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QCS6490Stable

vhdr=3

Activation Flag

Linear ↔ SHDR

Seamless Switch

Pre-initialized

Low Latency
Platform Scope:
This feature is applicable for QCS6490 only.

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01 · What Is It?

This feature enables on-the-fly switching between Linear and SHDR v2 mode pipelines without terminating the active camera session. Key architectural benefits include:
  • Session Continuity: Prevents video session interruption during light-level (lux) fluctuations.
  • Latency Optimization: Pipelines are pre-initialized during session creation to minimize switch overhead.
  • Resource Management: Automatically releases and re-acquires hardware blocks (Sensor, IFE, IPE) during the reconfiguration phase.
This feature works only for SHDR v2 and Linear mode pipelines.

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02 · Verification Setup

Connect to the device console using SSH. See How To SSH? for instructions.
1

Initialize Log Collection

Run the following command on the device to monitor runtime events:
Log Collection
# journalctl -f > /opt/log.txt

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03 · Feature Validation

Use vhdr=3 in a GST command to enable this feature. To enable the feature and toggle between Linear and SHDR modes:
1

Execute Metadata Application

Run the gst-camera-metadata-example application to support runtime vendor tag configuration.
GStreamer (Auto Mode Switch)
gst-camera-metadata-example -p "qtiqmmfsrc name=camsrc camera=0 vhdr=3 ! \
video/x-raw,format=NV12,width=3840,height=2160,framerate=30/1,\
interlace-mode=progressive,colorimetry=bt601 ! queue ! v4l2h264enc capture-io-mode=4 \
output-io-mode=5 ! queue ! h264parse ! mp4mux ! queue ! filesink location=/opt/mux4k.mp4"
2

Transition to READY

In the application, select (1) READY.
3

Initialize PLAYING State

Select (3) PLAYING. The camera starts in linear mode.
4

Open Metadata Menu

Select (4) META. The following menu is shown:
Metadata Root Menu
 ---------MENU---------
(1)        video-metadata
(2)        image-metadata
(3)        static-metadata
(4)        session-metadata
5

Select Video Category

Select (1) video-metadata. The following menu is shown:
Video Metadata Menu
 ---------video-metadata---------
(1)        List all available tags
(2)        Dump all tags values in a file
(3)        Dump custom tags values in a file
(4)        Get a tag
(5)        Set a tag
6

Invoke Tag Modification

Select (5) Set a tag.
7

Define Vendor Tag

A prompt appears to enter the section name and tag name separated by spaces without quotes. Enter: org.quic.camera.videoHDRmode modeType
8

Trigger Mode Switch

A prompt appears to set the value. Enter 1 to switch to SHDR mode.
To toggle between Linear and SHDR modes, repeat this process and enter 1 (SHDR mode) and 0 (Linear mode) as needed.
To close the camera, select (q) QUIT or press CTRL + C.

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04 · Log Verification

Verify the pipeline reconfiguration by checking the following log signatures:

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Linear Mode Selection

CamX Status (Linear)
cam-server[1693]: CamX: [REQMAP]1693 2652 [CORE   ] camxsession.cpp:4811
ProcessRequest() chiFrameNum: 0 <==> requestId: 1 <==> sequenceId: 0
<==> CSLSyncId: 1 -- RealTimeFeatureZSLPreviewRawYUV_0

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SHDR Mode Selection

CamX Status (SHDR)
cam-server[1693]: CamX: [REQMAP]1693 2652 [CORE   ] camxsession.cpp:4811
ProcessRequest() chiFrameNum: 296 <==> requestId: 297 <==> sequenceId:
296 <==> CSLSyncId: 297 -- RealTimeSHDR_0