esp-idf/examples/peripherals/usb/host/uvc

Supported Targets	ESP32-S2	ESP32-S3

USB Camera Example

Overview

This example demonstrates how to:

• Capture video from a USB camera using the libuvc library.
• Stream the video over WiFi by hosting a TCP server.

The example enumerates connected camera, negotiates selected resolution together with FPS and starts capturing video. frame_callback function is then invoked after receiving each frame. User can process received frame according to his needs.

Optionally, captured video can be visualized on computer with help of player.py script located in this example. After setting Enable streaming menuconfig option, example will create TCP server upon start, and wait until player.py connects to server. Once connection is established, example streams each received frame to computer for visualization.

Notice that libuvc selects highest possible dwMaxPayloadTransferSize by default, so example has to manually overwrite this value to 512 bytes (maximum transfer size supported by ESP32-S2/S3).

(See the README.md file in the upper level 'examples' directory for more information about examples.)

How to Use Example

Hardware Required

This example requires any ESP32-S2 or ESP32-S3 with external PSRAM and exposed USB connector attached to USB camera. ESP module without external PSRAM will fail to initialize

Configure the project

Following configuration is needed for streaming video:

Open the project configuration menu (idf.py menuconfig).

In the Example Connection Configuration menu:

• Set the Wi-Fi configuration.
  • Set WiFi SSID.
  • Set WiFi Password.

In the Example Configuration menu:

• Set the Example configuration
  • Enable streaming

Optional: If you need, change the other options according to your requirements.

Additionally, player.py python script makes use of opencv-python and numpy packages, not included in idf-env environment. Run following commands to install:

• pip install opencv-python
• pip install numpy

Build and Flash

Build the project and flash it to the board, then run the monitor tool to view the serial output:

Run idf.py set-target esp32s2 to set target chip.

Run idf.py -p PORT flash monitor to build, flash and monitor the project.

(To exit the serial monitor, type Ctrl-].)

See the Getting Started Guide for all the steps to configure and use the ESP-IDF to build projects.

Known limitations

Having only Full Speed USB peripheral and hardware limited MPS (maximum packet size) to 512 bytes, ESP32-S2/S3 is capable of reading about 0.5 MB of data per second. When connected to Full Speed USB host, cameras normally provide resolution no larger than 640x480 pixels. Following two supported formats are the most common (both encoded in MJPEG):

• 320x240 30 FPS
• 640x480 15 FPS

Tested cameras

• Logitech C980
• CANYON CNE-CWC2

Example Output

...
Waiting for device
Device found
DEVICE CONFIGURATION (0c45:6340/        S) ---
Status: idle
VideoControl:
        bcdUVC: 0x0100
VideoStreaming(1):
        bEndpointAddress: 129
        Formats:
        MJPEGFormat(1)
                  bits per pixel: 0
                  GUID: 4d4a5047000000000000000000000000 (MJPG)
                  default frame: 1
                  aspect ratio: 0x0
                  interlace flags: 00
                  copy protect: 00
                        FrameDescriptor(1)
                          capabilities: 00
                          size: 640x480
                          bit rate: 24576000-147456000
                          max frame size: 614400
                          default interval: 1/30
                          interval[0]: 1/30
                          interval[1]: 1/25
                          interval[2]: 1/20
                          interval[3]: 1/15
                          interval[4]: 1/10
                          interval[5]: 1/5
                        FrameDescriptor(2)
                          capabilities: 00
                          size: 352x288
                          bit rate: 8110080-48660480
                          max frame size: 202752
                          default interval: 1/30
                          interval[0]: 1/30
                          interval[1]: 1/25
                          interval[2]: 1/20
                          interval[3]: 1/15
                          interval[4]: 1/10
                          interval[5]: 1/5
                        FrameDescriptor(3)
                          capabilities: 00
                          size: 320x240
                          bit rate: 6144000-36864000
                          max frame size: 153600
                          default interval: 1/30
                          interval[0]: 1/30
                          interval[1]: 1/25
                          interval[2]: 1/20
                          interval[3]: 1/15
                          interval[4]: 1/10
                          interval[5]: 1/5
                        FrameDescriptor(4)
                          capabilities: 00
                          size: 176x144
                          bit rate: 2027520-12165120
                          max frame size: 50688
                          default interval: 1/30
                          interval[0]: 1/30
                          interval[1]: 1/25
                          interval[2]: 1/20
                          interval[3]: 1/15
                          interval[4]: 1/10
                          interval[5]: 1/5
                        FrameDescriptor(5)
                          capabilities: 00
                          size: 160x120
                          bit rate: 1536000-9216000
                          max frame size: 38400
                          default interval: 1/30
                          interval[0]: 1/30
                          interval[1]: 1/25
                          interval[2]: 1/20
                          interval[3]: 1/15
                          interval[4]: 1/10
                          interval[5]: 1/5
                        StillFrameDescriptor
                          bEndPointAddress: 00
                          wWidth(1) = 640
                          wHeight(1) = 480
                          wWidth(2) = 352
                          wHeight(2) = 288
                          wWidth(3) = 320
                          wHeight(3) = 240
                          wWidth(4) = 176
                          wHeight(4) = 144
                          wWidth(5) = 160
                          wHeight(5) = 120
END DEVICE CONFIGURATION
bmHint: 0001
bFormatIndex: 1
bFrameIndex: 3
dwFrameInterval: 333333
wKeyFrameRate: 0
wPFrameRate: 0
wCompQuality: 0
wCompWindowSize: 0
wDelay: 20905
dwMaxVideoFrameSize: 153600
dwMaxPayloadTransferSize: 512
bInterfaceNumber: 1
Streaming...
I (4801) example: fps: 35, bytes per second: 170480
I (5821) example: fps: 34, bytes per second: 172448
I (6841) example: fps: 34, bytes per second: 172448
I (7871) example: fps: 34, bytes per second: 172448
I (8891) example: fps: 34, bytes per second: 172448
I (9921) example: fps: 35, bytes per second: 177520
I (10941) example: fps: 34, bytes per second: 172448
I (11961) example: fps: 34, bytes per second: 172448
I (12991) example: fps: 34, bytes per second: 172448
I (14011) example: fps: 34, bytes per second: 172448
I (15041) example: fps: 34, bytes per second: 172448
I (16061) example: fps: 34, bytes per second: 172448
I (17081) example: fps: 34, bytes per second: 172448
Done streaming.
UVC exited