From 583aa3a9b5ca846a84f7dd87bdc4b75dca07b011 Mon Sep 17 00:00:00 2001 From: Hans Verkuil Date: Wed, 11 Jan 2012 06:45:05 -0300 Subject: [media] V4L2: Add per-device-node capabilities If V4L2_CAP_DEVICE_CAPS is set, then the new device_caps field is filled with the capabilities of the opened device node. The capabilities field traditionally contains the capabilities of the physical device, being a superset of all capabilities available at the several device nodes. E.g., if you open /dev/video0, then if it contains VBI caps then that means that there is a corresponding vbi node as well. And the capabilities field of both the video and vbi nodes should contain identical caps. However, it would be very useful to also have a capabilities field that contains just the caps for the currently open device, hence the new CAP bit and field. Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- Documentation/DocBook/media/v4l/compat.xml | 4 +++ Documentation/DocBook/media/v4l/v4l2.xml | 9 +++++- .../DocBook/media/v4l/vidioc-querycap.xml | 36 ++++++++++++++++++++-- 3 files changed, 45 insertions(+), 4 deletions(-) (limited to 'Documentation/DocBook') diff --git a/Documentation/DocBook/media/v4l/compat.xml b/Documentation/DocBook/media/v4l/compat.xml index c736380b4647..c93298ff3279 100644 --- a/Documentation/DocBook/media/v4l/compat.xml +++ b/Documentation/DocBook/media/v4l/compat.xml @@ -2393,6 +2393,10 @@ details. to the User controls class. + + Added the device_caps field to struct v4l2_capabilities and added the new + V4L2_CAP_DEVICE_CAPS capability. + diff --git a/Documentation/DocBook/media/v4l/v4l2.xml b/Documentation/DocBook/media/v4l/v4l2.xml index e97c512861bb..dce3fef15bc9 100644 --- a/Documentation/DocBook/media/v4l/v4l2.xml +++ b/Documentation/DocBook/media/v4l/v4l2.xml @@ -127,6 +127,13 @@ structs, ioctls) must be noted in more detail in the history chapter (compat.xml), along with the possible impact on existing drivers and applications. --> + + 3.3 + 2012-01-11 + hv + Added device_caps field to struct v4l2_capabilities. + + 3.2 2011-08-26 @@ -417,7 +424,7 @@ and discussions on the V4L mailing list. Video for Linux Two API Specification - Revision 3.2 + Revision 3.3 &sub-common; diff --git a/Documentation/DocBook/media/v4l/vidioc-querycap.xml b/Documentation/DocBook/media/v4l/vidioc-querycap.xml index e3664d6f2de4..4643505cd4ca 100644 --- a/Documentation/DocBook/media/v4l/vidioc-querycap.xml +++ b/Documentation/DocBook/media/v4l/vidioc-querycap.xml @@ -124,12 +124,35 @@ printf ("Version: %u.%u.%u\n", __u32 capabilities - Device capabilities, see . + Available capabilities of the physical device as a whole, see . The same physical device can export + multiple devices in /dev (e.g. /dev/videoX, /dev/vbiY and /dev/radioZ). + The capabilities field should contain a union + of all capabilities available around the several V4L2 devices exported + to userspace. + For all those devices the capabilities field + returns the same set of capabilities. This allows applications to open + just one of the devices (typically the video device) and discover whether + video, vbi and/or radio are also supported. + __u32 - reserved[4] + device_caps + Device capabilities of the opened device, see . Should contain the available capabilities + of that specific device node. So, for example, device_caps + of a radio device will only contain radio related capabilities and + no video or vbi capabilities. This field is only set if the capabilities + field contains the V4L2_CAP_DEVICE_CAPS capability. + Only the capabilities field can have the + V4L2_CAP_DEVICE_CAPS capability, device_caps + will never set V4L2_CAP_DEVICE_CAPS. + + + + __u32 + reserved[3] Reserved for future extensions. Drivers must set this array to zero. @@ -276,6 +299,13 @@ linkend="async">asynchronous I/O methods. The device supports the streaming I/O method. + + V4L2_CAP_DEVICE_CAPS + 0x80000000 + The driver fills the device_caps + field. This capability can only appear in the capabilities + field