test: add tests for zimg RGB repacking

This tests the RGB repacker code in zimg, which deserves to be tested
because it's tricky and there will be more formats.

scale_test.c contains some code that can be used to test any scaler. Or
at least that would be great; currently it can only test repacking of
some byte-aligned-component RGB formats. It should be called
repack_test.c, but I'm too lazy to change the filename now.

The idea is that libswscale is used to cross-check the conversions
performed by the zimg wrapper. This is why it's "OK" that scale_test.c
does libswscale calls.

scale_sws.c is the equivalent to scale_zimg.c, and is of course
worthless (because it tests libswscale by comparing the results with
libswscale), but still might help with finding bugs in scale_test.c.

This borrows a sorted list of image formats from test/img_format.c, for
the same reason that file sorts them.

There's a slight possibility that this can be used to test vo_gpu.c too
some times in the future.

test/img_format.c

@@ -7,8 +7,9 @@
 #include "video/mp_image.h"
 #include "video/sws_utils.h"
 
-static int imgfmts[IMGFMT_AVPIXFMT_END - IMGFMT_AVPIXFMT_START + 100];
-static int num_imgfmts;
+int imgfmts[IMGFMT_AVPIXFMT_END - IMGFMT_AVPIXFMT_START + 100];
+int num_imgfmts;
+
 static enum AVPixelFormat pixfmt_unsup[100];
 static int num_pixfmt_unsup;
 static bool imgfmts_initialized;
@@ -21,7 +22,7 @@ static int cmp_imgfmt_name(const void *a, const void *b)
     return strcmp(name_a, name_b);
 }
 
-static void find_all_imgfmts(void)
+void init_imgfmts_list(void)
 {
     if (imgfmts_initialized)
         return;
@@ -61,7 +62,7 @@ static const char *comp_type(enum mp_component_type type)
 
 static void run(struct test_ctx *ctx)
 {
-    find_all_imgfmts();
+    init_imgfmts_list();
 
     FILE *f = test_open_out(ctx, "img_formats.txt");
 

test/ref/repack_sws.log

@@ -0,0 +1,18 @@
+0bgr using gbrp
+0rgb using gbrp
+abgr using gbrap
+argb using gbrap
+bgr0 using gbrp
+bgr24 using gbrp
+bgr48 using gbrp16
+bgr48be using gbrp16
+bgra using gbrap
+bgra64 using gbrap16
+bgra64be using gbrap16
+rgb0 using gbrp
+rgb24 using gbrp
+rgb48 using gbrp16
+rgb48be using gbrp16
+rgba using gbrap
+rgba64 using gbrap16
+rgba64be using gbrap16

test/ref/repack_zimg.log

@@ -0,0 +1,8 @@
+0bgr using gbrp
+0rgb using gbrp
+bgr0 using gbrp
+bgr24 using gbrp
+bgr48 using gbrp16
+rgb0 using gbrp
+rgb24 using gbrp
+rgb48 using gbrp16

test/scale_sws.c

@@ -0,0 +1,45 @@
+// Test scaling using libswscale.
+// Note: libswscale is already tested in FFmpeg. This code serves mostly to test
+//       the functionality scale_test.h using the already tested libswscale as
+//       reference.
+
+#include "scale_test.h"
+#include "video/sws_utils.h"
+
+static bool scale(void *pctx, struct mp_image *dst, struct mp_image *src)
+{
+    struct mp_sws_context *ctx = pctx;
+    return mp_sws_scale(ctx, dst, src) >= 0;
+}
+
+static bool supports_fmts(void *pctx, int imgfmt_dst, int imgfmt_src)
+{
+    struct mp_sws_context *ctx = pctx;
+    return mp_sws_supports_formats(ctx, imgfmt_dst, imgfmt_src);
+}
+
+static const struct scale_test_fns fns = {
+    .scale = scale,
+    .supports_fmts = supports_fmts,
+};
+
+static void run(struct test_ctx *ctx)
+{
+    struct mp_sws_context *sws = mp_sws_alloc(NULL);
+
+    struct scale_test *stest = talloc_zero(NULL, struct scale_test);
+    stest->fns = &fns;
+    stest->fns_priv = sws;
+    stest->test_name = "repack_sws";
+    stest->ctx = ctx;
+
+    repack_test_run(stest);
+
+    talloc_free(stest);
+    talloc_free(sws);
+}
+
+const struct unittest test_repack_sws = {
+    .name = "repack_sws",
+    .run = run,
+};

