# Video wall
Source: [https://docs.qualcomm.com/doc/80-70022-50/topic/gst-concurrent-videoplay-composition.html](https://docs.qualcomm.com/doc/80-70022-50/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 about the plugins used in this
pipeline, see [Pipeline flow](https://docs.qualcomm.com/doc/80-70022-50/topic/gst-concurrent-videoplay-composition.html#gst-concurrent-videoplay-composition__section_s22_qsf_4bc).
Figure : gst-concurrent-videoplay-composition pipeline with 4 streams
## Run the application
The following 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 several participants.
Useful in a multi-party video conference scenario where the application manages several video streams.
|
| Surveillance systems | Concurrently decodes video feeds from two separate cameras. |
| Digital signage | Allows simultaneous changes or updates to centrally managed information that's electronically displayed across several locations. |
To run the use cases, do the following:
1. Ensure that you complete the [Prerequisites](https://docs.qualcomm.com/doc/80-70022-50/topic/mm_sample_apps_prerequisites.html).
2. Input at least one `MP4 AVC (H.264)` video file on the target
device.
3. In the terminal of the target device, use the following command to run the use
case:
gst-concurrent-videoplay-composition -c -i .mp4 -i .mp4Copy to clipboard
The following 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, and 16.
|
| `-i` | Specifies the absolute path to the input video file. |
For example, 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
4. To stop the use case, use CTRL +
C.
5. In the terminal of the target device, run the following command in the SSH shell
to display the available help
options:
gst-concurrent-videoplay-composition --helpCopy to clipboard
## Expected output
The individual composed streams are tiled together to display as a unified
stream.
Figure : Expected output for gst-concurrent-videoplay-composition application
## Pipeline flow
The following 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/80-70022-50/topic/v4l2h264dec.html) | Decodes the H.264 video streams. |
| [qtivcomposer](https://docs.qualcomm.com/doc/80-70022-50/topic/qtivcomposer.html) | Composes the decoded streams and sends them over the display. |
| [Waylandsink](https://docs.qualcomm.com/doc/80-70022-50/topic/waylandsink.html) | Displays the composed video streams on Wayland display. |
## Known issue
Video playback closes or freezes. About an hour later, it continues running with 16
H.264 720p concurrent video playback sessions.
## Related information
[Concurrent video playback (video wall) using Python](https://docs.qualcomm.com/doc/80-70022-50/topic/video-wall-using-python.html)
**Parent Topic:** [Run sample applications for video and audio](https://docs.qualcomm.com/doc/80-70022-50/topic/audio-sample-applications.html)
Last Published: Feb 20, 2026
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