5.1 formats to 5.1 AC3 [Archive]

View Full Version : 5.1 formats to 5.1 AC3

MrC

3rd July 2009, 22:24

Kurtnoise

3rd July 2009, 23:27

http://avisynth.org/mediawiki/GetChannel or from the Avisynth doc...

tebasuna51

3rd July 2009, 23:51

Dealing with 6 channels audio conversions, what are the correct channels mappings (using AviSynth's GetChannel) for following formats?

5.1 AC3 -> 5.1 AC3 ... should be GetChannel(1,3,2,5,6,4)
5.1 AAC -> 5.1 AC3
5.1 DTS -> 5.1 AC3
5.1 WAV -> 5.1 AC3

I can't understand your question.
The order inside AviSynth is always FL,FR,FC,LF,BL,BR

The audio decoders NicAudio, BassAudio, DirectShowSource always suply the uncompressed audio in that order.

And AviSynth must suply uncompressed audio in that order to compliant encoders like Aften or NeroAacEnc (DTS encoders need mono wav's)

The internal channel order in compressed formats can be ignored by the users and only must be know by decoders/encoders

Kurtnoise

4th July 2009, 00:05

I think he wants to know the correct channels orders to use Aften with different sources...

Brazil2

4th July 2009, 01:56

5.1 AAC -> 5.1 AC3
Take care because AFAIK channel order for AAC 5.1 is C, L, R, SL, SR, LFE.

tebasuna51

4th July 2009, 02:50

I think he wants to know the correct channels orders to use Aften with different sources...

But inside AviSynth don't exist different sources, is always uncompressed audio with the same channel order.

And also out of AviSynth you can use Faad (aac decoder) and Aften without remapping:

faad -w input.aac | aften -readtoeof 1 - output.ac3

Only broken decoders output uncompressed audio with the internal channel order. Do you know any?

MrC

4th July 2009, 20:44

Ok, more info about the whole scenario.

- The encoders are Wavi+Aften
- The input file is a very simple avs script that point to a audio file (ac3/aac/dts/wav) thru DSS and GetChannel.

AC3
GetChannel(DirectShowSource(InputAudio),1,3,2,5,6,4)
It matches with AviSynth doc and it works.

AAC
GetChannel(DirectShowSource(InputAudio),2,1,3,4,5,6)
It does not match with AviSynth doc but it works. Thanks Brazil2.

DTS
GetChannel(DirectShowSource(InputAudio),3,1,2,5,6,4)
Assuming that AviSynth doc is correct, it should be like that.

WAV
GetChannel(DirectShowSource(InputAudio),1,2,3,4,5,6)
Assuming that AviSynth doc is correct, it should be like that.

What do you think?

Bye

tebasuna51

4th July 2009, 22:40

What do you think?

I don't know for what you ask if you don't read the answers.

All is wrong, except WAV of course.

MrC

5th July 2009, 12:43

All is wrong, except WAV of course.

Really? If my ears do not fail, AC3->AC3 and AAC->AC3 using those settings and the listed software (AviSynth, Wavi and Aften) are correct.

;)

Bye

tebasuna51

5th July 2009, 18:34

Try with a channel test like http://www-mmsp.ece.mcgill.ca/Documents/AudioFormats/WAVE/Samples/Microsoft/6_Channel_ID.wav

MrC

5th July 2009, 20:26

:thanks:

I will make some tests and will post the results

;)

Bye

MrC

6th July 2009, 22:27

I made some tests and, tebasuna51, you are absolutely right: using a valid AC3 encoder (Aften) there is no need to remap channels, whatever source format. Instead using a *not so good* AC3 encoder, QuEnc, I found that remapping is necessary (1,3,2,5,6,4).

I apologize for having spread my wrong assumptions, but I really found a lot of confusing stuff about this item around the web.

:)

Bye