[Mp4-tech] Decoding an MPEG-2 AAC stream : Help

[ramesh raman]

  Hi all,
I am new to MPEG-4.  I downloaded the public distribution code and i 
have compiled the MPEG-4 Decoder code on Linux.
I try to run it with the following options :
./mp4audec test.mp4 -o test.raw
                                           test.mp4 is an MPEG-2 AAC 
ADTS stream (which decodes correctly on a MPEG-2 AAC decoder) present in 
local dir.
When i run  the program, i get the following error,
mp4audec: WARNING: error decoding audio file test.mp4
Could anybody please tell me what options i need to set to decode an 
MPEG-2 AAC Encoded stream.
Now, here are few things i observed while trying to step through:
1. While stepping through the function  "MP4ParseAtomUsingProtoList"   
 in the libisomedia.a library, there is a comparison of the FIRST 4 
Bytes read from the stream with the File size.  (In file MP4atoms.c   : 
 exact code is as below :
    err = MP4CreateBaseAtom( atomProto ); if ( err ) goto bail;
    /* atom size */
    err = inputStream->read32( inputStream, &atomProto->size, NULL ); if 
( err ) goto bail;
    if ( atomProto->size == 0 )
        BAILWITHERROR( MP4NoQTAtomErr )
    if ( (atomProto->size < 0) || ((atomProto->size - 4) > 
inputStream->available) )
        BAILWITHERROR( MP4BadDataErr )
the atomProto->size in my case become 0xfff94d80    and this check fails 
here  )
2. The .mp4 file that i have doesnt contain the file size in the first 4 
bytes (It actually contains  0xff 0xf9 0x4D 0x80 , while the file size 
in hex is  0xB637CB bytes)
Can anybody please tell me if i need to give any specific options to the 
MPEG4 decoder , so that it can decode this stream.  
I apologize if my question has already been answered earlier.
thanks in advance
regards
/ramesh
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