File formats?

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ProDigit
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Post by ProDigit » June 5th, 2018, 2:49 pm

What fileformats are accepted for abook uploads?

I recently got aware of Opus, an excellent encoder for audio books.
I was thinking of creating 24 bit, 96kHz WAV files, that after conversion will reduce to 48kHz mono Opus files at around 64kbps.
Should create superior sound; but not sure if the server only accepts MP3 or M4A?

TriciaG
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Post by TriciaG » June 5th, 2018, 2:55 pm

For LibriVox, it must be:

MP3
128 kbps constant bit rate
44,100 Hz sample rate
Mono

How you get there (using WAV or whatever in earlier steps) is up to you. :)

Reason being that we upload the files to Archive.org, and they take them and derive other file formats. The bit rate and sample rate are their requirements to get these derivations.
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annise
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Post by annise » June 5th, 2018, 2:57 pm

If you mean the uploader - it only accepts mp3 files and flac files
If you mean for LV to accept the books to the catalogue we use mp3 files
Channels: 1 (Mono)
Bit Rate: 128 kbps
Sample Rate: 44.1 kHz

Anne
cross post

ProDigit
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Post by ProDigit » June 5th, 2018, 4:31 pm

Thanks,
Easiest for me, would probably be to upload 48kHz flac files (mono).
If I upload them in that format, will they appear here in different formats, or as Flac files?

I just think it's a pity, this site can't serve opus or WMA files. I find them of much higher quality than the outdated MP3 format (especially CBR MP3).

TriciaG
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Post by TriciaG » June 5th, 2018, 4:44 pm

Easiest for me, would probably be to upload 48kHz flac files (mono).
If I upload them in that format, will they appear here in different formats, or as Flac files?
They wouldn't appear at all. We'd have to have you convert them to 44.1kHz MP3 files.

(Just because the uploader accepts them doesn't mean they can go to the catalog that way. FLACs are often used in dramatic works, for example, where parts are edited together. But the final file is always MP3 with the specs given above.)
The Panama Canal Zone during construction: Zone Policeman 88
Report of the President's Commission on Immigration and Naturalization (1953)
Christmas Lore: LINK
Proofs The Earth Isn't a Globe! LINK

ProDigit
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Post by ProDigit » June 5th, 2018, 5:08 pm

The MP3 format,
I've seen plenty of MP3 formats on this site of 64 to 128kbps, 22kHz to 44.1kHz, mainly mono files.
I suppose you'd want the MP3 to be CBR; but the bitrate has to be below 128kbps?

Is it possible to use VBR or ABR instead (simply because I find CBR MP3 to be of such low quality)?

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Post by annise » June 5th, 2018, 5:15 pm

No - we need the format as said above for the catalogue.
Our files need to be compatable with portable mp3 players

Anne

TriciaG
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Post by TriciaG » June 5th, 2018, 5:24 pm

We send Archive the 128 kbps CBR, 44.1 kHz files.

They derive the 64 kbps, 22050 Hz files from those files.

So we need to start with 128 CBR, 44.1. :)
The Panama Canal Zone during construction: Zone Policeman 88
Report of the President's Commission on Immigration and Naturalization (1953)
Christmas Lore: LINK
Proofs The Earth Isn't a Globe! LINK

ProDigit
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Post by ProDigit » June 5th, 2018, 6:25 pm

Thanks!
I understand what I have to do, and for the time being, I will post any audio books as 128kbps CBR books.
annise wrote:
June 5th, 2018, 5:15 pm
No - we need the format as said above for the catalogue.
Our files need to be compatible with portable mp3 players

Anne


Anne,
The last time I found an MP3 player that played only MP3 CBR (and WAV) was probably between 1999 and 2003; about 15-20 years ago.
I can't even remember the last "MP3 only" player I've owned.
Any device purchased in the last 15 years, will play back at least 3 or 4 formats, some as many as 10;
And any MP3 player purchased in the last 15 years will support Variable bitrate or Average Bitrate MP3s, just as it does CBR MP3.
Manufacturers just added the feat, as it costed them literally pennies to implement in their players, and gave much more flexibility; and didn't affect any royalties they had to pay (as the royalties are the same for playing back VBR or CBR MP3s, I believe. They don't charge more for it anymore).

