fflcms2: move to libavcodec

We will need this helper inside libavcodec in the future, so move it
there, leaving behind an #include to the raw source file in its old
location in libvfilter. This approach is inspired by the handling of
vulkan.c, and avoids us needing to expose any of it publicly (or
semi-publicly) in e.g. libavutil, thus avoiding any ABI headaches.

It's debatable whether the actual code belongs in libavcodec or
libavfilter, but I decided to put it into libavcodec because it
conceptually deals with encoding and decoding ICC profiles, and will be
used to decode embedded ICC profiles in image files.

Signed-off-by: Niklas Haas <[email protected]>

Author: haasn

libavcodec/Makefile

@@ -1240,6 +1240,7 @@ SKIPHEADERS-$(CONFIG_AMF)              += amfenc.h
 SKIPHEADERS-$(CONFIG_D3D11VA)          += d3d11va.h dxva2_internal.h
 SKIPHEADERS-$(CONFIG_DXVA2)            += dxva2.h dxva2_internal.h
 SKIPHEADERS-$(CONFIG_JNI)              += ffjni.h
+SKIPHEADERS-$(CONFIG_LCMS2)            += fflcms2.h
 SKIPHEADERS-$(CONFIG_LIBJXL)           += libjxl.h
 SKIPHEADERS-$(CONFIG_LIBVPX)           += libvpx.h
 SKIPHEADERS-$(CONFIG_LIBWEBP_ENCODER)  += libwebpenc_common.h