test/scale_test.c

@@ -0,0 +1,190 @@
+#include <libavcodec/avcodec.h>
+
+#include "scale_test.h"
+#include "video/image_writer.h"
+#include "video/sws_utils.h"
+
+static struct mp_image *gen_repack_test_img(int w, int h, int bytes, bool rgb,
+                                            bool alpha)
+{
+    struct mp_regular_imgfmt planar_desc = {
+        .component_type = MP_COMPONENT_TYPE_UINT,
+        .component_size = bytes,
+        .forced_csp = rgb ? MP_CSP_RGB : 0,
+        .num_planes = alpha ? 4 : 3,
+        .planes = {
+            {1, {rgb ? 2 : 1}},
+            {1, {rgb ? 3 : 2}},
+            {1, {rgb ? 1 : 3}},
+            {1, {4}},
+        },
+        .chroma_w = 1,
+        .chroma_h = 1,
+    };
+    int mpfmt = mp_find_regular_imgfmt(&planar_desc);
+    assert(mpfmt);
+    struct mp_image *mpi = mp_image_alloc(mpfmt, w, h);
+    assert(mpi);
+
+    // Well, I have no idea what makes a good test image. So here's some crap.
+    // This contains bars/tiles of solid colors. For each of R/G/B, it toggles
+    // though 0/100% range, so 2*2*2 = 8 combinations (16 with alpha).
+    int b_h = 16, b_w = 16;
+
+    for (int y = 0; y < h; y++) {
+        for (int p = 0; p < mpi->num_planes; p++) {
+            void *line = mpi->planes[p] + mpi->stride[p] * (ptrdiff_t)y;
+
+            for (int x = 0; x < w; x += b_w) {
+                unsigned i = x / b_w + y / b_h * 2;
+                int c = ((i >> p) & 1);
+                if (bytes == 1) {
+                    c *= (1 << 8) - 1;
+                    for (int xs = x; xs < x + b_w; xs++)
+                        ((uint8_t *)line)[xs] = c;
+                } else if (bytes == 2) {
+                    c *= (1 << 16) - 1;
+                    for (int xs = x; xs < x + b_w; xs++)
+                        ((uint16_t *)line)[xs] = c;
+                }
+            }
+        }
+    }
+
+    return mpi;
+}
+
+static void dump_image(struct scale_test *stest, const char *name,
+                       struct mp_image *img)
+{
+    char *path = mp_tprintf(4096, "%s/%s.png", stest->ctx->out_path, name);
+
+    struct image_writer_opts opts = image_writer_opts_defaults;
+    opts.format = AV_CODEC_ID_PNG;
+
+    if (!write_image(img, &opts, path, stest->ctx->global, stest->ctx->log)) {
+        MP_FATAL(stest->ctx, "Failed to write '%s'.\n", path);
+        abort();
+    }
+}
+
+// Compare 2 images (same format and size) for exact pixel data match.
+// Does generally not work with formats that include undefined padding.
+// Does not work with non-byte aligned formats.
+static void assert_imgs_equal(struct scale_test *stest, FILE *f,
+                              struct mp_image *ref, struct mp_image *new)
+{
+    assert(ref->imgfmt == new->imgfmt);
+    assert(ref->w == new->w);
+    assert(ref->h == new->h);
+
+    assert(ref->fmt.flags & MP_IMGFLAG_BYTE_ALIGNED);
+    assert(ref->fmt.bytes[0]);
+
+    for (int p = 0; p < ref->num_planes; p++) {
+        for (int y = 0; y < ref->h; y++) {
+            void *line_r = ref->planes[p] + ref->stride[p] * (ptrdiff_t)y;
+            void *line_o = new->planes[p] + new->stride[p] * (ptrdiff_t)y;
+            size_t size = ref->fmt.bytes[p] * (size_t)new->w;
+
+            bool ok = memcmp(line_r, line_o, size) == 0;
+            if (!ok) {
+                stest->fail += 1;
+                char *fn_a = mp_tprintf(80, "img%d_ref", stest->fail);
+                char *fn_b = mp_tprintf(80, "img%d_new", stest->fail);
