SLIDE 1
Contents
- Introduction
- Future (from last years presentation)
- Emulated controls
- When to enable?
- Video processing
- Future
libv4l Hans de Goede Red Hat Contents Introduction Future (from - - PowerPoint PPT Presentation
libv4l Hans de Goede Red Hat Contents Introduction Future (from - - PowerPoint PPT Presentation
libv4l Hans de Goede Red Hat Contents Introduction Future (from last years presentation) Emulated controls When to enable? Video processing Future Introduction Fedora better webcam support feature:
SLIDE 2
SLIDE 3
Introduction
- Fedora better webcam support feature:
http://fedoraproject.org/wiki/Features/BetterWebcamSupport
- Get gspca into the mainline kernel
- Remove format conversion from gspca
- Applications don't handle the new formats
- Sollution: Write a conversion library
- And patch ALL applications to use it
SLIDE 4
The Future?
- Add emulated controls
- Better handle rotation
- Software image quality enhancements:
– White balance – Normalize
- Software image quality enhancements have a
separate measure / transform phase
- GET_WEBCAM_ATTR ioctl
- Emulated controls persistency
SLIDE 5
Emulated controls
- Persistent
- Shared
- Using shared memory:
/dev/shm/libv4l-hans:usb-0000:00:1d.7-5: BisonCam NB Pro
- Disadvantage: settings are per user
SLIDE 6
When to enable ?
- Enabling emulated controls, forces libv4l to go
through the conversion path, even when not converting.
- libv4l has a device table for devices which
benefit from software video processing.
- Also enabled when the device will always need
conversion.
SLIDE 7
Video Processing
- White balancing, simple make image gray on
average algorithm
- Gamma correction
- Manipulate per component (RGB) component
lookup tables, so once sort of processing is enabled, further processing is essentially free.
- Only works in RGB color space, requires YUV
- > RGB -> YUV conversion in certain cases
SLIDE 8
The Future
- Add plugable processing algorithms, so that we
can have driver specific algorithms
- Move quirk table to a config file ?
- Support for software auto focus ?
- Support for video input device sharing ?
- Get more out of tree drivers into the mainline,
port mainline v4l1 drivers to v4l2
SLIDE 9
libv4l
Hans de Goede Red Hat
SLIDE 10
Contents
- Introduction
- Future (from last years presentation)
- Emulated controls
- When to enable?
- Video processing
- Future
SLIDE 11
Introduction
- Fedora better webcam support feature:
http://fedoraproject.org/wiki/Features/BetterWebcamSupport
- Get gspca into the mainline kernel
- Remove format conversion from gspca
- Applications don't handle the new formats
- Sollution: Write a conversion library
- And patch ALL applications to use it
SLIDE 12
The Future?
- Add emulated controls
- Better handle rotation
- Software image quality enhancements:
– White balance – Normalize
- Software image quality enhancements have a
separate measure / transform phase
- GET_WEBCAM_ATTR ioctl
- Emulated controls persistency
SLIDE 13
Emulated controls
- Persistent
- Shared
- Using shared memory:
/dev/shm/libv4l-hans:usb-0000:00:1d.7-5: BisonCam NB Pro
- Disadvantage: settings are per user
SLIDE 14
When to enable ?
- Enabling emulated controls, forces libv4l to go
through the conversion path, even when not converting.
- libv4l has a device table for devices which
benefit from software video processing.
- Also enabled when the device will always need
conversion.
SLIDE 15
Video Processing
- White balancing, simple make image gray on
average algorithm
- Gamma correction
- Manipulate per component (RGB) component
lookup tables, so once sort of processing is enabled, further processing is essentially free.
- Only works in RGB color space, requires YUV
- > RGB -> YUV conversion in certain cases
SLIDE 16
The Future
- Add plugable processing algorithms, so that we
can have driver specific algorithms
- Move quirk table to a config file ?
- Support for software auto focus ?
- Support for video input device sharing ?
- Get more out of tree drivers into the mainline,
port mainline v4l1 drivers to v4l2