> ## Documentation Index
> Fetch the complete documentation index at: https://dragonwingdocs.qualcomm.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Multi-Camera Offline IFE

> Enable concurrent streaming from up to 4 bayer cameras on a single IFE hardware instance by routing frames through DDR using the Offline IFE feature on IQ-9075-EVK and IQ-8275-EVK.

<div style={{display:'flex',gap:'8px',flexWrap:'wrap',marginBottom:'16px'}}>
  <span style={{background:'#ede9fe',color:'#5b21b6',padding:'2px 10px',borderRadius:'999px',fontSize:'12px',fontWeight:600}}>IQ-9075-EVK</span>
  <span style={{background:'#ede9fe',color:'#5b21b6',padding:'2px 10px',borderRadius:'999px',fontSize:'12px',fontWeight:600}}>IQ-8275-EVK</span>
  <span style={{background:'#f0fdf4',color:'#166534',padding:'2px 10px',borderRadius:'999px',fontSize:'12px',fontWeight:600}}>Stable</span>
</div>

<CardGroup cols={4}>
  <Card title="4" icon="camera">Cameras (IQ-9075-EVK)</Card>
  <Card title="3" icon="camera">Cameras (IQ-8275-EVK)</Card>
  <Card title="1" icon="microchip">IFE Hardware Used</Card>
  <Card title="SFE" icon="bolt">Bus Fetch Engine</Card>
</CardGroup>

<Note>
  **Platform Scope:**<br />
  This feature is applicable for **IQ-9075-EVK** and **IQ-8275-EVK** only.<br />
  Both platforms have two IFEs that natively support real-time de-bayering of bayer camera images.
</Note>

***

## 01 · What Is It?

The Offline IFE feature allows a single IFE hardware instance to process bayer images from **multiple cameras** by running in **offline mode**. Instead of real-time de-bayering, frames are first stored in DDR via IFE-Lite's RDI port, then fetched by the IFE using the SFE Lite bus engine for bayer-to-YUV conversion.

```
Real-Time Path:    Sensor → IFE-Lite (RDI) → DDR
Offline Path:      DDR → SFE Lite (Fetch) → IFE Offline → YUV Output
```

<img src="https://mintcdn.com/qualcomm-prod/mGpYCfBsZaJSFIEo/Technologies/Camera/images/multi_camera_offline_IFE.png?fit=max&auto=format&n=mGpYCfBsZaJSFIEo&q=85&s=120b2a652e7852d26447e3d2493a07c0" style={{borderRadius:'8px', marginBottom:'24px', width:'100%'}} width="709" height="361" data-path="Technologies/Camera/images/multi_camera_offline_IFE.png" />

***

## 02 · What Does It Control?

Controls how many concurrent bayer cameras can stream simultaneously by reusing a single IFE in offline mode rather than requiring dedicated IFE instances per camera.

| Capability               | Without Offline IFE | With Offline IFE              |
| ------------------------ | ------------------- | ----------------------------- |
| Concurrent bayer cameras | 2 cameras max       | 4 cameras (IQ-9075-EVK)       |
| IFE instances required   | 1 per 2 cameras     | 1 shared (offline)            |
| Frame routing            | Direct sensor → IFE | Sensor → IFE-Lite → DDR → IFE |
| SFE Lite usage           | Not used            | Used as bus fetch engine      |
| IQ-8275-EVK camera count | 2 cameras max       | 3 cameras                     |

***

## 03 · Feature Validation

<Note>
  Connect to the device console using SSH. See [How To SSH?](https://dragonwingdocs.qualcomm.com/Linux/devices/iq9075-evk/set-up-the-device#connect-over-ssh) for instructions.
</Note>

### Platform Reference Configurations

Ensure you have connected one of the following camera configurations:

* **IQ-9075-EVK**: Four OV9282 MIPI cameras connected to four MIPI CSI slots (0, 1, 2, and 3).
* **IQ-8275-EVK**: Three OV9282 MIPI cameras connected to three MIPI CSI slots (0, 1, and 2).

