[FFmpeg-devel] [PATCH] avformat/jpegxl_probe: fix incorrect cw_mask probing

[Leo Izen]

Fix incorrectly skipping over the upX_weights
if the cw_mask is present and it is not a multiple of 4.
---
 libavformat/jpegxl_probe.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/libavformat/jpegxl_probe.c b/libavformat/jpegxl_probe.c
index 9cd00da194..c03dc3bd1d 100644
--- a/libavformat/jpegxl_probe.c
+++ b/libavformat/jpegxl_probe.c
@@ -368,15 +368,19 @@ int ff_jpegxl_verify_codestream_header(const uint8_t *buf, int buflen)
 
     /* default transform */
     if (!jxl_bits(1)) {
+        uint32_t cw_mask;
+
         /* opsin inverse matrix */
         if (xyb_encoded && !jxl_bits(1))
             jxl_bits_skip(16 * 16);
+
         /* cw_mask and default weights */
-        if (jxl_bits(1))
+        cw_mask = jxl_bits(3);
+        if (cw_mask & 1)
             jxl_bits_skip(16 * 15);
-        if (jxl_bits(1))
+        if (cw_mask & 2)
             jxl_bits_skip(16 * 55);
-        if (jxl_bits(1))
+        if (cw_mask & 4)
             jxl_bits_skip(16 * 210);
     }
 
-- 
2.36.0