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, mjpeg, time

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

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

# Add frames.
for i in range(100):
    c.tick()
    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:

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.