and never in the device_caps field. + -- cgit v1.2.3 From 6b4f12523db46536c750473abdd380763cb0409b Mon Sep 17 00:00:00 2001 From: Hans Verkuil Date: Thu, 24 Nov 2011 09:55:53 -0300 Subject: [media] v4l spec: document VIDIOC_(TRY_)DECODER_CMD Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- Documentation/DocBook/media/v4l/v4l2.xml | 1 + .../DocBook/media/v4l/vidioc-decoder-cmd.xml | 256 +++++++++++++++++++++ .../DocBook/media/v4l/vidioc-encoder-cmd.xml | 9 +- 3 files changed, 262 insertions(+), 4 deletions(-) create mode 100644 Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml (limited to 'Documentation/DocBook') diff --git a/Documentation/DocBook/media/v4l/v4l2.xml b/Documentation/DocBook/media/v4l/v4l2.xml index dce3fef15bc9..dcf9e33b695f 100644 --- a/Documentation/DocBook/media/v4l/v4l2.xml +++ b/Documentation/DocBook/media/v4l/v4l2.xml @@ -480,6 +480,7 @@ and discussions on the V4L mailing list. &sub-cropcap; &sub-dbg-g-chip-ident; &sub-dbg-g-register; + &sub-decoder-cmd; &sub-dqevent; &sub-encoder-cmd; &sub-enumaudio; diff --git a/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml b/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml new file mode 100644 index 000000000000..466fe27d3ffe --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml @@ -0,0 +1,256 @@ + + + ioctl VIDIOC_DECODER_CMD, VIDIOC_TRY_DECODER_CMD + &manvol; + + + + VIDIOC_DECODER_CMD + VIDIOC_TRY_DECODER_CMD + Execute an decoder command + + + + + + int ioctl + int fd + int request + struct v4l2_decoder_cmd *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_DECODER_CMD, VIDIOC_TRY_DECODER_CMD + + + + argp + + + + + + + + + Description + + + Experimental + + This is an experimental +interface and may change in the future. + + + These ioctls control an audio/video (usually MPEG-) decoder. +VIDIOC_DECODER_CMD sends a command to the +decoder, VIDIOC_TRY_DECODER_CMD can be used to +try a command without actually executing it. To send a command applications +must initialize all fields of a &v4l2-decoder-cmd; and call +VIDIOC_DECODER_CMD or VIDIOC_TRY_DECODER_CMD +with a pointer to this structure. + + The cmd field must contain the +command code. Some commands use the flags field for +additional information. + + + A write() or &VIDIOC-STREAMON; call sends an implicit +START command to the decoder if it has not been started yet. + + + A close() or &VIDIOC-STREAMOFF; call of a streaming +file descriptor sends an implicit immediate STOP command to the decoder, and all +buffered data is discarded. + + These ioctls are optional, not all drivers may support +them. They were introduced in Linux 3.3. + + + struct <structname>v4l2_decoder_cmd</structname> + + &cs-str; + + + __u32 + cmd + + + The decoder command, see . + + + __u32 + flags + + + Flags to go with the command. If no flags are defined for +this command, drivers and applications must set this field to zero. + + + union + (anonymous) + + + + + + + struct + start + + Structure containing additional data for the +V4L2_DEC_CMD_START command. + + + + + __u32 + speed + Playback speed and direction. The playback speed is defined as +speed/1000 of the normal speed. So 1000 is normal playback. +Negative numbers denote reverse playback, so -1000 does reverse playback at normal +speed. Speeds -1, 0 and 1 have special meanings: speed 0 is shorthand for 1000 +(normal playback). A speed of 1 steps just one frame forward, a speed of -1 steps +just one frame back. + + + + + + __u32 + format + Format restrictions. This field is set by the driver, not the +application. Possible values are V4L2_DEC_START_FMT_NONE if +there are no format restrictions or V4L2_DEC_START_FMT_GOP +if the decoder operates on full GOPs (Group Of Pictures). +This is usually the case for reverse playback: the decoder needs full GOPs, which +it can then play in reverse order. So to implement reverse playback the application +must feed the decoder the last GOP in the video file, then the GOP before that, etc. etc. + + + + + struct + stop + + Structure containing additional data for the +V4L2_DEC_CMD_STOP command. + + + + + __u64 + pts + Stop playback at this pts or immediately +if the playback is already past that timestamp. Leave to 0 if you want to stop after the +last frame was decoded. + + + + + struct + raw + + + + + + + __u32 + data[16] + Reserved for future extensions. Drivers and +applications must set the array to zero. + + + +