<CardGroup cols={2}>
  <Card title="IQ-9075-EVK Config" icon="server">
    | Key            | Value         |
    | -------------- | ------------- |
    | Camera count   | 4             |
    | Sensor         | OV9282 MIPI   |
    | MIPI CSI slots | 0, 1, 2, 3    |
    | Format         | NV12 1280×720 |
  </Card>

  <Card title="IQ-8275-EVK Config" icon="server">
    | Key            | Value         |
    | -------------- | ------------- |
    | Camera count   | 3             |
    | Sensor         | OV9282 MIPI   |
    | MIPI CSI slots | 0, 1, 2       |
    | Format         | NV12 1280×720 |
  </Card>
</CardGroup>

<Steps>
  <Step title="Collect user log">
    ```text Collect User Log theme={null}
    # On device console
    journalctl -f > /opt/user_log.txt
    ```
  </Step>

  <Step title="Collect kernel log">
    ```text Collect Kernel Log theme={null}
    dmesg -w  > /opt/kernel_log.txt
    ```
  </Step>

  <Step title="Run GStreamer pipeline with multicamera-hint=true">
    Run the following for **each camera** (change `camera=0` to `1`, `2`, `3` accordingly):

    ```bash GStreamer Pipeline theme={null}
    gst-launch-1.0 -e qtiqmmfsrc name=camsrc camera=0 multicamera-hint=true ! \
    video/x-raw,format=NV12,width=1280,height=720,framerate=30/1,\
    interlace-mode=progressive,colorimetry=bt601 ! v4l2h264enc \
    capture-io-mode=4 output-io-mode=5 extra-controls="controls,video_bitrate=6000000,\
    video_bitrate_mode=0;" ! h264parse ! mp4mux ! filesink location=/opt/mux_avc.mp4
    ```

    <Warning>
      **Repeat for each camera**\
      Run similarly for `camera=1`, `camera=2`, and `camera=3` (IQ-9075-EVK) or up to `camera=2` (IQ-8275-EVK) with `multicamera-hint=true` on each.
    </Warning>
  </Step>

  <Step title="Verify log output">
    After running the pipeline, confirm the feature is active by checking these exact log entries:

    **User log — CamX pipeline status:**

    ```text User Log Trace theme={null}
    CamX: [CORE_CFG]3509 3556 [CORE   ] camxpipeline.h:4222 SetPipelineStatus() RealTimeFeatureZSLPreviewRawOfflineIFE_0_cam_0 status is now PipelineStatus::STREAM_ON
    ```

    **Kernel log — IFE acquisition confirmation:**

    ```text Kernel Log Trace theme={null}
    CAM_INFO: CAM-ISP: cam_ife_hw_mgr_print_acquire_info: 1733: 0:4:11.835 Acquired Single IFE[0] SFE[0] OFFLINE: Y with [9 pix] [0 pd] [0 rdi] ports for ctx:1
    ```

    <Tip>
      `OFFLINE: Y` in the kernel log confirms the IFE is running in offline mode. `STREAM_ON` in the user log confirms the CamX pipeline is live.
    </Tip>
  </Step>
</Steps>

***

## 🛠️ Troubleshooting

| Issue                                  | Cause                                                 | Fix                                                             |
| -------------------------------------- | ----------------------------------------------------- | --------------------------------------------------------------- |
| Only 2 cameras stream; 3rd/4th dropped | `multicamera-hint=true` not set on all streams        | Ensure every `gst-launch` call includes `multicamera-hint=true` |
| `OFFLINE: N` in kernel log             | Offline IFE not acquired — possible resource conflict | Restart camera service; verify no other pipeline is holding IFE |
| Pipeline stalls or drops frames        | DDR bandwidth saturation at 4-camera load             | Reduce framerate to 24fps or lower resolution to 720p           |