From 849369d6c66d3054688672f97d31fceb8e8230fb Mon Sep 17 00:00:00 2001 From: root Date: Fri, 25 Dec 2015 04:40:36 +0000 Subject: initial_commit --- Documentation/DocBook/v4l/vidioc-g-enc-index.xml | 213 +++++++++++++++++++++++ 1 file changed, 213 insertions(+) create mode 100644 Documentation/DocBook/v4l/vidioc-g-enc-index.xml (limited to 'Documentation/DocBook/v4l/vidioc-g-enc-index.xml') diff --git a/Documentation/DocBook/v4l/vidioc-g-enc-index.xml b/Documentation/DocBook/v4l/vidioc-g-enc-index.xml new file mode 100644 index 00000000..9f242e4b --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-g-enc-index.xml @@ -0,0 +1,213 @@ + + + ioctl VIDIOC_G_ENC_INDEX + &manvol; + + + + VIDIOC_G_ENC_INDEX + Get meta data about a compressed video stream + + + + + + int ioctl + int fd + int request + struct v4l2_enc_idx *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_G_ENC_INDEX + + + + argp + + + + + + + + + Description + + + Experimental + + This is an experimental +interface and may change in the future. + + + The VIDIOC_G_ENC_INDEX ioctl provides +meta data about a compressed video stream the same or another +application currently reads from the driver, which is useful for +random access into the stream without decoding it. + + To read the data applications must call +VIDIOC_G_ENC_INDEX with a pointer to a +&v4l2-enc-idx;. On success the driver fills the +entry array, stores the number of elements +written in the entries field, and +initializes the entries_cap field. + + Each element of the entry array +contains meta data about one picture. A +VIDIOC_G_ENC_INDEX call reads up to +V4L2_ENC_IDX_ENTRIES entries from a driver +buffer, which can hold up to entries_cap +entries. This number can be lower or higher than +V4L2_ENC_IDX_ENTRIES, but not zero. When the +application fails to read the meta data in time the oldest entries +will be lost. When the buffer is empty or no capturing/encoding is in +progress, entries will be zero. + + Currently this ioctl is only defined for MPEG-2 program +streams and video elementary streams. + + + struct <structname>v4l2_enc_idx</structname> + + &cs-str; + + + __u32 + entries + The number of entries the driver stored in the +entry array. + + + __u32 + entries_cap + The number of entries the driver can +buffer. Must be greater than zero. + + + __u32 + reserved[4] + Reserved for future extensions. +Drivers must set the array to zero. + + + &v4l2-enc-idx-entry; + entry[V4L2_ENC_IDX_ENTRIES] + Meta data about a compressed video stream. Each +element of the array corresponds to one picture, sorted in ascending +order by their offset. + + + +
+ + + struct <structname>v4l2_enc_idx_entry</structname> + + &cs-str; + + + __u64 + offset + The offset in bytes from the beginning of the +compressed video stream to the beginning of this picture, that is a +PES packet header as defined in or a picture +header as defined in . When +the encoder is stopped, the driver resets the offset to zero. + + + __u64 + pts + The 33 bit Presentation Time +Stamp of this picture as defined in . + + + __u32 + length + The length of this picture in bytes. + + + __u32 + flags + Flags containing the coding type of this picture, see . + + + __u32 + reserved[2] + Reserved for future extensions. +Drivers must set the array to zero. + + + +
+ + + Index Entry Flags + + &cs-def; + + + V4L2_ENC_IDX_FRAME_I + 0x00 + This is an Intra-coded picture. + + + V4L2_ENC_IDX_FRAME_P + 0x01 + This is a Predictive-coded picture. + + + V4L2_ENC_IDX_FRAME_B + 0x02 + This is a Bidirectionally predictive-coded +picture. + + + V4L2_ENC_IDX_FRAME_MASK + 0x0F + AND the flags field with +this mask to obtain the picture coding type. + + + +
+ + + + &return-value; + + + + EINVAL + + The driver does not support this ioctl. + + + + + + + -- cgit v1.2.3