Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

Remove burst-based chroma gain calculation #481

Merged
merged 8 commits into from
Apr 24, 2020
Merged

Remove burst-based chroma gain calculation #481

merged 8 commits into from
Apr 24, 2020

Commits on Apr 22, 2020

  1. Remove automatic chroma gain. 

    This is no longer necessary because ld-decode has MTF compensation and
produces reasonable chroma levels by default.

--chroma-gain now defaults to 1.0, and works for both PAL and NTSC.

As with the old PAL code, the NTSC YIQ to RGB conversion wasn't applying
an appropriate scaling factor to the IQ components. Poynton "Digital
Video and HDTV" 1st edition p514 says that the scaling factor is the
same as for Y -- i.e. when 7.5% setup is in use, the chroma range is
proportionately smaller.
    @atsampson
    atsampson committed Apr 22, 2020
    Configuration menu
    Copy the full SHA
    5107168 View commit details
    Browse the repository at this point in the history

  2. Have a "Chroma gain" slider rather than a "Black and white" checkbox.

    @atsampson
    atsampson committed Apr 22, 2020
    Configuration menu
    Copy the full SHA
    a37affa View commit details
    Browse the repository at this point in the history

  3. --blackandwhite just sets chroma gain to 0.

    @atsampson
    atsampson committed Apr 22, 2020
    Configuration menu
    Copy the full SHA
    1d922f3 View commit details
    Browse the repository at this point in the history

  4. More precise YIQ -> RGB matrix from Poynton. 

    As with PAL, we have about 5 s.f. in our samples, so the 6 s.f.
constants are worthwhile.
    @atsampson
    atsampson committed Apr 22, 2020
    Configuration menu
    Copy the full SHA
    82e7e81 View commit details
    Browse the repository at this point in the history

  5. Rename the PAL dialog to "Chroma Decoder Configuration". 

    No UI changes.
    @atsampson
    atsampson committed Apr 22, 2020
    Configuration menu
    Copy the full SHA
    7caea37 View commit details
    Browse the repository at this point in the history

  6. Add support for NTSC decoder settings. 

    No new UI yet, but ChromaDecoderConfigDialog now has both sets of
settings, the PAL widgets are disabled in NTSC mode, and the chroma gain
slider works for both.
    @atsampson
    atsampson committed Apr 22, 2020
    Configuration menu
    Copy the full SHA
    086f023 View commit details
    Browse the repository at this point in the history

  7. Rename whitePoint100 to whitePoint75. 

    It's true when white is at 75 IRE (and this matches the name of the same
option in the RGB class).
    @atsampson
    atsampson committed Apr 22, 2020
    Configuration menu
    Copy the full SHA
    c78a8ba View commit details
    Browse the repository at this point in the history

  8. Add UI for the most useful NTSC chroma settings.

    @atsampson
    atsampson committed Apr 22, 2020
    Configuration menu
    Copy the full SHA
    5be34ee View commit details
    Browse the repository at this point in the history