пн, 9 сент. 2024 г., 18:06 Andrew Randrianasulu <randrianas...@gmail.com>:
> Looking at libswscale/swscale.c (due to > https://trac.ffmpeg.org/ticket/11182#comment:5) I do not understand > how it works :) > > why shits to 11 and to 12 ? > > // FIXME all pal and rgb srcFormats could do this conversion as well > // FIXME all scalers more complex than bilinear could do half of this > transform > static void chrRangeToJpeg_c(int16_t *dstU, int16_t *dstV, int width) > { > int i; > for (i = 0; i < width; i++) { > dstU[i] = (FFMIN(dstU[i], 30775) * 4663 - 9289992) >> 12; // -264 > dstV[i] = (FFMIN(dstV[i], 30775) * 4663 - 9289992) >> 12; // -264 > } > } > > static void chrRangeFromJpeg_c(int16_t *dstU, int16_t *dstV, int width) > { > int i; > for (i = 0; i < width; i++) { > dstU[i] = (dstU[i] * 1799 + 4081085) >> 11; // 1469 > dstV[i] = (dstV[i] * 1799 + 4081085) >> 11; // 1469 > } > } > > === > can anyone knowledgeable write/add some more comments in code ? please :) > it seems that same code (under slightly different name) was living in swscale_template.c since at least 2009 ... https://git.ffmpeg.org/gitweb/ffmpeg.git/blobdiff/c1977fbbd7d1e7825010e301fa236e910b760aab..bae76dc3eb6e5cd07f5881092d375ddc0270f693:/libswscale/swscale_template.c _______________________________________________ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
