What's your preferred audio format for fansubs?

[goku888]

What's your preferred audio format for fansubs? and Why?

[Devastator]

This isn't really much of a preference, but more of what I gathered from reading around.

Most sites seem to claim that OGG boasts the best quality retention at low bitrates. Plus, OGG also results in smaller file sizes given a specific bitrate target when compared to other formats such as AAC. One area where OGG currently fails (it's a known problem), is when you go beyond 2-channel audio output. Rather than resulting in a file maybe even just slightly larger than 2-channel output, you wind up getting a file that's roughly 3x (from what I've seen through experimentation) larger given 6-channel output. Also, I take it that OGG is likely not as portable as other formats such as AAC and MP3.

In such cases as MP4 encoders, from what I've read, it is not "normally" possible to include OGG audio, in which case AAC reigns supreme. AAC also boasts comparable file sizes regardless of whether 2-channel or 6-channel is desired. Being a standardized format, it does also have the advantage of portability on other hardware aside from the computer. As stated before however, a lower bitrate needs to be used in order to achieve equal file size comparisons with OGG.

MP3 has fallen into the deep end as far as most groups that use MP4/MKV go, mainly for the bitrate vs file size vs quality comparison. That's not to say that people will refrain from using MP3 in the near future though. Such devices as MP3 players and other such hardware allow MP3 to continue, as well as the fact that many have already adapted to its existence. Whether it will continue to be in use further in the future is really up to those that provide them. As far as MP3 in fansubbing goes though, I'd say it'll likely only continue to live on in AVI releases.

I choose to use OGG due to private quality experimentations, but I plan to use AAC in such cases as when 6-channel audio is provided on a DVD source and for web content.

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I forgot to add that I have no problem with people requesting an AAC version of the audio. If such is requested, I will provide an AAC file separately for all releases of the given series when the DVDs come about.

[ffdshow]

I prefer 128k AAC, or simply muxing the original audio if it isn't too big (usually cfr MP3). I just hope that it won't sound very bad.

[martino]

For DTV sources with 2ch:
If going above 80kbps and below 128kbps - Vorbis (DVD rips as well)
If going below 80kbps - AAC-HE

multichannel:
AAC-HE
AAC-LC (if final size isn't of importance, possibly DVD rips)

These are my guidelines which I use to decide as to which format I will use on a realease, but lately I have decided to fully drop Vorbis (since I don't do DVD rips) and switch to AAC.

AAC is very heavily patented though. As far as I know no other hardware devices than PSP and iPod can play AAC audio and video in an MP4 container. As for Vorbis, well...from one point of view you could say that it's even worse, since IIRC there are no devices which can possibly play it in any of the containers that you can find today, apart from it's native OGG container in which you can't have video. It's usually up to the person who is encoding it to choose what he/she thinks is the most appropriate choice.

And for most hardware support, MP3.

[TheFluff]

Stereo:
AAC for <96kps
Vorbis for 97-192kpbs
Original AC3 for >192kpbs, if it's aviable.

5.1:
AAC, unless I have lots of space to waste, in which case I'd keep the original AC3, if aviable.

[Sai the Dreamer]

I generally prefer AC3 whenever possible. It's about the best quality we're ever going to get, and in the grand scheme of modern connections, converting to a lesser format might save you a few minutes of download time. Hardly worth it IMO.

If the source already comes with pre-transcoded audio, assuming that the quality's acceptably high, I'll just leave it as is. Converting from one lossy format to another doesn't serve any constructive purpose.

[goku888]

How much bigger is a AC3 compared to let's say a 192kpbs mp3 in terms of file size?

[martino]

Originally Posted by goku888

How much bigger is a AC3 compared to let's say a 192kpbs mp3 in terms of file size?

You can't really compare those two, since mp3 is up to 2ch and ac3 up to 6. However it all depends on the bitrate (and having ac3 at 192kbps wouldn't sound too nice as far as I know), but without any encodes handy at the moment I can't say for sure; but it will be much bigger. More than 40MB for 25 minutes for sure to have good quality...

[Devastator]

From one review of OGG, they said that 6-channel output results in a file size representable by an AC3 file. So I think that might give some hints to the size of AC3.

[complich8]

To be perfectly honest, I, like most fansub viewers I know, don't care at all about the audio format the fansubs I download are using, as long as it plays and doesn't sound like garbage. I'd probably avoid wma for compatibility reasons, but other than that, whatever's fine.

[sangofe]

Originally Posted by goku888

What's your preferred audio format for fansubs? and Why?

I believe it's called AC3? It's what we use on our dvd rips along with the h264 video codec.
And why? It's got clearer and better sound

[DryFire]

Originally Posted by sangofe

I believe it's called AC3? It's what we use on our dvd rips along with the h264 video codec.
And why? It's got clearer and better sound

Who's we?

AC3 for stereo is a waste imo, unless it's origionally 192kbps (no point in transcoding it), but most ac3 i see on dvd's these days is 448kbps or 384kbps.

[Scab]

Originally Posted by DryFire

Who's we?

Saizen, although sangofe is confused. We use AAC in the MP4's and Vorbis in the MKV's.

[TheFluff]

AC3 at 192kbps (some stereo AC3 comes as that) takes the same space as Vorbis or MP3 does at 192 kbps (ignoring container overhead). 5.1 AC3 is usually comes as 384 or 448kbps, meaning 75-85 MB for a 25-minute ep.
AC3 is less efficient than AAC or Vorbis, so it doesn't sound as good at the same bitrate.

Also, never ever ever use Vorbis for 5.1. Even if it works (which it may or may not do, last time I tried everything except CoreVorbis failed to decode it properly, and even then there are THREE possible channel orders, and which one your file has is anyone's guess) it's horribly inefficient. It's gotten better than it used to be though, it used to be worse than DTS compression-wise.

[xat]

Depending on the format. Assuming an mkv container:

AAC-HE for low bitrates. 96kbps or less. ("high efficiency"; what it's designed for, although I personally haven't seen releases of this nature)
For mid to high bitrates, I'd lean towards Vorbis. Otherwise I'd go with AAC-LC.

Like Fluff & co. mentioned, the main reason for using AAC-LC at higher bitrates is that it supports channel coupling when dealing with >2 channel audio. SomeRandomPost™ suggests an optimal bitrate (in general) of around 350kbps, but your mileage WILL vary from source to source.

5.1 audio is expensive; if you can afford to have it in your encode, it's almost as likely that you can include the original AC3 instead (unless of course you have some kind of cap demanding a lesser file size).

For good old AVI? MP3 :P

There's a lot of interesting reading down at hydrogen audio (they're generally on the cutting edge of this stuff; something like the audio equivalent of doom9), and their knowledge base can provide a lot of insight that gives credibility to the reasoning you see in this thread.

Some quick links to their wiki:

Channel coupling (mentioned earlier)
Vorbis
AAC
AC3

[jfs]

I just quickly skimmed over this thread and I'm surprised nobody mentions just leaving the audio alone for TV raws. From my experience the audio from Japanese TV caps is already heavily compressed and it'll be stupid to compress it any further. So unless there is a good reason, I'd just keep the original audio from those.

(Otherwise I prefer Vorbis when possible and sensible.)

[ShadowVlican]

OGG for stereo (best lossy codec)
Original AC3/DTS for multichannel surround (nothing for novices to butcher)

and of course i prefer the MKV container to hold these

[Harukalover]

Depends on what I plan to do.

If final output is going to be in MKV then I likely will use Vorbis as long as my source is 2.0. (Or even leave the original audio as long as the capper doesn't change the audio format every episode) If source is 5.1 then I use AAC or the original source.

If final output is MP4 then I use AAC or just the original source if it's usable. (Meaning whether MP4 supports it)

If final output is AVI then mp3 is the usual choice. (or original source if possible)

Also, OGG is not an audio format. So stop saying OGG.

OGG is just a container for the commonly used Vorbis audio.

[Sylf]

Originally Posted by jfs

I just quickly skimmed over this thread and I'm surprised nobody mentions just leaving the audio alone for TV raws. From my experience the audio from Japanese TV caps is already heavily compressed and it'll be stupid to compress it any further. So unless there is a good reason, I'd just keep the original audio from those.

(Otherwise I prefer Vorbis when possible and sensible.)

I guess the "good reason" for me is that the way we handle the raws... I may have a raw that has the sponsors announcements included, and the audio is in mp3 vbr. For the releases we make, we usually cut out the sponsors section. We really can't splice vbr mp3s well, so we go ahead and decode the audio to linear pcm wav first. When we do that, we say might as well recompress the audio to what makes the best sense.

But even that reason aside, I think most of us (myself included) just automatically converts the audio from mp3 to whatever format that seems to be preferred for the destination containers - ogg vorbis for mkv and aac for mp4, without really thinking about benefits or drawbacks of doing so.

[edogawaconan]

Originally Posted by jfs

I just quickly skimmed over this thread and I'm surprised nobody mentions just leaving the audio alone for TV raws. From my experience the audio from Japanese TV caps is already heavily compressed and it'll be stupid to compress it any further. So unless there is a good reason, I'd just keep the original audio from those.

(Otherwise I prefer Vorbis when possible and sensible.)

Already mentioned at least twice.

Originally Posted by Sai the Dreamer

I generally prefer AC3 whenever possible. It's about the best quality we're ever going to get, and in the grand scheme of modern connections, converting to a lesser format might save you a few minutes of download time. Hardly worth it IMO.

If the source already comes with pre-transcoded audio, assuming that the quality's acceptably high, I'll just leave it as is. Converting from one lossy format to another doesn't serve any constructive purpose.

Originally Posted by ffdshow

I prefer 128k AAC, or simply muxing the original audio if it isn't too big (usually cfr MP3). I just hope that it won't sound very bad.

I do too btw. And use vorbis when in need of small filesize.