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Topic: AAC frames and ADTS frames (Read 12308 times) previous topic - next topic
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Re: AAC frames and ADTS frames

Reply #25 –
Quote from: Replica9000 on
My car stereo will pay AAC-LC, but won't play any of the other AAC profiles.

Good for you.

Quote from: Octocontrabass on
Quote from: Klymins on
Thanks, but there's nothing that can indicate that's HE-AAC so how does the player know it's HE-AAC?
The player finds SBR elements in the frame when it decodes the audio (and PS elements if it's HE-AACv2).

Thanks. For making a variation of AAC, how many sync bits of ADTS can be used for giving important information?

Re: AAC frames and ADTS frames

Reply #27 –
Quote from: Replica9000 on
Quote from: Klymins on

Good for you.


I mention it because someone said HE-AAC is backwards compatible with AAC-LC, but some players still might not play them.

Thanks for clarification, sorry for not understanding it at the first time. Does it don't play at all, @Replica9000 ? If yes, this means it's a bad decoder (as I learned, an AAC-LC player has everything required for playing HE-AAC streams but with a low bandwidth).

Re: AAC frames and ADTS frames

Reply #28 –
Quote from: Klymins on
For making a variation of AAC, how many sync bits of ADTS can be used for giving important information?
None of them, unless you convince someone at MPEG to change the ADTS specification for you.
 

Re: AAC frames and ADTS frames

Reply #29 –
Quote from: Octocontrabass on
Quote from: Klymins on
For making a variation of AAC, how many sync bits of ADTS can be used for giving important information?
None of them, unless you convince someone at MPEG to change the ADTS specification for you.

If I can, or I decide to make a non-standard variation, changing how many of them is theorically possible?

Re: AAC frames and ADTS frames

Reply #30 –
Just do it and stop talking. Here's an appropriate start for you:

Code: [Select]
main( ) { printf("hello, world"); }

Re: AAC frames and ADTS frames

Reply #31 –
Quote from: Klymins on
Quote from: Octocontrabass on
Quote from: Klymins on
For making a variation of AAC, how many sync bits of ADTS can be used for giving important information?
None of them, unless you convince someone at MPEG to change the ADTS specification for you.

If I can, or I decide to make a non-standard variation, changing how many of them is theorically possible?

If you don't care about being compliant with the standard you can change literally anything.  Add as many sync bits as you need.

Re: AAC frames and ADTS frames

Reply #32 –
Quote from: saratoga on
Quote from: Klymins on
Quote from: Octocontrabass on
Quote from: Klymins on
For making a variation of AAC, how many sync bits of ADTS can be used for giving important information?
None of them, unless you convince someone at MPEG to change the ADTS specification for you.

If I can, or I decide to make a non-standard variation, changing how many of them is theorically possible?

If you don't care about being compliant with the standard you can change literally anything.  Add as many sync bits as you need.

Thanks, I was trying to say "how many of them can be sacrificed (starting from the last) while keeping resync possible?". Sacrificing one of them is already made in MPEG 2.5 Audio Layer 3 and I guess three of them can be sacrificed but I'm not sure.