diff --git a/Documentation/DocBook/v4l/planar-apis.xml b/Documentation/DocBook/v4l/planar-apis.xml index 7f3f5527057e049490e20ae154317a1092e3c28c..878ce204048831d8e70662ff8331288ac9e621dd 100644 --- a/Documentation/DocBook/v4l/planar-apis.xml +++ b/Documentation/DocBook/v4l/planar-apis.xml @@ -2,10 +2,10 @@ Single- and multi-planar APIs Some devices require data for each input or output video frame - to be placed in discontiguous memory buffers. In such cases one + to be placed in discontiguous memory buffers. In such cases, one video frame has to be addressed using more than one memory address, i.e. one - pointer per "plane". A plane is a sub-buffer of current frame. For examples - of such formats see . + pointer per "plane". A plane is a sub-buffer of the current frame. For + examples of such formats see . Initially, V4L2 API did not support multi-planar buffers and a set of extensions has been introduced to handle them. Those extensions constitute @@ -14,8 +14,8 @@ Some of the V4L2 API calls and structures are interpreted differently, depending on whether single- or multi-planar API is being used. An application can choose whether to use one or the other by passing a corresponding buffer - type to its ioctl calls. Multi-planar versions of buffer types are suffixed with - an `_MPLANE' string. For a list of available multi-planar buffer types + type to its ioctl calls. Multi-planar versions of buffer types are suffixed + with an `_MPLANE' string. For a list of available multi-planar buffer types see &v4l2-buf-type;. @@ -24,28 +24,9 @@ Multi-planar API introduces new multi-planar formats. Those formats use a separate set of FourCC codes. It is important to distinguish between the multi-planar API and a multi-planar format. Multi-planar API calls can - handle all single-planar formats as well, while the single-planar API cannot - handle multi-planar formats. Applications do not have to switch between APIs - when handling both single- and multi-planar devices and should use the - multi-planar API version for both single- and multi-planar formats. - Drivers that do not support multi-planar API can still be handled with it, - utilizing a compatibility layer built into standard V4L2 ioctl handling. - - - -
- Single and multi-planar API compatibility layer - In most casesThe compatibility layer does not cover - drivers that do not use video_ioctl2() call., applications - can use the multi-planar API with older drivers that support - only its single-planar version and vice versa. Appropriate conversion is - done seamlessly for both applications and drivers in the V4L2 core. The - general rule of thumb is: as long as an application uses formats that - a driver supports, it can use either API (although use of multi-planar - formats is only possible with the multi-planar API). The list of formats - supported by a driver can be obtained using the &VIDIOC-ENUM-FMT; call. - It is possible, but discouraged, for a driver or an application to support - and use both versions of the API. + handle all single-planar formats as well (as long as they are passed in + multi-planar API structures), while the single-planar API cannot + handle multi-planar formats.
diff --git a/Documentation/DocBook/v4l/vidioc-querycap.xml b/Documentation/DocBook/v4l/vidioc-querycap.xml index 93699769cd07fc3e999ca3bc9663903f755fb6c1..f29f1b86213c68b55744420f8cb65eeaff708806 100644 --- a/Documentation/DocBook/v4l/vidioc-querycap.xml +++ b/Documentation/DocBook/v4l/vidioc-querycap.xml @@ -142,30 +142,28 @@ this array to zero. V4L2_CAP_VIDEO_CAPTURE 0x00000001 - The device supports single-planar formats through the Video Capture interface. An application can use either -the single or the multi-planar API. + The device supports the single-planar API through the Video Capture interface. V4L2_CAP_VIDEO_CAPTURE_MPLANE 0x00001000 - The device supports multi-planar formats through the Video Capture interface. An application has to use the -multi-planar API. + The device supports the + multi-planar API through the + Video Capture interface. V4L2_CAP_VIDEO_OUTPUT 0x00000002 - The device supports single-planar formats through the Video Output interface. An application can use either -the single or the multi-planar API. + The device supports the single-planar API through the Video Output interface. V4L2_CAP_VIDEO_OUTPUT_MPLANE 0x00002000 - The device supports multi-planar formats through the Video Output interface. An application has to use the -multi-planar API. + The device supports the + multi-planar API through the + Video Output interface. V4L2_CAP_VIDEO_OVERLAY