Help with BPM Sync vs Timeline

[Digi]

[topic moved into its own thread by moderator]

My clips are DXV.
I'm noticing considerable frame rate drop on clips both 30 and 60fps when using BPM sync. I've been letting it do its initial calculation of 64 beats and leaving the bpm at 120.
In timeline both my 30 and 60 fps clips play back smoothly then toggle back to BPM and it literally looks like the clips are playing at half its frame rate and its a bit depressing. Is this a normal expectation since BPM will fluctuate during an event and it seems unrealistic to have matching fps to bpm clips prepared for everything.

An example of whats happening.
My clip is 60fps - 30seconds = 1800 frames
Synced to BPM it gives me 64 Beats. I should be getting at least 28 frames between beat yet I count 14 by nudging the time slider in the transport.
Which means my total frame count is 896 with BPM sync which is exactly what I'm seeing with my eyes.

The time slider also appears to be moving between beats very incrementally in BPM sync vs timeline mode.

I don't see why the fps has to be sacrificed at this level by loosing half its frame rate just to maintain play back speed at a slightly new duration. Is this a coding problem, I mean it quite literally makes clips look like trash. ><

[Joris]

I moved your question into a new topic. Aside from getting help with your problem for your personal benefit, a forum also serves as a knowledge base for others. Having things in their own topic makes the information easier to find. Ideally a QA based topic asks a single question and a single best answer is provided.

[Joris]

As to your problem:

When a clip is set to BPM Sync, it will 'snap' to the nearest multiple of 4 beats, while keeping the speed at 120 bpm as close as possible to the original playback speed. This is because you want to sync the playback to beats, and multiples of 4 are the 'natural' phrase lengths in 4/4 music.

A 30 second clip would play back in 60 beats at 120 bpm, so it snaps to 64. With the snapping making the clip duration slightly longer than it actually has frames for, you might see a double frame here or there, not a halving of the framerate.

My guess is you have your buffer size set very low while using the internal sound card, which causes the bpm counter to go wonky. Either increase your buffer size, or get an external sound card if you need the low latency.

[Zoltán]

holding ALT will give you a finer resolution adjusting the timeline playhead.

having a 30 seconds clip, bpm set to 120, you would have 60 beats during the clip plays in timeline mode,
so 64 - which is a multiple of 4 and 16 - would give you 4 Bars clip time, which is a nice round number in musical terms.

so the question is does your clip look choppy when you play it back at 64 beats/120BPM?

edit: btw, there is a timecode counter which shows you the clip position in seconds:frames in BPM mode, so you can check you are not losing any frames.

[Digi]

I moved your question into a new topic. Aside from getting help with your problem for your personal benefit, a forum also serves as a knowledge base for others. Having things in their own topic makes the information easier to find. Ideally a QA based topic asks a single question and a single best answer is provided.

Ahh thank you, I just didn't want to be an annoyance and start creating multiple threads! Good to know ^^

[Digi]

As to your problem:

When a clip is set to BPM Sync, it will 'snap' to the nearest multiple of 4 beats, while keeping the speed at 120 bpm as close as possible to the original playback speed. This is because you want to sync the playback to beats, and multiples of 4 are the 'natural' phrase lengths in 4/4 music.

A 30 second clip would play back in 60 beats at 120 bpm, so it snaps to 64. With the snapping making the clip duration slightly longer than it actually has frames for, you might see a double frame here or there, not a halving of the framerate.

My guess is you have your buffer size set very low while using the internal sound card, which causes the bpm counter to go wonky. Either increase your buffer size, or get an external sound card if you need the low latency.

Before I give you credit as genius! I will say my buffer size was already 4096! I simply changed it back down to 2048 and suddenly the play back way instantly smooth giving my more play back points between beat during playback only. I'll admit my sound internal sound card is not that awesome being a EVGA FTW mobo.

Ironically I immediately googled "Resolume buffer size" and read another thread in the past that hit on this topic. Problem is I didn't know to look at the buffer to google it at the time. Anyways thanks for mentioning it and leading me down the right path. I figured surely this isn't a limitation!

[Digi]

holding ALT will give you a finer resolution adjusting the timeline playhead.

having a 30 seconds clip, bpm set to 120, you would have 60 beats during the clip plays in timeline mode,
so 64 - which is a multiple of 4 and 16 - would give you 4 Bars clip time, which is a nice round number in musical terms.

so the question is does your clip look choppy when you play it back at 64 beats/120BPM?

edit: btw, there is a timecode counter which shows you the clip position in seconds:frames in BPM mode, so you can check you are not losing any frames.

Yeah I was actually using the nudge option when you mouse over the slider to count instead of holding alt. Joris Pretty much help point me in the right direction with the buffer issue but I noticed after changing the buffer from 4096 to 2048 the frame count between beets didn't change.

So I thought about this some more. If the bmp is 122 thats 60 seconds. Half of that is 64 (30 seconds)
My clip is 30 seconds which is 60 fps. The time slider is showing about 14 frames per beat. So almost 30 fps between 2 beats.

64 beats / 2 = 32 beats x (about 28 frames per 2 beats) = 896 total frames for the clip in Resolume. So yes without a doubt the time slider is showing my 60 fps clip to have a frame rate of 30 with a 2048 buffer size. Hmm

At least its playing back smoother with the smaller buffer xD