Commit aee1838d for libheif

commit aee1838d5c757704f5bb4eb2d40bac516db95f11
Author: ojvasquez830 <oj.vasquez830@gmail.com>
Date:   Fri Aug 28 08:34:49 2026 -0700

    support 12, 14 and 16 bit monochrome in the FFmpeg decoder plugin

    ffmpeg_get_chroma_format() only mapped GRAY8 and GRAY10LE to
    heif_chroma_monochrome. Any monochrome frame above 10 bit fell through to the
    default branch and returned heif_chroma_undefined, so the decode failed with
    heif_error_Unsupported_feature / heif_suberror_Unsupported_color_conversion.

    get_ffmpeg_format_bpp(), directly below it in the same file, already handles
    GRAY12LE, GRAY14LE and GRAY16LE. The two switches simply disagreed.

    This also affects colour images: an alpha channel is stored as a separate
    monochrome item, so a 12 bit image with an alpha plane failed as well even
    though the image itself is not monochrome.

diff --git a/libheif/plugins/decoder_ffmpeg.cc b/libheif/plugins/decoder_ffmpeg.cc
index 0f7f05cb..3f5313be 100644
--- a/libheif/plugins/decoder_ffmpeg.cc
+++ b/libheif/plugins/decoder_ffmpeg.cc
@@ -339,6 +339,9 @@ static heif_chroma ffmpeg_get_chroma_format(AVPixelFormat pix_fmt) {
   switch (pix_fmt) {
     case AV_PIX_FMT_GRAY8:
     case AV_PIX_FMT_GRAY10LE:
+    case AV_PIX_FMT_GRAY12LE:
+    case AV_PIX_FMT_GRAY14LE:
+    case AV_PIX_FMT_GRAY16LE:
       return heif_chroma_monochrome;

     case AV_PIX_FMT_YUV420P: