img_format: add gray/alpha planar formats

The zimg wrapper "needs" these formats as intermediary when repacking
the normal gray/alpha packed format. The packed format is used by the
png decoder and encoder, and is thus interesting.

Unfortunately, mpv-only formats are a mess right now, because all the
existing code is focused around using the FFmpeg metadata for pixel
formats. This should be improved, but not now, so make the mess worse.

This commit doesn't add support for it to the zimg wrapper yet.

test/ref/img_formats.txt

@@ -1039,6 +1039,20 @@ ya8: [GENERIC] ctype=uint
   AVD: name=ya8 chroma=0:0 flags=0x80 [alpha]
     0: p=0  st=2  o=0  sh=0  d=8
     1: p=0  st=2  o=1  sh=0  d=8
+yap16: ctype=uint
+  Legacy desc: [ba][yuvp][yuv][le]
+    planes=2, chroma=0:0 align=1:1 bits=16 cbits=16
+    {2/16/[0:0] 2/16/[0:0] 0/0/[0:0] 0/0/[0:0] }
+  Regular: planes=2 compbytes=2 bitpad=0 chroma=1x1 ctype=uint
+    0: {1}
+    1: {4}
+yap8: ctype=uint
+  Legacy desc: [ba][yuvp][yuv][le]
+    planes=2, chroma=0:0 align=1:1 bits=8 cbits=8
+    {1/8/[0:0] 1/8/[0:0] 0/0/[0:0] 0/0/[0:0] }
+  Regular: planes=2 compbytes=1 bitpad=0 chroma=1x1 ctype=uint
+    0: {1}
+    1: {4}
 yuv410p: [GENERIC] ctype=uint
   Legacy desc: [ba][yuvp][yuv][le][be]
     planes=3, chroma=2:2 align=4:4 bits=8 cbits=8

video/img_format.c

@@ -37,6 +37,8 @@ static const struct mp_imgfmt_entry mp_imgfmt_list[] = {
     // not in ffmpeg
     {"vdpau_output",    IMGFMT_VDPAU_OUTPUT},
     {"rgb30",           IMGFMT_RGB30},
+    {"yap8",            IMGFMT_YAP8},
+    {"yap16",           IMGFMT_YAP16},
     // FFmpeg names have an annoying "_vld" suffix
     {"videotoolbox",    IMGFMT_VIDEOTOOLBOX},
     {"vaapi",           IMGFMT_VAAPI},
@@ -121,6 +123,34 @@ static struct mp_imgfmt_desc mp_only_imgfmt_desc(int mpfmt)
             .plane_bits = 30,
             .component_bits = 10,
         };
+    case IMGFMT_YAP8:
+        return (struct mp_imgfmt_desc) {
+            .id = mpfmt,
+            .avformat = AV_PIX_FMT_NONE,
+            .flags = MP_IMGFLAG_BYTE_ALIGNED | MP_IMGFLAG_NE | MP_IMGFLAG_YUV |
+                     MP_IMGFLAG_YUV_P,
+            .num_planes = 2,
+            .align_x = 1,
+            .align_y = 1,
+            .bytes = {1, 1},
+            .bpp = {8, 8},
+            .plane_bits = 8,
+            .component_bits = 8,
+        };
+    case IMGFMT_YAP16:
+        return (struct mp_imgfmt_desc) {
+            .id = mpfmt,
+            .avformat = AV_PIX_FMT_NONE,
+            .flags = MP_IMGFLAG_BYTE_ALIGNED | MP_IMGFLAG_NE | MP_IMGFLAG_YUV |
+                     MP_IMGFLAG_YUV_P,
+            .num_planes = 2,
+            .align_x = 1,
+            .align_y = 1,
+            .bytes = {2, 2},
+            .bpp = {16, 16},
+            .plane_bits = 16,
+            .component_bits = 16,
+        };
     }
     return (struct mp_imgfmt_desc) {0};
 }
@@ -336,7 +366,9 @@ enum mp_csp mp_imgfmt_get_forced_csp(int imgfmt)
 
 enum mp_component_type mp_imgfmt_get_component_type(int imgfmt)
 {
-    if (imgfmt == IMGFMT_RGB30)
+    if (imgfmt == IMGFMT_RGB30 ||
+        imgfmt == IMGFMT_YAP8 ||
+        imgfmt == IMGFMT_YAP16)
         return MP_COMPONENT_TYPE_UINT;
 
     const AVPixFmtDescriptor *pixdesc =
@@ -363,6 +395,39 @@ static bool is_native_endian(const AVPixFmtDescriptor *pixdesc)
     return pixdesc && (is_le != !!(pixdesc->flags & AV_PIX_FMT_FLAG_BE));
 }
 
+static bool mp_only_regular_imgfmt(struct mp_regular_imgfmt *dst, int imgfmt)
+{
+    switch (imgfmt) {
+    case IMGFMT_YAP8:
+        *dst = (struct mp_regular_imgfmt) {
+            .component_type = MP_COMPONENT_TYPE_UINT,
+            .component_size = 1,
+            .num_planes = 2,
+            .planes = {
+                {.num_components = 1, .components = {1}},
+                {.num_components = 1, .components = {4}},
+            },
+            .chroma_w = 1,
+            .chroma_h = 1,
+        };
+        return true;
+    case IMGFMT_YAP16:
+        *dst = (struct mp_regular_imgfmt) {
+            .component_type = MP_COMPONENT_TYPE_UINT,
+            .component_size = 2,
+            .num_planes = 2,
+            .planes = {
+                {.num_components = 1, .components = {1}},
+                {.num_components = 1, .components = {4}},
+            },
+            .chroma_w = 1,
+            .chroma_h = 1,
+        };
+        return true;
+    }
+    return false;
+}
+
 bool mp_get_regular_imgfmt(struct mp_regular_imgfmt *dst, int imgfmt)
 {
     struct mp_regular_imgfmt res = {0};
@@ -370,7 +435,10 @@ bool mp_get_regular_imgfmt(struct mp_regular_imgfmt *dst, int imgfmt)
     const AVPixFmtDescriptor *pixdesc =
         av_pix_fmt_desc_get(imgfmt2pixfmt(imgfmt));
 
-    if (!pixdesc || (pixdesc->flags & AV_PIX_FMT_FLAG_BITSTREAM) ||
+    if (!pixdesc)
+        return mp_only_regular_imgfmt(dst, imgfmt);
+
+    if ((pixdesc->flags & AV_PIX_FMT_FLAG_BITSTREAM) ||
         (pixdesc->flags & AV_PIX_FMT_FLAG_HWACCEL) ||
         (pixdesc->flags & AV_PIX_FMT_FLAG_PAL) ||
         pixdesc->nb_components < 1 ||

video/img_format.h

@@ -151,6 +151,10 @@ enum mp_imgfmt {
     IMGFMT_Y8,
     IMGFMT_Y16,
 
+    // Planar gray/alpha.
+    IMGFMT_YAP8,
+    IMGFMT_YAP16,
+
     // Packed YUV formats (components are byte-accessed)
     IMGFMT_UYVY,                // U  Y0 V  Y1