BEWARE @tida and TIMELAPSERS !!!

Analysing the framesizes (and also checking for content) of footage shot with Shutter Speeds (SS) below 1/25 reveals that the "Real" Framerate is NOT 1/SS as should be expected!

SS - Frequency of new frames - Ideal patch GOP

1/2s - 1/13 - GOP13

1/2.5 - 1/10 - GOP10

1/3.2 - 1/8 - GOP8

1/4 - 1/7 - GOP7

1/5 - 1/5 - GOP5

1/6 - 1/4 - GOP4

1/8 - 1/4 - GOP4

1/10 - 1/3 - GOP3

1/13 - 1/2 - GOP2

1/15 - 1/2 - GOP2

1/20 - 1/2 - GOP2

This means that when shooting with SS=1/20s, the content of frame1=frame0, frame3=frame2, etc. There is no new content every 1/SS frames!!!

Yes, MJPEG frame rate is fixed and set in the patch to 2fps and yes, in AVCHD you do need to set the SS to 1/2s to marry GOP13.

• The major difference will be (and this is an estimate since it will depend on the content, on the quantizers that are different and also a lot on the P-Frame size reduction) that you'll be able to record around 5x more content because I've set the 24p GOP to 13 (instead of 3) and because since I won't be using the P-Frames, I've totally trashed their quality in 24 p to T4 (instead of T1). I've recorded a timelapse with 1.1 similar to the one I posted on the first thread that would record for ~22h on a 64GB SD card. At night! Oh wait, that's impossible at this latitude... ;)

• The second difference is that I reduced the Quantizer for 1080 modes to 20 (from 22 in Cake). That should give you a perceivable boost in IQ. All that happens while still managing to keep the average bitrate below 5.925.925bps which is the "Magic" number that gives you 24h on a 64GB SD, the major objective of this patch.

IIRC other than these two differences the patches are identical when it cames to AVCHD.

BTW, the Quantizer for 1080 modes is the single most important parameter in this patch. At 2fps it could easily give you either half or double the time if you are willing to trade recording time for quality.

The other is 1080i50 and 1080p24 GOP Size, and if you don't give a rat about continuous motion flow then by all means, go bananas, put 26 or 39 in there and near double or triple the recording time. Hell, go bonkers and set it to 117!!! You can record for close to ONE WEEK if you also raise a little bit on the quantizer. You'll compromise playback however, and 60i.

(edit) You can't go over GOP 50.

@duratix there is the basic expression in rheology: "everything flows"

Might be one time you will see the glass of your windows flowing...

@PapaRomeo, I don't know FCPX but I'd bet it can do something as simple as accelerating the video as can After Effects. I just gave @Hallvalla this workflow because it was the simplest I could imagine and it used only one piece of software. I can't tell you how VDub works under Wine because I use it natively on Windows 7 64bit. Anyway a google search for that error message leads here: http://forum.videohelp.com/threads/286901-VirtualDub-Now-Has-a-Directshow-Driver-Plugin

@tida: That would make sense had I not totally trashed P-Frames IQ with "1080p24 T2=1080p24 T4". But you do have some point however. I could give it a go at using B-Frames and trashing them while keeping P-Frames with more balanced IQ.

If the bitrate wasn't compromised at QP=20 and there was more demand for SSs other than 1/2s, I could make an alternative patch with GOP104, but analysing the traditional GOP structure I BB P BB P (...) it looks like there will be a lot of P-Frame waste on a lot of SSs. This "traditional" I(BBP)* structure is best fitted for GOP3/6/9/12 which only suits 1/10s. If I could get the GOP structure to behave like I(BBBP)* (which ATM I don't even know if it's possible) it would suit a few more cases : 1/6s, 1/8s and 1/3.2s. I'm starting to think that it's not worth it, because it will waste a lot of bitrate on all others... :(

Probably the best option for specific SSs is to have a set tailored patches for specific SSs on different SD cards and upgrade the FW on the field according to the footage demand. Just to give you an idea, on a GOP8 patch for 1/3.2s, I estimate the bitrate to be around 50% more at the same quality when compared to the GOP13 for 1/2s. I also don't believe there are nasty consequences to taking my patch and just suiting "1080i50 and 1080p24 GOP Size" to your current needs.

Thanks.

