From: Niklas Haas <g...@haasn.dev> The spec specifies x^31 + x^3 + 1 as the polynomial, but the diagram in Figure 1-1 omits the +1 offset. The initial implementation was based on the diagram, but this is wrong (produces subtly incorrect results). --- libavcodec/h274.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/libavcodec/h274.c b/libavcodec/h274.c index a69f9411429..fc111cdb50d 100644 --- a/libavcodec/h274.c +++ b/libavcodec/h274.c @@ -38,7 +38,7 @@ static void prng_shift(uint32_t *state) { // Primitive polynomial x^31 + x^3 + 1 (modulo 2) uint32_t x = *state; - uint8_t feedback = (x >> 2) ^ (x >> 30); + uint8_t feedback = 1u ^ (x >> 2) ^ (x >> 30); *state = (x << 1) | (feedback & 1u); } -- 2.42.0 _______________________________________________ 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".