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Can we Hack the .jpg Burst Mode for Video Use?
  • Anybody think it's possible to hack the .jpg Burst Mode for Video Use?

    I would find it useful to have 3 seconds or more at 24 fps.
    Since there's no audio, the applications would be B-Roll, Slow Motion, Reframing in post and Green Screen.

    Currently, we get most useful 40 sequential .jpg frames 3600 x 1400 at approx 2.0MB/frame
    generated by the burst mode . Drop it on a 4K timeline in PPro and it looks decent scaled
    to fit the frame and exported to DPX sequence. I am not sure of what exactly the fps is however yet.

    I assume the 2 MB/frame approaches the Maximum Limit of the GH2 for continuous Video use also?
    Frames show up as 24 bit .jpg, but I am confused... are they 4:2:0 colorspace or above that?

    I will like to compare the image quality of Hack Frames to the Burst Mode Frame.
    I think they are getting closer...

    Anybody think it's possible to EXTEND the number of BURST frames by
    limiting the data rate to say something like 1MB/frame?


    *********************************
    11/13 Update: shooting 40 shot bursts (note, not exactly 40fps) consecutively at 2400x1600 resolution.
    testing latest 95MB/s Sandisk Extreme Pro 8GB Card. Consecutive bursts required waiting for the
    "data writing red light" to go off and then I repressed the shutter release button.

    Lens Cap On, 1/50th Shutter:
    6 bursts in 58 seconds, Ave: 9.7 sec per burst, Midrange Frame Size: 286KB
    Midrange Data Rate: 1179KB/s

    Manual Lens focused on Online-Stopwatch (minute and seconds only), 1/50th Shutter:
    5 bursts in 64 seconds, Ave: 12.8 sec per burst, Midrange Frame Size: 794KB
    Midrange Data Rate: 2481KB/s

    still searching for a test chart/video that will show peak data rate...
  • 14 Replies sorted by
  • Its been hacked. Its called MJPEG.
  • Well...not really. The burst mode is 4k while the MJPEG mode is 1920x1080.
  • I thinks its only 2k at 40fps
  • Eyepatch guy did a test on this.

    Burst mode had more detail, but the image kept flickering. In the comments he said it was from the LED light he used to light the test. So that and it would probably be more susceptible to CFL flicker.
  • Hacking mjpeg should be easier than hacking burst mode though... Also, there is no reason to expect that burst mode would bring something different out of the sensor = work on avchc / mjpeg is therefore be more valuable.
  • 40fps burst mode use special sensor mode, not one used by MJPEG video mode.
  • You reckon it is worth exploring, Vitaliy?
  • As I already said I would love to have that mode hacked the other way around you guys want (less fps, better quality for silent mode still shooting), but VK already said that he looked at it, and it is very complex (the burst mode in general, not my wishes)
  • well, @Vitaliy_Kiselev ask me to move this from another thread :(, wich is kind of a let down, but here it is

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    image The Personal View video mode!

    i have an idea, that came up to me from @balazer comment on the "MJPEG FPS setting for Timelapse on GH2" thread:

    "if you put the GH2 in burst mode with the burst rate set to SH, it shoots using the electronic shutter only - no mechanical shutter... ...Frames can be 4:3 or 3:2 with 4 megapixels, or 1920 x 1080. "

    so according to the manual, from factory we have 40fps at 1920*1080, but limited only to 1 second, so if @Vitaliy_Kiselev can hack the limit of the fps and the limit of the recording, we can have a new video mode that uses the full sensor, and can be played back in camera as a video (but at a lower framerate, and with no audio, and you would have to keep the still button press down during the entire recording),
    but it can be interesting, perhaps we can have more than 40fps :D, and at 4:3 it can be bigger than full HD, we can have an image up to 2336*1752 pixels, something like a 2.2k, and with an anamorphic adapter it will get wider :D

    according to the manual the frames on S mode have this size
    aspect ratio / size:
    4:3 /2336*1752
    3:2 /2400*1600
    16:9 / 1920*1080
    1:1 / 1744*1744

    The Personal View video mode!
    :D!

