Re: Lame optimization questions

I think the DA doesn't appear to have an FPU, rather an MDU, so some
of this is starting to make sense.

On Mon, Aug 28, 2017 at 9:20 AM, Erik Friesen <[email protected]> wrote:
> So I got LAME running on my MZ DA series pic32(200mhz w fpu, 32mb
> ddr), with dissapointing results.  With a mono channel at 44.1khz
> encoding is quite slow, calculated to around 200% real time.
>
> For a 7680 size input, cycles are around 50,000,000.
>
> Profiling results are:
> CYCLES 62275    : snd_pcm_read 7680
> CYCLES 241      : @lame_encode_buffer_template
> CYCLES 407477   : lame_copy_inbuffer
> CYCLES 569180   : Stage 1: vbrpsy_attack_detection
> CYCLES 96       : Stage 1: vbrpsy_compute_block_type
> CYCLES 1076469  : Stage 1: LONG BLOCK CASE
> CYCLES 996      : Stage 1: SHORT BLOCK CASE
> CYCLES 4367     : Stage 1: short block pre-echo control
> CYCLES 89       : Stage 1: vbrpsy_apply_block_type
> CYCLES 560029   : Stage 1: vbrpsy_attack_detection
> CYCLES 18       : Stage 1: vbrpsy_compute_block_type
> CYCLES 1075629  : Stage 1: LONG BLOCK CASE
> CYCLES 757      : Stage 1: SHORT BLOCK CASE
> CYCLES 4225     : Stage 1: short block pre-echo control
> CYCLES 54       : Stage 1: vbrpsy_apply_block_type
> CYCLES 10304    : Stage 1: psychoacoustic model
> CYCLES 1669433  : @Stage 2: MDCT
> CYCLES 129      : @Stage 3: MS/LR decision
> CYCLES 2240782  : @Stage 4: quantization loop
> CYCLES 29909    : @Stage 5: bitstream formatting
>
>
> The shine encoder is around %10 real time.
>
> The same LAME code on the previous hardware(i.mx6 single core on linux
> at 1ghz) runs less than 10% CPU. My shoot from the hip calcs say
> 200mhz without OS should at least be capable of 1/5 performance.
>
> The questions I have:
>
> 1. Is there something obvious I am missing on this all?
> 2. What would be involved realistically to convert LAME to fixed point?
> 3. If fixed point, would 64 bit fixed point be best?
> 4. I see shine and lame have calc_xmin. Could the psymodel of lame be
> shoehorned to shine?(I know, this isn't shine, but it obviously has
> the same author)

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