Andreas Rheinhardt: > Zhao Zhili: >> --- >> libavutil/display.h | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/libavutil/display.h b/libavutil/display.h >> index 515adad795..d87bf68425 100644 >> --- a/libavutil/display.h >> +++ b/libavutil/display.h >> @@ -88,7 +88,7 @@ >> double av_display_rotation_get(const int32_t matrix[9]); >> >> /** >> - * Initialize a transformation matrix describing a pure counterclockwise >> + * Initialize a transformation matrix describing a pure clockwise >> * rotation by the specified angle (in degrees). >> * >> * @param matrix an allocated transformation matrix (will be fully >> overwritten >> > > If you look at the documentation, you will notice that the matrix > returned from the function is supposed to be multiplied from the right > to the coordinate (row) vector, not from the left to the coordinate > (column) vector as is standard in linear algebra. This is tantamount to > transposing the matrix which for rotation matrices means negating the > degree. So this doxy is correct. > Notice that last time I looked at this, I came to the conclusion that > the whole H.2645 SEI parsing code uses it wrongly. >
Wait, there is another difference to ordinary linear algebra: The y axis is directed downwards. Maybe you are right. Let me think this through... - Andreas _______________________________________________ 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".