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    image_gl_gl 11:09AM

    @Iolo, +100, but I would want it for timelapses. That would give us 4k shots + lots of aspect options, without burning out the mechanical shutter (apparently the GH2's are only specced for 50,000 to 70,000 activations). And audio isn't needed for 'lapses anyway.

    I think removing the 1 second limit for high fps shooting won't work - the issue (especially with 4K) is how fast the frames can be written to the internal buffer & the memory card. But it would work perfectly for timelapses.

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    imagelolololo 11:20AM

    @_gl well, lets wait what the almighty has to say, but as you said using the electronic shooter for the M (7megapixels) and L (14 megapixels) would bring up other big oportunities, and let´s dream that it can be placed at 24 fps , that it is perhaps possible for a limited amount of time, we would have a pretty nice new video mode

    The Personal View video mode!!!
    :D!

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    image velociveloci 11:23AM

    @_gl but then we are limited by the lowest electronic shutter speed of 1/40th of a second, even then we have the issue of the current electronic shutter being not very good at certain light sources (e.g. point it at a LCD screen).

    However if it's hackable like you have described, I am all for it ;)

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    imagelolololo 11:47AM

    The Personal View video mode!

    let´s dream that Vitaliy can unlock the raw for the electronic shutter :D and make it at 24fps for more than a second :DDDDDD

    raw footage at full hd!

    i´m praying that the buffer can take it

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    image_gl_gl 12:26PM

    @veloci, true but maybe the shutter speeds can be hacked too. After all you can use much slower speeds in MF for video modes.

    @lolo, the 40fps mode doesn't support RAWs (the buffer would fill up too fast as they are much larger than JPGs).

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    imagelolololo 12:33PM

    @_gl i know, that´s why i said let´s dream, but also because 24fps is lower than the 40fps so maybe there is a chance as the buffer almost doubles the capacity available for each frame

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    imagelolololo 1:10PM

    The Personal View video mode!

    btw, according to the manual (page 76)
    "the burst mode speed may become slower depending on the following settings.
    sensitivity- page90
    picture size-page119
    quality-p120
    focus priority-page130
    focus mode"

    so this means that there has to be a sweet spot on the buffer in order for us to squeeze the maximum of it,

    but of course all of this proposal depends if this is actually a software limitation and not a hardware one

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    imagejohnnymjohnnym 1:22PM

    @lolo

    if you shoot sh burst, it's writing for 20 seconds to my Sandisk Extreme 30MB/s card, so i doubt if the length of shooting could be extended past 1 second.

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    imagelolololo 1:37PM

    @johnnym i have only a sd card slower than yours, the kingston 100x, are you saying that the 1 second limitation was caused by my slower card, are you sure you have 20 seconds at 40fps?

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    image_gl_gl 1:45PM ReportAwesome
    @lolo no what he's saying is that after 1sec recording has stopped, his card still takes 20 seconds to write out the data. In other words, the 1sec recording writes directly to an internal buffer, which then has to be flushed out to the card. So the limit is the size of the internal buffer and can't be changed.

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    imagelolololo 2:03PM

    well i have just counted the seconds,
    with manual focus it takes 8 seconds,
    with autofocus on it takes 16 seconds
    both with focus priority off

    quality doesnt seems to make any difference in writing time

    still, we have to see if lowering the fps from 40 to 24, has any big consecuence in the 1 second limitation

    because, this means that it is writing in the card as the buffer in the camera records the picture, so perhaps, if we are lucky, if we lower the fps the internal buffer will record at the same time that it writes in the sd

    but i don´t know, it is possible that panasonic aint squezzing all the buffer that this mode can take, i´m mean from the other options hacked we know that much at least, so

    still think is worth hacking

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    imagelolololo 2:25PM

    i´m mean even having raw, or a size bigger than HD with the electronic shutter is a huge improvement for the timelapse


    but if we can have raw footage in hd, or resolution bigger than HD for at least 15-20 seconds, i crap my pants, as that would be absolutely useful for narrative work