+ + + Decoder Commands + + &cs-def; + + + V4L2_DEC_CMD_START + 0 + Start the decoder. When the decoder is already +running or paused, this command will just change the playback speed. +That means that calling V4L2_DEC_CMD_START when +the decoder was paused will not resume the decoder. +You have to explicitly call V4L2_DEC_CMD_RESUME for that. +This command has one flag: +V4L2_DEC_CMD_START_MUTE_AUDIO. If set, then audio will +be muted when playing back at a non-standard speed. + + + + V4L2_DEC_CMD_STOP + 1 + Stop the decoder. When the decoder is already stopped, +this command does nothing. This command has two flags: +if V4L2_DEC_CMD_STOP_TO_BLACK is set, then the decoder will +set the picture to black after it stopped decoding. Otherwise the last image will +repeat. If V4L2_DEC_CMD_STOP_IMMEDIATELY is set, then the decoder +stops immediately (ignoring the pts value), otherwise it +will keep decoding until timestamp >= pts or until the last of the pending data from +its internal buffers was decoded. + + + + V4L2_DEC_CMD_PAUSE + 2 + Pause the decoder. When the decoder has not been +started yet, the driver will return an &EPERM;. When the decoder is +already paused, this command does nothing. This command has one flag: +if V4L2_DEC_CMD_PAUSE_TO_BLACK is set, then set the +decoder output to black when paused. + + + + V4L2_DEC_CMD_RESUME + 3 + Resume decoding after a PAUSE command. When the +decoder has not been started yet, the driver will return an &EPERM;. +When the decoder is already running, this command does nothing. No +flags are defined for this command. + + + +
+ + + + + &return-value; + + + + EINVAL + + The cmd field is invalid. + + + + EPERM + + The application sent a PAUSE or RESUME command when +the decoder was not running. + + + + + diff --git a/Documentation/DocBook/media/v4l/vidioc-encoder-cmd.xml b/Documentation/DocBook/media/v4l/vidioc-encoder-cmd.xml index af7f3f2a36dd..f431b3ba79bd 100644 --- a/Documentation/DocBook/media/v4l/vidioc-encoder-cmd.xml +++ b/Documentation/DocBook/media/v4l/vidioc-encoder-cmd.xml @@ -74,15 +74,16 @@ only used by the STOP command and contains one bit: If the encoding will continue until the end of the current Group Of Pictures, otherwise it will stop immediately. - A read() call sends a START command to -the encoder if it has not been started yet. After a STOP command, + A read() or &VIDIOC-STREAMON; call sends an implicit +START command to the encoder if it has not been started yet. After a STOP command, read() calls will read the remaining data buffered by the driver. When the buffer is empty, read() will return zero and the next read() call will restart the encoder. - A close() call sends an immediate STOP -to the encoder, and all buffered data is discarded. + A close() or &VIDIOC-STREAMOFF; call of a streaming +file descriptor sends an implicit immediate STOP to the encoder, and all buffered +data is discarded. These ioctls are optional, not all drivers may support them. They were introduced in Linux 2.6.21. -- cgit v1.2.3 From 77bd4c0ff1671214ee026c175b4a5e1cc8776a0a Mon Sep 17 00:00:00 2001 From: Hans Verkuil Date: Thu, 15 Dec 2011 10:52:57 -0300 Subject: [media] Document decoder controls Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- Documentation/DocBook/media/v4l/controls.xml | 59 ++++++++++++++++++++++++++++ 1 file changed, 59 insertions(+) (limited to 'Documentation/DocBook') diff --git a/Documentation/DocBook/media/v4l/controls.xml b/Documentation/DocBook/media/v4l/controls.xml index a1be37897ad7..3f3d2e2d424e 100644 --- a/Documentation/DocBook/media/v4l/controls.xml +++ b/Documentation/DocBook/media/v4l/controls.xml @@ -1284,6 +1284,49 @@ values are: capturing. This is not done by muting audio hardware, which can still produce a slight hiss, but in the encoder itself, guaranteeing a fixed and reproducible audio bitstream. 