media/v4l/diff-v4l.rst

7 Differences between V4L and V4L2
13 the much improved V4L2 API replaces the V4L API. The support for the old
15 supports the conversion of a V4L API system call into a V4L2 one.
21 for V4L2 video capture, overlay, radio and raw vbi capture devices did
25 The teletext devices (minor range 192-223) have been removed in V4L2 and
31 recommend that V4L2 drivers by default register devices with the same
56 V4L2 drivers *may* support multiple opens, see :ref:`open` for details
59 V4L drivers respond to V4L2 ioctls with an ``EINVAL`` error code.
64 The V4L ``VIDIOCGCAP`` ioctl is equivalent to V4L2's
69 was replaced by ``capabilities``. Note V4L2 does not distinguish between
121       - This flag indicates if the hardware can scale images. The V4L2 API
137 	of the full picture ("cropping" in V4L2). If not, the ioctl
176 device. The equivalent V4L2 ioctls are
198 input, V4L2 assumes each video input is connected to at most one tuner.
207 ``VIDEO_VC_AUDIO`` flag was replaced by the ``audioset`` field. V4L2
217 meantime. V4L2 has a similar, albeit more comprehensive approach to
225 V4L TV or radio device. The equivalent V4L2 ioctls are
268 V4L2 has no equivalent of the ``VIDIOCGPICT`` and ``VIDIOCSPICT`` ioctl
270 replaced by V4L2 controls accessible with the
281       - V4L2 Control ID
294 particular reset value. The V4L2 API permits arbitrary limits and
300 implied by the selected image format. V4L2 does not explicitly provide
313       - :ref:`V4L2_PIX_FMT_GREY <V4L2-PIX-FMT-GREY>`
325       - :ref:`V4L2_PIX_FMT_YUYV <V4L2-PIX-FMT-YUYV>`
327       - :ref:`V4L2_PIX_FMT_YUYV <V4L2-PIX-FMT-YUYV>`
329       - :ref:`V4L2_PIX_FMT_UYVY <V4L2-PIX-FMT-UYVY>`
333       - :ref:`V4L2_PIX_FMT_Y41P <V4L2-PIX-FMT-Y41P>` [#f6]_
337       - :ref:`V4L2_PIX_FMT_YUV422P <V4L2-PIX-FMT-YUV422P>`
339       - :ref:`V4L2_PIX_FMT_YUV411P <V4L2-PIX-FMT-YUV411P>` [#f8]_
341       - :ref:`V4L2_PIX_FMT_YVU420 <V4L2-PIX-FMT-YVU420>`
343       - :ref:`V4L2_PIX_FMT_YVU410 <V4L2-PIX-FMT-YVU410>`
345 V4L2 image formats are defined in :ref:`pixfmt`. The image format can
353 of a V4L device. The equivalent V4L2 ioctls are
368 programmes in this field. In the V4L2 API this information is stored in
375 The following fields where replaced by V4L2 controls accessible with the
386       - V4L2 Control ID
398 ``VIDEO_AUDIO_TREBLE`` and ``VIDEO_AUDIO_BALANCE``. In the V4L2 API the
404 All V4L2 controls have a ``step`` attribute replacing the struct
407 V4L2 API permits arbitrary limits and defaults which can be queried with
414 The V4L2 ioctls equivalent to ``VIDIOCGFBUF`` and ``VIDIOCSFBUF`` are
417 ``video_buffer`` remained unchanged, except V4L2 defines
425 Instead of the special ioctls ``VIDIOCGWIN`` and ``VIDIOCSWIN`` V4L2
462 ``video_capture``. The equivalent V4L2 ioctls are
472 the V4L2 API the scaling factor is implied by the size of the cropping
490 V4L2 device using the :c:func:`read()` function, however V4L2
493 :ref:`VIDIOC_QUERYCAP` ioctl. All V4L2 devices
499 ``VIDIOCSWIN`` ioctls. V4L2 uses the general-purpose data format
506 For more information about the V4L2 read interface see :ref:`rw`.
514 read method. V4L2 supports memory mapping as well, with a few
523       - V4L2
605 parameters. These ioctls are only partially compatible with the V4L2 VBI
614 semantics differ from those specified for V4L2 in two ways. The
622 V4L2 has no equivalent of the ``VIDIOCGUNIT`` ioctl. Applications can
634    compatible with V4L or V4L2.
641    This is a custom format used by the BTTV driver, not one of the V4L2
646    drivers might interpret them according to machine endianness. V4L2