channels
can be encoded.
I tried using ffmpeg; this is working for 8 channels:
ffmpeg -f lavfi -i "anoisesrc=d=1:c=pink:a=0.5" -c:a flac -f ogg
-ac 8
-y noise-8c.ogg
But this is not working for 16 channels:
ffmpeg -f lavfi -i "anoisesrc=d=1:c=pink:a=0.5" -c:a flac -f ogg
-ac 16
-y noise-16c.ogg
The returned error is: "[flac @ 0x562603bd8540] 16 channels not
supported (max 8)"
And when specifying a channel number higher than 8 but lower than 16,
the result is a mono file.
It could be that ffmpeg is not capable of encoding more than 8
channels
for FLAC streams.
What tool (or method) would you suggest to encode more than 8
channels
in a Ogg container?
Marc
Le 2023-04-30 à 14 h 11, Panos Kouvelis a écrit :
> Native FLAC can support up to 8 channels; you are right.
>
> To support more channels using FLAC, you should use Ogg FLAC, an OGG
> container containing FLAC-encoded material.
>
> If that helps you, you can find more here:
> https://xiph.org/flac/faq.html#general__native_vs_ogg
> Here: https://xiph.org/flac/faq.html#general__native_or_ogg
> And here: https://xiph.org/flac/ogg_mapping.html
>
> I hope that helps in your case.
>
> Cheers!
>
> *Pan Athen*
> SoundFellas <https://soundfellas.com/>, *MediaFlake Ltd
> <http://mediaflake.com/>*
> Digital Media Services, Content, and Tools
>
>
> On Sun, Apr 30, 2023 at 9:02 PM Bo-Erik Sandholm
<bosses...@gmail.com>
> wrote:
>
>> Can someone comment on the double message i think i find in the
spec?
>>
>> There is a the specification of max number of channels in
stream info
>> chapter 8.2
>>
>> u(3) | (number of channels)-1. FLAC supports from 1 to |
>> | | 8 channels.
>>
>>
>> In chapter 8.6.2
>>
>> A WAVEFORMATEXTENSIBLE_CHANNEL_MASK field of 0x0 can be used to
>> indicate that none of the audio channels of a file
correlate with
>> speaker positions. This is the case when audio needs to be
decoded
>> into speaker positions (e.g. Ambisonics B-format audio) or
when a
>> multitrack recording is contained.
>>
>>
>> .....
>>
>> What does this mean?
>>
>> Is it that ambisonics cannot be streamed in second or third
order with
>> flac?
>>
>>
>> In todays widebandwith internet this feels a bit too
restrictive, is
>> it a Dolby business thing?
>>
>>
>> https://datatracker.ietf.org/doc/draft-ietf-cellar-flac/
>>
>> Any information or ideas about this?
>>
>> Bosse Sandholm
>> Ambisonics hobbyist.
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