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    imagelolololo 4:18PM

    ok, i run a test to determine wich iso is the fastest in writing in burst, these are the results
    on a static test

    the fastest are:
    160-200-250-320 / first
    400-500-800 / second
    10000-12800 / third

    jpeg quality set to 2 increases consistenly in 1 second the time of writing needed more than jpeg quality set to 1

    The dial S (shutter priority) mode is in average 1 second slower in both jpeg´s qualities than the M (Manual) mode

    In S mode
    Iso / time in seconds for jpeg jpeg quality 2 / time in seconds for jpeg quality 1

    160-200-250-320 / 10 / 9
    400-500 / 10-11 / 9-10
    640 / 11 / 10
    800 / 10-11 / 9-10
    1000-1250-1600 / 11 / 10
    2000-2500 / 11-12 / 10-11
    3200-4000 / 12 / 10
    5000-6400-8000 / 12-11 / 11-10
    10000-12800 / 11 / 10

    I didn´t test the A mode.

    the camera was looking at the paintings in my room. manual focus, focus priority off

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    image_gl_gl 4:27PM

    @lolo very interesting. Speaking as a programmer, I'm surprised that higher ISO values are slower. I'm trying to figure out why that should be... [penny drops] actually it's probably due to the NR processing (higher ISO needs stronger NR).

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    imagelolololo 4:29PM

    ap it was shooted on vibrant and the noise reduction was set to -2

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    imagelolololo 4:32PM

    so, with no NR more buffer :D, so perhaps more real Personal View Video Mode (pvvm for the friends) :) if you are correct of course

    i´m praying jajajajajaj

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    imagelolololo 6:25PM

    i was thinking that perhaps the lens distortion correction in-camera may increase the time of writing so i will perform another test with the panasonic 14-140 and a canon fd to see if there is any diference

    the writing time should decrease if the camera uses the same buffer for this

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    image lolololo 8:42PM

    ok, so here are the results, seems like the lens distortion correction or other process of the pana lens does slow the burst:

    manual focus, focus priority off, Manual mode, burst

    static scene, at night with artificial light

    Iso / time in seconds for jpeg quality 2 / time in seconds for jpeg quality 1

    Panasonic 14-140:
    160 / 10 / 9
    400 / 10-11 / 9-10
    800 / 11 / 10
    1250 / 11 / 10
    3200 / 11-12 / 10
    10.000 / 11 / 11

    Canon FD (there is an average of 1 second less than the Panasonic)
    160 / 9 / 8
    400 / 10 / 8-9
    800 / 10 / 9
    1250 / 10-11 / 9
    3200 / 10-12 / 9-11
    10.000 / 10-11 / 9-10

    Body cap (i take this one also to see how much the difference is between a no detailed scene and a detailed one, and there is an average difference of 1 second less than the Canon FD)
    160 / 8 / 8
    400 / 8-9 / 8
    800 / 8-9 / 8
    1250 / 9 / 8
    3200 / 9-11 / 8-9
    10.000 / 10-11 / 9

    *interesting find
    the first burst inmediatly after the on of the camera doubles the time, the second burst has 1 second more than the average time of the chart above, and the third burst gets the right timing (this is at any iso)

    So the question raises, there is another process that can be shut down to have more available buffer space, therefore reducing the writing time needed?

    as _gl says there is the real noise reduction,

    but is there another setting already available than can reduce the time?
    lolo.png
    40 x 40 - 2K
    veloci.png
    40 x 40 - 2K
    _gl.png
    40 x 40 - 4K
    johnnym.png
    40 x 40 - 2K
  • If the 2MP burst mode could shoot continuously 40fps or 24fps that would be superb.
    I hope the speed won't vary though, which would be a problem if it were.
    But if the speed is stable, then it could be interesting to shoot anamorphic. I doubt whether the buffer could hold it though, without changing the resolution of these modes. But maybe even that could be possible? Like a 4:3 mode that is not 4MP but rather 1.5MP (1440x1080) or a 1:1 2MP mode (1440x1440) ? It would seriously enhance anamorphic shooting compared to the VGA video mode, if the speed is stable.
  • @rigs. Nope it's 4K at 40fps :-)
  • 11/13 update posted of latest media test

  • Hi All --- I posted this a while ago, but it was in a different topic and I never heard anyone expand upon it until I now, these tests could be of interest...

