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.
Furthermore, if a sequence display extension has to be added, the
earlier code set some fields to their default value twice. This has been
changed, too.
Signed-off-by: Andreas Rheinhardt <andreas.rheinha...@gmail.com>
---
I implemented your solution, because it is easy to add the check I just
removed back in should it be needed some day because of the
AVCodecParameter stuff.
libavcodec/cbs_mpeg2.c | 15 +++++++++++++
libavcodec/cbs_mpeg2_syntax_template.c | 4 ++++
libavcodec/mpeg2_metadata_bsf.c | 30 +++++++++++---------------
3 files changed, 31 insertions(+), 18 deletions(-)
diff --git a/libavcodec/cbs_mpeg2.c b/libavcodec/cbs_mpeg2.c
index ce22e32c15..5e971f3a54 100644
--- a/libavcodec/cbs_mpeg2.c
+++ b/libavcodec/cbs_mpeg2.c
@@ -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 READ
@@ -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)
diff --git a/libavcodec/cbs_mpeg2_syntax_template.c
b/libavcodec/cbs_mpeg2_syntax_template.c
index e0cf716874..d9ef480f39 100644
--- a/libavcodec/cbs_mpeg2_syntax_template.c
+++ b/libavcodec/cbs_mpeg2_syntax_template.c
@@ -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);
diff --git a/libavcodec/mpeg2_metadata_bsf.c b/libavcodec/mpeg2_metadata_bsf.c
index ba3a74afda..57eded0808 100644
--- a/libavcodec/mpeg2_metadata_bsf.c
+++ b/libavcodec/mpeg2_metadata_bsf.c
@@ -111,9 +111,9 @@ static int mpeg2_metadata_update_fragment(AVBSFContext *bsf,
}
if (ctx->video_format >= 0 ||
- ctx->colour_primaries >= 0 ||
- ctx->transfer_characteristics >= 0 ||
- ctx->matrix_coefficients >= 0) {
+ ctx->colour_primaries > 0 ||
+ ctx->transfer_characteristics > 0 ||
+ ctx->matrix_coefficients > 0) {
if (!sde) {
add_sde = 1;
ctx->sequence_display_extension.extension_start_code =
@@ -140,25 +140,19 @@ static int mpeg2_metadata_update_fragment(AVBSFContext
*bsf,
if (ctx->video_format >= 0)
sde->video_format = ctx->video_format;
- if (ctx->colour_primaries >= 0 ||
- ctx->transfer_characteristics >= 0 ||
- ctx->matrix_coefficients >= 0) {
+ if (ctx->colour_primaries > 0 ||
+ ctx->transfer_characteristics > 0 ||
+ ctx->matrix_coefficients > 0) {
sde->colour_description = 1;
- if (ctx->colour_primaries >= 0)
+ if (ctx->colour_primaries > 0)
sde->colour_primaries = ctx->colour_primaries;
- else if (add_sde)
- sde->colour_primaries = 2;
- if (ctx->transfer_characteristics >= 0)
+ if (ctx->transfer_characteristics > 0)
sde->transfer_characteristics = ctx->transfer_characteristics;
- else if (add_sde)
- sde->transfer_characteristics = 2;
- if (ctx->matrix_coefficients >= 0)
+ if (ctx->matrix_coefficients > 0)
sde->matrix_coefficients = ctx->matrix_coefficients;
- else if (add_sde)
- sde->matrix_coefficients = 2;
}
}
@@ -283,13 +277,13 @@ static const AVOption mpeg2_metadata_options[] = {
{ .i64 = -1 }, -1, 7, FLAGS },
{ "colour_primaries", "Set colour primaries (table 6-7)",
OFFSET(colour_primaries), AV_OPT_TYPE_INT,
- { .i64 = -1 }, -1, 255, FLAGS },
+ { .i64 = 0 }, 0, 255, FLAGS },
{ "transfer_characteristics", "Set transfer characteristics (table 6-8)",
OFFSET(transfer_characteristics), AV_OPT_TYPE_INT,
- { .i64 = -1 }, -1, 255, FLAGS },
+ { .i64 = 0 }, 0, 255, FLAGS },
{ "matrix_coefficients", "Set matrix coefficients (table 6-9)",
OFFSET(matrix_coefficients), AV_OPT_TYPE_INT,
- { .i64 = -1 }, -1, 255, FLAGS },
+ { .i64 = 0 }, 0, 255, FLAGS },
{ NULL }
};
--
2.21.0
_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
To unsubscribe, visit link above, or email
ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
