opt jpeg scanline copy with yuv format

pikvm · Oct 9, 2023 · 2ae82cc · 2ae82cc
1 parent ec33425
commit 2ae82cc
Showing 1 changed file with 34 additions and 41 deletions.
diff --git a/src/ustreamer/encoders/cpu/encoder.c b/src/ustreamer/encoders/cpu/encoder.c
@@ -26,6 +26,7 @@
 
 
 #include "encoder.h"
+#include <stdint.h>
 
 
 typedef struct {
@@ -64,7 +65,7 @@ void us_cpu_encoder_compress(const us_frame_s *src, us_frame_s *dest, unsigned q
 	jpeg.image_width = src->width;
 	jpeg.image_height = src->height;
 	jpeg.input_components = 3;
-	jpeg.in_color_space = JCS_RGB;
+	jpeg.in_color_space = (src->format == V4L2_PIX_FMT_YUYV || src->format == V4L2_PIX_FMT_UYVY)? JCS_YCbCr: JCS_RGB;
 
 	jpeg_set_defaults(&jpeg);
 	jpeg_set_quality(&jpeg, quality, TRUE);
@@ -119,28 +120,23 @@ static void _jpeg_write_scanlines_yuyv(struct jpeg_compress_struct *jpeg, const
 
 	const unsigned padding = us_frame_get_padding(frame);
 	const uint8_t *data = frame->data;
-	unsigned z = 0;
 
 	while (jpeg->next_scanline < frame->height) {
 		uint8_t *ptr = line_buf;
 
 		for (unsigned x = 0; x < frame->width; ++x) {
-			const int y = (!z ? data[0] << 8 : data[2] << 8);
-			const int u = data[1] - 128;
-			const int v = data[3] - 128;
-
-			const int r = YUV_R(y, u, v);
-			const int g = YUV_G(y, u, v);
-			const int b = YUV_B(y, u, v);
-
-			*(ptr++) = NORM_COMPONENT(r);
-			*(ptr++) = NORM_COMPONENT(g);
-			*(ptr++) = NORM_COMPONENT(b);
-
-			if (z++) {
-				z = 0;
-				data += 4;
-			}
+			// see also: https://www.kernel.org/doc/html/v4.8/media/uapi/v4l/pixfmt-yuyv.html
+			const bool is_odd_pixel = x & 1;
+			const uint8_t y = data[is_odd_pixel ? 2: 0];
+			const uint8_t u = data[1];
+			const uint8_t v = data[3];
+
+			ptr[0] = y;
+			ptr[1] = u;
+			ptr[2] = v;
+			ptr += 3;
+
+			data += is_odd_pixel? 4: 0;
 		}
 		data += padding;
 
@@ -157,28 +153,23 @@ static void _jpeg_write_scanlines_uyvy(struct jpeg_compress_struct *jpeg, const
 
 	const unsigned padding = us_frame_get_padding(frame);
 	const uint8_t *data = frame->data;
-	unsigned z = 0;
 
 	while (jpeg->next_scanline < frame->height) {
 		uint8_t *ptr = line_buf;
 
 		for (unsigned x = 0; x < frame->width; ++x) {
-			const int y = (!z ? data[1] << 8 : data[3] << 8);
-			const int u = data[0] - 128;
-			const int v = data[2] - 128;
-
-			const int r = YUV_R(y, u, v);
-			const int g = YUV_G(y, u, v);
-			const int b = YUV_B(y, u, v);
-
-			*(ptr++) = NORM_COMPONENT(r);
-			*(ptr++) = NORM_COMPONENT(g);
-			*(ptr++) = NORM_COMPONENT(b);
-
-			if (z++) {
-				z = 0;
-				data += 4;
-			}
+			// see also: https://www.kernel.org/doc/html/v4.8/media/uapi/v4l/pixfmt-uyvy.html
+			const bool is_odd_pixel = x & 1;
+			const uint8_t y = data[is_odd_pixel ? 3: 1];
+			const uint8_t u = data[0];
+			const uint8_t v = data[2];
+
+			ptr[0] = y;
+			ptr[1] = u;
+			ptr[2] = v;
+			ptr += 3;
+
+			data += is_odd_pixel? 4: 0;
 		}
 		data += padding;
 
@@ -207,9 +198,10 @@ static void _jpeg_write_scanlines_rgb565(struct jpeg_compress_struct *jpeg, cons
 		for (unsigned x = 0; x < frame->width; ++x) {
 			const unsigned int two_byte = (data[1] << 8) + data[0];
 
-			*(ptr++) = data[1] & 248; // Red
-			*(ptr++) = (uint8_t)((two_byte & 2016) >> 3); // Green
-			*(ptr++) = (data[0] & 31) * 8; // Blue
+			ptr[0] = data[1] & 248; // Red
+			ptr[1] = (uint8_t)((two_byte & 2016) >> 3); // Green
+			ptr[2] = (data[0] & 31) * 8; // Blue
+			ptr += 3;
 
 			data += 2;
 		}
@@ -234,9 +226,10 @@ static void _jpeg_write_scanlines_bgr24(struct jpeg_compress_struct *jpeg, const
 
 		// swap B and R values
 		for (unsigned x = 0; x < frame->width * 3; x+=3) {
-			*(ptr++) = data[x+2];
-			*(ptr++) = data[x+1];
-			*(ptr++) = data[x];
+			ptr[0] = data[x+2];
+			ptr[1] = data[x+1];
+			ptr[2] = data[x];
+			ptr += 3;
 		}
 
 		JSAMPROW scanlines[1] = {line_buf};