X-Git-Url: https://main.carlh.net/gitweb/?a=blobdiff_plain;f=src%2Flib%2Fimage.cc;h=792bf3ab469c2ffd363b81de850a0bedb8fe98c6;hb=4a23fb5dd58c6439f240f678be2e26a5bee17881;hp=c3795dfa2a1adc8f7107d1ddafc6851fb4d2b90a;hpb=f484570d7fe219ec68aa48c9830d7bd2c76e9144;p=dcpomatic.git

diff --git a/src/lib/image.cc b/src/lib/image.cc
index c3795dfa2..792bf3ab4 100644
--- a/src/lib/image.cc
+++ b/src/lib/image.cc
@@ -183,8 +183,8 @@ Image::crop_scale_window (
 		0, 1 << 16, 1 << 16
 		);
 
-	AVPixFmtDescriptor const * desc = av_pix_fmt_desc_get (_pixel_format);
-	if (!desc) {
+	AVPixFmtDescriptor const * in_desc = av_pix_fmt_desc_get (_pixel_format);
+	if (!in_desc) {
 		throw PixelFormatError ("crop_scale_window()", _pixel_format);
 	}
 
@@ -196,16 +196,23 @@ Image::crop_scale_window (
 		   round down so that we don't crop a subsampled pixel until
 		   we've cropped all of its Y-channel pixels.
 		*/
-		int const x = lrintf (bytes_per_pixel(c) * crop.left) & ~ ((int) desc->log2_chroma_w);
+		int const x = lrintf (bytes_per_pixel(c) * crop.left) & ~ ((int) in_desc->log2_chroma_w);
 		scale_in_data[c] = data()[c] + x + stride()[c] * (crop.top / vertical_factor(c));
 	}
 
 	/* Corner of the image within out_size */
 	Position<int> const corner ((out_size.width - inter_size.width) / 2, (out_size.height - inter_size.height) / 2);
 
+	AVPixFmtDescriptor const * out_desc = av_pix_fmt_desc_get (out_format);
+	if (!out_desc) {
+		throw PixelFormatError ("crop_scale_window()", out_format);
+	}
+
 	uint8_t* scale_out_data[out->planes()];
 	for (int c = 0; c < out->planes(); ++c) {
-		scale_out_data[c] = out->data()[c] + lrintf (out->bytes_per_pixel(c) * corner.x) + out->stride()[c] * (corner.y / out->vertical_factor(c));
+		/* See the note in the crop loop above */
+		int const x = lrintf (out->bytes_per_pixel(c) * corner.x) & ~ ((int) out_desc->log2_chroma_w);
+		scale_out_data[c] = out->data()[c] + x + out->stride()[c] * (corner.y / out->vertical_factor(c));
 	}
 
 	sws_scale (
@@ -246,7 +253,7 @@ Image::scale (dcp::Size out_size, dcp::YUVToRGB yuv_to_rgb, AVPixelFormat out_fo
 	struct SwsContext* scale_context = sws_getContext (
 		size().width, size().height, pixel_format(),
 		out_size.width, out_size.height, out_format,
-		fast ? SWS_FAST_BILINEAR : SWS_BICUBIC, 0, 0, 0
+		(fast ? SWS_FAST_BILINEAR : SWS_BICUBIC) | SWS_ACCURATE_RND, 0, 0, 0
 		);
 
 	DCPOMATIC_ASSERT (yuv_to_rgb < dcp::YUV_TO_RGB_COUNT);