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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