@@ -82,6 +82,10 @@
(get_bits_left(rw) >= width && \
(var = show_bits(rw, width)) == (compare))
+#define infer(name, value) do { \
+ current->name = value; \
+ } while (0)
+
#include "cbs_mpeg2_syntax_template.c"
#undef READ
@@ -91,6 +95,7 @@
#undef xsi
#undef marker_bit
#undef nextbits
+#undef infer
#define WRITE
@@ -116,6 +121,15 @@
#define nextbits(width, compare, var) (var)
+#define infer(name, value) do { \
+ if (current->name != (value)) { \
+ av_log(ctx->log_ctx, AV_LOG_WARNING, "Warning: " \
+ "%s does not match inferred value: " \
+ "%"PRId64", but should be %"PRId64".\n", \
+ #name, (int64_t)current->name, (int64_t)(value)); \
+ } \
+ } while (0)
+
#include "cbs_mpeg2_syntax_template.c"
#undef WRITE
@@ -125,6 +139,7 @@
#undef xsi
#undef marker_bit
#undef nextbits
+#undef infer
static void cbs_mpeg2_free_user_data(void *unit, uint8_t *content)
@@ -144,6 +144,10 @@ static int FUNC(sequence_display_extension)(CodedBitstreamContext *ctx, RWContex
uir(8, transfer_characteristics);
uir(8, matrix_coefficients);
#endif
+ } else {
+ infer(colour_primaries, 2);
+ infer(transfer_characteristics, 2);
+ infer(matrix_coefficients, 2);
}
ui(14, display_horizontal_size);
@@ -213,6 +213,18 @@ static int mpeg2_metadata_init(AVBSFContext *bsf)
CodedBitstreamFragment *frag = &ctx->fragment;
int err;
+#define VALIDITY_CHECK(name) do { \
+ if (!ctx->name) { \
+ av_log(bsf, AV_LOG_ERROR, "The value 0 for %s is " \
+ "forbidden.\n", #name); \
+ return AVERROR(EINVAL); \
+ } \
+ } while (0)
+ VALIDITY_CHECK(colour_primaries);
+ VALIDITY_CHECK(transfer_characteristics);
+ VALIDITY_CHECK(matrix_coefficients);
+#undef VALIDITY_CHECK
+
err = ff_cbs_init(&ctx->cbc, AV_CODEC_ID_MPEG2VIDEO, bsf);
if (err < 0)
return err;
If a sequence display extension is read with colour_description equal to zero, but a user wants to add one or more of the colour_description elements, then the colour_description elements the user did not explicitly request to be set are set to zero and not to the value equal to unknown/unspecified (namely 2). A value of zero is not only inappropriate, but explicitly forbidden. This is fixed by inferring the right default values during the reading process if the elements are absent; moreover, changing any of the colour_description elements to zero is now no longer possible. Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com> --- libavcodec/cbs_mpeg2.c | 15 +++++++++++++++ libavcodec/cbs_mpeg2_syntax_template.c | 4 ++++ libavcodec/mpeg2_metadata_bsf.c | 12 ++++++++++++ 3 files changed, 31 insertions(+)