# Video wall
Source: [https://docs.qualcomm.com/doc/80-70015-50/topic/gst-concurrent-videoplay-composition.html](https://docs.qualcomm.com/doc/80-70015-50/topic/gst-concurrent-videoplay-composition.html)
The **gst-concurrent-videoplay-composition** application supports concurrent video
playback for MP4 AVC (H.264) videos and performs composition on a video wall display.
In the concurrent video playback and composition pipeline, four decode and composition
pipelines run concurrently. For more information on the plugins used in this pipeline,
see [Pipeline flow](https://docs.qualcomm.com/doc/80-70015-50/topic/gst-concurrent-videoplay-composition.html#gst-concurrent-videoplay-composition__section_s22_qsf_4bc).
Figure : gst-concurrent-videoplay-composition pipeline with 4 streams
This video shows you how to stream from multiple cameras simultaneously, display the
feeds side-by-side, or encode for storage.
## Prerequisites
- To access your host device, enable SSH. For instructions, see [Use SSH](https://docs.qualcomm.com/bundle/publicresource/topics/80-70015-254/how_to.html#use-ssh).
- Enter the SSH shell and run the use cases:
ssh root@Copy to clipboard
- Enable the
display:
export XDG_RUNTIME_DIR=/dev/socket/weston && export WAYLAND_DISPLAY=wayland-1Copy to clipboard
- Push the files from the host
machine:
scp root@:/opt/Copy to clipboard
## Use cases
The application requires at least one input video file. The input file must be an MP4
AVC (H.264) file.
The table lists the use cases that are supported through the
gst-concurrent-videoplay-composition application:| Use case | Description |
| --- | --- |
| Video conferencing |
Simultaneously decodes the video streams of multiple participants.
Useful in a multi-party video conference scenario where the application manages multiple video streams.
|
| Surveillance systems | Concurrently decodes video feeds from two separate cameras. |
| Digital signage | Enables simultaneous changes or updates to centrally managed information that is electronically displayed across multiple locations. |
To run the use cases, do the following:
1. Load the AVC-encoded MP4 (H.264) files onto the device.
2. To run the application for your use case, use the following syntax
command:
gst-concurrent-videoplay-composition -c -i .mp4 -i .mp4Copy to clipboard
The table provides a description of the command-line
parameters: | Command-line parameter | Description |
| --- | --- |
| `-c` |
Number of streams to decode for composition.
Supported values are 2, 4, 8.
|
| `-i` | Specifies the absolute path to the input video file |
Use the following commands to run the concurrent playback use
cases:
- Concurrent playback of two
sessions:
gst-concurrent-videoplay-composition -c 2 -i .mp4 -i .mp4Copy to clipboard
If
one video is provided as input, the same file is played
concurrently.
- Concurrent playback of four
sessions:
gst-concurrent-videoplay-composition -c 4 -i .mp4 -i .mp4 -i .mp4 -i .mp4Copy to clipboard
To stop the use case, press CTRL + C.
## Expected output
The individual composed
streams are tiled together to display as a unified stream.
## Pipeline flow
The table lists the plugins used to run the video wall pipeline:| Plugin | Description |
| --- | --- |
| filesrc | Reads the video data. |
| qtdemux | Demultiplexes the video data. |
| h264parse | Parses the H.264 video streams. |
| [v4l2h264dec](https://docs.qualcomm.com/doc/80-70015-50/topic/v4l2h264dec.html) | Decodes the H.264 video streams. |
| [qtivcomposer](https://docs.qualcomm.com/doc/80-70015-50/topic/qtivcomposer.html) | Composes the decoded streams and sends them over the display. |
| [Waylandsink](https://docs.qualcomm.com/doc/80-70015-50/topic/waylandsink.html) | Displays the composed video streams on Wayland display. |
**Known issues**: Video playback is closing or freezing. After an hour
(approximately), it continues running with 16 H.264 720p concurrent video playback
sessions.
**Parent Topic:** [Sample applications for video and audio](https://docs.qualcomm.com/doc/80-70015-50/topic/audio-sample-applications.html)
Last Published: Oct 27, 2025
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