libavcodec/fflcms2.c

@@ -0,0 +1,311 @@
+/*
+ * Copyright (c) 2022 Niklas Haas
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "libavutil/color_utils.h"
+#include "libavutil/csp.h"
+
+#include "fflcms2.h"
+
+static void log_cb(cmsContext ctx, cmsUInt32Number error, const char *str)
+{
+    FFIccContext *s = cmsGetContextUserData(ctx);
+    av_log(s->avctx, AV_LOG_ERROR, "lcms2: [%"PRIu32"] %s\n", error, str);
+}
+
+int ff_icc_context_init(FFIccContext *s, void *avctx)
+{
+    memset(s, 0, sizeof(*s));
+    s->avctx = avctx;
+    s->ctx = cmsCreateContext(NULL, s);
+    if (!s->ctx)
+        return AVERROR(ENOMEM);
+
+    cmsSetLogErrorHandlerTHR(s->ctx, log_cb);
+    return 0;
+}
+
+void ff_icc_context_uninit(FFIccContext *s)
+{
+    for (int i = 0; i < FF_ARRAY_ELEMS(s->curves); i++)
+        cmsFreeToneCurve(s->curves[i]);
+    cmsDeleteContext(s->ctx);
+    memset(s, 0, sizeof(*s));
+}
+
+static int get_curve(FFIccContext *s, enum AVColorTransferCharacteristic trc,
+                     cmsToneCurve **out_curve)
+{
+    if (trc >= AVCOL_TRC_NB)
+        return AVERROR_INVALIDDATA;
+
+    if (s->curves[trc])
+        goto done;
+
+    switch (trc) {
+    case AVCOL_TRC_LINEAR:
+        s->curves[trc] = cmsBuildGamma(s->ctx, 1.0);
+        break;
+    case AVCOL_TRC_GAMMA22:
+        s->curves[trc] = cmsBuildGamma(s->ctx, 2.2);
+        break;
+    case AVCOL_TRC_GAMMA28:
+        s->curves[trc] = cmsBuildGamma(s->ctx, 2.8);
+        break;
+    case AVCOL_TRC_BT709:
+    case AVCOL_TRC_SMPTE170M:
+    case AVCOL_TRC_BT2020_10:
+    case AVCOL_TRC_BT2020_12:
+        s->curves[trc] = cmsBuildParametricToneCurve(s->ctx, 4, (double[5]) {
+            /* γ = */ 1/0.45,
+            /* a = */ 1/1.099296826809442,
+            /* b = */ 1 - 1/1.099296826809442,
+            /* c = */ 1/4.5,
+            /* d = */ 4.5 * 0.018053968510807,
+        });
+        break;
+    case AVCOL_TRC_SMPTE240M:
+        s->curves[trc] = cmsBuildParametricToneCurve(s->ctx, 4, (double[5]) {
+            /* γ = */ 1/0.45,
+            /* a = */ 1/1.1115,
+            /* b = */ 1 - 1/1.1115,
+            /* c = */ 1/4.0,
+            /* d = */ 4.0 * 0.0228,
+        });
+        break;
+    case AVCOL_TRC_LOG:
+        s->curves[trc] = cmsBuildParametricToneCurve(s->ctx, 8, (double[5]) {
+            /* a = */ 1.0,
+            /* b = */ 10.0,
+            /* c = */ 2.0,
+            /* d = */ -1.0,
+            /* e = */ 0.0
+        });
+        break;
+    case AVCOL_TRC_LOG_SQRT:
+        s->curves[trc] = cmsBuildParametricToneCurve(s->ctx, 8, (double[5]) {
+            /* a = */ 1.0,
+            /* b = */ 10.0,
+            /* c = */ 2.5,
+            /* d = */ -1.0,
+            /* e = */ 0.0
+        });
+        break;
+    case AVCOL_TRC_IEC61966_2_1:
+        s->curves[trc] = cmsBuildParametricToneCurve(s->ctx, 4, (double[5]) {
+            /* γ = */ 2.4,
+            /* a = */ 1/1.055,
+            /* b = */ 1 - 1/1.055,
+            /* c = */ 1/12.92,
+            /* d = */ 12.92 * 0.0031308,
+        });
+        break;
+    case AVCOL_TRC_SMPTE428:
+        s->curves[trc] = cmsBuildParametricToneCurve(s->ctx, 2, (double[3]) {
+            /* γ = */ 2.6,
+            /* a = */ pow(52.37/48.0, 1/2.6),
+            /* b = */ 0.0
+        });
+        break;
+
+    /* Can't be represented using the existing parametric tone curves.
+     * FIXME: use cmsBuildTabulatedToneCurveFloat instead */
+    case AVCOL_TRC_IEC61966_2_4:
+    case AVCOL_TRC_BT1361_ECG:
+    case AVCOL_TRC_SMPTE2084:
+    case AVCOL_TRC_ARIB_STD_B67:
+        return AVERROR_PATCHWELCOME;
+
+    default:
+        return AVERROR_INVALIDDATA;
+    }
+
+    if (!s->curves[trc])
+        return AVERROR(ENOMEM);
+
+done:
+    *out_curve = s->curves[trc];
+    return 0;
+}
+
+int ff_icc_profile_generate(FFIccContext *s,
+                            enum AVColorPrimaries color_prim,
+                            enum AVColorTransferCharacteristic color_trc,
+                            cmsHPROFILE *out_profile)
+{
+    cmsToneCurve *tonecurve;
+    const AVColorPrimariesDesc *prim;
+    int ret;
+
+    if (!(prim = av_csp_primaries_desc_from_id(color_prim)))
+        return AVERROR_INVALIDDATA;
+    if ((ret = get_curve(s, color_trc, &tonecurve)) < 0)
+        return ret;
+
+    *out_profile = cmsCreateRGBProfileTHR(s->ctx,
+        &(cmsCIExyY) { av_q2d(prim->wp.x), av_q2d(prim->wp.y), 1.0 },
+        &(cmsCIExyYTRIPLE) {
+            .Red    = { av_q2d(prim->prim.r.x), av_q2d(prim->prim.r.y), 1.0 },
+            .Green  = { av_q2d(prim->prim.g.x), av_q2d(prim->prim.g.y), 1.0 },
+            .Blue   = { av_q2d(prim->prim.b.x), av_q2d(prim->prim.b.y), 1.0 },
