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TI C674x AAC Encoder Limitation - need help

hb chen
Expert 2640 points

 Dear TI member and Experts,

We got request from Customer.

To support AAC Encoder, Customer need AAC-LC <bitrate:64kbps/ sampling rate:16kHZ>.

But in TI AAC Encoder document

“AAC_LC_Encoder_C674x_UserGuide.pdf - Appendix A - AAC LC Encoder Bit-rate and Sampling Frequency Combination”,

The 16000(16kHz) sampling can only support 32000~ 39999 bps. This cannot support customer’s request.

 

1)      Does TI have new AAC codec to support <64kbps/16kHz>?

2)      Can I get any assistant to achieve this target?

 

Thx

HB

  • 0
    Expert 2640 points
    Hello ~
    anyone can help?

    By the way, I found some other discussion threads:
    e2e.ti.com/.../325263

    In this discussion thread, Mohd. Harris (TI Employee) said:
    "Yes. C64x+ is upwardly compatible with C674x core. So, C64x+ AAC-LC/AAC-HE should run on C6748 as well. "

    Does this description mean: I can use C64x+ in DM8168(ARM Cortex+C674xDSP) to encode 16000(16kHz) sampling rate audio to 64kbps AAC-LC????

    Because C64x+ does not have <64kbps/16kHz> limitation.

    If yes, how can I achieve that? Someone can teach me?

    thx ~

    HB
  • 0 in reply to hb chen
    TI__Mastermind 30480 points
    Hi HB,
    AAC encoder on C64x+ supports 16kHz at 64kbps. This has different implementation compared to C674x AAC encoder.
    But this version of C64x+ encoder is available only in COFF format, no ELF version available.
  • 0 in reply to Ramprasad
    Expert 2640 points
    Dear Ramprasad,

    >>AAC encoder on C64x+ supports 16kHz at 64kbps. This has different implementation compared to C674x AAC encoder.
    Can you describe the difference? or your conclusion is DM8168(C674x) cannot use C64x+??

    >>AAC encoder on C64x+ supports 16kHz at 64kbps. This has different implementation compared to C674x AAC encoder.
    >>But this version of C64x+ encoder is available only in COFF format, no ELF version available.
    About this, I cannot understand.
    OMAP35 is C64x inside, it should can use C64x+ encoder in linux system.
    Why do you say C64x+ encoder is available only in COFF format, no ELF version available??

    thx ~

    HB
  • 0 in reply to hb chen
    TI__Mastermind 30480 points
    Hi HB,
    The source code for AAC encoder C64x+ and C674x are different and hence the features supported also are different.
    AAC Encoder on C64x+ is purely fixed point codec and encoder source on C674x is floating point implementaion.

    AAC-LC encoder on C64x+ v1.20.005 library is available in only COFF format. The source code needs to be rebuilt for ELF format.
    If your SDK's other components compiled as ELF, you need to compile AAC-LC encoder also in ELF to integrate with SDK
  • 0 in reply to Ramprasad
    Expert 2640 points
    Dear Ramprasad,

    >>AAC Encoder on C64x+ is purely fixed point codec and encoder source on C674x is floating point implementaion.
    What are the effects if I use C64x+ to replace C674x? quality or performance or ...?
    or I must modify C64x+ source code and compile it to ELF format to apply it in DM8168?

    Can TI provide c64x+ AAC-LC in ELF format?
    If I got c64x+ AAC-LC encorder in ELF format, Can I just replace it without any source code modification in DM8168?
    (Of course, I might need to modify some makefile/rule.make/..., or TI will provide update process document)

    I want to request local FAE to provide that, is it possible?

    HB.