Lanczos for general case, sinc for upscaling, Gaussian for
downscaling. According to current literature these scalers
should be the best quality-wise algorithms for each case.
Inspired from a patch by wm4 <nfxjfg@googlemail.com>
Signed-off-by: Luca Barbato <lu_zero@gentoo.org>
SWS_SINC |
SWS_SPLINE |
SWS_BICUBLIN);
- if (!i || (i & (i - 1))) {
+
+ /* provide a default scaler if not set by caller */
+ if (!i) {
+ if (dstW < srcW && dstH < srcH)
+ flags |= SWS_GAUSS;
+ else if (dstW > srcW && dstH > srcH)
+ flags |= SWS_SINC;
+ else
+ flags |= SWS_LANCZOS;
+ c->flags = flags;
+ } else if (i & (i - 1)) {
av_log(c, AV_LOG_ERROR,
"Exactly one scaler algorithm must be chosen\n");
return AVERROR(EINVAL);