# v4l2h264dec

Source: [https://docs.qualcomm.com/doc/80-70015-50/topic/v4l2h264dec.html](https://docs.qualcomm.com/doc/80-70015-50/topic/v4l2h264dec.html)

The v4l2h264dec plugin uses the V4L2 APIs to decode the video stream.

- The plugin uses the H264 video decoder to provide hardware accelerated H.264 (MPEG-4
                Part 10) decoding on supported platforms.
- The plugin is based on the [GstVideoDecoder](https://gstreamer.freedesktop.org/documentation/video/gstvideodecoder.html) 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) → [GstVideoDecoder](https://gstreamer.freedesktop.org/documentation/video/gstvideodecoder.html) → GstV4l2VideoDec →
                v4l2h264dec

The following tables provide information on pad templates and element properties of
                v4l2h264dec. For use cases, see [Video playback use cases](https://docs.qualcomm.com/doc/80-70015-50/topic/video-playback-use-cases.html).

## Pad configuration

| Pad Name | Capabilities | Capabilities | Capabilities |
| --- | --- | --- | --- |
| SINK template: 'sink'<br><ul class="ul" id="v4l2h264dec__ul_nn5_q3t_5zb"><br>                                    <li class="li"><em class="ph i">Availability:</em> Always</li><br><br>                                    <li class="li"><em class="ph i">Direction:</em> sink</li><br><br>                                </ul> | video/x-h264 | alignment: | au |
| SINK template: 'sink'<br><ul class="ul" id="v4l2h264dec__ul_nn5_q3t_5zb"><br>                                    <li class="li"><em class="ph i">Availability:</em> Always</li><br><br>                                    <li class="li"><em class="ph i">Direction:</em> sink</li><br><br>                                </ul> | video/x-h264 | stream-format: | byte-stream |
| SINK template: 'sink'<br><ul class="ul" id="v4l2h264dec__ul_nn5_q3t_5zb"><br>                                    <li class="li"><em class="ph i">Availability:</em> Always</li><br><br>                                    <li class="li"><em class="ph i">Direction:</em> sink</li><br><br>                                </ul> | video/x-h264 | level: | { (string)1, (string)1b, (string)1.1, (string)1.2, (string)1.3,<br>                                (string)2, (string)2.1, (string)2.2, (string)3, (string)3.1,<br>                                (string)3.2, (string)4, (string)4.1, (string)4.2, (string)5,<br>                                (string)5.1 } |
| SINK template: 'sink'<br><ul class="ul" id="v4l2h264dec__ul_nn5_q3t_5zb"><br>                                    <li class="li"><em class="ph i">Availability:</em> Always</li><br><br>                                    <li class="li"><em class="ph i">Direction:</em> sink</li><br><br>                                </ul> | video/x-h264 | profile: | { (string)baseline, (string)constrained-baseline, (string)main,<br>                                (string)high, (string)constrained-high } |
| SRC template: 'src'<br><ul class="ul" id="v4l2h264dec__ul_on5_q3t_5zb"><br>                                    <li class="li"><em class="ph i">Availability:</em> Always</li><br><br>                                    <li class="li"><em class="ph i">Direction:</em> source</li><br><br>                                </ul> | video/x-raw | format: | { (string)NV12, (string)NV21 } |
| SRC template: 'src'<br><ul class="ul" id="v4l2h264dec__ul_on5_q3t_5zb"><br>                                    <li class="li"><em class="ph i">Availability:</em> Always</li><br><br>                                    <li class="li"><em class="ph i">Direction:</em> source</li><br><br>                                </ul> | video/x-raw | width: | [ 1, 32768 ] |
| SRC template: 'src'<br><ul class="ul" id="v4l2h264dec__ul_on5_q3t_5zb"><br>                                    <li class="li"><em class="ph i">Availability:</em> Always</li><br><br>                                    <li class="li"><em class="ph i">Direction:</em> source</li><br><br>                                </ul> | video/x-raw | height: | [ 1, 32768 ] |
| SRC template: 'src'<br><ul class="ul" id="v4l2h264dec__ul_on5_q3t_5zb"><br>                                    <li class="li"><em class="ph i">Availability:</em> Always</li><br><br>                                    <li class="li"><em class="ph i">Direction:</em> source</li><br><br>                                </ul> | video/x-raw | framerate: | [ 0/1, 2147483647/1 ] |
|  |  |  |  |
|  |  |  |  |
|  |  |  |  |

