media: hantro: jpeg: Add JFIF APP0 segment to JPEG encoder output

While the V4L2_PIX_FMT_JPEG format doesn't specify any requirements for
the APP0 or APP1 segments, it would be nice if the output is JFIF
compliant. While some programs can read JPEG streams that aren't, some
guess work is involved.

Add the standard JFIF APP0 segment to the JPEG header, so that the JPEG
encoder output is JFIF compliant.
Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
Reviewed-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

drivers/staging/media/hantro/hantro_jpeg.c

@@ -12,15 +12,15 @@
 #include "hantro_jpeg.h"
 #include "hantro.h"
 
-#define LUMA_QUANT_OFF		7
-#define CHROMA_QUANT_OFF	72
-#define HEIGHT_OFF		141
-#define WIDTH_OFF		143
+#define LUMA_QUANT_OFF		25
+#define CHROMA_QUANT_OFF	90
+#define HEIGHT_OFF		159
+#define WIDTH_OFF		161
 
-#define HUFF_LUMA_DC_OFF	160
-#define HUFF_LUMA_AC_OFF	193
-#define HUFF_CHROMA_DC_OFF	376
-#define HUFF_CHROMA_AC_OFF	409
+#define HUFF_LUMA_DC_OFF	178
+#define HUFF_LUMA_AC_OFF	211
+#define HUFF_CHROMA_DC_OFF	394
+#define HUFF_CHROMA_AC_OFF	427
 
 /* Default tables from JPEG ITU-T.81
  * (ISO/IEC 10918-1) Annex K, tables K.1 and K.2
@@ -144,6 +144,11 @@ static const unsigned char hantro_jpeg_header[JPEG_HEADER_SIZE] = {
 	/* SOI */
 	0xff, 0xd8,
 
+	/* JFIF-APP0 */
+	0xff, 0xe0, 0x00, 0x10, 0x4a, 0x46, 0x49, 0x46,
+	0x00, 0x01, 0x01, 0x00, 0x00, 0x01, 0x00, 0x01,
+	0x00, 0x00,
+
 	/* DQT */
 	0xff, 0xdb, 0x00, 0x84,
 

drivers/staging/media/hantro/hantro_jpeg.h

 /* SPDX-License-Identifier: GPL-2.0+ */
 
-#define JPEG_HEADER_SIZE	601
+#define JPEG_HEADER_SIZE	619
 #define JPEG_QUANT_SIZE		64
 
 struct hantro_jpeg_ctx {