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Topic: Last call on FLAC specification (Read 3495 times) previous topic - next topic
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Re: Last call on FLAC specification

Reply #25
I was just curious as to why the RFC was happening now
But I didn't say anything about why  :))

If you want to know why, see the working group charter

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The preservation of audiovisual materials faces challenges from technological obsolescence, analog media deterioration, and the use of proprietary formats that lack formal open standards. While obsolescence and material degradation are widely addressed, the standardization of open, transparent, self-descriptive, lossless formats remains an important mission to be undertaken by the open source community.

So this working group has produced an RFC on FFV1 (versions 0, 1 and 3), which is a open lossless video codec, and is working on RFCs for Matroska, FLAC and a new revision of FFV1 (version 4).
Music: sounds arranged such that they construct feelings.

Re: Last call on FLAC specification

Reply #26
I believe all issues raised in this topic up until this point have been addressed in PRs. See here: https://github.com/ietf-wg-cellar/flac-specification/pulls

Thanks for all your input.
Music: sounds arranged such that they construct feelings.


Re: Last call on FLAC specification

Reply #28
Thank you for the effort documenting the bitstream format. For fun I'm implementing a basic parser and it took a matter of hours to go from nothing to being able to parse the entire test suite (except number 27 which is an old variable-blocksize edge case). Not decoding fully (not decoding residual or subframes), just reading everything and doing validation on header fields and crc. With just the old html and not the spec I would have been stuck as the html is missing details about how to store warm-up samples (particularly that side channels use an extra bit).

Re: Last call on FLAC specification

Reply #29
The document has now entered a two-week period called working group last call.

I guess I missed the boat on this, so I won't read through the whole spec  :(

Would be nice if the spec didn't "explicitly" specify JPEG/PNG as album art (if it actually does), or at the very least, had a provision for including new image formats. e.g. I can happily embed WEBP artwork in a FLAC file using foobar2000, and I think with recent updates to foobar, I can use any images that Windows Explorer is currently equipped to handle. So AVIF, HEIC, etc if you have the relevant Store downloads should all work.

Some apps like PowerAmp on Android will display WEBP artwork just fine. MPV or VLC on the other hand just don't know what to do with them. I haven't tested the other two formats or older ones like JPEG2000, newer but loss common ones like JPEG XL/XR or whatever they're called, etc.

Not even sure if that'd be the right place to put it in, or how to put it in to words so that more applications are likely to support it in the future.

Re: Last call on FLAC specification

Reply #30
The document has now entered a two-week period called working group last call.

I guess I missed the boat on this, so I won't read through the whole spec  :(
There isn't much progress yet, and there will probably be changes for the next 6 months, maybe even longer. It still has to be extensively reviewed by IETF people.

Here's the latest draft: https://datatracker.ietf.org/doc/draft-ietf-cellar-flac/
Here's the nice HTML version of it: https://www.ietf.org/archive/id/draft-ietf-cellar-flac-07.html

So if you want to read it and comment, I can probably get some stuff in. In fact, I got some comments from Josh Coalson (the original author of FLAC) himself just this morning.

Quote
Would be nice if the spec didn't "explicitly" specify JPEG/PNG as album art (if it actually does)
It doesn't. There's no restriction on format. In fact, during the last call, some people commented that provisions should be made for vector formats like SVG, as they don't have a width or height. So the following was added
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In case a picture has no concept for any of these fields (e.g. vector images may not have a height or width in pixels) or the content of any field is unknown, the affected fields MUST be set to zero.
Music: sounds arranged such that they construct feelings.