## Element configuration

Note: For the current release, in the read-write properties, only
                    **capture-io-mode** and **output-io-mode** are supported, and they are
                supported only with **(5): dmabuf-import - GST\_V4L2\_IO\_DMABUF\_IMPORT**
                property.

Table : Element properties of v4l2h264dec

| Property | Description |
| --- | --- |
| automatic-request-sync-point-flags: | Flags to use when automatically requesting sync points.<br><ul class="ul" id="v4l2h264dec__ul_rnl_s3t_5zb"><br>                                    <li class="li">flags: readable, writable</li><br><br>                                    <li class="li"><br>                                        <p class="p">Flags "GstVideoDecoderRequestSyncPointFlags" Default:<br>                                            0x00000003, "corrupt-output+discard-input"</p><ul class="ul" id="v4l2h264dec__ul_atw_m15_q1c"><br>                                            <li class="li"> (0x00000001): discard-input -<br>                                                GST_VIDEO_DECODER_REQUEST_SYNC_POINT_DISCARD_INPUT</li><br><br>                                            <li class="li"> (0x00000002): corrupt-output -<br>                                                GST_VIDEO_DECODER_REQUEST_SYNC_POINT_CORRUPT_OUTPUT</li><br><br>                                        </ul><br><br>                                    </li><br><br>                                </ul> |
| automatic-request-sync-points | Automatically request sync points when required.<br><ul class="ul" id="v4l2h264dec__ul_snl_s3t_5zb"><br>                                    <li class="li">flags: readable, writable</li><br><br>                                    <li class="li">Boolean. Default: false</li><br><br>                                </ul> |
| capture-io-mode | Capture I/O mode (matches src pad).<br><ul class="ul" id="v4l2h264dec__ul_tnl_s3t_5zb"><br>                                    <li class="li">flags: readable, writable</li><br><br>                                    <li class="li">Enum "GstV4l2IOMode" Default: 0, "auto"<ul class="ul" id="v4l2h264dec__ul_ifv_g15_q1c"><br>                                            <li class="li"> (0): auto - GST_V4L2_IO_AUTO</li><br><br>                                            <li class="li"> (1): rw - GST_V4L2_IO_RW</li><br><br>                                            <li class="li"> (2): mmap - GST_V4L2_IO_MMAP</li><br><br>                                            <li class="li"> (3): userptr - GST_V4L2_IO_USERPTR</li><br><br>                                            <li class="li"> (4): dmabuf - GST_V4L2_IO_DMABUF</li><br><br>                                            <li class="li"> (5): dmabuf-import - GST_V4L2_IO_DMABUF_IMPORT</li><br><br>                                        </ul><br></li><br><br>                                </ul> |
| device | Device location.<br><ul class="ul" id="v4l2h264dec__ul_unl_s3t_5zb"><br>                                    <li class="li">flags: readable</li><br><br>                                    <li class="li">String. Default: "/dev/video0"</li><br><br>                                </ul> |
| device-fd | File descriptor of the device.<br><ul class="ul" id="v4l2h264dec__ul_vnl_s3t_5zb"><br>                                    <li class="li">flags: readable</li><br><br>                                    <li class="li">Integer. Range: -1 - 2147483647 Default: -1</li><br><br>                                </ul> |
| device-name | Name of the device.<br><ul class="ul" id="v4l2h264dec__ul_wnl_s3t_5zb"><br>                                    <li class="li">flags: readable</li><br><br>                                    <li class="li">String. Default: null</li><br><br>                                </ul> |