I should also say that the quality is already amazing @2fps... :) even without frame blending. IIRC I had to reduce aperture to about F5.6 on my 45mm F1.8 Olympus to keep the highlights on the timelapse I posted... and that was at ISO160 when the ISO test thread shows that ISO640 is the least noisy!

@PapaRomeo: You're welcome.

Next on the shortlist is:

• balancing 720p

• trying starved B-Frames

• trying very long GOPs

720p is fixed now (it's now based on FlowMotion with a 22 QP as it still dropped some frames on torture charts), running the other tests and I hope to have it published in a few days.

Totally different targets, objectives, priorities and means.

@dannywong: Sorry, almost zero possibilty. Mine is mostly about saving bitrate, @driftwood 's is about spending. Mine is mostly about long GOP, driftwood's about short GOP. Mine's about VBR, his is is about CBR (if I'm not mistaken). On top of it all, we both had to concentrate on 24p, so they are as incompatible as you can imagine.

Or were you talking about the 720p modes?

(edit) BTW, don't get me wrong, this is a mainly VBR patch and will use all the bitrate available to it while keeping the quality of the I_Frames at Q20. And the bitrate caps are not even close to stock settings, it's 80Mbps and 70Mbps IIRC so at 2fps it's as if it wasn't even capped with the QP as the main controller.

Releasing Timebuster v1.2

TimeBuster 1.2 is out, featuring one significant change which now gives it a fully featured 720p mode:

• Since @balazer 's Cake 1.1 is now heavily based on @LPowell 's FlowMotion 100, I decided to copy LPowells 720p settings since they will probably play better with the other modes. The only difference on 720p is a constant QP which had to be lowered yet from 20 to 21 because it still dropped frames on torture charts and/or sometimes present speed issues at very high ISO (>3200) on Class 10 SDs.

Tried a few dead ends:

• Starving B-Frames - didn't work even after messing with scaling tables. B-Frames at 2fps were still twice as big as the P-Frames it is still using.

• Very LOOOOOONG GOPs - The biggest GOP that I could get to marry 2fps without freezing the camera was 50. If you are willing to sacrifice three out of four frames every 2s, use GOP50, I managed to get bitrates a little below 1,900,000bps at ISO160 which could give you 3 DAYS recording time on a 64GB SD. Getting even more would start to require some kind of success in getting rid of the parasite bitrates (like audio) or giving up IQ (by raising the quantizer).

As for the current settings it still will typically give you 24+ hours at 2fps with excellent IQ on 64GB.

The day is not over. :)

ATTENTION!

"Quantiser for 720 modes" will most probably be set to 22 again in the next release. It turns out I've been testing 720p60 the wrong way all along and it was still dropping P-Frames... :(

Cheers, Timelapsers and Timebusters!

Yesterday I discovered I had made a such a stupid slip up when testing Timebuster that it could even compromise my whole approach to the patch set.

To put it simple and blunt, I mistook 30p/60i for PAL and 25p/50i for NTSC. So, while in my PAL tests I thought I was testing Quantizer for 720p=21 for 60p, in reality it was only 50p, and P-Frames were still being dropped in real 60p. It doesn't happen anymore now with Quantiser for 720p=22 at least up until the very last extreme ISOs.

Sorry for that! My fault! But the main objective of the patch wasn't compromised in any way and the solution is simple! :)

(edit) Since it's a very small change and the patch looks very stable already, I won't be updating it until the patched fw 1.1 comes out which will possibly trigger a new version of FlowMotion.

Now, what might be compromised is the approach to the patch set. My first take was tackling GOP just in 60i in order to keep the rest of the modes uncrippled (especially 24p) and having an all round patch that could be left forever in the camera. Since my testing was wrong I and I was lead to believe that the "GOP for 60i"parameter wasn't working at all, I quickly changed the approach to use 24p instead. There were a few benefits in this approach as 60i being interlaced doesn't suit itself all that well to GOP games (because the real content changes at 2fps are spread into 2 frames/fields, and by starving P-Frames I'll be strongly compromising the IQ of one of the fields!). The other big benefit was still keeping the 60i uncrippled, which might be dear to extreme frame rate aficionados.

Does anyone see other benefits/problems in trying that opposite approach by tackling 60i instead?

Those are great @AmandaNL , the highway timelapse works really well with the soundtrack. But it left me with a doubt, is the motion flow really continuous at 2fps? The tail red light strikes seem interrupted but it might have come from the Premiere speed up, so how is the original footage?