cbs_mpeg2: Improve checks for invalid values

MPEG-2 contains several elements that mustn't be zero according to the
specifications: horizontal/vertical_size_value, aspect_ratio_information,
frame_rate_code, the quantiser matrices, the colour_description
elements, picture_coding_type, the f_code[r][s] values and
quantiser_scale_code. It is now checked that the invalid values don't
occur.

The colour_description elements are treated specially in this regard:
Given that there are files in the wild which use illegal values for the
colour_description elements (some of them created by mpeg2_metadata),
they will be corrected to the value meaning "unknown" (namely 2) during
reading. This has been done in such a way that trace_headers will
nevertheless report the original value, together with a message about
the fixup.

Furthermore, the trace_headers output of user_data has been beautified.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>

1 files changed, 10 insertions, 6 deletions

diff --git a/libavcodec/cbs_mpeg2.c b/libavcodec/cbs_mpeg2.c
index f9f1d86b49..4605b2056e 100644
--- a/libavcodec/cbs_mpeg2.c
+++ b/libavcodec/cbs_mpeg2.c
@@ -41,20 +41,24 @@
 #define SUBSCRIPTS(subs, ...) (subs > 0 ? ((int[subs + 1]){ subs, __VA_ARGS__ }) : NULL)
 
 #define ui(width, name) \
-        xui(width, name, current->name, 0)
+        xui(width, name, current->name, 0, MAX_UINT_BITS(width), 0)
+#define uir(width, name) \
+        xui(width, name, current->name, 1, MAX_UINT_BITS(width), 0)
 #define uis(width, name, subs, ...) \
-        xui(width, name, current->name, subs, __VA_ARGS__)
+        xui(width, name, current->name, 0, MAX_UINT_BITS(width), subs, __VA_ARGS__)
+#define uirs(width, name, subs, ...) \
+        xui(width, name, current->name, 1, MAX_UINT_BITS(width), subs, __VA_ARGS__)
 
 
 #define READ
 #define READWRITE read
 #define RWContext GetBitContext
 
-#define xui(width, name, var, subs, ...) do { \
+#define xui(width, name, var, range_min, range_max, subs, ...) do { \
         uint32_t value = 0; \
         CHECK(ff_cbs_read_unsigned(ctx, rw, width, #name, \
                                    SUBSCRIPTS(subs, __VA_ARGS__), \
-                                   &value, 0, (1 << width) - 1)); \
+                                   &value, range_min, range_max)); \
         var = value; \
     } while (0)
 
@@ -81,10 +85,10 @@
 #define READWRITE write
 #define RWContext PutBitContext
 
-#define xui(width, name, var, subs, ...) do { \
+#define xui(width, name, var, range_min, range_max, subs, ...) do { \
         CHECK(ff_cbs_write_unsigned(ctx, rw, width, #name, \
                                     SUBSCRIPTS(subs, __VA_ARGS__), \
-                                    var, 0, (1 << width) - 1)); \
+                                    var, range_min, range_max)); \
     } while (0)
 
 #define marker_bit() do { \