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Official Low GOP topic, series 4
  • 586 Replies sorted by
  • OedipaxOedipax

    @LPowell, don't forget the global shutter hack ;)

  • driftwooddriftwood

    If I did a long gop patch.... A new theory for Long GOP fans in patch vault. ;-)

  • proaudio4proaudio4

    Thank you Nick!

  • plasmasmpplasmasmp

    I'm sure you'll get 4:2:2!

    On the hacked GH4

  • bkmcwdbkmcwd

    @driftwood Your new theory is very interesting. Thanks Nick! :-)

  • duartixduartix

    Hei!

    Won't we be needing an "Official High GOP topic" now? :)

  • fatpigfatpig

    @Rszanto: if you want to have your look even more not-DSLR-like, you should definitely use a 180 degree shutter, which would be 1/50th for most cases. reduces the "stuttering", also.

  • driftwooddriftwood

    @bkmcwd Yeah, have a play with the settings see what works under 3 GOP... You never know it might work out.., let me know mate.

    LOL @duartix ! Actually, Its pretty good at 720p60 that patch... may incorporate a final version of its kind in a version of Quantum ... I'd like you to test it further - maybe play with the settings a bit more? Thanks mate.

  • cpliu60cpliu60

    Just run a quick recording on 'XDCAM' patch indoor, total 11 mins were recorded consum around 1.3G SD card. The video quality seems no visible change in such low bit rate when compare with Q100 patch IMHO, kind of strange feeling myself >"< ...

  • onionbrainonionbrain

    @driftwood

    I just tested the XDCAM patch -- primarily for image quality (viewed on a calibrated production monitor), and I'll react to that after throwing a thought at you.

    A few days back I wrote a long request complete with reasoning requesting a replica of AVCCAM (Panasonic's "professional implementation of the AVC/H.264 codec") except with the bitrate multiplied by three -- meaning a stable bitrate between 63 and 72 Mbps. In the unimaginative and conservative broadcast world this could be considered the rough equivalent of 144 Mbps intraframe, yet would capitalize on the efficiency of LongGOP. In theory, the above replicated AVCCAM multiplied by 3 would trounce the new Nikon codec "with B frames," beat the XF codec (yes, it's not 4:2:2, but 4:2:2 doesn't mean the same thing it meant four years ago now that editors (NLE's) are ingesting, correcting, and editing at 12 bit 4:4:4), vaguely be equivalent in image quality to the new Canon "All-I," and trounce many varieties of XDCAM.

    I decided to sit on the above request to see what the new Ptools brings and the new patches.

    SO -- when I saw this XDCAM patch -- I was very, very intrigued. In theory, I'm convinced the winning formula for the hacked GH2 is a high bitrate LongGOP -- that capitalizes on the efficiency of LongGOP while reducing compression. For example, in theory, a 100 Mbps LongGOP is equivalent to a 200 Mbps intraframe stream.

    So -- if any of the above makes any sense to anyone -- I'm grateful if you pros will think about it. The key to the above is that AVCCAM is replicated as closely as possible (don't lower the GOPs) and that the bitrate remains relatively constant.

    OK -- regarding the XDCAM patch... the first thing that screamed out at me when I looked at the files in the folder was the extremely low bitrates. Most of these files were coming in around the 17 Mbps range.

    Image quality was good, on par with a stock GH2, and there was, essentially, no banding in blue skies. There was, however, blocky noise in the blue skies.

    In some shots image detail was very, very good. It handled motion perfectly well.

    So, it didn't look like a 17 Mpbs stream, but it also didn't look like a 50Mbps stream. Frankly, the not-joke here is that it looked like a 35 Mbps EXDCAM EX stream, except with elements of mpeg-4 detail.

  • LPowellLPowell

    @onionbrain - "They key to the above is that AVCCAM is replicated as closely as possible and that the bitrate remains relatively constant."

    Sorry, but there's nothing special about AVCCAM, it's just an early version of AVCHD that Panasonic chose to implement in their pro video cameras. A constant bitrate is useful for broadcast and streaming media, but offers no technical advantages in video capture applications. Long-GOP formats are likewise effective for commercial delivery formats such as DVD and Blu-ray, but are not optimal for real-time encoders with constrained resources and time frames.

  • driftwooddriftwood

    @onionbrain There will be a higher bitrate version of the XDCAM implementation later which could be what you need. I'll take a look at the old AVCCAM standard but Lee is right, its nothing special. However, its nice to try and emulate different codecs using the GH2. I'll give it a shot as it won't take long.

  • redbaronredbaron

    Here's some footage, from a creative commons gathering, shot with Quantum 9b all around 1250 ISO at night and indoors. A little grading with ColorGHear:

  • spacewigspacewig

    Nice @redbaron

    The image is virtually noise free. Did you post remove noise with ColorGhear or Neat Video (or other)?

  • daisukedaisuke

    Please say you used a denoiser, my iso 160 doesn't even look this clean.

  • ahblezaahbleza

    I just ran a test using Driftwood's XDCAM 50Mbps on a GH2 with manual lens (Voigtlander) and Sandisk 8 MB class 10 (30 Mbps.)

    First two recordings worked, but the third one locked up the camera with the usual message, requiring battery removal. I'll do some more tests, as I liked the look of the footage.

  • driftwooddriftwood

    @ahbleza Don't forget 720p mode under stock settings is restricted to an i frame/p frame GOP whereas 1080p and 1080i isn't. This means Panasonic couldn't get 720p mode to work reliably straight out of the camera (switch on/hit record 720) using an i/p/b frame GOP configuration - or they felt it unneccesary (who knows).

    The XDCAM patch brings b frames to 720p modes but you can't hit Record straight out after a switch on. However, the workaround is to first record a second or two of 1080i or 1080p and then STOP, switch to 720 mode and record fine.

  • ahblezaahbleza

    @driftwood Thanks for the tips. Here's some video I shot before it crashed:

    Next, I have a comparison showing video shot with 720p mode using the Voigtlander 0.95 25mm, followed by the same scene with the Olympus Zuiko f2.0 zoom @ 25mm. I'll post those too -- no sign of a crash with this so far.

  • proaudio4proaudio4

    Yes, @redbaron please let us know how you managed to get this 1250 ISO footage so damn clean?

  • TifoseTifose

    @driftwood , next week i will be shooting a Short Movie and i would like to know whats the best Patch for Film like Look?

    whats the best Patch for Movie or Film look?

  • driftwooddriftwood

    SeAQuake, Quantum 7 or Quantum 9b. Theyre all similar but 9b should be good to go.

  • TifoseTifose

    thanks will post the film when finish

  • sebbensebben

    @driftwood Was shooting on location today - Quantum 100, 32gb extreme hd video 30mbs, under florescent lighting so had to shoot 1080 50i because of flicker. Using manual focus lenses.

    Crashed twice when I had the audio levels displayed on the screen, worked alright for most of the day after I switched them off, crashed once more.

    First time this has happened to me whilst using Quantum 100, but I have been using 24p mostly before this.

  • redbaronredbaron

    @spacewig @daisuke @proaudio4 Yes, I did use the grainkiller. Here is a before and after color grade:

    BEFORE

    image

    AFTER

    image

  • spacewigspacewig

    Your footage still looks relatively clean before processing. Perhaps the sensor in your camera behaves better than average. At any rate, good job!

    Cheers

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