0 = unmuted, 1 = muted. + + + + V4L2_CID_MPEG_AUDIO_DEC_PLAYBACK  + enum v4l2_mpeg_audio_dec_playback + Determines how monolingual audio should be played back. +Possible values are: + + + + + + V4L2_MPEG_AUDIO_DEC_PLAYBACK_AUTO  + Automatically determines the best playback mode. + + + V4L2_MPEG_AUDIO_DEC_PLAYBACK_STEREO  + Stereo playback. + + + V4L2_MPEG_AUDIO_DEC_PLAYBACK_LEFT  + Left channel playback. + + + V4L2_MPEG_AUDIO_DEC_PLAYBACK_RIGHT  + Right channel playback. + + + V4L2_MPEG_AUDIO_DEC_PLAYBACK_MONO  + Mono playback. + + + V4L2_MPEG_AUDIO_DEC_PLAYBACK_SWAPPED_STEREO  + Stereo playback with swapped left and right channels. + + + + + + + V4L2_CID_MPEG_AUDIO_DEC_MULTILINGUAL_PLAYBACK  + enum v4l2_mpeg_audio_dec_playback + Determines how multilingual audio should be played back. @@ -1447,6 +1490,22 @@ of the video. The supplied 32-bit integer is interpreted as follows (bit + + + V4L2_CID_MPEG_VIDEO_DEC_PTS  + integer64 + This read-only control returns the +33-bit video Presentation Time Stamp as defined in ITU T-REC-H.222.0 and ISO/IEC 13818-1 of +the currently displayed frame. This is the same PTS as is used in &VIDIOC-DECODER-CMD;. + + + + V4L2_CID_MPEG_VIDEO_DEC_FRAME  + integer64 + This read-only control returns the +frame counter of the frame that is currently displayed (decoded). This value is reset to 0 whenever +the decoder is started. + -- cgit v1.2.3 From 29fa0eedd4703b0c7c93738faf28ac9d6f930224 Mon Sep 17 00:00:00 2001 From: Sylwester Nawrocki Date: Fri, 20 Jan 2012 15:38:50 -0300 Subject: [media] V4L: Add JPEG compression control class documentation Add DocBook entries for the JPEG control class. Signed-off-by: Sylwester Nawrocki Signed-off-by: Kyungmin Park Signed-off-by: Mauro Carvalho Chehab --- Documentation/DocBook/media/v4l/biblio.xml | 20 +++ Documentation/DocBook/media/v4l/compat.xml | 10 ++ Documentation/DocBook/media/v4l/controls.xml | 161 +++++++++++++++++++++ Documentation/DocBook/media/v4l/v4l2.xml | 9 ++ .../DocBook/media/v4l/vidioc-g-jpegcomp.xml | 16 +- 5 files changed, 214 insertions(+), 2 deletions(-) (limited to 'Documentation/DocBook') diff --git a/Documentation/DocBook/media/v4l/biblio.xml b/Documentation/DocBook/media/v4l/biblio.xml index cea6fd3ed428..7dc65c592a87 100644 --- a/Documentation/DocBook/media/v4l/biblio.xml +++ b/Documentation/DocBook/media/v4l/biblio.xml @@ -128,6 +128,26 @@ url="http://www.ijg.org">http://www.ijg.org) Version 1.02 + + ITU-T.81 + + International Telecommunication Union +(http://www.itu.int) + + ITU-T Recommendation T.81 +"Information Technology — Digital Compression and Coding of Continous-Tone +Still Images — Requirements and Guidelines" + + + + W3C JPEG JFIF + + The World Wide Web Consortium (http://www.w3.org) + + JPEG JFIF + + SMPTE 12M diff --git a/Documentation/DocBook/media/v4l/compat.xml b/Documentation/DocBook/media/v4l/compat.xml index c93298ff3279..dd958b5a34e6 100644 --- a/Documentation/DocBook/media/v4l/compat.xml +++ b/Documentation/DocBook/media/v4l/compat.xml @@ -2400,6 +2400,16 @@ details. +
+ V4L2 in Linux 3.4 + + + Added JPEG compression control + class. + + +
+
Relation of V4L2 to other Linux multimedia APIs diff --git a/Documentation/DocBook/media/v4l/controls.xml b/Documentation/DocBook/media/v4l/controls.xml index 3f3d2e2d424e..b84f25e9cc87 100644 --- a/Documentation/DocBook/media/v4l/controls.xml +++ b/Documentation/DocBook/media/v4l/controls.xml @@ -3436,6 +3436,167 @@ interface and may change in the future. +
+ +
