Lame optimization questions
Erik Friesen <[email protected]> Mon, 28 Aug 2017 09:20:09 -0400
| Newsgroups | gmane.comp.audio.mp3.lame |
|---|---|
| Message-ID | <CAEuupivapdu89suqycjSdvTXSmFTBQoqrFVezWgp4BiUjNFuhQ@mail.gmail.com> |
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) ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot