`mjpeg` — mjpeg recording#

The mjpeg module is used for mjpeg recording. Use it to record long video clips as compressed image data. Use gif for short clips.

Example usage:

import csi
import mjpeg
import time

# Setup camera.
csi0 = csi.CSI()
csi0.reset()
csi0.pixformat(csi.RGB565)
csi0.framesize(csi.QVGA)
csi0.snapshot(time=2000)

# Create the mjpeg object.
m = mjpeg.Mjpeg("example.mjpeg")

# Record for 20 seconds.
start = time.ticks_ms()
while time.ticks_diff(time.ticks_ms(), start) < 20000:
    m.add_frame(csi0.snapshot())

# Finalize.
m.close()

class Mjpeg – Mjpeg recorder#

class mjpeg.Mjpeg(path: str, width: int | None = None, height: int | None = None)#

Create a Mjpeg object which you can add frames to.

path is the file system path to save the mjpeg recording to.

width is the horizontal resolution of the mjpeg file. Defaults to the main framebuffer width when not specified.

height is the vertical resolution of the mjpeg file. Defaults to the main framebuffer height when not specified.

is_closed() → bool#: Returns True if the file has been closed. No more data can be written to a closed file.

width() → int#: Returns the horizontal resolution of the mjpeg file.

height() → int#: Returns the vertical resolution of the mjpeg file.

count() → int#: Returns the number of frames written to the mjpeg file.

size() → int#: Returns the size of the mjpeg file in bytes.

add_frame(image: image.Image, roi: Tuple[int, int, int, int] | None = None, rgb_channel: int = -1, alpha: int = 255, color_palette: image.Image | None = None, alpha_palette: image.Image | None = None, hint: int = 0, quality: int = 90) → None#

Append image to the mjpeg recording. The image is automatically scaled while preserving aspect ratio to the resolution specified when the file was created. Any image format is accepted; this method decompresses, scales/converts, and re-compresses as needed.

roi is the region-of-interest rectangle tuple (x, y, w, h) of image to copy. Defaults to the whole image.

rgb_channel is the RGB channel (0=R, 1=G, 2=B) to extract from an RGB565 source image and render in grayscale. -1 (default) disables channel extraction.

alpha (0-255) controls how much of the source image to blend into the destination. 255 is opaque; lower values blend with a black background; 0 results in a black frame.

color_palette is either a color palette enum (e.g. image.PALETTE_RAINBOW) or a 256-pixel RGB565 image used as a color lookup table on the grayscale value of the source image. Applied after rgb_channel extraction.

alpha_palette is a 256-pixel grayscale image used as an alpha lookup table modulating alpha per source pixel based on its grayscale value. 255 is opaque; 0 is transparent. Applied after rgb_channel extraction.

hint is a logical OR of:

image.AREA: Use area scaling when downscaling.
image.BILINEAR: Use bilinear scaling.
image.BICUBIC: Use bicubic scaling.
image.CENTER: Center the image on the destination.
image.HMIRROR: Horizontally mirror the image.
image.VFLIP: Vertically flip the image.
image.TRANSPOSE: Transpose the image (swap x/y).
image.EXTRACT_RGB_CHANNEL_FIRST: Apply rgb_channel before scaling.
image.APPLY_COLOR_PALETTE_FIRST: Apply color_palette before scaling.
image.SCALE_ASPECT_KEEP: Scale to fit inside the destination.
image.SCALE_ASPECT_EXPAND: Scale to fill the destination (crops).
image.SCALE_ASPECT_IGNORE: Scale to fill the destination (stretches).
image.ROTATE_90: Rotate by 90 degrees (VFLIP | TRANSPOSE).
image.ROTATE_180: Rotate by 180 degrees (HMIRROR | VFLIP).
image.ROTATE_270: Rotate by 270 degrees (HMIRROR | TRANSPOSE).

quality (0-100) is the JPEG compression quality used for non-JPEG source images.

write(image: image.Image, roi: Tuple[int, int, int, int] | None = None, rgb_channel: int = -1, alpha: int = 255, color_palette: image.Image | None = None, alpha_palette: image.Image | None = None, hint: int = 0, quality: int = 90) → None#: Alias for Mjpeg.add_frame().

sync() → None#: Flushes the mjpeg file to disk while keeping it open for further writes. Call periodically to ensure data is saved.

close() → None#: Finalizes the mjpeg recording. Must be called once recording is complete to make the file viewable.

mjpeg — mjpeg recording#

class Mjpeg – Mjpeg recorder#

`mjpeg` — mjpeg recording#