Runs on half speed on RPi 3

[jthecodebuilder]

Compiles successfully on Raspbian, but seems to play at half speed. How do we/us fix this?

[jgilje]

I'll try to have a look at it within the next couple of days. I've got a Pi3 standing by :)

[jgilje]

Hi, just compiled and ran it successfully on my Pi3. No playback issues. Which song where you testing?

[jthecodebuilder]

we have accidently borrowed your votedisk.v2m
Also there's garbled synth in the left channel
but the right channel sounds somewhat ok

[jgilje]

Sorry, I've got none of your issues. I've uploaded my compiled version here, https://jgilje.net/prosjekter/v2m/, if you'd like to compare.

I also checked against a recording of the original demo, at https://www.youtube.com/watch?v=muMqrNZz0dQ, and noticed some effects are missing when played with this player. But this don't match the problem you're describing.

[jthecodebuilder]

Still runs on half speed on your own binary.
Maybe there is something in my alsamixer or SDL that I don't know about that is bottle-necking the speed??

[jgilje]

I'm starting to think you don't get the expected audio format back from SDL. In https://github.com/jgilje/v2m-player/blob/master/tinyplayer.cpp#L36. I never implemented a check on whether the actual SDL_AudioSpec matches the requested format.

Are you able to debug this code yourself? If not, I can compile a test-build to try to pinpoint the bug.

[frranck]

jgilje, what's special about this format ? couldn't find much info.

[jgilje]

@frranck it's a soft-synth created by farbrausch (https://en.wikipedia.org/wiki/Farbrausch) and used in many (most? all?) of their demos.

[jthecodebuilder]

perhaps, but right now we are focusing on a issue related to sample rate & speed. Also I might be able to debug the code, and a SDL_AudioSpec check sounds like it would fix this problem.

[jgilje]

@jthecodebuilder i just added some code for checking and validating the actual audio format returned by SDL. give it a go, and let me know if it reports any errors.

[jgilje]

@frranck probably, but as already noted this issue is for a different topic. feel free to open a new issue when they land a stable API :)

[jthecodebuilder]

got "INFO: Failed to get requested format, wanted 8120, got 8010" when attempting to play it and then it quits

[jthecodebuilder]

Just now, while looking through the code (thinking the values im looking for will never be found), line 63 of v2mplayer.h contains a very important value which can alter the speed, which would be the perfect place to implement a failsafe for when the audio format isn't the expected one! yay

[jthecodebuilder]

but ive also found that the static values in synth_core need to be auto-tweaked as well...!

[jgilje]

Nope, the failed format message means SDL failed to open the audio output device using the requested format. The requested format is 32-bit floats (which is what the soft-synth itself outputs), but the actual format returned by the audio device is 16-bit integers (ref. SDL_audio.h).

I just committed a change which should cause SDL to do this conversion automaticly.

[jthecodebuilder]

Well, darn. I thought I had caught the bug in it's tracks. Atleast it finally plays fine now. Now all it needs now is those effects fixed and then this is a very good port to SDL!