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-   -   What are the recommended audio bitrates for Vorbis and AAC? (http://forums.animesuki.com/showthread.php?t=47641)

Starks 2007-05-16 11:37

What are the recommended audio bitrates for Vorbis and AAC?
 
Also, which is more popular?

martino 2007-05-16 13:08

For Vorbis I use VBR q2.0 (~96kbps) for my music collection. For anime I would use q4 or higher (~128kbps). Both encoded using AoTuVb5. Vorbis doesn't sound too good when going below q2.0.

For AAC you can go much lower. I usually use 64kbps HE in most cases. If the source is low quality then there's nothing personally stopping me from using HE v2 (PS) @ 48kbps. However I guess if you don't mind having the audio use up some space and go for a standard 170MB for 24 minutes then 80-96kbps and higher would work very well. Depends on how much you want to use for the video stream, and then just adapt the audio to it to achieve a fine balance between them.

Which is more popular... Hehe, I doubt that there is one. Both seem to have roughly the same popularity. Though perhaps AAC is more common with TV caps, and Vorbis more with DVD rips.

EDIT:
Quote:

Originally Posted by TheFluff's next post
Edit: if you use vorbis q2 for your music your ears are broken. :|

Not much point imo to encode it at q3 or q4 when the sources came as a 128/160kbps mp3... >_> (no-one has complained about it so far who listened to it and neither can I, and I don't consider myself as deaf; not yet anyway.)

TheFluff 2007-05-16 14:37

HE-AAC compresses insanely good but it also sounds like shit, don't use it unless you're extremely pressed for space or the original audio is shit already. For normal sized (120-230 MB) TV-rips I wouldn't advise going below Vorbis q 3 or 80kbps AAC, it's not really worth going much lower, since you don't save all that much bitrate but the quality degrades rather sharply.

For 5.1 AAC you want at least 250 kbps or so.

As for popularity, AAC seems slightly more popular, especially since all the MP4 releases use it.

Edit: if you use vorbis q2 for your music your ears are broken. :|

xat 2007-05-16 14:45

Using aoTuV I usually try -q 5 first (generally regarded as transparent by the guys at HA). Bitrates tend to be around 160kbps (VBR) and file size is around 24mb under normal (24min episode) circumstances.

LS5 2007-05-16 15:04

I use Vorbis at q1.0 myself (around 80kbps), which doesn't sound bad at all. In my opinion, AAC and Vorbis are pretty much tied quality wise around that bitrate. Only at 64kbps and below, HE-AAC really starts to have the upper hand, while Vorbis does better at bitrates of 96kbps and up.

Zero1 2007-05-16 15:08

Well there isn't much in it between Vorbis and AAC now, some cases Vorbis edges ahead, others AAC is better.

Though in true Hydrogenaudio style, I should say ABX OR GTFO. It's kind of a shame that LC-AAC has become the defacto standard for AAC, because if Nero were to implement LTP into their free encoder, I'm sure it would give Vorbis a very hard time (since it's already holding it's own).

A shame, but to some extent it's the community that makes things the way they are.

http://www.soundexpert.info/

Some of these are a bit old, but perhaps will serve some insight. It suggests that AAC has (or had) the upper hand at 105/128kbps, with Vorbis pulling back at 192kbps. Not surprisingly, at the low end (64kbps) AAC had quite an advantage, even with LC-AAC. Since these tests, the Nero CLI AAC encoder has had a few updates, so it has potentially closed the gap; however I don't know how Vorbis is progressing, so it might be so damn close it doesn't even matter.

Mixed results, but you should be the judge ultimately.

Harukalover 2007-05-16 16:21

Quote:

Originally Posted by LS5 (Post 949143)
I use Vorbis at q1.0 myself (around 80kbps), which doesn't sound bad at all.

My eyes bled from reading that statement and I can't imagine how my ears would react... >_>

LS5 2007-05-16 17:11

Heh. Are you sure you're not simply prejudiced? Very few people should find Vorbis at q1.0 annoying to listen to. And remember, being able to ABX it does not mean you'll notice its faults in normal occasions. Audio codecs have improved quite a lot over the past few years, and auToV has done excellent work on improving Vorbis.

