MPEG Surround decoding

[ddichiera]

Hi everyone,

I have some MPEG Surround material (adts) which I would like to transcode to another format. I've tried all manner of programs, including FFMPEG, Wavewizard and eac3to, none of which recognize the extra metadata stream.

Does anyone have any suggestions?

I see there's another thread here about the Faunhofer aac codec, is that the same thing?

[tebasuna51]

Please put a sample or a MediaInfo report.

[ddichiera]

Here is a Mediainfo report:

General
Complete name : V:\Music Classical\1958\9LC_1_Hymn_Once_in_royal-mps_r348_xmas_320k.aac
Format : ADTS
Format/Info : Audio Data Transport Stream
File size : 12.3 MiB
Duration : 5mn 21s
Overall bit rate : 320 Kbps

Audio
Format : AAC
Format/Info : Advanced Audio Codec
Format version : Version 4
Format profile : LC
Duration : 5mn 21s
Bit rate mode : Constant
Bit rate : 320 Kbps
Channel(s) : 2 channels
Channel positions : Front: L R
Sampling rate : 44.1 KHz
Compression mode : Lossy
Stream size : 12.3 MiB (100%)



I also have a link to a sample here:

https://rapidshare.com/files/243013076/Kings_9LC_SS_1958.zip

[tebasuna51]

Yes, they are aac streams with adts headers.

To decode with eac3to you need Nero 7 installed.
But you can decode also with CLI Faad (http://www.rarewares.org/), Foobar2000 or BeHappy (BassAudio)

[hello_hello]

I tried MediaInfo, eac3to, foobar2000, Mp3tag, MPC-HC and ffdshow, and they all seem to be of the opinion the samples are stereo.

[tebasuna51]

Sorry, I forget the initial question.

The audio is stereo but, maybe, was mixed with Dolby ProLogic.
The ADTS header don't carry info about this kind of mixes and don't exist any extra metadata.

Headers analyze with LeeAudBi:
File ........: D:\9LC_23_The_Blessed_Son_of_God-mps_r348_xmas_320k.aac
Size ........: 6417066 bytes

----------------------------------------- First Frame Info
ID ..........................: 0 (MPEG-4)
Protection absent ...........: 1
Profile .....................: 1 (Low Complexity, LC)
Sample Rate .................: 44100 Hz.
Private bit .................: 0
Channels ....................: 2
Original/Copy ...............: 0
Home ........................: 0
Copyright identification bit : 0
Copyright identif. start ....: 0
Aac Frame Length ............: 928
Bytes before first header ...: 0
Adts buffer fullness ........: 75
No raw data blocks in frame .: 0
--------------------------------------------- Revised Info
Total Frames ......: 6909
BitRate ...........: 319 Kb/s
Duration ..........: 160,427 seconds. ( 0 h. 2 m. 40,427 s.)
------------------------------------------------- End Info

[ddichiera]

They're supposed to be MPEG Surround made with the Fraunhofer IIS codec.
See here: http://www.iis.fraunhofer.de/en/bf/amm/download/9lc/

There's more info over here: http://www.bbc.co.uk/blogs/radio3/2011/12/the-festival-of-nine-lessons-and-carols-in-surround-sound.shtml

If I use their player, on my PC, it does come out in surround (in fact my PC has a 4.0 system as per their recommendation). I sent the sample to a friend who uses a WD TV player fed into a surround sound amp (brand unknown) and it wouldn't even play it. (perhaps he meant the player, not the amp)

If I understand it correctly, the spatial information is encoded as a difference signal and put back into the stream as auxiliary data.