+ JPEG Control Reference + The JPEG class includes controls for common features of JPEG + encoders and decoders. Currently it includes features for codecs + implementing progressive baseline DCT compression process with + Huffman entrophy coding. + + JPEG Control IDs + + + + + + + + + + + ID + Type + Description + + + + + + V4L2_CID_JPEG_CLASS  + class + The JPEG class descriptor. Calling + &VIDIOC-QUERYCTRL; for this control will return a description of this + control class. + + + + + V4L2_CID_JPEG_CHROMA_SUBSAMPLING + menu + + + The chroma subsampling factors describe how + each component of an input image is sampled, in respect to maximum + sample rate in each spatial dimension. See , + clause A.1.1. for more details. The + V4L2_CID_JPEG_CHROMA_SUBSAMPLING control determines how + Cb and Cr components are downsampled after coverting an input image + from RGB to Y'CbCr color space. + + + + + + + V4L2_JPEG_CHROMA_SUBSAMPLING_444 + No chroma subsampling, each pixel has + Y, Cr and Cb values. + + + V4L2_JPEG_CHROMA_SUBSAMPLING_422 + Horizontally subsample Cr, Cb components + by a factor of 2. + + + V4L2_JPEG_CHROMA_SUBSAMPLING_420 + Subsample Cr, Cb components horizontally + and vertically by 2. + + + V4L2_JPEG_CHROMA_SUBSAMPLING_411 + Horizontally subsample Cr, Cb components + by a factor of 4. + + + V4L2_JPEG_CHROMA_SUBSAMPLING_410 + Subsample Cr, Cb components horizontally + by 4 and vertically by 2. + + + V4L2_JPEG_CHROMA_SUBSAMPLING_GRAY + Use only luminance component. + + + + + + V4L2_CID_JPEG_RESTART_INTERVAL + integer + + + The restart interval determines an interval of inserting RSTm + markers (m = 0..7). The purpose of these markers is to additionally + reinitialize the encoder process, in order to process blocks of + an image independently. + For the lossy compression processes the restart interval unit is + MCU (Minimum Coded Unit) and its value is contained in DRI + (Define Restart Interval) marker. If + V4L2_CID_JPEG_RESTART_INTERVAL control is set to 0, + DRI and RSTm markers will not be inserted. + + + + V4L2_CID_JPEG_COMPRESION_QUALITY + integer + + + + V4L2_CID_JPEG_COMPRESION_QUALITY control + determines trade-off between image quality and size. + It provides simpler method for applications to control image quality, + without a need for direct reconfiguration of luminance and chrominance + quantization tables. + + In cases where a driver uses quantization tables configured directly + by an application, using interfaces defined elsewhere, + V4L2_CID_JPEG_COMPRESION_QUALITY control should be set + by driver to 0. + The value range of this control is driver-specific. Only + positive, non-zero values are meaningful. The recommended range + is 1 - 100, where larger values correspond to better image quality. + + + + + V4L2_CID_JPEG_ACTIVE_MARKER + bitmask + + + Specify which JPEG markers are included + in compressed stream. This control is valid only for encoders. + + + + + + + V4L2_JPEG_ACTIVE_MARKER_APP0 + Application data segment APP0. + + V4L2_JPEG_ACTIVE_MARKER_APP1 + Application data segment APP1. + + V4L2_JPEG_ACTIVE_MARKER_COM + Comment segment. + + V4L2_JPEG_ACTIVE_MARKER_DQT + Quantization tables segment. + + V4L2_JPEG_ACTIVE_MARKER_DHT + Huffman tables segment. + + + + + + + +
+ For more details about JPEG specification, refer + to , , + .
diff --git a/Documentation/DocBook/media/v4l/v4l2.xml b/Documentation/DocBook/media/v4l/v4l2.xml index dcf9e33b695f..8ae38876172e 100644 --- a/Documentation/DocBook/media/v4l/v4l2.xml +++ b/Documentation/DocBook/media/v4l/v4l2.xml @@ -127,6 +127,15 @@ structs, ioctls) must be noted in more detail in the history chapter (compat.xml), along with the possible impact on existing drivers and applications. --> + + 3.4 + 2012-01-25 + sn + Added JPEG compression + control class. + + + 3.3 2012-01-11 diff --git a/Documentation/DocBook/media/v4l/vidioc-g-jpegcomp.xml b/Documentation/DocBook/media/v4l/vidioc-g-jpegcomp.xml index 01ea24b84385..48748499c097 100644 --- a/Documentation/DocBook/media/v4l/vidioc-g-jpegcomp.xml +++ b/Documentation/DocBook/media/v4l/vidioc-g-jpegcomp.xml @@ -57,6 +57,11 @@ Description + These ioctls are deprecated. + New drivers and applications should use + JPEG class controls for image quality and JPEG markers control. + + [to do] Ronald Bultje elaborates: @@ -86,7 +91,10 @@ to add them. int quality - + Deprecated. If + V4L2_CID_JPEG_IMAGE_QUALITY control is exposed by + a driver applications should use it instead and ignore this field. + int @@ -116,7 +124,11 @@ to add them. __u32 jpeg_markers - See . + See . Deprecated. + If + V4L2_CID_JPEG_ACTIVE_MARKER control + is exposed by a driver applications should use it instead + and ignore this field. -- cgit v1.2.3 From 1b1301e67bbcad0649a8b3c6a944d2b2acddc411 Mon Sep 17 00:00:00 2001 From: Hans Verkuil Date: Fri, 24 Feb 2012 08:15:39 -0300 Subject: [media] Fix small DocBook typo Here is a small patch which fixes a DocBook mistake in the decoder_cmd documentation. Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'Documentation/DocBook') diff --git a/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml b/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml index 466fe27d3ffe..74b87f6e480a 100644 --- a/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml +++ b/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml @@ -118,7 +118,7 @@ this command, drivers and applications must set this field to zero. - __u32 + __s32 speed Playback speed and direction. The playback speed is defined as speed/1000 of the normal speed. So 1000 is normal playback. -- cgit v1.2.3 From 9d1721733038bda56c38e1e0807885a85f08d7a7 Mon Sep 17 00:00:00 2001 From: Hans Verkuil Date: Mon, 27 Feb 2012 05:36:38 -0300 Subject: [media] V4L2 Spec: return -EINVAL on unsupported wrap_around value This is a small extension to the S_HW_FREQ_SEEK ioctl: if the wrap_around value is not support by the hardware, then -EINVAL is returned. Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- Documentation/DocBook/media/v4l/vidioc-s-hw-freq-seek.xml | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'Documentation/DocBook') diff --git a/Documentation/DocBook/media/v4l/vidioc-s-hw-freq-seek.xml b/Documentation/DocBook/media/v4l/vidioc-s-hw-freq-seek.xml index e013da845b11..18b1a8266f7c 100644 --- a/Documentation/DocBook/media/v4l/vidioc-s-hw-freq-seek.xml +++ b/Documentation/DocBook/media/v4l/vidioc-s-hw-freq-seek.xml @@ -96,8 +96,8 @@ field and the &v4l2-tuner; index field. __u32 reserved[7] - Reserved for future extensions. Drivers and - applications must set the array to zero. + Reserved for future extensions. Applications + must set the array to zero. @@ -112,7 +112,7 @@ field and the &v4l2-tuner; index field. EINVAL The tuner index is out of -bounds or the value in the type field is +bounds, the wrap_around value is not supported or the value in the type field is wrong. -- cgit v1.2.3 From 9080d5d3fa9888facd6898c6705b1a6713882955 Mon Sep 17 00:00:00 2001 From: Sylwester Nawrocki Date: Fri, 9 Mar 2012 06:46:28 -0300 Subject: [media] V4L: Improve the selection API documentation Make the VIDIOC_G/S_SELECTION ioctls documentation more consistent with the rest of media Docbook, use capital letters where necessary and correct few minor errors. Signed-off-by: Sylwester Nawrocki Signed-off-by: Kyungmin Park Signed-off-by: Mauro Carvalho Chehab --- Documentation/DocBook/media/v4l/selection-api.xml | 8 +- .../DocBook/media/v4l/vidioc-g-selection.xml | 106 +++++++++++---------- include/linux/videodev2.h | 30 +++--- 3 files changed, 76 insertions(+), 68 deletions(-) (limited to 'Documentation/DocBook') diff --git a/Documentation/DocBook/media/v4l/selection-api.xml b/Documentation/DocBook/media/v4l/selection-api.xml index 2f0bdb4d5551..b299e4779354 100644 --- a/Documentation/DocBook/media/v4l/selection-api.xml +++ b/Documentation/DocBook/media/v4l/selection-api.xml @@ -52,6 +52,10 @@ cropping and composing rectangles have the same size. + +For complete list of the available selection targets see table +
@@ -186,7 +190,7 @@ V4L2_SEL_TGT_COMPOSE_ACTIVE target.
- Scaling control. + Scaling control An application can detect if scaling is performed by comparing the width and the height of rectangles obtained using V4L2_SEL_TGT_CROP_ACTIVE @@ -200,7 +204,7 @@ the scaling ratios using these values.
