On 4/13/2024 7:55 AM, Frank Plowman wrote:
sps_log2_ctu_size_minus5 is between 0 and 2, with 3 reserved for future
use.  The VVC decoder allows sps_log2_ctu_size_minus5 to be 3, and so
ctb_size_y should be at least 16 bits to prevent overflows.  An
alternative patch would leave sps_log2_ctu_size_minus5 as 8 bits and
disallow sps_log2_ctu_size_minus5 = 3.

The spec says a value of 3 should be ignored, which i assume means decoding is not meant to stop. So this patch is probably better than outright rejecting the value in CBS.


Signed-off-by: Frank Plowman <p...@frankplowman.com>
---
  libavcodec/vvc/ps.h | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavcodec/vvc/ps.h b/libavcodec/vvc/ps.h
index 78f1687fef..6656a06320 100644
--- a/libavcodec/vvc/ps.h
+++ b/libavcodec/vvc/ps.h
@@ -69,7 +69,7 @@ typedef struct VVCSPS {
      uint8_t     bit_depth;                                          ///< 
BitDepth
      uint8_t     qp_bd_offset;                                       ///< 
QpBdOffset
      uint8_t     ctb_log2_size_y;                                    ///< 
CtbLog2SizeY
-    uint8_t     ctb_size_y;                                         ///< 
CtbSizeY
+    uint16_t    ctb_size_y;                                         ///< 
CtbSizeY
      uint8_t     min_cb_log2_size_y;                                 ///< 
MinCbLog2SizeY
      uint8_t     min_cb_size_y;                                      ///< 
MinCbSizeY
      uint8_t     max_tb_size_y;                                      ///< 
MaxTbSizeY
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