@@ -620,7 +620,7 @@ vips_avifsave_go(VipsImage *in, void **buf, size_t *len, int quality, int speed)
"Q", quality,
"compression", VIPS_FOREIGN_HEIF_COMPRESSION_AV1,
#if VIPS_SUPPORT_AVIF_EFFORT
- "effort", speed,
+ "effort", 9-speed,
#elif VIPS_SUPPORT_AVIF_SPEED
"speed", speed,
#endif
DarthSim