1. Common API Elements

Programming a V4L2 device consists of these steps:

• Opening the device
• Changing device properties, selecting a video and audio input, video standard, picture brightness a. o.
• Negotiating a data format
• Negotiating an input/output method
• The actual input/output loop
• Closing the device

In practice most steps are optional and can be executed out of order. It depends on the V4L2 device type, you can read about the details in Interfaces. In this chapter we will discuss the basic concepts applicable to all devices.

• 1.1. Opening and Closing Devices
• 1.2. Querying Capabilities
• 1.3. Application Priority
• 1.4. Video Inputs and Outputs
• 1.5. Audio Inputs and Outputs
• 1.6. Tuners and Modulators
• 1.7. Video Standards
• 1.8. Digital Video (DV) Timings
• 1.9. User Controls
• 1.10. Extended Controls
• 1.11. Data Formats
• 1.12. Single- and multi-planar APIs
• 1.13. Image Cropping, Insertion and Scaling
• 1.14. API for cropping, composing and scaling
• 1.15. Streaming Parameters