avcodec/cbs_av1: add missing valid range of values for num_cb_points and num_cr_points

It is a requirement of bitstream conformance that num_cr_points is less than or equal to 10.
It is a requirement of bitstream conformance that num_cb_points is less than or equal to 10.
Signed-off-by: James Almer <jamrial@gmail.com>

libavcodec/cbs_av1.h

@@ -260,11 +260,11 @@ typedef struct AV1RawFrameHeader {
     uint8_t  point_y_scaling[14];
     uint8_t  chroma_scaling_from_luma;
     uint8_t  num_cb_points;
-    uint8_t  point_cb_value[16];
-    uint8_t  point_cb_scaling[16];
+    uint8_t  point_cb_value[10];
+    uint8_t  point_cb_scaling[10];
     uint8_t  num_cr_points;
-    uint8_t  point_cr_value[16];
-    uint8_t  point_cr_scaling[16];
+    uint8_t  point_cr_value[10];
+    uint8_t  point_cr_scaling[10];
     uint8_t  grain_scaling_minus_8;
     uint8_t  ar_coeff_lag;
     uint8_t  ar_coeffs_y_plus_128[24];

libavcodec/cbs_av1_syntax_template.c

@@ -1174,12 +1174,12 @@ static int FUNC(film_grain_params)(CodedBitstreamContext *ctx, RWContext *rw,
         infer(num_cb_points, 0);
         infer(num_cr_points, 0);
     } else {
-        fb(4, num_cb_points);
+        fc(4, num_cb_points, 0, 10);
         for (i = 0; i < current->num_cb_points; i++) {
             fbs(8, point_cb_value[i],   1, i);
             fbs(8, point_cb_scaling[i], 1, i);
         }
-        fb(4, num_cr_points);
+        fc(4, num_cr_points, 0, 10);
         for (i = 0; i < current->num_cr_points; i++) {
             fbs(8, point_cr_value[i],   1, i);
             fbs(8, point_cr_scaling[i], 1, i);