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 permitted.
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> --- libavcodec/cbs_mpeg2.c | 8 ++++++++ libavcodec/cbs_mpeg2_syntax_template.c | 4 ++++ libavcodec/mpeg2_metadata_bsf.c | 18 ++++++++++++------ 3 files changed, 24 insertions(+), 6 deletions(-) diff --git a/libavcodec/cbs_mpeg2.c b/libavcodec/cbs_mpeg2.c index 066ea83970..954adc7d57 100644 --- a/libavcodec/cbs_mpeg2.c +++ b/libavcodec/cbs_mpeg2.c @@ -70,6 +70,10 @@ (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 @@ -78,6 +82,7 @@ #undef xuir #undef marker_bit #undef nextbits +#undef infer #define WRITE @@ -96,6 +101,8 @@ #define nextbits(width, compare, var) (var) +#define infer(name, value) + #include "cbs_mpeg2_syntax_template.c" #undef READ @@ -104,6 +111,7 @@ #undef xuir #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 745a123649..7b3f225396 100644 --- a/libavcodec/cbs_mpeg2_syntax_template.c +++ b/libavcodec/cbs_mpeg2_syntax_template.c @@ -128,6 +128,10 @@ static int FUNC(sequence_display_extension)(CodedBitstreamContext *ctx, RWContex uir(8, colour_primaries, 1, 255); uir(8, transfer_characteristics, 1, 255); uir(8, matrix_coefficients, 1, 255); + } 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..bb69001cef 100644 --- a/libavcodec/mpeg2_metadata_bsf.c +++ b/libavcodec/mpeg2_metadata_bsf.c @@ -147,18 +147,12 @@ static int mpeg2_metadata_update_fragment(AVBSFContext *bsf, if (ctx->colour_primaries >= 0) sde->colour_primaries = ctx->colour_primaries; - else if (add_sde) - sde->colour_primaries = 2; if (ctx->transfer_characteristics >= 0) sde->transfer_characteristics = ctx->transfer_characteristics; - else if (add_sde) - sde->transfer_characteristics = 2; if (ctx->matrix_coefficients >= 0) sde->matrix_coefficients = ctx->matrix_coefficients; - else if (add_sde) - sde->matrix_coefficients = 2; } } @@ -229,6 +223,18 @@ 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; -- 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".