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Topic: MPEG-4 AAC-LC Conformance Streams (Read 6606 times) previous topic - next topic
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MPEG-4 AAC-LC Conformance Streams

Folks,

We recently purchased "MPEG-4 AAC-LC Conformance Streams" from the ISO along with the reference code for MPEG-4 Audio etc.  The package contained the raw *.pcm files and the encoded streams as *.mp4

We found that the test streams could not even pass the original reference code !


Then I tried to listen to the Conformance Streams using the Real Player and found that those *.mp4  files could not be opened. 

Looks like, the guys at ISO shipped us buggy test streams.

Has this happened to anybody else ?

Any idea, where I can find the correct Test Streams ?


Thanks.

MPEG-4 AAC-LC Conformance Streams

Reply #2 –
Ivan,

It seems like your link is not working ( it does not exist !).

I know that the guys at AT&T have the MPEG page at

http://www.research.att.com/projects/mpegaudio/

Their is an interim archive (by Fraunhofer Institute) available via the AT&T link.  But the Fraunhofer link is also no good and provides no access to the Test Stream data.

Any comments on that .... are welcome.

MPEG-4 AAC-LC Conformance Streams

Reply #3 –
Works perfectly here

MPEG-4 AAC-LC Conformance Streams

Reply #4 –
Ivan, Hi,

I finally managed to get hold of the bitstreams for the AAC-LC from the interim archives of the Fraunhofer institute.  The correct link location is

ftp://mpaudconf:adif2mp4@ftp.iis.fhg.de/

Surprisingly, the interim archives are also buggy !!!!!!


For Example:

Bitstream number al00_44.wav is a reference wave files with a single channel ( channel 0 ) .

al00_44.mp4 is its corresposing reference encoded stream.

When I pass al00_44.mp4 through the reference decoder available from the mpeg ( ISO/IEC), I get an output wave file which has two channels ( channel 0 and channel 1) !!!  This is just one of the many examples that I can give.


Now obviously this means that I cannot establish the conformance test criterion for the generated .wav output with respect to the reference .wav file......


Even more interestingly, Fraunhofer guys have come up with their own series of AL files starting from al14_*.*  to al19_*.*

None of these files find a mention in the MPEG-4, Part 4, Conformance Testing document. 

If what I have written above makes sense then it is a catch-22 situation.  The MPEG-4 AAC Decoder cannot be  validated until some body ( hopefully ISO ) comes up with a set of correct conformance test streams.

What I would really like to know is, is anybody out their having similar problems towards the development of the AAC Decoder for MPEG-4. 

Is their any immediate solution out their ?

Thanks,

Circle

MPEG-4 AAC-LC Conformance Streams

Reply #5 –
Quote
Works perfectly here

maybe because you have the right password?

MPEG-4 AAC-LC Conformance Streams

Reply #6 –
Quote
Quote
Works perfectly here

maybe because you have the right password?

Password is in link

-Eugene
The  greatest  programming  project of all took six days;  on the seventh  day  the  programmer  rested.  We've been trying to debug the !@#$%&* thing ever since. Moral: design before you implement.

MPEG-4 AAC-LC Conformance Streams

Reply #7 –
Eltoder, Robert -

Can you please explain what you mean when you say that the "password is in the link" ?

The Fraunhofer institute website containing the MPEG-4 AAC bitsreams is open to public; it does not ask for any password....

Eltoder - What MPEG-4 AAC Decoder are you using ? 
I hope that it is the Natural Audio Decoder available with the reference MPEG-4 software, in the Audio Reference software at

audio/natural/rewrite/mp4AudVm

Please clarify.

Regards,

MPEG-4 AAC-LC Conformance Streams

Reply #8 –
Quote
Can you please explain what you mean when you say that the "password is in the link" ?

I'm neither eltoder nor robert but I can help you at least with the URL thing...

ftp://mpaudconf:adif2mp4@ftp.iis.fhg.de/

Protocol: FTP
Username: mpaudconf
Password: adif2mp4
Server: ftp.iis.fhg.de
Basedirectory: /

MPEG-4 AAC-LC Conformance Streams

Reply #9 –
Thanks ErikS.


I knew that the Fraunhofer site containing the AAC-LC bistreams is at:


ftp://mpaudconf:adif2mp4@ftp.iis.fhg.de/


Thanks for deciphering the various pieces of that link for me.


I am currently more concerned about the bitstreams kept at the Fraunhofer Institute URL.  They are not passing the MPEG-4 Reference Decoder !!!!  Please look at my message posting on the 19th June ( above ).

What's is the take on that ?

MPEG-4 AAC-LC Conformance Streams

Reply #10 –
I think the best to do is to contact Ralph Sperschneider from FhG through the M4IF techical notes mailing list and explain the problems - I am sure he will help.

MPEG-4 AAC-LC Conformance Streams

Reply #11 –
Ivan,

Thanks for your input.

Regards.