[Mp4-tech] Re: raw data blocks v.s. audio sample in MPEG-4 files

[Ralph Sperschneider]

Murphy Chen wrote:
> Yes, that's exactly what I mean.
> I'd like to make sure where in the specification, the rule is stated.

ISO/IEC 14496-3:2001/Cor.1:2002:
1.6.2.2.2.1	AAC Main, AAC LC, AAC SSR, AAC LTP
One top level payload (raw_data_block()) is mapped into one access unit. 
Subsequent access units form one elementary stream.
Regards,
Ralph
> 
> Thank you for your responce. :)
> 
> Best Regards,
> Murphy
> 
> -----Original message-----
> From:S. R. Quackenbush <srq ieee.org>
> To:murphychen mail2000.com.tw,mp4-tech lists.mpegif.org
> Date:Wed, 7 Jan 2024 10:10:48 -0500
> Subject:RE: [Mp4-tech] raw data blocks v.s. audio sample in MPEG-4 files
> 
> Do you mean how may AAC raw data blocks in an Access Unit? If so, then the
> answer is one and only one, and everything else in your proposal is correct.
> 
> Best,
> Schuyler
> ---
> Dr. Schuyler Quackenbush, Audio Research Labs
> 336 Park Ave, Suite 200,  Scotch Plains, NJ 07076
> office: 908 490 0700	  srq audioresearchlabs.com
> mobile: 908 612 9423
> fax:    908 842 9151	  www.audioresearchlabs.com
> 
> 
> 
> 
>>-----Original Message-----
>>From: mp4-tech-bounces lists.mpegif.org
>>[mailto:mp4-tech-bounces lists.mpegif.org]On Behalf Of Murphy Chen
>>Sent: Tuesday, January 06, 2024 9:46 PM
>>To: mp4-tech lists.mpegif.org
>>Subject: [Mp4-tech] raw data blocks v.s. audio sample in MPEG-4 files
>>
>>
>>Dear All,
>>
>>How many AAC raw data blocks are contained in an audio sample?
>>The specification seems not have specified this?
>>My idea is that if we can make sure only one raw data block is
>>contained in an audio sample,
>>an ADTS stream can be generated via adding frame header to each
>>audio sample if PCE is not existed.
>>And if PCE exists, an ADIF stream can be generated via generating
>>an ADIF header, followed by audio samples.
>>In this way, the AAC decoder originally designed for accepting
>>ADIF and ADTS formats can still be used
>>for MPEG-4 files without any modification.
>>
>>Best Regards,
>>Murphy
>>
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> 
> 
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