[FFmpeg-devel] [PATCH] AAC encoder: refactor to resynchronize MIPS port

Claudio Freire klaussfreire at gmail.com
Wed Sep 16 16:04:32 CEST 2015

On Tue, Sep 15, 2015 at 8:11 AM, Michael Niedermayer <michaelni at gmx.at> wrote:
> On Tue, Sep 15, 2015 at 04:24:02AM -0300, Claudio Freire wrote:
>> This patch refactors the AAC coders to reuse code
>> between the MIPS port and the regular, portable C code.
>> There were two main functions that had to use
>> hand-optimized versions of quantization code:
>>  - search_for_quantizers_twoloop
>>  - codebook_trellis_rate
>> Those two were split into their own template header
>> files so they can be inlined inside both the MIPS port
>> and the generic code. In each context, they'll link
>> to their specialized implementations, and thus be
>> optimized by the compiler.
>> This approach I believe is better than maintaining
>> several copies of each function. As past experience has
>> proven, having to keep those in sync was error prone.
>> In this way, they will remain in sync by default.
>> Also, an implementation of the reconstructed output
>> argument for the optimized quantize_and_encode
>> functions is included in the patch. While the current
>> implementation of search_for_pred still isn't using
>> it, future iterations of main prediction probably will.
>> It should not imply any measurable performance hit while
>> not being used.
>> Patch attached.
>> I thought it was worth a review.
>> It does include lots of copypaste.
>> FTR, I tested MIPS 74Kf and x86_64 with make fate-aac
> full fate passes on qemu mips here as well!

If there's no objections then, I will be pushing it later today,
before it stops applying cleanly.

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