# v4l2h264enc The v4l2h264enc plugin uses the V4L2 APIs to encode the video stream. - The plugin uses the H.264 video encoder to provide hardware accelerated H.264 (MPEG-4 Part 10) encoding on supported platforms. - The plugin is based on the [GstVideoEncoder](https://gstreamer.freedesktop.org/documentation/video/gstvideoencoder.html?gi-language=c) base class. ## Inheritance chain [GObject](https://docs.gtk.org/gobject/) → [GstObject](https://gstreamer.freedesktop.org/documentation/gstreamer/gstobject.html?gi-language=c) → [GstElement](https://gstreamer.freedesktop.org/documentation/gstreamer/gstelement.html?gi-language=c) → [GstVideoEncoder](https://gstreamer.freedesktop.org/documentation/video/gstvideoencoder.html?gi-language=c) → GstV4l2VideoEnc → v4l2h264enc The following tables provide information on pad templates and element properties of v4l2h264enc. For use cases, see [Video encode and decode](https://docs.qualcomm.com/doc/80-80021-50/topic/camera-and-video-encode.html) and [Slice-based encoding](https://docs.qualcomm.com/doc/80-80021-50/topic/camera-and-video-encode.html#slice-based-encoding). ## Pad configuration | Pad Name | Capabilities | Capabilities | Capabilities | | --- | --- | --- | --- | |
SINK template: 'sink'

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Availability: Always

Direction: sink

| video/x-raw | format: | { (string)NV12, (string)NV21 } | |
SINK template: 'sink'

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Availability: Always

Direction: sink

Availability: Always

Direction: sink

Availability: Always

Direction: sink

Availability: Always

Direction: source

Availability: Always

Direction: source

Availability: Always

Direction: source

| video/x-h264 | level: | { (string)1, (string)1b, (string)1.1, (string)1.2, (string)1.3, (string)2, (string)2.1, (string)2.2, (string)3, (string)3.1, (string)3.2, (string)4, (string)4.1, (string)4.2, (string)5, (string)5.1 } | |
SRC template: 'src'

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Availability: Always

Direction: source

| video/x-h264 | profile: | { (string)baseline, (string)constrained-baseline, (string)main, (string)high, (string)constrained-high } | | | | | | | | | | | | | | | | ## Element configuration Table : Element properties of v4l2h264enc | Property | Description | | --- | --- | | capture-io-mode | - Capture I/O mode (matches src pad).
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flags: readable, writable

Enum "GstV4l2IOMode"; default: 0, "auto"
- (0): auto - GST_V4L2_IO_AUTO
- (1): rw - GST_V4L2_IO_RW
- (2): mmap - GST_V4L2_IO_MMAP
- (3): userptr - GST_V4L2_IO_USERPTR
- (4): dmabuf - GST_V4L2_IO_DMABUF
- (5): dmabuf-import - GST_V4L2_IO_DMABUF_IMPORT

| | device | - Device location.
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flags: readable

String. Default: "/dev/video1"

| | device-fd | - File descriptor of the device.
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flags: readable

Integer. Range: ˗1 to 2147483647, default: ˗1

| | device-name | - Name of the device.
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flags: readable

String. Default: null

| | extra-controls | - Extra v4l2 control IDs (CIDs) for the device.
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flags: readable, writable

Boxed pointer of type "GstStructure"

| | min-force-key-unit-interval | - Minimum interval between force-key unit requests in nanoseconds.
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flags: readable, writable

Unsigned Integer 64

Range: 0 - 18446744073709551615; default: 0

| | name | - The name of the object.
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flags: readable, writable, 0x2000

String. Default: "v4l2h264enc0"

| | output-io-mode | - Output side I/O mode (matches sink pad).
-

flags: readable, writable

Enum "GstV4l2IOMode" Default: 0, "auto"
- (0): auto - GST_V4L2_IO_AUTO
- (1): rw - GST_V4L2_IO_RW
- (2): mmap - GST_V4L2_IO_MMAP
- (3): userptr - GST_V4L2_IO_USERPTR
- (4): dmabuf - GST_V4L2_IO_DMABUF
- (5): dmabuf-import - GST_V4L2_IO_DMABUF_IMPORT

| | parent | - The parent of the object.
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flags: readable, writable, 0x2000

Object of type "GstObject"

| | qos | - Handle Quality-of-Service events from downstream.
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flags: readable, writable

Boolean. Default: true

| Table : v4l2ctl extra-controls–user controls | Control name | Control type | Parameters | | --- | --- | --- | | horizontal\_flip | Boolean |

value=0; this is the default value

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flags=execute-on-write

| | vertical\_flip | Boolean |

value=0; this is the default value

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flags= execute-on-write

| | rotate | Integer |

min=0

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max=270

step=90

value=0; this is the default value

flags=execute-on-write and modify-layout

| Table : v4l2ctl extra-controls–codec controls | Control name | Control type | Parameters | | --- | --- | --- | | video\_b\_frames | Integer |

min=0

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max=7

step=1

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- value=0; this is the default value
- flags=update and execute-on-write
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| | video\_gop\_size | Integer |

min=0

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max=2147483647

step=1

value=59; this is the default value

flags=execute-on-write

| | video\_bitrate\_mode | Menu |

min=0

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max=3

value=0: Variable Bitrate

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- 0: Variable Bitrate; this is the default value
- 1: Constant Bitrate
- 3: Maximum Bitrate
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flags=update, execute-on-write

