drivers: video: Add helper to estimate format size

Add a helper to estimate format size and pitch.

Signed-off-by: Phi Bang Nguyen <[email protected]>

Author: ngphibang

drivers/video/video_common.c

@@ -443,3 +443,26 @@ int64_t video_get_csi_link_freq(const struct device *dev, uint8_t bpp, uint8_t l
 	/* CSI D-PHY is using a DDR data bus so bitrate is twice the frequency */
 	return ctrl.val64 * bpp / (2 * lane_nb);
 }
+
+int video_estimate_fmt_size(struct video_format *fmt)
+{
+	if (fmt == NULL) {
+		return -EINVAL;
+	}
+
+	switch (fmt->pixelformat) {
+	case VIDEO_PIX_FMT_JPEG:
+		/* Rough estimate for the worst case (quality = 100) */
+		fmt->pitch = 0;
+		fmt->size = fmt->width * fmt->height * 2;
+		return 0;
+	default:
+		/* Uncompressed format */
+		fmt->pitch = fmt->width * video_bits_per_pixel(fmt->pixelformat) / BITS_PER_BYTE;
+		if (fmt->pitch == 0) {
+			return -ENOTSUP;
+		}
+		fmt->size = fmt->pitch * fmt->height;
+		return 0;
+	}
+}

include/zephyr/drivers/video.h

@@ -988,6 +988,22 @@ void video_closest_frmival(const struct device *dev, struct video_frmival_enum *
  */
 int64_t video_get_csi_link_freq(const struct device *dev, uint8_t bpp, uint8_t lane_nb);
 
+/**
+ * @brief Estimate the size and pitch in bytes of a @ref video_format
+ *
+ * This helper should only be used by drivers that support the whole image frame.
+ *
+ * For uncompressed formats, it gives the actual size and pitch of the
+ * whole raw image without any padding.
+ *
+ * For compressed formats, it gives a rough estimate size of a complete
+ * compressed frame.
+ *
+ * @param fmt Pointer to the video format structure
+ * @return 0 on success, otherwise a negative errno code
+ */
+int video_estimate_fmt_size(struct video_format *fmt);
+
 /**
  * @defgroup video_pixel_formats Video pixel formats
  * The '|' characters separate the pixels or logical blocks, and spaces separate the bytes.