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ST: MJPEG Encoder team
  • 36 Replies sorted by
  • LPowellLPowell
    @Vitaliy_Kiselev "AF has very strong AA filter placed before high resolution sensor."

    Good point, however, I found the BBC's AF100 resolution charts unexpectedly revealing. In a camera with an effective OLPF, you'll see the outer concentric circles in the zone plate resolution charts blur into gray as they become more detailed than the camera's optical resolution. With the AF100's charts, however, instead of blurring, what I saw were sharply defined aliasing patterns, artifacts that were produced by ultra-fine details beyond 1080p. The 750-line rated resolution was actually the point where the amount of aliased details began to exceed the genuine details in the image.

    http://thebrownings.name/WHP034/pdf/WHP034-ADD66_rev_2_Panasonic_AF101.pdf

    The conclusion I drew was that the AF100 has a weaker than expected OLPF designed to pass considerable image detail in the region between 1080-1400 lines of resolution. This ultra-fine image detail generates aliasing artifacts that are reflected down into the 750-1080 line region, producing artificially enhanced high resolution image details. With the test charts, it was easy to identify the details beyond 750 lines as aliasing artifacts, simply because I knew what the chart was supposed to look like and the alias patterns were recognizably different. With a real-life image, it would not be so easy to distinguish real detail from high-resolution artifact detail.
  • LPowellLPowell
    Here are 100Mbps MJPEG settings optimized for native anamorphic shooting with both 1.33X adapters in HD video mode, as well as 2X adapters in VGA video mode. Used with an appropriate anamorphic lens, these MJPEG modes will produce videos that are automatically played back at the correct widescreen aspect ratio, without need for post-production stretching:

    HD mode: 1920x810 videos for 1.33X anamorphic adapters, with peak bitrates of 100Mbps.
    VGA mode: 2160x810 videos for 2X anamorphic adapters, with peak bitrates of 100Mbps.

    Note that the 2160x810 VGA mode produces an aspect ratio of 2.66:1. For a 2.37:1 aspect ratio, you'll want to crop these videos to a 1920x810 frame size.
    100Mbps GH2 MJPEG Low-Light Anamorphic Patch.zip
    469B
  • kikiskikis
    @lpowell

    does this patch work with the GH1 also? in particular for the 2160x810 VGA settings, can that be achieved with the GH1 or is it limited only to the GH2?
  • LPowellLPowell
    No, the GH2 MJPEG encoder behaves quite differently than the GH1. The GH2 can easily handle a 100Mbps MJPEG bitrate without any reliability issues. The GH1 will need patches that work at lower bitrates.
  • kikiskikis
    @lpowell

    Ok, I understand. Is the size of 2160x810 achievable for GH1 with PTool 3.62d though?
  • LPowellLPowell
    I think there's a good chance 2160x810 will work on the GH1, though it may need some tweaking. I'll likely have time to test it early this week.
  • LPowellLPowell
    @kikis
    I tested PTool 3.62d GH1 MJPEG patches, and frame sizes wider than 1920x1080 can be used only on patches for the GH2.
  • Vitaliy_KiselevVitaliy_Kiselev
    @LPowell

    I'll try to port them to other cameras in next versions.

    @LPowell

    Can you make some excel table looking at compression of individual block, not whole frame.
    So, we could make bitrate setting that won't be dependent fo resolution selected.
  • humpmanhumpman

    After testing gf1 mjpeg, i found that 1280x720 mjpeg is upscaled too, i think from real native 848x480, which come from older panasonic cameras. After lowering resolution in ptool to 848x480, table settings works fine with 1 or even with 0, without dropped pixels, quality settings must be around 300-400, with, for example 200, there will be dropped pixels.

  • humpmanhumpman

    After upscaling on comp it looks a little better, but pity that gf1 is not hd camera at all..

    P1110518.JPG
    848 x 480 - 522K
  • invievinviev

    what's your GF2 settings? I could do 2048x854 25p with the quality and table settings of the T9 on a SanDisk 45mbs card. Bitrate was about 88mbps

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