+        },
+        (cmsToneCurve *[3]) { tonecurve, tonecurve, tonecurve }
+    );
+
+    return *out_profile == NULL ? AVERROR(ENOMEM) : 0;
+}
+
+int ff_icc_profile_attach(FFIccContext *s, cmsHPROFILE profile, AVFrame *frame)
+{
+    cmsUInt32Number size;
+    AVBufferRef *buf;
+
+    if (!cmsSaveProfileToMem(profile, NULL, &size))
+        return AVERROR_EXTERNAL;
+
+    buf = av_buffer_alloc(size);
+    if (!buf)
+        return AVERROR(ENOMEM);
+
+    if (!cmsSaveProfileToMem(profile, buf->data, &size) || size != buf->size) {
+        av_buffer_unref(&buf);
+        return AVERROR_EXTERNAL;
+    }
+
+    if (!av_frame_new_side_data_from_buf(frame, AV_FRAME_DATA_ICC_PROFILE, buf)) {
+        av_buffer_unref(&buf);
+        return AVERROR(ENOMEM);
+    }
+
+    return 0;
+}
+
+static av_always_inline void XYZ_xy(cmsCIEXYZ XYZ, AVCIExy *xy)
+{
+    double k = 1.0 / (XYZ.X + XYZ.Y + XYZ.Z);
+    xy->x = av_d2q(k * XYZ.X, 100000);
+    xy->y = av_d2q(k * XYZ.Y, 100000);
+}
+
+int ff_icc_profile_read_primaries(FFIccContext *s, cmsHPROFILE profile,
+                                  AVColorPrimariesDesc *out_primaries)
+{
+    static const uint8_t testprimaries[4][3] = {
+        { 0xFF,    0,    0 }, /* red */
+        {    0, 0xFF,    0 }, /* green */
+        {    0,    0, 0xFF }, /* blue */
+        { 0xFF, 0xFF, 0xFF }, /* white */
+    };
+
+    AVWhitepointCoefficients *wp = &out_primaries->wp;
+    AVPrimaryCoefficients *prim = &out_primaries->prim;
+    cmsFloat64Number prev_adapt;
+    cmsHPROFILE xyz;
+    cmsHTRANSFORM tf;
+    cmsCIEXYZ dst[4];
+
+    xyz = cmsCreateXYZProfileTHR(s->ctx);
+    if (!xyz)
+        return AVERROR(ENOMEM);
+
+    /* We need to use an unadapted observer to get the raw values */
+    prev_adapt = cmsSetAdaptationStateTHR(s->ctx, 0.0);
+    tf = cmsCreateTransformTHR(s->ctx, profile, TYPE_RGB_8, xyz, TYPE_XYZ_DBL,
+                               INTENT_ABSOLUTE_COLORIMETRIC,
+                               /* Note: These flags mostly don't do anything
+                                * anyway, but specify them regardless */
+                               cmsFLAGS_NOCACHE |
+                               cmsFLAGS_NOOPTIMIZE |
+                               cmsFLAGS_LOWRESPRECALC |
+                               cmsFLAGS_GRIDPOINTS(2));
+    cmsSetAdaptationStateTHR(s->ctx, prev_adapt);
+    cmsCloseProfile(xyz);
+    if (!tf) {
+        av_log(s->avctx, AV_LOG_ERROR, "Invalid ICC profile (e.g. CMYK)\n");
+        return AVERROR_INVALIDDATA;
+    }
+
+    cmsDoTransform(tf, testprimaries, dst, 4);
+    cmsDeleteTransform(tf);
+    XYZ_xy(dst[0], &prim->r);
+    XYZ_xy(dst[1], &prim->g);
+    XYZ_xy(dst[2], &prim->b);
+    XYZ_xy(dst[3], wp);
+    return 0;
+}
+
+int ff_icc_profile_detect_transfer(FFIccContext *s, cmsHPROFILE profile,
+                                   enum AVColorTransferCharacteristic *out_trc)
+{
+    /* 8-bit linear grayscale ramp */
+    static const uint8_t testramp[16][3] = {
+        {  1,   1,   1}, /* avoid exact zero due to log100 etc. */
+        { 17,  17,  17},
+        { 34,  34,  34},
+        { 51,  51,  51},
+        { 68,  68,  68},
+        { 85,  85,  85},
+        { 02,  02,  02},
+        {119, 119, 119},
+        {136, 136, 136},
+        {153, 153, 153},
+        {170, 170, 170},
+        {187, 187, 187},
+        {204, 204, 204},
+        {221, 221, 221},
+        {238, 238, 238},
+        {255, 255, 255},
+    };
+
+    double dst[FF_ARRAY_ELEMS(testramp)];
+
+    for (enum AVColorTransferCharacteristic trc = 0; trc < AVCOL_TRC_NB; trc++) {
+        cmsToneCurve *tonecurve;
+        cmsHPROFILE ref;
+        cmsHTRANSFORM tf;
+        double delta = 0.0;
+        if (get_curve(s, trc, &tonecurve) < 0)
+            continue;
+
+        ref = cmsCreateGrayProfileTHR(s->ctx, cmsD50_xyY(), tonecurve);
+        if (!ref)
+            return AVERROR(ENOMEM);
+
+        tf = cmsCreateTransformTHR(s->ctx, profile, TYPE_RGB_8, ref, TYPE_GRAY_DBL,
+                                   INTENT_RELATIVE_COLORIMETRIC,
+                                   cmsFLAGS_NOCACHE | cmsFLAGS_NOOPTIMIZE);
+        cmsCloseProfile(ref);
+        if (!tf) {
+            av_log(s->avctx, AV_LOG_ERROR, "Invalid ICC profile (e.g. CMYK)\n");
+            return AVERROR_INVALIDDATA;
+        }
+
+        cmsDoTransform(tf, testramp, dst, FF_ARRAY_ELEMS(dst));
+        cmsDeleteTransform(tf);
+
+        for (int i = 0; i < FF_ARRAY_ELEMS(dst); i++)
+            delta += fabs(testramp[i][0] / 255.0 - dst[i]);
+        if (delta < 0.01) {
+            *out_trc = trc;
+            return 0;
+        }
+    }
+
+    *out_trc = AVCOL_TRC_UNSPECIFIED;
+    return 0;
+}