And I'm surprised you quoted me there, instead of martino's 64kbps HE-AAC. I can assure you 80kbps Vorbis sounds better than that.

shock 2007-05-16 17:53

From a practical standpoint I see little reason to use Vorbis. Usually, my target bitrate for stereo audio is 96-128 kbps. Vorbis is not substantially better than AAC in that range, and if I'm making an mp4 I have to use AAC regardless. For low bitrates, HE-AAC performs better than Vorbis. Also, most of the surround files I come across are AAC or AC3, and reencoding them hurts the audio quality too much. Vorbis is attractive because it is open source with no strings attached, but AAC encoding and decoding support is strong and unlikely to vanish anytime soon.

YMMV.

Harukalover 2007-05-16 18:22

Quote:

Originally Posted by LS5 (Post 949287)
Heh. Are you sure you're not simply prejudiced? Very few people should find Vorbis at q1.0 annoying to listen to. And remember, being able to ABX it does not mean you'll notice its faults in normal occasions. Audio codecs have improved quite a lot over the past few years, and auToV has done excellent work on improving Vorbis.

I've done some test encodes with a few samples and found that below Q3, artifacts become rather noticeable. Audio is more of a subjective media anyway. I know many a person who would find Q1 == amazing quality.

But I highly think it should _not_ be recommended as a good quality level to encode to. Remember people do read these forums and actually do some of the things recommended in them. We don't need a bunch of fansubs having Q1 vorbis in them coupled with bad or good video.

Quote:

Originally Posted by LS5 (Post 949287)
And I'm surprised you quoted me there, instead of martino's 64kbps HE-AAC. I can assure you 80kbps Vorbis sounds better than that.

No need for that. TheFluff already covered it.

Maybe I'll waste some time one day and ABX on the differences between 64kbps HE-AAC and 80kbps vorbis. Or better yet, I'll save my ears from the torture and just not care...

LS5 2007-05-16 18:44

Fair enough. I found a quote in the link posted by xat which is quite relevant to my reason for using it: '[...] It improves further on low bit-rate, to such extent that some reports -q 1 (approx. 80 kbps) is good enough for streaming.' I don't need perfect quality, 'not annoying' is good enough for me. Furthermore, most of the time anime consists of just spoken text, which is relatively easy to compress. I aim for quite low bitrate encodes at --crf 20, and in my opinion, Vorbis at q1.0 fits that perfectly. Certainly not the best quality possible, but 'excellent quality' to 90% of the people, especially with a good source. I do agree that higher bitrates should be used for bigger encodes, as q1.0 Vorbis definitely isn't the best quality you'll be able to get.

xat 2007-05-16 19:26

Quote:

Originally Posted by shock (Post 949334)
From a practical standpoint I see little reason to use Vorbis. Usually, my target bitrate for stereo audio is 96-128 kbps. Vorbis is not substantially better than AAC in that range, and if I'm making an mp4 I have to use AAC regardless. For low bitrates, HE-AAC performs better than Vorbis. Also, most of the surround files I come across are AAC or AC3, and reencoding them hurts the audio quality too much. Vorbis is attractive because it is open source with no strings attached, but AAC encoding and decoding support is strong and unlikely to vanish anytime soon.

YMMV.

Indeed, I think it's more of a bias on my part. LC-AAC and vorbis (encoded via aoTuV) should give similar results at bitrates above 128kbps, but I have a natural tendency to use vorbis anyway. I don't exactly have a target bitrate, but I'd like an audio encode to be as transparent as practically possible. Dealing with captures, I'd stick with the original encoded track if possible.

edogawaconan 2007-05-17 03:41

I use flac!
...no, vorbis q3 is what I use
and lancer builds are quite fast ;)

TheFluff 2007-05-17 06:08

Quote:

Originally Posted by shock (Post 949334)
From a practical standpoint I see little reason to use Vorbis. Usually, my target bitrate for stereo audio is 96-128 kbps. Vorbis is not substantially better than AAC in that range, and if I'm making an mp4 I have to use AAC regardless. For low bitrates, HE-AAC performs better than Vorbis. Also, most of the surround files I come across are AAC or AC3, and reencoding them hurts the audio quality too much. Vorbis is attractive because it is open source with no strings attached, but AAC encoding and decoding support is strong and unlikely to vanish anytime soon.

YMMV.

Hay, aren't you the Anime-Kraze encoder/raw provider? In that case can you please tell whoever's encoding Seirei no Moribito to stop transcoding 5.1 AAC to 5.1 AC3, it's really stupid. plzkthxtia.

Edit: wait, stop, sorry, I didn't notice that you actually did stop that already. Thanks. Now the only thing I could wish for is that you wouldn't blur it to hell, but you can't have everything I guess.
And I do find it somewhat amusing that you've switched audio formats on almost every single episode so far.
(01: stereo AAC, 02v2: 5.1 AC3, 03: 5.1 AC3, 04-05: 5.1 AAC)

shock 2007-05-17 09:36

Quote:

Originally Posted by TheFluff (Post 950065)
Hay, aren't you the Anime-Kraze encoder/raw provider? In that case can you please tell whoever's encoding Seirei no Moribito to stop transcoding 5.1 AAC to 5.1 AC3, it's really stupid. plzkthxtia.

The reason for the changes was precisely to avoid transcoding. The raw capper was not consistent for the first few eps. As to the rest, if you don't like it you don't have to watch it.

Starks 2007-05-25 21:45

So, let's say I have 86MB 5.1ch AC3 track for a 26 minute OVA (for which I am ripping myself). What kind of Vorbis or AAC settings should I use? I'm a bit torn on what to use if I am giving myself a 300MB cap for the entire encode.

Also, is it worth using the unaltered AC3?

Zero1 2007-05-26 01:58

Quote:

Originally Posted by Starks (Post 963270)
So, let's say I have 86MB 5.1ch AC3 track for a 26 minute OVA (for which I am ripping myself). What kind of Vorbis or AAC settings should I use? I'm a bit torn on what to use if I am giving myself a 300MB cap for the entire encode.

Also, is it worth using the unaltered AC3?

Depends on the situation. If with AAC you can half the filesize with little or no noticable degredation in quality, then that might be a consideration for you. If you are adamant on getting the absolute best quality, then just mux the AC3 and avoid transcoding; but bearing in mind what I just said, if you can more or less halve the bitrate, then that frees up 43MB extra to encode the video. It's important to balance the audio and video quality. I can't think of much more annoying things than having awesome audio and blocky shit video, or good video and 56kbps MP3 audio (ala default Fraunhofer encoder, which I've seen people use before).

Starks 2007-05-26 13:22

Quote:

Originally Posted by Zero1 (Post 963478)
Depends on the situation. If with AAC you can half the filesize with little or no noticable degredation in quality, then that might be a consideration for you. If you are adamant on getting the absolute best quality, then just mux the AC3 and avoid transcoding; but bearing in mind what I just said, if you can more or less halve the bitrate, then that frees up 43MB extra to encode the video. It's important to balance the audio and video quality. I can't think of much more annoying things than having awesome audio and blocky shit video, or good video and 56kbps MP3 audio (ala default Fraunhofer encoder, which I've seen people use before).

I've heard about people having filesize nightmares with multi-channel Vorbis, so what profile and/or bitrate would you recommend for AAC if I want transcode and have no noticeable loss of quality?

ffdshow 2007-05-26 18:31

128K AAC (with iTunes), it's better than nero or faac, at least it was the case in my tests of last year.

Nicholi 2007-05-27 01:57

Quote:

Originally Posted by ffdshow (Post 964231)
128K AAC (with iTunes), it's better than nero or faac, at least it was the case in my tests of last year.

Well thats also one of the main reasons few people care about iTunes encoder. It is CBR only and if I recall correctly only does 2 channels (or maybe they finally added 5.1 support, I don't recall remember). In this situation it is particularly useless and I would say in most others it is as well. VBR is quite useful in maintaining a certain quality level and also most importantly efficiently using bits.

Since you are encoding from a 5.1 source it would most likely be best to use AAC over Vorbis. Especially if you are going for a low filesize in the end. Since Vorbis has no lossy channel coupling it should not be able to compress as well as AAC per a given quality level. All you are left to do is choose your AAC encoder, however most are 2ch only or CBR only. I think most people would point to Nero AAC which has the most AAC features as well as having the best VBR encoder.

Edit: I could be running off old info for all the iTunes stuff, but back in the day their encoder was extremely limited and Nero was the only useful choice.


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