| | video\_bitrate | Integer |

min=1

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max=100000000

step=1

value=20000000

flags=execute-on-write

| | frame\_level\_rate\_control\_enable | Integer |

value=1; this is the default value

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flags=execute-on-write

| | maximum\_bytes\_in\_a\_slice | Integer |

min=512

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max=12500000

step=1

value=512; this is the default value

flags=execute-on-write

| | number\_of\_mbs\_in\_a\_slice | Integer |

min=1

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max=36864

step=1

value=1; this is the default value

flags=execute-on-write

| | slice\_partitioning\_method | Menu |

min=0

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max=2

value=0:Single

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- 0: Single; this is the default value
- 1: Max macro blocks
- 2: Max Bytes
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flags=execute-on-write

| | ltr\_count | Integer |

min=0

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max=2

step=1

value=0; this is the default value

flags=execute-on-write

| | frame\_ltr\_index | Integer |

min=-1

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max=1

step=1

value=-1; this is the default value

flags=execute-on-write

| | use\_ltr\_frames | Bitmask |

max=0x00000003

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default=0x00000000

value=0

flags=execute-on-write

| | intra\_refresh\_period | Integer |

min=0

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max=2147483647

step=1

value=0; this is the default value

flags=execute-on-write

| | intra\_refresh\_period\_type | Menu |

min=0

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max=1

value=0

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- 0: Random; this is the default value
- 1: Cyclic
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flags=execute-on-write

| Table : v4l2ctl extra-controls–H.264 codec controls | Control name | Control type | Parameters | | --- | --- | --- | | h264\_i\_frame\_qp\_value | Integer |

min=1

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max=51

step=1

value=20; this is the default value

flags=execute-on-write

| | h264\_p\_frame\_qp\_value | Integer |

min=1

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max=51

step=1

value=20; this is the default value

flags=execute-on-write

| | h264\_b\_frame\_qp\_value | Integer |

min=1

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max=51

step=1

value=20; this is the default value

flags=execute-on-write

| | h264\_minimum\_qp\_value | Integer |

min=1

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max=51

step=1

value=1; this is the default value

flags=execute-on-write

| | h264\_maximum\_qp\_value | Integer |

min=1

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max=51

step=1

value=51; this is the default value

flags=execute-on-write

| | h264\_entropy\_mode | Menu |

min=0

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max=1

value=1 (CABAC)

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- 0: CAVLC
- 1: CABAC; this is the default value
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flags=execute-on-write

| | h264\_level | Menu |

min=0

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max=15

value=15 (5.1)

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- 0: 1
- 1: 1b
- 2: 1.1
- 3: 1.2
- 4: 1.3
- 5: 2
- 6: 2.1
- 7: 2.2
- 8: 3
- 9: 3.1
- 10: 3.2
- 11: 4
- 12: 4.1
- 13: 4.2
- 14: 5
- 15: 5.1; this is the default value
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flags=execute-on-write

| | h264\_profile | Menu |

min=0

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max=17

value=4 (High)

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- 0: Baseline
- 1: Constrained Baseline
- 2: Main
- 4: High; this is the default value
- 17: Constrained High
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flags=execute-on-write

| | enable\_h264\_hierarchical\_coding | Integer |

min=0

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max=1

step=1

value=0; this is the default value

flags=execute-on-write

| | h264\_hierarchical\_coding\_type | Menu |

min=0

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max=1

value =1

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- 0: Hier Coding B
- 1: Hier Coding P; this is the default value
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flags=execute-on-write

| | h264\_number\_of\_hc\_layers | Integer |

min=0

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max=5

step=1

value=0; this is the default value

flags=execute-on-write

| | h264\_i\_frame\_minimum\_qp\_value | Integer |

min=1

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max=51

step=1

value=1; this is the default value

flags=execute-on-write

| | h264\_i\_frame\_maximum\_qp\_value | Integer |

min=1

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max=51

step=1

value=51; this is the default value

flags=execute-on-write

| | h264\_p\_frame\_minimum\_qp\_value | Integer |

min=1

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max=51

step=1

value=1; this is the default value

flags=execute-on-write

| | h264\_p\_frame\_maximum\_qp\_value | Integer |

min=1

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max=51

step=1

value=51; this is the default value

flags=execute-on-write

| | h264\_b\_frame\_minimum\_qp\_value | Integer |

min=1

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max=51

step=1

value=1; this is the default value

flags=execute-on-write

| | h264\_b\_frame\_maximum\_qp\_value | Integer |

min=1

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max=51

step=1

value=51; this is the default value

flags=execute-on-write

| | h264\_hierarchical\_lay\_0\_bitrate | Integer |

min=1

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max=100000000

step=1

value=20000000; this is the default value

flags=execute-on-write

| | h264\_hierarchical\_lay\_1\_bitrate | Integer |

min=1

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max=100000000

step=1

value=20000000; this is the default value

flags=execute-on-write

| | h264\_hierarchical\_lay\_2\_bitrate | Integer |

min=1

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max=100000000

step=1

value=20000000; this is the default value

flags=execute-on-write

| | h264\_hierarchical\_lay\_3\_bitrate | Integer |

min=1

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max=100000000

step=1

value=20000000; this is the default value

flags=execute-on-write

| | h264\_hierarchical\_lay\_4\_bitrate | Integer |

min=1

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max=100000000

step=1

value=20000000; this is the default value

flags=execute-on-write

| | h264\_hierarchical\_lay\_5\_bitrate | Integer |

min=1

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max=100000000

step=1

value=20000000; this is the default value

flags=execute-on-write

| Last Published: Mar 26, 2026 [Previous Topic v4l2h265dec](https://docs.qualcomm.com/bundle/publicresource/80-80021-50/topics/v4l2h265dec.md) [Next Topic v4l2h265enc](https://docs.qualcomm.com/bundle/publicresource/80-80021-50/topics/v4l2h265enc.md) Source: [https://docs.qualcomm.com/doc/80-80021-50/topic/v4l2h264enc.html](https://docs.qualcomm.com/doc/80-80021-50/topic/v4l2h264enc.html)