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GH2 - 2.5fps AVCHD 24h Timebuster/TimeHBusteR 2.0 settings - The day is not over!
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  • @duartix I know there was a big discussion with @balazer about GOP 12 or GOP 13 for 1/2 sec at 24p but is that really 100% sure to use GOP 13. Why has Panasonic used the standard parameter GOP 12. For 25p I understand that it must be GOP 13 but... maybe I should try your patch with GOP 12 and look how it behaves under stress. What is your practical experience...

    13/23.976 = 1/1.844 > 1/2s == go, but why not the next....

    12/23.976 = 1/1.998 > 1/2s == go

    12/25 = 1/2.083 < 1/2s == no go

    13/25 = 1/1.923 > 1/2s == go

    @Vitaliy_Kiselev is there already something which you know about standard GOP settings for 25p from the new firmware.

    In a GOP12 at 24p case I would have to implement for my macro

    StepSize1 = round(ShutterSpeed_s*FrameRate_fps) == GOP

    which sounds more logic for me...

  • I believe it's a common thing among all patches I tried. I don't know if it's the camera normal behavior saving up bitrate to build up a buffer for rainy days, but I know there's a parameter called "Initial quantizer". I suggest you lower it from 20 to let's say 18 and see what happens.

  • @duartix what could be the reason that I find with your patch that especially under stress the 13st-1 frame answers with high bitrate.

  • OK, thanks for the clarification. I'll perform some tests to compute the impact.

  • Lowering the QP by six doubles the precision of the coefficients. It doesn't necessarily mean the coded frame sizes will double.

  • Let's see what are the most desirable SSs:

    • SS=1/2s then you get: 1/2*24+1=GOP13

    • SS=1/4s then you get: 1/4*24+1= GOP7

    • SS=1/6s then you get: 1/6*24+1= GOP5

    • SS=1/8s then you get: 1/8*24+1= GOP4

    • SS=1/12 then you get: 1/12*24+1 = GOP3

    (EDIT) THIS LOGIC ISN'T WORKING. Look further in this thread:

    Apparently the formula guarantees that you'll have a new I-Frame that is pretty much in synch with your later frame sampling rate and that the rest are tiny null P-Frames to be discarded. If I were in your shoes, I wouldn't go for other funny SSs like 1/5 or 1/10 since 1/4 and 1/8(12) are very close and will work even without scripting tools.

    In Timebuster 1.1, I've lowered the QP from 22 to 20 so we get a little better IQ but still get around 24h. In principle the patch will keep it's IQ performance but it will pay for that in bitrate and recording length. All other things equal a 1/4 SS will spend 13/7x the bitrate when compared to 1/2s, so you'll get just short of 13h of footage on 64GB. At 1/8s it's well over 7h. Do take into account that this will always vary with footage content and mostly with ISO.

    Having said that, this is a game of just matching GOP with SS. The beauty of recording footage at lower SS is that it's much less demanding on the Camera CPU, on the codec and on the storage card. If you have recording length to spare you can even be adventurous and lower the value of "Quantizer for 1080 modes", but remember that if you lower that QP by 6, you'll end up with approximately 2x bigger frames and then you might already be hitting the ceiling on the 1080p24 Frame Limit.

    Q20 even though it is the default stock setting, it is very good quality already IMHO and if the stock GH2 wasn't so limited in buffers, frame limits and bitrates, it would be spitting out so much quality we wouldn't be using any hacks...

  • @duartix thanks, looking forward to use it. If one would like to use higher shutter speed than 1/2s would the patch keep it's performance by just lowering the GOP. Would the calculation in below mentioned macro fit?

    StepSize1 = abs(ShutterSpeed_s*FrameRate_fps)+1 //For your Patch StepSize1 == GOP13 at 1/2s

  • TimeBuster 1.1 is out, featuring 2 significant changes:

    • Since this is based on @balazer 's Cake 1.1 it has switched to using the Rate Control mechanism from @LPowell 's FlowMotion 100.

    • 720p mode was broken due to use of a very low quantizer (12) which lead to skipped frames in 720p. It now uses QP=20 on both 720 & 1080 modes which will have an observable effect in both bitrate & quality even though it still gives you 24+ hours on 64GB.

    The day is not over. :)

  • @duartix Thanks. Hmmm, just found out VirtualDub runs on Mac OS X through Wine (like pTools). Will give it a shot.

  • @Hallvalla:

    1 - Camera top Dial must be set to M Movie, video mode must be set at 24p (cinema) and focus to MF, with the rear dial set shutter speed to 1/2s (pressing the rear dial against the camera changes control from A to S).

    2 - Record.

    3 - Copy MTS file to disk .

    4 - Open VirtualDub (make sure you have the DirectShow filter installed )

    5 - Go to File Open (make sure that in "File of type" you select "DirectShow input driver") and open the file.

