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cbs_mpeg2: Improve checks for invalid values

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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>
This commit is contained in:
Andreas Rheinhardt 2019-05-22 03:04:32 +02:00 committed by Mark Thompson
parent cfe4389d47
commit 9c3f2a8894
2 changed files with 50 additions and 30 deletions
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16
libavcodec/cbs_mpeg2.c
View File

@ -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 { \

64
libavcodec/cbs_mpeg2_syntax_template.c
View File

@ -26,14 +26,14 @@ static int FUNC(sequence_header)(CodedBitstreamContext *ctx, RWContext *rw,
ui(8, sequence_header_code);
ui(12, horizontal_size_value);
ui(12, vertical_size_value);
uir(12, horizontal_size_value);
uir(12, vertical_size_value);
mpeg2->horizontal_size = current->horizontal_size_value;
mpeg2->vertical_size = current->vertical_size_value;
ui(4, aspect_ratio_information);
ui(4, frame_rate_code);
uir(4, aspect_ratio_information);
uir(4, frame_rate_code);
ui(18, bit_rate_value);
marker_bit();
@ -44,13 +44,13 @@ static int FUNC(sequence_header)(CodedBitstreamContext *ctx, RWContext *rw,
ui(1, load_intra_quantiser_matrix);
if (current->load_intra_quantiser_matrix) {
for (i = 0; i < 64; i++)
uis(8, intra_quantiser_matrix[i], 1, i);
uirs(8, intra_quantiser_matrix[i], 1, i);
}
ui(1, load_non_intra_quantiser_matrix);
if (current->load_non_intra_quantiser_matrix) {
for (i = 0; i < 64; i++)
uis(8, non_intra_quantiser_matrix[i], 1, i);
uirs(8, non_intra_quantiser_matrix[i], 1, i);
}
return 0;
@ -79,7 +79,7 @@ static int FUNC(user_data)(CodedBitstreamContext *ctx, RWContext *rw,
#endif
for (k = 0; k < current->user_data_length; k++)
xui(8, user_data, current->user_data[k], 0);
uis(8, user_data[k], 1, k);
return 0;
}
@ -125,9 +125,25 @@ static int FUNC(sequence_display_extension)(CodedBitstreamContext *ctx, RWContex
ui(1, colour_description);
if (current->colour_description) {
ui(8, colour_primaries);
ui(8, transfer_characteristics);
ui(8, matrix_coefficients);
#ifdef READ
#define READ_AND_PATCH(name) do { \
ui(8, name); \
if (current->name == 0) { \
current->name = 2; \
av_log(ctx->log_ctx, AV_LOG_WARNING, "%s in a sequence display " \
"extension had the invalid value 0. Setting it to 2 " \
"(meaning unknown) instead.\n", #name); \
} \
} while (0)
READ_AND_PATCH(colour_primaries);
READ_AND_PATCH(transfer_characteristics);
READ_AND_PATCH(matrix_coefficients);
#undef READ_AND_PATCH
#else
uir(8, colour_primaries);
uir(8, transfer_characteristics);
uir(8, matrix_coefficients);
#endif
}
ui(14, display_horizontal_size);
@ -163,7 +179,7 @@ static int FUNC(picture_header)(CodedBitstreamContext *ctx, RWContext *rw,
ui(8, picture_start_code);
ui(10, temporal_reference);
ui(3, picture_coding_type);
uir(3, picture_coding_type);
ui(16, vbv_delay);
if (current->picture_coding_type == 2 ||
@ -190,10 +206,10 @@ static int FUNC(picture_coding_extension)(CodedBitstreamContext *ctx, RWContext
HEADER("Picture Coding Extension");
ui(4, f_code[0][0]);
ui(4, f_code[0][1]);
ui(4, f_code[1][0]);
ui(4, f_code[1][1]);
uir(4, f_code[0][0]);
uir(4, f_code[0][1]);
uir(4, f_code[1][0]);
uir(4, f_code[1][1]);
ui(2, intra_dc_precision);
ui(2, picture_structure);
@ -250,25 +266,25 @@ static int FUNC(quant_matrix_extension)(CodedBitstreamContext *ctx, RWContext *r
ui(1, load_intra_quantiser_matrix);
if (current->load_intra_quantiser_matrix) {
for (i = 0; i < 64; i++)
uis(8, intra_quantiser_matrix[i], 1, i);
uirs(8, intra_quantiser_matrix[i], 1, i);
}
ui(1, load_non_intra_quantiser_matrix);
if (current->load_non_intra_quantiser_matrix) {
for (i = 0; i < 64; i++)
uis(8, non_intra_quantiser_matrix[i], 1, i);
uirs(8, non_intra_quantiser_matrix[i], 1, i);
}
ui(1, load_chroma_intra_quantiser_matrix);
if (current->load_chroma_intra_quantiser_matrix) {
for (i = 0; i < 64; i++)
uis(8, intra_quantiser_matrix[i], 1, i);
uirs(8, intra_quantiser_matrix[i], 1, i);
}
ui(1, load_chroma_non_intra_quantiser_matrix);
if (current->load_chroma_non_intra_quantiser_matrix) {
for (i = 0; i < 64; i++)
uis(8, chroma_non_intra_quantiser_matrix[i], 1, i);
uirs(8, chroma_non_intra_quantiser_matrix[i], 1, i);
}
return 0;
@ -342,7 +358,7 @@ static int FUNC(slice_header)(CodedBitstreamContext *ctx, RWContext *rw,
ui(7, priority_breakpoint);
}
ui(5, quantiser_scale_code);
uir(5, quantiser_scale_code);
if (nextbits(1, 1, current->slice_extension_flag)) {
ui(1, slice_extension_flag);
@ -366,16 +382,16 @@ static int FUNC(slice_header)(CodedBitstreamContext *ctx, RWContext *rw,
if (!current->extra_information)
return AVERROR(ENOMEM);
for (k = 0; k < current->extra_information_length; k++) {
xui(1, extra_bit_slice, bit, 0);
xui(1, extra_bit_slice, bit, 1, 1, 0);
xui(8, extra_information_slice[k],
current->extra_information[k], 1, k);
current->extra_information[k], 0, 255, 1, k);
}
}
#else
for (k = 0; k < current->extra_information_length; k++) {
xui(1, extra_bit_slice, 1, 0);
xui(1, extra_bit_slice, 1, 1, 1, 0);
xui(8, extra_information_slice[k],
current->extra_information[k], 1, k);
current->extra_information[k], 0, 255, 1, k);
}
#endif
}