    2fps E-SHUTTER LIMIT

    I have been doing some tests using the electronic shutter in the still mode... which I know is not the main focus of the hack... however I have found some very interesting results that might spark the interest in terms of using it to shoot video.

    The manual shutter is slow... we know that. However the electronic shutter will shoot 2.3K images at 40fps in SH burst mode, but only for one second before it needs to buffer that info.

    I began to wonder... using a modified external controller instead of a shutter release, how many frames could fire through the camera consistently before the camera needs to buffer?

    I have come up with some interesting results...

    The still's manual shutter, when shooting a full 16 megapixel image will consistently do 1fps on a class 10 card with no buffer. At 2fps it will do 57 frames before skipping three frames to buffer and continue for another 57 frames, then buffer three etc... When you set the camera to burst mode using the H setting, the manual says it can do 4-7fps before "slowing down half way through".

    When you lower the size to a 2.3k image (there about, full JPEG 3.8 megapixel) it can take photos at 4fps, no problem, fully buffering as it goes, no lag time (at 6fps it skips frames so we'll say 4fps is its max at 2.3K).

    So if the manual shutter can perform at 4or 5fps consistently at 2.3K without slowing, this all makes one think that the electronic shutter could vastly outperform this.

    Wrong-- !

    The electronic shutter has a built in "cripple limit" at only 2fps!!! Half of what the manual shutter can do with ease!!

    This cripple is really disconcerting.. as I feel there is the possibility for the GH2 to perform in the SH burst mode at 24fps (taking single still images) with no buffer on a class 10 or higher card. Seeing how the camera is capable of taking 40 still photos in one second with one second to buffer after... theoretically at 20fps it may have enough time to buffer electronically in between stills and perhaps that could be pushed to 24fps.

    So....

    I would love to find out, if at all possible, if the 2fps electronic shutter burst mode limit could be removed.

    This limit's terminology pretty much states:

    "when consecutive (not held down burst) shooting is firing the camera, limit those pulses to only 2 stills per second".

    This is of course arbitrary, because the manual shutter will keep trying to take as many stills as it can physically keep up with no matter how many a second.

    In an interesting note, at 1fps the e-shutter is fine. At 2fps the e-shutter is fine. At 4fps the e-shutter skips exactly half the pictures (mathematically) and when you send 100 shots to the camera the number taken is only 50. This continues at 6fps, 8fps etc... the total shots taken only ever amount to 2fps which is how I know it is an imposed limit.

    With my present set up I would be able to test the camera's ability to take stills at 1/2/4/6/8/12/16 and 24fps and assemble the stills as a movie (standard procedure for animators). If I am correct and the camera can process 2.3K stills in 24 stills per second, we will have uncovered a new 2K imaging device... with the full range of JPEG settings available (not just video mode and bit rates... but still frames like a film camera!) Perhaps even the hack could rewrite the burst mode to take 24fps instead of 40fps and we'd have a built in mode for shooting those stills as frames.

    At the very least, if the camera could only produce a max of 18fps (stills per second) or 16fps, before buffering, then there is the possibility that with a simple timing device, the camera could offer multiple frames per second shooting... an option for fast motion, animation, timelapse.

    My request is to see if the 2 stills per second electronic shutter "cripple limit" in the SH still mode on the camera could be removed or modified via the firmware. I strongly feel this could be a breakthrough and would love the opportunity to explore and test this possibility.

    Thanks,

    Dbdaws

  • I'd love to see 4fps via the e-shutter for time lapses ala Magic Lantern.