    6 - On Video menu select Frame Rate. There are two options on panel Frame Rate Conversion:

    a) Decimate by 12 (null frames will be deleted but you won't get the speed effect)

    b) Convert to 300fps (accelerated)

    7 - On Video menu configure the Compression codec.

    8 - Save file as...

    This is the easiest workflow I can imagine (on my video I applied some basic filters (menu Video | Filters) and used the Blend option to blend a B&W Fade Out and Fade In.

    The guaranteed better way to do it (to make sure you are only selecting I-Frames) should be with AviSynth and this post should give you an idea:

    There are also blending options on After Effects but I know very little about it.

  • @rafa As it was said just before, you need to be on Manual Movie mode, and set the camera to MF. Only then can you reduce the shutter speed below 1/25(30)

    @Vitaliy_Kiselev : That would be really great as P-Frames sometimes still get hungry and audio also can account for up to 5% at the moment, any chances those would be possible?

    Until then, there is a saying here in Portugal that goes like this: "He who doesn't have a dog, hunts with a cat."

  • @duartix

    Real approach to this must be ability to change encoder so it'll skip the frames and you must be able to specify how many you want to skip. It'll also require to completely turn off audio.

  • @duartix : How you get the 2fps in camera? Sorry but I don't find the way.

  • @Hallvalla : Yes, you still need to put the camera into MF so that you can then slow the shutter speed manually to 2fps. The camera will still record 24fps, the thing is that most of those frames will be subjectively NULL (they still occupy some minimal space) as you see in the first StreamParser capture. When there is significant movement however, some of the P-Frames surrounding the I-Frames will occupy some noticeable space.

    I'll try to capture something today and post it here. I'll try to post the workflow too.

  • @duartix A couple questions:

    Does this patch actually record @ 2fps in AVCHD? or does the camera still record 24fps and you have to remove all of the duplicated frames? I couldn't find in the pTool settings where you switched 24fps ---> 2fps.

    Do you still have to use a 1/2 second shutter, Manual mode + manual focus?

    Could you write a simple workflow from start to finish (camera settings to post) about the timelapse video you've posted?

    This is very exciting, thanks for you time and efforts!


  • @tida : Yes, well to be honest, keeping 60i was an accident. I was going for an all round patch trying to preserve 24p for regular shooting and dedicating just 60i for timelapses. But as I wrote before, something I didn't foresee made me reconsider: 60 is "i", which means that at 2fps when the footage changes are recorded by the camera from t=#0 they will be spread across 2 fields at frames #30 and #31 and to encode these changes properly in Full Intra, you would need GOP1 which defeats the purpose of getting long record times.

    In the end, I'm glad this happened because this is a timelapse dedicated patch and this way you can preserve the modes that work on extreme timing ends. 720p60 is preserved, 2fps @1080 has great recording times and IQ, and you still have 1080i60 with very good quality and resolution. I've tried to set 60i GOP length to GOP1 but as I said before, it doesn't stick, and the camera goes with 13 in that mode. (edit) Stupid me, (I was testing PAL, that's why it didn't look like it sticked) (/edit) It's not too bad but it's not ideal either, so if someone has an idea on how to change it, please let me know as I'd like to try it!

    It's all about choices, as much as I'd like to do an all round patch, the focus here is on timelapses and if you really need 24p at the same time, well then you might as well use another SD card with a better 24p patch on it. Provided you have 2 cards, you can change the patches on the field as many times as you need, all it takes is 3min at a time and a full battery (two things that timelapsers usually can spare :D ). Timelapses can be done with amazing quality in the smallest & cheapest cards, so I think the card is not an issue.

  • @duartix does it mean you would have created the perfect patch to combine timelapse at 2fps (which would give factor 13x as a base) with slow motion at 60i transferred to 24p (which would give factor 1/2.5 as a base) and all at 1080p.

    If you can combine it like I did it as shown below it would be an awesome timebuster with extreme possibilites of dynamic range...

  • @duartix, ok I don't tell you. keep up the good work. Maybe we'll talk soon.

  • @eyefi:

    Yes, busted!

    Don't tell me you are the guy with the girl... :)

  • Impressive stuff!

  • @duartix, are you in lisbon?

  • This is awesome! naf SAID!

  • Here's what it looks like on 24p @2fps on static footage. Almost as good as 2fps MJPEG would look. And the only impairing I observed (on 60i) was the long GOPs, but with good P-Frame size. The beauty of the patch is that you can now easily trade IQ for recording length with very little changes to Cake (as I did). Probably all you need is to balance the frame limits with the QP.

    This is how 24H looks on a very detailed and colored chart. Average Total Bitrate = 7.012.276. On real life and detailed footage but with less texture, I got under 5Mbps (on 24H).

    On a 64GB SD this translates into 29 hours.


    2fps 24P.png
    1726 x 841 - 824K
    30fps 60i.png
    1726 x 841 - 159K