VBR makes A LOT of sense in any audiobook encoding; and trying to keep CBR MP3 as a norm, is like producing VHS or DVD movies, when 4k LED tv's are the norm.

Even if other formats (like AAC, M4A, OGG, FLAC, Opus, or WMA) are not considered, I think the least is they should move on to VBR MP3 (as a compromise).
For an audio codec compatibility list, click here

Not only from a quality perspective, but also a file size perspective.
CBR will give worse quality and larger file sizes than a similar VBR recording; which could help with:
  1. Server bandwidth cost
  2. Server disk space

I (as well as others) find continual irritation listening to audiobooks that sizzle due to necro-encoders that should have been kept 6ft under, a decade ago, when they were superseded by better things.
The quality is okay for 1995 to 2005, but is far inferior for today's standards; and will definitely inferior for the future, when 24 bit audio will be the norm!

I understand that Librivox is dependent on their file server concerning file formats.
Maybe it's time to reconsider, or renegotiate the terms on file formats for upload?

If Librivox wants many good quality recordings, Librivox will also have to budge a bit in the file formats or encoding settings they allow for upload.
They say "don't fix what ain't broken".
The library ain't broken, but it's becoming totally obsolete if it's not being updated, and using a 25 year old codec, definitely falls under 'in need for updating' !

Availle
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Post by Availle » June 5th, 2018, 10:54 pm

Another way to look at this is that we are using a file format that has stood the test of time and is still around while anything else may not even get off the ground for longer than a year or two.

So, let's stay on the safe side. :D
Cheers,
Ava.

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Post by Cori » June 7th, 2018, 10:36 am

It's really not up to us. You're welcome to post in the archive.org forums and ask them to review their format policies, though. :D
There's honestly no such thing as a stupid question -- but I'm afraid I can't rule out giving a stupid answer : : To Posterity and Beyond!

SkyRider
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Post by SkyRider » June 10th, 2018, 2:23 pm

ProDigit wrote:
June 5th, 2018, 6:25 pm
The last time I found an MP3 player that played only MP3 CBR (and WAV) was probably between 1999 and 2003; about 15-20 years ago.
May I suggest that this is a very first-world outlook? Technology that is, to us, old is being actively exported to developing countries who expect to get an extra score of years out of it. Personally, I'm happy that Librivox is a globally accessible site rather than an enclave of wealthy Westerners (even if I am one).

TBH, I think there's a certain amount of hyperbole in the original statement. It's probably true for portable audio players, but all manner of other things play audio too. My car's not a decade old, but the built-in audio system will croak at anything other than a CD of CBR MP3s. Mind you, it also shatters the occasional disc so perhaps it's just in a permanent passive-aggressive sulk. :roll:

Cheers,
Paul

knightsdice
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Post by knightsdice » August 23rd, 2018, 3:06 pm

I would like to see librivox use an encoding format that especially designed for voice, so the download speeds are faster and the archive requirements are smaller.

I have some knowledge of Ogg Opus, but I am sure there are others. Opus can make filesizes really very small.

annise
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Post by annise » August 23rd, 2018, 4:15 pm

Archive does produce ogg vorbis on our files - just check out the Archive page. You could check their forums to see what else they make ?

Anne

knightsdice
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Post by knightsdice » September 2nd, 2018, 5:50 am

So I actually have some second-hand experience with the Archive.org file format situation, as I talked with the fellow from Xiph who created the software for conversions. Archive.org was hoping there would be a shift toward Ogg Theora video, in the online community, and they wanted to have all their files additionally available in Ogg-enclosed formats. When that did not happen, they resigned themselves to the MPEG standards, while leaving the Ogg conversion tools in place. But, while Xiph's formats are great, it is not great to take a lossy encoded file (MP3) and then convert it to another lossy encoded file (Ogg Vorbis). It doesn't sound very good afterward. Anyhow, that's just a little backstory.

Back to the topic of voice-specific audio encoding, I want to emphasis the file-size savings that it can produce. I do not have the numbers in front of me, but when I was playing with the Ogg Opus tools a long time back, I was shocked (shocked I say) to see such small file sizes. And now, when I wait impatiently for a 200 MB Librivox book download, I spend a lot of time thinking there must be a better way, If you want to talk about being considerate of "developing countries", then I think one thing to consider is the bandwidth limitations of someone downloading through a cellular service provider. Having an optimal file size would go a long way to help them access Librivox content.

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