- Comparison with old cropping API. + Comparison with old cropping API The selection API was introduced to cope with deficiencies of previous API , that was designed to control simple capture diff --git a/Documentation/DocBook/media/v4l/vidioc-g-selection.xml b/Documentation/DocBook/media/v4l/vidioc-g-selection.xml index a9d36e0c090e..bb04eff75f45 100644 --- a/Documentation/DocBook/media/v4l/vidioc-g-selection.xml +++ b/Documentation/DocBook/media/v4l/vidioc-g-selection.xml @@ -58,43 +58,43 @@ The ioctls are used to query and configure selection rectangles. - To query the cropping (composing) rectangle set -&v4l2-selection;::type to the respective buffer type. Do not -use multiplanar buffers. Use V4L2_BUF_TYPE_VIDEO_CAPTURE + To query the cropping (composing) rectangle set &v4l2-selection; + type field to the respective buffer type. +Do not use multiplanar buffers. Use V4L2_BUF_TYPE_VIDEO_CAPTURE instead of V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE . Use V4L2_BUF_TYPE_VIDEO_OUTPUT instead of V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE . The next step is -setting &v4l2-selection;::target to value - V4L2_SEL_TGT_CROP_ACTIVE ( +setting the value of &v4l2-selection; target field +to V4L2_SEL_TGT_CROP_ACTIVE ( V4L2_SEL_TGT_COMPOSE_ACTIVE ). Please refer to table or for additional -targets. Fields &v4l2-selection;::flags and - &v4l2-selection;::reserved are ignored and they -must be filled with zeros. The driver fills the rest of the structure or +targets. The flags and reserved + fields of &v4l2-selection; are ignored and they must be filled +with zeros. The driver fills the rest of the structure or returns &EINVAL; if incorrect buffer type or target was used. If cropping (composing) is not supported then the active rectangle is not mutable and it is -always equal to the bounds rectangle. Finally, structure -&v4l2-selection;::r is filled with the current cropping +always equal to the bounds rectangle. Finally, the &v4l2-rect; +r rectangle is filled with the current cropping (composing) coordinates. The coordinates are expressed in driver-dependent units. The only exception are rectangles for images in raw formats, whose coordinates are always expressed in pixels. - To change the cropping (composing) rectangle set -&v4l2-selection;::type to the respective buffer type. Do not + To change the cropping (composing) rectangle set the &v4l2-selection; +type field to the respective buffer type. Do not use multiplanar buffers. Use V4L2_BUF_TYPE_VIDEO_CAPTURE instead of V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE . Use V4L2_BUF_TYPE_VIDEO_OUTPUT instead of V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE . The next step is -setting &v4l2-selection;::target to value - V4L2_SEL_TGT_CROP_ACTIVE ( +setting the value of &v4l2-selection; target to +V4L2_SEL_TGT_CROP_ACTIVE ( V4L2_SEL_TGT_COMPOSE_ACTIVE ). Please refer to table or for additional -targets. Set desired active area into the field -&v4l2-selection;::r . Field -&v4l2-selection;::reserved is ignored and must be filled with -zeros. The driver may adjust the rectangle coordinates. An application may -introduce constraints to control rounding behaviour. Set the field - &v4l2-selection;::flags to one of values: +targets. The &v4l2-rect; r rectangle need to be +set to the desired active area. Field &v4l2-selection; reserved + is ignored and must be filled with zeros. The driver may adjust +coordinates of the requested rectangle. An application may +introduce constraints to control rounding behaviour. The &v4l2-selection; +flags field must be set to one of the following: @@ -129,7 +129,7 @@ and vertical offset and sizes are chosen according to following priority: - Satisfy constraints from &v4l2-selection;::flags. + Satisfy constraints from &v4l2-selection; flags. Adjust width, height, left, and top to hardware limits and alignments. @@ -145,7 +145,7 @@ and vertical offset and sizes are chosen according to following priority: -On success the field &v4l2-selection;::r contains +On success the &v4l2-rect; r field contains the adjusted rectangle. When the parameters are unsuitable the application may modify the cropping (composing) or image parameters and repeat the cycle until satisfactory parameters have been negotiated. If constraints flags have to be @@ -162,38 +162,38 @@ exist no rectangle that satisfies the constraints. V4L2_SEL_TGT_CROP_ACTIVE - 0 - area that is currently cropped by hardware + 0x0000 + The area that is currently cropped by hardware. V4L2_SEL_TGT_CROP_DEFAULT - 1 - suggested cropping rectangle that covers the "whole picture" + 0x0001 + Suggested cropping rectangle that covers the "whole picture". V4L2_SEL_TGT_CROP_BOUNDS - 2 - limits for the cropping rectangle + 0x0002 + Limits for the cropping rectangle. V4L2_SEL_TGT_COMPOSE_ACTIVE - 256 - area to which data are composed by hardware + 0x0100 + The area to which data is composed by hardware. V4L2_SEL_TGT_COMPOSE_DEFAULT - 257 - suggested composing rectangle that covers the "whole picture" + 0x0101 + Suggested composing rectangle that covers the "whole picture". V4L2_SEL_TGT_COMPOSE_BOUNDS - 258 - limits for the composing rectangle + 0x0102 + Limits for the composing rectangle. V4L2_SEL_TGT_COMPOSE_PADDED - 259 - the active area and all padding pixels that are inserted or modified by the hardware + 0x0103 + The active area and all padding pixels that are inserted or modified by hardware. @@ -209,12 +209,14 @@ exist no rectangle that satisfies the constraints. V4L2_SEL_FLAG_GE 0x00000001 - indicate that adjusted rectangle must contain a rectangle from &v4l2-selection;::r + Indicates that the adjusted rectangle must contain the original + &v4l2-selection; r rectangle. V4L2_SEL_FLAG_LE 0x00000002 - indicate that adjusted rectangle must be inside a rectangle from &v4l2-selection;::r + Indicates that the adjusted rectangle must be inside the original + &v4l2-rect; r rectangle. @@ -245,27 +247,29 @@ exist no rectangle that satisfies the constraints. __u32 type - Type of the buffer (from &v4l2-buf-type;) + Type of the buffer (from &v4l2-buf-type;). __u32 target - used to select between cropping and composing rectangles + Used to select between cropping + and composing rectangles. __u32 flags - control over coordinates adjustments, refer to selection flags + Flags controlling the selection rectangle adjustments, refer to + selection flags. &v4l2-rect; r - selection rectangle + The selection rectangle. __u32 reserved[9] - Reserved fields for future use + Reserved fields for future use. @@ -278,24 +282,24 @@ exist no rectangle that satisfies the constraints. EINVAL - The buffer &v4l2-selection;::type -or &v4l2-selection;::target is not supported, or -the &v4l2-selection;::flags are invalid. + Given buffer type type or +the selection target target is not supported, +or the flags argument is not valid. ERANGE - it is not possible to adjust a rectangle -&v4l2-selection;::r that satisfies all contraints from - &v4l2-selection;::flags . + It is not possible to adjust &v4l2-rect; +r rectangle to satisfy all contraints given in the +flags argument. EBUSY - it is not possible to apply change of selection rectangle at the moment. -Usually because streaming is in progress. + It is not possible to apply change of the selection rectangle +at the moment. Usually because streaming is in progress. diff --git a/include/linux/videodev2.h b/include/linux/videodev2.h index 3fab6cacccbe..c9c9a4680cc5 100644 --- a/include/linux/videodev2.h +++ b/include/linux/videodev2.h @@ -762,20 +762,20 @@ struct v4l2_crop { /* Selection targets */ -/* current cropping area */ -#define V4L2_SEL_TGT_CROP_ACTIVE 0 -/* default cropping area */ -#define V4L2_SEL_TGT_CROP_DEFAULT 1 -/* cropping bounds */ -#define V4L2_SEL_TGT_CROP_BOUNDS 2 -/* current composing area */ -#define V4L2_SEL_TGT_COMPOSE_ACTIVE 256 -/* default composing area */ -#define V4L2_SEL_TGT_COMPOSE_DEFAULT 257 -/* composing bounds */ -#define V4L2_SEL_TGT_COMPOSE_BOUNDS 258 -/* current composing area plus all padding pixels */ -#define V4L2_SEL_TGT_COMPOSE_PADDED 259 +/* Current cropping area */ +#define V4L2_SEL_TGT_CROP_ACTIVE 0x0000 +/* Default cropping area */ +#define V4L2_SEL_TGT_CROP_DEFAULT 0x0001 +/* Cropping bounds */ +#define V4L2_SEL_TGT_CROP_BOUNDS 0x0002 +/* Current composing area */ +#define V4L2_SEL_TGT_COMPOSE_ACTIVE 0x0100 +/* Default composing area */ +#define V4L2_SEL_TGT_COMPOSE_DEFAULT 0x0101 +/* Composing bounds */ +#define V4L2_SEL_TGT_COMPOSE_BOUNDS 0x0102 +/* Current composing area plus all padding pixels */ +#define V4L2_SEL_TGT_COMPOSE_PADDED 0x0103 /** * struct v4l2_selection - selection info @@ -785,7 +785,7 @@ struct v4l2_crop { * @r: coordinates of selection window * @reserved: for future use, rounds structure size to 64 bytes, set to zero * - * Hardware may use multiple helper window to process a video stream. + * Hardware may use multiple helper windows to process a video stream. * The structure is used to exchange this selection areas between * an application and a driver. */ -- cgit v1.2.3