From 670c6b766ed06b27c0537160e7edb944f7b23e3b Mon Sep 17 00:00:00 2001 From: Frode Langelo Date: Tue, 6 Oct 2015 22:15:50 +0000 Subject: [PATCH] GUAC-1365: Don't send JPEG image refreshes if the image size is less than 4096 pixels. WebP decision should not include the size check. --- src/common/guac_surface.c | 26 ++++++++++++++++++++++---- 1 file changed, 22 insertions(+), 4 deletions(-) diff --git a/src/common/guac_surface.c b/src/common/guac_surface.c index c2e9e57f..a316ddb5 100644 --- a/src/common/guac_surface.c +++ b/src/common/guac_surface.c @@ -91,6 +91,12 @@ */ #define GUAC_COMMON_SURFACE_JPEG_FRAMERATE 3 +/** + * Minimum JPEG bitmap size (area). If the bitmap is smaller than this threshold, + * it should be compressed as a PNG image to avoid the JPEG compression tax. + */ +#define GUAC_SURFACE_JPEG_MIN_BITMAP_SIZE 4096 + /** * The WebP image quality ('quantization') setting to use. Range 0-100 where * 100 is the highest quality/largest file size, and 0 is the lowest @@ -408,14 +414,20 @@ static int __guac_common_surface_should_use_jpeg(guac_common_surface* surface, /* Calculate the average framerate for the given rect */ int framerate = __guac_common_surface_calculate_framerate(surface, rect); - /* JPEG is preferred if framerate is high enough */ + int rect_size = rect->width * rect->height; + + /* JPEG is preferred if: + * - frame rate is high enough + * - image size is large enough + * - PNG is not more optimal based on image contents */ return framerate >= GUAC_COMMON_SURFACE_JPEG_FRAMERATE + && rect_size > GUAC_SURFACE_JPEG_MIN_BITMAP_SIZE && __guac_common_surface_png_optimality(surface, rect) < 0; } /** - * Returns whether the given rectangle would be optimally encoded as WebP + * Returns whether the given rectangle would be optimally encoded as WebP * rather than PNG. * * @param surface @@ -435,8 +447,14 @@ static int __guac_common_surface_should_use_webp(guac_common_surface* surface, if (!guac_client_supports_webp(surface->client)) return 0; - /* Usage criteria are currently the same as JPEG */ - return __guac_common_surface_should_use_jpeg(surface, rect); + /* Calculate the average framerate for the given rect */ + int framerate = __guac_common_surface_calculate_framerate(surface, rect); + + /* WebP is preferred if: + * - frame rate is high enough + * - PNG is not more optimal based on image contents */ + return framerate >= GUAC_COMMON_SURFACE_JPEG_FRAMERATE + && __guac_common_surface_png_optimality(surface, rect) < 0; }