From 4266129964b8238526936d723de65b419d8069c6 Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Tue, 31 May 2011 16:27:44 -0300 Subject: [media] DocBook: Move all media docbook stuff into its own directory This patch addresses several issues pointed by Randy Dunlap at changeset ece722c: - In the generated index.html file, "media" is listed first, but it should be listed in alphabetical order, not first. - The generated files are (hidden) in .tmpmedia/ - The link from the top-level index.html file to "media" is to media/index.html, but the file is actually in .tmpmedia/media/index.html - Please build docs with and without using "O=builddir" and test that. - Would it be possible for media to have its own Makefile instead of merging into this one? Due to the way cleandocs target works, I had to rename the media DocBook to media_api, otherwise cleandocs would remove the /media directory. Thanks-to: Randy Dunlap Signed-off-by: Mauro Carvalho Chehab --- Documentation/DocBook/v4l/dev-output.xml | 114 ------------------------------- 1 file changed, 114 deletions(-) delete mode 100644 Documentation/DocBook/v4l/dev-output.xml (limited to 'Documentation/DocBook/v4l/dev-output.xml') diff --git a/Documentation/DocBook/v4l/dev-output.xml b/Documentation/DocBook/v4l/dev-output.xml deleted file mode 100644 index 919e22c5385..00000000000 --- a/Documentation/DocBook/v4l/dev-output.xml +++ /dev/null @@ -1,114 +0,0 @@ - Video Output Interface - - Video output devices encode stills or image sequences as -analog video signal. With this interface applications can -control the encoding process and move images from user space to -the driver. - - Conventionally V4L2 video output devices are accessed through -character device special files named /dev/video -and /dev/video0 to -/dev/video63 with major number 81 and minor -numbers 0 to 63. /dev/video is typically a -symbolic link to the preferred video device. Note the same device -files are used for video capture devices. - -
- Querying Capabilities - - Devices supporting the video output interface set the -V4L2_CAP_VIDEO_OUTPUT or -V4L2_CAP_VIDEO_OUTPUT_MPLANE flag in the -capabilities field of &v4l2-capability; -returned by the &VIDIOC-QUERYCAP; ioctl. As secondary device functions -they may also support the raw VBI -output (V4L2_CAP_VBI_OUTPUT) interface. At -least one of the read/write or streaming I/O methods must be -supported. Modulators and audio outputs are optional. -
- -
- Supplemental Functions - - Video output devices shall support audio output, modulator, controls, -cropping and scaling and streaming parameter ioctls as needed. -The video output and video standard ioctls must be supported by -all video output devices. -
- -
- Image Format Negotiation - - The output is determined by cropping and image format -parameters. The former select an area of the video picture where the -image will appear, the latter how images are stored in memory, &ie; in -RGB or YUV format, the number of bits per pixel or width and height. -Together they also define how images are scaled in the process. - - As usual these parameters are not reset -at &func-open; time to permit Unix tool chains, programming a device -and then writing to it as if it was a plain file. Well written V4L2 -applications ensure they really get what they want, including cropping -and scaling. - - Cropping initialization at minimum requires to reset the -parameters to defaults. An example is given in . - - To query the current image format applications set the -type field of a &v4l2-format; to -V4L2_BUF_TYPE_VIDEO_OUTPUT or -V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE and call the -&VIDIOC-G-FMT; ioctl with a pointer to this structure. Drivers fill -the &v4l2-pix-format; pix or the -&v4l2-pix-format-mplane; pix_mp member of the -fmt union. - - To request different parameters applications set the -type field of a &v4l2-format; as above and -initialize all fields of the &v4l2-pix-format; -vbi member of the -fmt union, or better just modify the -results of VIDIOC_G_FMT, and call the -&VIDIOC-S-FMT; ioctl with a pointer to this structure. Drivers may -adjust the parameters and finally return the actual parameters as -VIDIOC_G_FMT does. - - Like VIDIOC_S_FMT the -&VIDIOC-TRY-FMT; ioctl can be used to learn about hardware limitations -without disabling I/O or possibly time consuming hardware -preparations. - - The contents of &v4l2-pix-format; and &v4l2-pix-format-mplane; -are discussed in . See also the specification of the -VIDIOC_G_FMT, VIDIOC_S_FMT -and VIDIOC_TRY_FMT ioctls for details. Video -output devices must implement both the -VIDIOC_G_FMT and -VIDIOC_S_FMT ioctl, even if -VIDIOC_S_FMT ignores all requests and always -returns default parameters as VIDIOC_G_FMT does. -VIDIOC_TRY_FMT is optional. -
- -
- Writing Images - - A video output device may support the write() function and/or streaming (memory mapping or user pointer) I/O. See for details. -
- - -- cgit v1.2.3-70-g09d2