espressif/esp_video

readme

# Espressif Video Component

Espressif video component provides a solution to call POSIX API plus Linux V4L2 commands to capture data streams from multi camera sensors, and transform stream data pixel format according to Linux V4L2 M2M codec device.

[![Component Registry](https://components.espressif.com/components/espressif/esp_video/badge.svg)](https://components.espressif.com/components/espressif/esp_video)

Now we have implementations based on:

- esp_cam_sensor

## Video Device

| Hardware | Video Device | Type | Input Format | Output Format |
|:-:|:-:|:-:|:-|:-|
| MIPI-CSI | /dev/video0 | Capture | / | camera output pixel format or ISP output format(1) |
| DVP | /dev/video2 | Capture  | / | camera output pixel format |
| JPEG encode | /dev/video10 | M2M | RGB565: V4L2_PIX_FMT_RGB565<br> RGB888: V4L2_PIX_FMT_RGB24<br> YUV422: V4L2_PIX_FMT_YUV422P<br> Gray8: V4L2_PIX_FMT_GREY | JPEG: V4L2_PIX_FMT_JPEG |
| H.264 encode | /dev/video11 | M2M | YUV420: V4L2_PIX_FMT_YUV420 | H.264: V4L2_PIX_FMT_H264 |

- (1): if camera output pixel format is RAW8, ISP can transform it to other pixel format: RGB565, RGB888, YUV420 and YUV422

## V4L2 Control IDs

| ID | Class | Type | Permission | Description |
|:-:|:-:|:-:|:-:|:-|
| V4L2_CID_VFLIP | V4L2_CID_USER_CLASS | Bool | Read/Write | Mirror the picture vertically. |
| V4L2_CID_HFLIP | V4L2_CID_USER_CLASS | Bool | Read/Write | Mirror the picture horizontally. |
| V4L2_CID_GAIN | V4L2_CID_USER_CLASS | Menu | Read/Write | Picrure pixel gain value. |
| V4L2_CID_EXPOSURE | V4L2_CID_USER_CLASS | Integer | Read/Write | Camera sensor exposure time, value unit depends on sensor |
| V4L2_CID_EXPOSURE_ABSOLUTE | V4L2_CID_CAMERA_CLASS | Integer | Read/Write | Camera sensor exposure time, value unit is 100us. |
| V4L2_CID_TEST_PATTERN | V4L2_CID_IMAGE_PROC_CLASS | Menu | Write | Camera sensor test pattern mode. |
| V4L2_CID_JPEG_COMPRESSION_QUALITY | V4L2_CID_JPEG_CLASS | Integer | Read/Write | JPEG encoded picture quality |
| V4L2_CID_JPEG_CHROMA_SUBSAMPLING | V4L2_CID_JPEG_CLASS | Menu | Read/Write | The chroma subsampling factors describe how each component of an input image is sampled. |
| V4L2_CID_MPEG_VIDEO_H264_I_PERIOD | V4L2_CID_CODEC_CLASS | Integer | Read/Write | Period between I-frames. |
| V4L2_CID_MPEG_VIDEO_BITRATE | V4L2_CID_CODEC_CLASS | Integer | Read/Write | Video bitrate in bits per second. |
| V4L2_CID_MPEG_VIDEO_H264_MIN_QP | V4L2_CID_CODEC_CLASS | Integer | Read/Write | Minimum quantization parameter for H264. |
| V4L2_CID_MPEG_VIDEO_H264_MAX_QP | V4L2_CID_CODEC_CLASS | Integer | Read/Write | Maximum quantization parameter for H264. |