From: Niklas Haas <g...@haasn.dev>
The current code has a number of issues:
1. The fg_model_id is specified in H.274 as u(2), not u(8)
2. This SEI has no ue(v) "repetition period", but a u(1) persistence flag
Additionally, we can get away with using the non-long version of
get_se_golomb() because the SEI spec as written limits these values to
2^(fgBitDepth)-1 where fgBitDepth maxes out at 2^3-1 + 8 = 15 bits.
Fixes: corrupt bistream values due to wrong number of bits read
Fixes: 4ff73add5dbe6c319d693355be44df2e17a0b8bf
Signed-off-by: Niklas Haas <g...@haasn.dev>
---
libavcodec/h264_sei.c | 6 +++---
libavcodec/h264_sei.h | 2 +-
libavcodec/h264_slice.c | 2 +-
3 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/libavcodec/h264_sei.c b/libavcodec/h264_sei.c
index 7797f24650..8de1ce4b90 100644
--- a/libavcodec/h264_sei.c
+++ b/libavcodec/h264_sei.c
@@ -424,7 +424,7 @@ static int
decode_film_grain_characteristics(H264SEIFilmGrainCharacteristics *h,
if (h->present) {
memset(h, 0, sizeof(*h));
- h->model_id = get_bits(gb, 8);
+ h->model_id = get_bits(gb, 2);
h->separate_colour_description_present_flag = get_bits1(gb);
if (h->separate_colour_description_present_flag) {
h->bit_depth_luma = get_bits(gb, 3) + 8;
@@ -448,11 +448,11 @@ static int
decode_film_grain_characteristics(H264SEIFilmGrainCharacteristics *h,
h->intensity_interval_lower_bound[c][i] = get_bits(gb, 8);
h->intensity_interval_upper_bound[c][i] = get_bits(gb, 8);
for (int j = 0; j < h->num_model_values[c]; j++)
- h->comp_model_value[c][i][j] = get_se_golomb_long(gb);
+ h->comp_model_value[c][i][j] = get_se_golomb(gb);
}
}
}
- h->repetition_period = get_ue_golomb_long(gb);
+ h->persistent = get_bits1(gb);
h->present = 1;
}
diff --git a/libavcodec/h264_sei.h b/libavcodec/h264_sei.h
index f9166b45df..dbceb15627 100644
--- a/libavcodec/h264_sei.h
+++ b/libavcodec/h264_sei.h
@@ -183,7 +183,7 @@ typedef struct H264SEIFilmGrainCharacteristics {
uint8_t intensity_interval_lower_bound[3][256];
uint8_t intensity_interval_upper_bound[3][256];
int16_t comp_model_value[3][256][6];
- int repetition_period;
+ int persistent;
} H264SEIFilmGrainCharacteristics;
typedef struct H264SEIContext {
diff --git a/libavcodec/h264_slice.c b/libavcodec/h264_slice.c
index 41338fbcb6..03606bf504 100644
--- a/libavcodec/h264_slice.c
+++ b/libavcodec/h264_slice.c
@@ -1381,7 +1381,7 @@ static int h264_export_frame_props(H264Context *h)
memcpy(&fgp->codec.h274.comp_model_value, &fgc->comp_model_value,
sizeof(fgp->codec.h274.comp_model_value));
- fgc->present = !!fgc->repetition_period;
+ fgc->present = fgc->persistent;
}
if (h->sei.picture_timing.timecode_cnt > 0) {
--
2.32.0
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