+                fprintf(f, "Images mismatching, dumping to %s/%s\n", fn_a, fn_b);
+                dump_image(stest, fn_a, ref);
+                dump_image(stest, fn_b, new);
+                return;
+            }
+        }
+    }
+}
+
+void repack_test_run(struct scale_test *stest)
+{
+    char *logname = mp_tprintf(80, "%s.log", stest->test_name);
+    FILE *f = test_open_out(stest->ctx, logname);
+
+    if (!stest->sws) {
+        init_imgfmts_list();
+
+        stest->sws = mp_sws_alloc(stest);
+
+        stest->img_repack_rgb8 = gen_repack_test_img(256, 128, 1, true, false);
+        stest->img_repack_rgba8 = gen_repack_test_img(256, 128, 1, true, true);
+        stest->img_repack_rgb16 = gen_repack_test_img(256, 128, 2, true, false);
+        stest->img_repack_rgba16 = gen_repack_test_img(256, 128, 2, true, true);
+
+        talloc_steal(stest, stest->img_repack_rgb8);
+        talloc_steal(stest, stest->img_repack_rgba8);
+        talloc_steal(stest, stest->img_repack_rgb16);
+        talloc_steal(stest, stest->img_repack_rgba16);
+    }
+
+    for (int a = 0; a < num_imgfmts; a++) {
+        int mpfmt = imgfmts[a];
+        struct mp_imgfmt_desc fmtdesc = mp_imgfmt_get_desc(mpfmt);
+        if (!fmtdesc.id || !(fmtdesc.flags & MP_IMGFLAG_RGB) ||
+            !fmtdesc.component_bits || (fmtdesc.component_bits % 8) ||
+            fmtdesc.num_planes > 1)
+            continue;
+
+        struct mp_image *test_img = NULL;
+        bool alpha = fmtdesc.flags & MP_IMGFLAG_ALPHA;
+        bool hidepth = fmtdesc.component_bits > 8;
+        if (alpha) {
+            test_img = hidepth ? stest->img_repack_rgba16 : stest->img_repack_rgba8;
+        } else {
+            test_img = hidepth ? stest->img_repack_rgb16 : stest->img_repack_rgb8;
+        }
+
+        if (test_img->imgfmt == mpfmt)
+            continue;
+
+        if (!stest->fns->supports_fmts(stest->fns_priv, mpfmt, test_img->imgfmt))
+            continue;
+
+        if (!mp_sws_supports_formats(stest->sws, mpfmt, test_img->imgfmt))
+            continue;
+
+        fprintf(f, "%s using %s\n", mp_imgfmt_to_name(mpfmt),
+                mp_imgfmt_to_name(test_img->imgfmt));
+
+        struct mp_image *dst = mp_image_alloc(mpfmt, test_img->w, test_img->h);
+        assert(dst);
+
+        // This tests packing.
+        bool ok = stest->fns->scale(stest->fns_priv, dst, test_img);
+        assert(ok);
+
+        // Cross-check with swscale in the other direction.
+        // (Mostly so we don't have to worry about padding.)
+        struct mp_image *src2 =
+            mp_image_alloc(test_img->imgfmt, test_img->w, test_img->h);
+        assert(src2);
+        ok = mp_sws_scale(stest->sws, src2, dst) >= 0;
+        assert_imgs_equal(stest, f, test_img, src2);
+
+        // Assume the other conversion direction also works.
+        assert(stest->fns->supports_fmts(stest->fns_priv, test_img->imgfmt, mpfmt));
+
+        struct mp_image *back = mp_image_alloc(test_img->imgfmt, dst->w, dst->h);
+        assert(back);
+
+        // This tests unpacking.
+        ok = stest->fns->scale(stest->fns_priv, back, dst);
+        assert(ok);
+
+        assert_imgs_equal(stest, f, test_img, back);
+
+        talloc_free(back);
+        talloc_free(src2);
+        talloc_free(dst);
+    }
+
+    fclose(f);
+
+    assert_text_files_equal(stest->ctx, logname, logname,
+                            "This can fail if FFmpeg adds or removes pixfmts.");
+}

