[Question] Real-time BPM update polling rate

[Wietjuh]

Is there a way we could limit the rt bpm function (or in call frequency/time)

I play with timecodes (vinyl) and vinyl flutters.

So, I would love a function that wouldn't update the file x times per second but once a 15/30 seconds (preferably before it sends it over the network to my other PC)

Maybe its an easy config for me locally, maybe more people would like to be able to define it.

Also I only need whole bpm info, not the 0,01 accuracy, but that can be filtered out at my end.

/edit: And I forgot to make it a readable title, please delete if needed 😂

[Unreal-Dan]

I see so you just want to slow down the rt bpm function so that it updates less often? Is that what I'm understanding?

You're saying you'd like it to run once every 15 seconds, and 30 seconds?

Are you comfortable making modifications to the module and rebuilding it yourself? All that is needed is visual studio there's no extra requirements. If you're not comfortable then I can put together some changes for you but it would probably be faster for you to do it.

This function here is responsible for queueing up a bpm update into the logging system:

https://github.com/Unreal-Dan/RekordBoxSongExporter/blob/master/Module/OlvcCallback.cpp#L146

You could add a simple time check inside that function, something like this:

#include <chrono>

// callback for when the bpm changes on a deck
static void bpm_changed(uint32_t deck_idx, uint32_t old_bpm, uint32_t new_bpm)
{
    // keep track of 8 last call times, one for each possible deck
    static std::chrono::steady_clock::time_point lastCallTime[8];

    // adjust period to be some measure of time in milliseconds to ratelimit to
    // 1000 / 15 = 15 times per second
    const auto period = std::chrono::milliseconds(1000 / 15);

    // grab curtime and calculate elapsed since last update on this deck
    auto now = std::chrono::steady_clock::now();
    auto elapsed = now - lastCallTime[deck_idx];

    // if we haven't waited long enough to queue the bpm change, then just discard this change
    if (elapsed < period) {
        // Discard the call as it is within the rate limit period
        return;
    }

    // otherwise update the last call time and proceed with queuing the bpm change
    lastCallTime[deck_idx] = now;

    // lookup a player for the deck
    djplayer_uiplayer *player = lookup_player(deck_idx);
    // make sure the player has a track loaded on it
    if (!player || !player->getTrackBrowserID()) {
        return;
    }
    info("BPM change deck %u: %.2f -> %.2f", deck_idx, old_bpm / 100.0, new_bpm / 100.0);
    // Push a message to the output file writer indicating the deck changed bpm
    push_deck_update(deck_idx, UPDATE_TYPE_BPM);
}

I honestly don't know if this will work the way we want, but I'm quite certain it should.

You're going to want to configure the code and rebuild the module how you want, here's a changeset that demonstrates adding this code to the program.

4666d3d

Let me know how this goes and if you need any help

[Wietjuh]

as i read this i think i can handle it.

My goal is, because my decks flutter .3 bpm while playing a track, to round of the bpm value to a whole and only push it to the text file every 15 seconds or so as that would be enough updates for my bot.

It rounding of can be done very easy at my end by just reading whole values with my bot.

They way you implemented as i can see is it pushes the data (rekordbox) to the hook (rbse) anyway, than we set a timer to check if enough time has past before we push to textfiles.

Its different than what i had in mind and maybe a tad compicated for my skil level to approach it like this, but why not. Ill try to build it tomorrow. Gonna be a first for me tho.

TBH if i can mod a config file in the program folder i'd be very happy. I got time to wait and im willing to cover the costs if you do it for me.

So maybe let me know when u have a little time to drop it in yourself. In the mean time ill try installing visual tomorrow and see what i can do. Kinda curious too.

I think with github i'd also be able to do more with it. But as said, my skil level with code is abominal. I can read, but writing is a whole new thing..

Kind regards and thanks for the quick reply

ill keep you updated

ps The whole reason i want this is because it sens hundreds of updates over the network and it even showed up in my logs as one of the most intens processes on my network. (if you dont count the bandwith but the amount of packages)

[erikrichardlarson]

Maybe if you just round bpm and last_bpm to the nearest integer then the bpm_change will trigger as much as you'd expect?

RekordBoxSongExporter/Module/OlvcCallback.cpp

Line 112 in 25e897a

if (bpm != last_bpm) {

[Unreal-Dan]

Maybe if you just round bpm and last_bpm to the nearest integer then the bpm_change will trigger as much as you'd expect?

RekordBoxSongExporter/Module/OlvcCallback.cpp

Line 112 in 25e897a

if (bpm != last_bpm) {

This is right, that would be an optimal way to do it in the engine. The bpm is an integer that represents the real bpm * 100, so 128.50 is 12850 in that integer, if I recall correctly. If you do something like:

bpm -= (bpm % 100);

This will round the bpm down to the nearest whole value, so something like 12850 will round down to 12800.

If you do this before storing the old_bpm[deck_idx] = bpm then it will always only track the whole-bpm changes.

Perhaps I can add a separate tag that only tracks the whole number bpms this way.

[Wietjuh]

That last suggestion would be the sollution I think.

Please let me know if you need more info, but I think we are on the right track here!

[Wietjuh]

I tried with VS last week, but I can tell you it's not a program that I understand in a day. So I'd rather have you make the change or get me a test build with the bpm this way. I'm sorry.

[erikrichardlarson]

Will create a new build right now and send you way

[erikrichardlarson]

@Unreal-Dan Looks like capstone is missing some header files which is preventing the build from being successful, are you able to include those header files in the repo here?

[erikrichardlarson]

@Wietjuh Was able to build the project, try out this build, uses the bpm change above. @Unreal-Dan Looks like an older version of capstone was needed, built 4.0.1 and it worked.
RekordBoxSongExporter.zip

[Wietjuh]

I'll try today @erikrichardlarson, thanks for the build.

I should really get to know VS once. Made some plans to be able to use my stream desk as a desktop, so it might come one day.

BTW, did I read the code correctly it updates 15 times a second? And only after it change a full bpm it'll update the txt file.

[Wietjuh]

So, I'm really sorry but it still pumps out waaaay to many changes (like in the 100s)

Maybe just update once every couple of seconds (my preference would be 10 seconds) and I'd really would like the whole bpm number as a result if possible.

But we are getting there, this wasn't a strain on my network as it used to be. And I'm sure it will be amazing to see it work out caus the test I did with the lighting and all the artwork on stream all synced up with the music went really well

[erikrichardlarson]

No worries, can send over another update. Can update to send out bpm update if last update was more than 10 seconds ago or if there's a large change in BPM, maybe a change of 5 or more? Just want to be sure that larger updates aren't slow / missed in real-time.

[Unreal-Dan]

Sorry guys, been busy, I'll put in some time tonight and see if I can put together a new feature that let's him control the rate of updates

[Wietjuh]

U both are the best! If we can get this to work I can set so much automation based on this info, the MIDI over network doesnt work with most streamer bots. I will show some results if you like when this all goes live!

As said, if we can do the round off to full bpm and if I can set the rate that would be amazing (even if it would be in a config file or whatever)

Really getting excited for the possibilities