https://github.com/tetsu-koba/v4l2capture

v4l2 video capturer written in Zig
https://github.com/tetsu-koba/v4l2capture

v4l2 video-streaming zig

Last synced: 3 months ago
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v4l2 video capturer written in Zig

• Host: GitHub
• URL: https://github.com/tetsu-koba/v4l2capture
• Owner: tetsu-koba
• License: mit
• Created: 2023-04-20T06:00:48.000Z (over 1 year ago)
• Default Branch: main
• Last Pushed: 2024-05-18T05:41:53.000Z (6 months ago)
• Last Synced: 2024-05-18T06:30:04.513Z (6 months ago)
• Topics: v4l2, video-streaming, zig
• Language: Zig
• Homepage:
• Size: 59.6 KB
• Stars: 4
• Watchers: 1
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

Awesome Lists containing this project

• awesome-zig - tetsu-koba/v4l2capture

README

        
#  V4L2 video capturer written in Zig

Capture video frames from V4l2 camera device.

## How to Build and Show Usage

```shell-session

$ zig version

0.11.0-dev.2777+b95cdf0ae

$ zig build

$ ./zig-out/bin/v4l2capture 

Usage: ./zig-out/bin/v4l2capture /dev/videoX URL [width height framerate pixelformat max_frames]

	URL is 'file://filename', 'tcp://hostname:port' or just filename.

	Default width, height and framerate is 640x480@30fps

	pixelformat is FourCC such as MJPG and YUYV. Defaut is MJPG.

	max_frames is the number of frames to capture. Default is unlimited(0). Stop by Control-C.

```

## Save to local file

```shell-session

$ ./zig-out/bin/v4l2capture /dev/video0 out.mjpg 320 240 30

warning: Requested format is 320x240 but set to 320x180.

^Cinfo: 1682150185282:Got SIGINT

info: 1682150185304:duration 24769ms, frame_count 743, 30.00fps

```

Stop the process by entering ^C at an appropriate point.

Although 320x240 was requested, the camera did not support it, so the message states that it has been changed to 320x180.

## Playing the generated mjpg file

```shell-session

$ ffprobe out.mjpg

...

Input #0, jpeg_pipe, from 'out.mjpg':

  Duration: N/A, bitrate: N/A

    Stream #0:0: Video: mjpeg (Baseline), yuvj422p(pc, bt470bg/unknown/unknown), 320x180, 25 fps, 25 tbr, 25 tbn, 25 tbc

```

Although it shows 25fps here, this is incorrect. The default value for ffprobe when the frame rate is unknown is 25fps.

When playing this with ffplay, you need to explicitly specify the frame rate.

```shell-session

$ ffplay -framerate 30 out.mjpg

```

## Sending MJPEG over TCP and remote playback

With the update of 2023/04/24, MJPEG can now be sent over TCP.

On the receiver:

```shell-session

$ ffplay -hide_banner -autoexit "tcp://:8999?listen"

```

On the sender:

```shell-session

$ zig-out/bin/v4l2capture /dev/video0 tcp://host:8999 320 240 15

```