VOGONS


First post, by st31276a

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Yesterday I played a 96kbps opus track on my everyday home laptop (2.8 Northwood / 1GB / XPSP4) with a modern-ish version of mplayer and noticed the sound stuttering badly while loading modern sites in mypal browser.

After closing everything, I noticed the cpu usage is between 13-17% while playing, with occasional spikes into the twenties. When I stop the player, it goes back to 0%.

Playing the same opus track on an iphone 14 also result in the occasional brief stutter here and there.

I find this insane.

I remember playing mp3 files on fast 486 machines back in the day, swallowing all the cpu time unless skipping half of the work. Pentiums did it fine with time to spare and p2’s hardly felt anything at all.

I did not do any speed testing, but anecdotally just eyeballing it, it looks like anything slower than a 500MHz wont work at all. Even faster stuff needs to decode ahead of time into a longer buffer, as the processing needed seems to be rather irregular in real time with occasional spikes that overrun the time in the codec’s frame decode buffer from time to time.

I get it that opus is designed with real time applications in mind, therefore such short latencies are involved, but for static playback it is not needed.

I tried searching for the term opus to see if anything has been posted about this on the forum, but on page 4 the search dingus switches to the term “opera” trying to be helpful. (Search dingus: an opus is a *work*, not an opera)

I will obviously do some testing in this regard in the future, but I was wondering if anybody here also has some anecdotes, experiences or results they could share.

Reply 1 of 4, by eM-!3

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About 2 years ago I've made some tests with a quest to find worst possible CPU that will be able to play some audio codecs ~ 128 bitrate. I use Opus audio codec a lot so it was part of my tests.
Important note. It wasn't on a real machine. I've used 86Box with SB16 as a sound card. My results:

Vorbis OGG - Cyrix 486 75 MHz
MPC - AMD 486 80 MHz
MP3/AAC - Cyrix 486 100 MHz
Opus - AMD 5x86 160MHz - forget it's name, this is 486

Edit: these results are wrong.

Command line used:

MPXPLAY -inl -sl 0 -ddma -f0 -v -bl -bn8 -sct s16

This is original text info from MPXPlay:

Mpxplay system requirements (mainly for DOS): […]
Show full quote

Mpxplay system requirements (mainly for DOS):

- Minimum CPU for playing 44.1khz, stereo, (128kbit/s) files (with '-f0 -sl 0 -bl -bn8' options):

AAC : Intel Pentium 66 (LC object type)
AC3 : Intel 80486 DX4-120 (48khz,2.0ch,192kbit)
APE : Intel Pentium 166 MMX (fast-mode encoded files work without MMX too)
DTS : Intel PII-300 (48kHz,5.1ch,768kbit)
FLAC: Intel Pentium 66 (depending on the compression ratio too)
MP2 : Intel 80486 DX2-66
MP3 : Intel 80486 DX4-100
MPC : Intel 80486 DX4-100
OGG : Intel 80486 DX4-133
WMA : Intel Pentium 90
WV : Intel Pentium 166
(note: demuxing from containers (ASF,AVI,MKV,MP4,OGG,TS) requires extra time if it contains more than one stream (video or audio))

Last edited by eM-!3 on 2026-04-19, 16:22. Edited 1 time in total.

Reply 2 of 4, by pachuco

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Isn't vorbis decoding spicier than mp3?

Reply 3 of 4, by leileilol

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those tests mean squat when cpu emulation doesn't take cache into account.

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FUCK "AI". It is a tool of fascism. We do not need it. We do not use it.

Reply 4 of 4, by eM-!3

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New results. 86Box 5.3, MPXPlay 1.68 DOS:

WAV - 486 DX 25 MHz
MP2 192 kbps - 486 DX2 66 MHz
MPC 128 kbps - 486 DX2 66 MHz (MPXPlay can't play SV8 Musepack files. SV7 needed)
OGG 128 kbps - 486 DX2 66 MHz (CPU over 100% but plays fine)
AC3 128 kbps - 486 DX2 66 MHz (CPU over 100% but plays fine; current version of MPXPlay has a bug which makes AC3 playback a bit louder)
FLAC - 486 DX2 66 MHz (CPU over 100% - only possible with no screen output)
MP3 128 kbps - 486 DX4 75 MHz (not far away from being able to play at 66 MHz)
AAC 128 kbps - AMD 486 DX4 90 MHz
OPUS 128 kbps - AMD Am5x86 150 MHz (nevermind the name, this is still 486. CPU over 100% - only possible with no screen output)

Pentium Overdrive 63 MHz plays everything.

86Box VM and OS setup:

Machine type: i486 Socket 3 PCI Machine: UMC 8881 Compaq Presario 7100 Series 486 (previous tests were on SiS 496 Soyo 4SAW2) CP […]
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Machine type: i486 Socket 3 PCI
Machine: UMC 8881 Compaq Presario 7100 Series 486 (previous tests were on SiS 496 Soyo 4SAW2)
CPU: Intel when possible
Memory: 16 MB
Sound card: ISA16 Sound Blaster 16, IRQ 5, DMA 1
Video card, keyboard, mouse: anything that works
1 GB HDD formatted in FAT32
FreeDOS kernel + himemx
no floppy drive
BIOS: no power management in BIOS, disabled some IRQs, no floppy

Command line with basic info during playback:

MPXPLAY -inl -sl 0 -ddma -fe -v -bl -bn8 -sct s16

Command line without any output during playback:

MPXPLAY -inl -sl 0 -ddma -f0 -v -bl -bn8 -sct s16

These short test were made with just a single 5 minute song so it's not enough to say that it would work for a playlist with multiple songs. Real world PC tests would be much better as I'm not sure how much can we trust 86Box emulator (cache - speed) but this is as far as I can get without buying 486 PC.