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avcodec/fflcms2: add ff_icc_profile_sanitize

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Buggy ICCv4 profiles are unfortunately used in the wild, and it's quite
easy to work around them by just forcing the white point to the correct
value. Display a warning just in case.

See-Also: https://trac.ffmpeg.org/ticket/9673
This commit is contained in:
Niklas Haas 2023-09-27 11:48:01 +02:00
parent 22530ad1ce
commit beac4a999c
2 changed files with 58 additions and 0 deletions
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51
libavcodec/fflcms2.c
View File

@ -201,6 +201,57 @@ static av_always_inline void XYZ_xy(cmsCIEXYZ XYZ, AVCIExy *xy)
xy->y = av_d2q(k * XYZ.Y, 100000);
}
static av_always_inline AVRational abs_sub_q(AVRational r1, AVRational r2)
{
AVRational diff = av_sub_q(r1, r2);
/* denominator assumed to be positive */
return av_make_q(abs(diff.num), diff.den);
}
static const AVCIExy wp_d50 = { {3457, 10000}, {3585, 10000} }; /* CIE D50 */
int ff_icc_profile_sanitize(FFIccContext *s, cmsHPROFILE profile)
{
cmsCIEXYZ *white, fixed;
AVCIExy wpxy;
AVRational diff, z;
if (!profile)
return 0;
if (cmsGetEncodedICCversion(profile) >= 0x4000000) { // ICC v4
switch (cmsGetHeaderRenderingIntent(profile)) {
case INTENT_RELATIVE_COLORIMETRIC:
case INTENT_ABSOLUTE_COLORIMETRIC: ;
/* ICC v4 colorimetric profiles are specified to always use D50
* media white point, anything else is a violation of the spec.
* Sadly, such profiles are incredibly common (Apple...), so make
* an effort to fix them. */
if (!(white = cmsReadTag(profile, cmsSigMediaWhitePointTag)))
return AVERROR_INVALIDDATA;
XYZ_xy(*white, &wpxy);
diff = av_add_q(abs_sub_q(wpxy.x, wp_d50.x), abs_sub_q(wpxy.y, wp_d50.y));
if (av_cmp_q(diff, av_make_q(1, 1000)) > 0) {
av_log(s->avctx, AV_LOG_WARNING, "Invalid colorimetric ICCv4 "
"profile media white point tag (expected %.4f %.4f, "
"got %.4f %.4f)\n",
av_q2d(wp_d50.x), av_q2d(wp_d50.y),
av_q2d(wpxy.x), av_q2d(wpxy.y));
/* x+y+z = 1 */
z = av_sub_q(av_sub_q(av_make_q(1, 1), wp_d50.x), wp_d50.y);
fixed.X = av_q2d(av_div_q(wp_d50.x, wp_d50.y)) * white->Y;
fixed.Y = white->Y;
fixed.Z = av_q2d(av_div_q(z, wp_d50.y)) * white->Y;
if (!cmsWriteTag(profile, cmsSigMediaWhitePointTag, &fixed))
return AVERROR_EXTERNAL;
}
break;
default: break;
}
}
return 0;
}
int ff_icc_profile_read_primaries(FFIccContext *s, cmsHPROFILE profile,
AVColorPrimariesDesc *out_primaries)
{

7
libavcodec/fflcms2.h
View File

@ -65,6 +65,13 @@ int ff_icc_profile_generate(FFIccContext *s,
*/
int ff_icc_profile_attach(FFIccContext *s, cmsHPROFILE profile, AVFrame *frame);
/**
* Sanitize an ICC profile to try and fix badly broken values.
*
* Returns 0 on success, or a negative error code.
*/
int ff_icc_profile_sanitize(FFIccContext *s, cmsHPROFILE profile);
/**
* Read the color primaries and white point coefficients encoded by an ICC
* profile, and return the raw values in `out_primaries`.