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Lossy Audio Compression => AAC => AAC - General => Topic started by: atod on 2011-02-09 22:49:40

Title: DTS 1536 Kb/s -> AAC, what bitrate to encode?
Post by: atod on 2011-02-09 22:49:40
Folks,

I'm converting a bunch of 5.1 DTS audio streams to AAC.  I'm able to convert the DTS stream to multichannel WAV for use with NeroAacEnc.  I'm performing 2-pass encoding with Nero.

Does anyone know what a good target (or max) bitrate for encoding should be?  I would like the AAC audio to be as identical to the source as possible.

Thanks
Title: DTS 1536 Kb/s -> AAC, what bitrate to encode?
Post by: sauvage78 on 2011-02-09 23:06:58
192Kbps VBR should be transparent for 2.0.

(2.0 Bitrate /2 X5) = 5.1 Bitrate with equivalent quality as 2.0

(192Kbps/2)X5=480Kbps VBR

If you want the equivalent quality for 5.1 channels as 192Kbps VBR for 2.0 channels then 480Kbps is your bitrate.

Anyway if I recall correctly when you use Nero with the default quality scale at 0.55, it adjusts the bitrate automatically according to the number of channels.

Also I think nowadays 2 pass isn't necessary with the default quality scale. I think the default scale is recommended.

Edit: If I can suggest you, try Eac3to (http://forum.doom9.org/showthread.php?t=125966) with the Nero CLI encoder, you can do DTS to AAC directly.
Title: DTS 1536 Kb/s -> AAC, what bitrate to encode?
Post by: atod on 2011-02-10 01:41:00
Quote from: sauvage78 on
Edit: If I can suggest you, try Eac3to (http://forum.doom9.org/showthread.php?t=125966) with the Nero CLI encoder, you can do DTS to AAC directly.


Thanks.  eac3to is for Windows.  I'm not sure it will run from Wine.
Title: DTS 1536 Kb/s -> AAC, what bitrate to encode?
Post by: atod on 2011-02-10 03:15:18
by the way, i tried encoding at 640kbps. sound quality is near original.  I compared to same source with "aften" AAC encoded file at 640k.  AAC one from Nero sounds far better!
Title: DTS 1536 Kb/s -> AAC, what bitrate to encode?
Post by: sauvage78 on 2011-02-10 08:52:55
(640x2)/5=256Kbps

IMHO, Nero AAC 256Kbps VBR is overkill for 2.0, so 640Kbps is even more overkill for 5.1 as there will likely not be hard sounds to encode in it (electronic music & applauds...), but only voice with background music.

By the way aften is a terrible encoder, AC3 is already very bad itself, but aften is the worse AC3 encoder I tested, it's no surprize that Nero AAC beats it.
Just because it's free, it doesn't mean that it's good. It's so bad that I am pretty confident that Nero AAC 320Kbps 5.1 can rival with aften 640Kbps 5.1 ...
Title: DTS 1536 Kb/s -> AAC, what bitrate to encode?
Post by: Sartre on 2011-03-05 21:51:19
Quote from: atod on
Folks,

I'm converting a bunch of 5.1 DTS audio streams to AAC.  I'm able to convert the DTS stream to multichannel WAV for use with NeroAacEnc.  I'm performing 2-pass encoding with Nero.

Does anyone know what a good target (or max) bitrate for encoding should be?  I would like the AAC audio to be as identical to the source as possible.

Thanks




You can convert directly from dts to aac with Foobar. I usually convert at 640kbps ABR. Using ~Q60-65 VBR should give you about the same rate.

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