test/scale_test.h

@@ -0,0 +1,28 @@
+#pragma once
+
+#include "tests.h"
+#include "video/mp_image.h"
+
+struct scale_test_fns {
+    bool (*scale)(void *ctx, struct mp_image *dst, struct mp_image *src);
+    bool (*supports_fmts)(void *ctx, int imgfmt_dst, int imgfmt_src);
+};
+
+struct scale_test {
+    // To be filled in by user.
+    const struct scale_test_fns *fns;
+    void *fns_priv;
+    const char *test_name;
+    struct test_ctx *ctx;
+
+    // Private.
+    struct mp_image *img_repack_rgb8;
+    struct mp_image *img_repack_rgba8;
+    struct mp_image *img_repack_rgb16;
+    struct mp_image *img_repack_rgba16;
+    struct mp_sws_context *sws;
+    int fail;
+};
+
+// Test color repacking between packed formats (typically RGB).
+void repack_test_run(struct scale_test *stest);

test/scale_zimg.c

@@ -0,0 +1,40 @@
+#include "scale_test.h"
+#include "video/zimg.h"
+
+static bool scale(void *pctx, struct mp_image *dst, struct mp_image *src)
+{
+    struct mp_zimg_context *ctx = pctx;
+    return mp_zimg_convert(ctx, dst, src);
+}
+
+static bool supports_fmts(void *pctx, int imgfmt_dst, int imgfmt_src)
+{
+    return mp_zimg_supports_in_format(imgfmt_src) &&
+           mp_zimg_supports_out_format(imgfmt_dst);
+}
+
+static const struct scale_test_fns fns = {
+    .scale = scale,
+    .supports_fmts = supports_fmts,
+};
+
+static void run(struct test_ctx *ctx)
+{
+    struct mp_zimg_context *zimg = mp_zimg_alloc();
+
+    struct scale_test *stest = talloc_zero(NULL, struct scale_test);
+    stest->fns = &fns;
+    stest->fns_priv = zimg;
+    stest->test_name = "repack_zimg";
+    stest->ctx = ctx;
+
+    repack_test_run(stest);
+
+    talloc_free(stest);
+    talloc_free(zimg);
+}
+
+const struct unittest test_repack_zimg = {
+    .name = "repack_zimg",
+    .run = run,
+};

test/tests.c

@@ -9,6 +9,10 @@ static const struct unittest *unittests[] = {
     &test_img_format,
     &test_json,
     &test_linked_list,
+    &test_repack_sws,
+#if HAVE_ZIMG
+    &test_repack_zimg,
+#endif
     NULL
 };
 

test/tests.h

@@ -41,6 +41,8 @@ extern const struct unittest test_gl_video;
 extern const struct unittest test_img_format;
 extern const struct unittest test_json;
 extern const struct unittest test_linked_list;
+extern const struct unittest test_repack_sws;
+extern const struct unittest test_repack_zimg;
 
 #define assert_true(x) assert(x)
 #define assert_false(x) assert(!(x))
@@ -69,3 +71,9 @@ void assert_text_files_equal_impl(const char *file, int line,
 
 // Open a new file in the out_path. Always succeeds.
 FILE *test_open_out(struct test_ctx *ctx, const char *name);
+
+// Sorted list of valid imgfmts. Call init_imgfmts_list() before use.
+extern int imgfmts[];
+extern int num_imgfmts;
+
+void init_imgfmts_list(void);

wscript_build.py

@@ -400,6 +400,9 @@ def build(ctx):
         ( "test/img_format.c",                   "tests" ),
         ( "test/json.c",                         "tests" ),
         ( "test/linked_list.c",                  "tests" ),
+        ( "test/scale_sws.c",                    "tests" ),
+        ( "test/scale_test.c",                   "tests" ),
+        ( "test/scale_zimg.c",                   "tests && zimg" ),
         ( "test/tests.c",                        "tests" ),
 
         ## Video