| discard-corrupted-frames | Discard frames marked as corrupted instead of processing them as<br>                                    the output.<br><ul class="ul" id="v4l2h264dec__ul_xnl_s3t_5zb"><br>                                    <li class="li">flags: readable, writable</li><br><br>                                    <li class="li">Boolean. Default: false</li><br><br>                                </ul> |
| extra-controls | Extra v4l2 controls (CIDs) for the device.<br><ul class="ul" id="v4l2h264dec__ul_ynl_s3t_5zb"><br>                                    <li class="li">flags: readable, writable</li><br><br>                                    <li class="li">Boxed pointer of type "GstStructure"</li><br><br>                                </ul> |
| max-errors | Maximum consecutive decoder errors before returning a flow<br>                                    error.<br><ul class="ul" id="v4l2h264dec__ul_znl_s3t_5zb"><br>                                    <li class="li">flags: readable, writable</li><br><br>                                    <li class="li">Integer. Range: -1 - 2147483647 Default: 10</li><br><br>                                </ul> |
| min-force-key-unit-interval | Minimum interval between force-keyunit requests in<br>                                    nanoseconds.<br><ul class="ul" id="v4l2h264dec__ul_a4l_s3t_5zb"><br>                                    <li class="li">flags: readable, writable</li><br><br>                                    <li class="li">Unsigned Integer64. Range: 0 - 18446744073709551615 Default:<br>                                        0</li><br><br>                                </ul> |
| name | The name of the object.<br><ul class="ul" id="v4l2h264dec__ul_b4l_s3t_5zb"><br>                                    <li class="li">flags: readable, writable, 0x2000</li><br><br>                                    <li class="li">String. Default: "v4l2h264dec0"</li><br><br>                                </ul> |
| output-io-mode | Output side I/O mode (matches sink pad).<br><ul class="ul" id="v4l2h264dec__ul_c4l_s3t_5zb"><br>                                    <li class="li">flags: readable, writable</li><br><br>                                    <li class="li"><br>                                        <p class="p">Enum "GstV4l2IOMode" Default: 0, "auto"</p><ul class="ul" id="v4l2h264dec__ul_a1w_t3t_5zb"><br>                                            <li class="li"> (0): auto - GST_V4L2_IO_AUTO</li><br><br>                                            <li class="li"> (1): rw - GST_V4L2_IO_RW</li><br><br>                                            <li class="li"> (2): mmap - GST_V4L2_IO_MMAP</li><br><br>                                            <li class="li"> (3): userptr - GST_V4L2_IO_USERPTR</li><br><br>                                            <li class="li"> (4): dmabuf - GST_V4L2_IO_DMABUF</li><br><br>                                            <li class="li"> (5): dmabuf-import - GST_V4L2_IO_DMABUF_IMPORT</li><br><br>                                        </ul><br><br>                                    </li><br><br>                                </ul> |
| parent | The parent of the object.<br><ul class="ul" id="v4l2h264dec__ul_d4l_s3t_5zb"><br>                                    <li class="li">flags: readable, writable, 0x2000</li><br><br>                                    <li class="li">Object of type "GstObject"</li><br><br>                                </ul> |
| qos | Handle Quality-of-Service events from downstream.<br><ul class="ul" id="v4l2h264dec__ul_e4l_s3t_5zb"><br>                                    <li class="li">flags: readable, writable</li><br><br>                                    <li class="li">Boolean. Default: true</li><br><br>                                </ul> |

**Parent Topic:** [Display, camera, encode and decode plugins](https://docs.qualcomm.com/doc/80-70015-50/topic/display-plugins.html)

Last Published: Oct 27, 2025

[Previous Topic
qtisocketsrc](https://docs.qualcomm.com/bundle/publicresource/80-70015-50/topics/qtisocketsrc.md) [Next Topic
v4l2h265dec](https://docs.qualcomm.com/bundle/publicresource/80-70015-50/topics/v4l2h265dec.md)