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GStreamer plugin architecture

The QIM SDK encapsulates hardware complexity within a modular plugin architecture, freeing developers from the burden of managing low-level platform libraries or hardware-specific details that vary across Qualcomm chipsets and generations. Each QIMSDK plugin in the SDK maps directly to a dedicated hardware accelerator — including video encode/decode, camera ISP, GPU, display, and AI/ML accelerators — giving developers a clean, unified API surface to build sophisticated multimedia and AI pipelines with minimal integration overhead

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Camera Architecture

The QIM SDK abstracts the underlying camera driver and hardware through a client-server architecture, shielding developers from the complexities of low-level camera management and enabling rapid construction of single-stream, multi-stream, multi-client, and multi-camera applications. At its core, the qticamsrc GStreamer element operates as a client to the le-camera service — a system-level service responsible for managing the camera HAL, stream lifecycle, buffer allocation, and capture control. This separation of responsibilities allows qticamsrc to surface the full camera capability set to the GStreamer pipeline through a developer-friendly interface of source pads, camera properties, and control signals. At runtime, qticamsrc performs the following on behalf of the pipeline:

• Opens and configures the target camera device
• Creates and manages video and image output streams
• Receives captured frames from the le-camera service
• Wraps camera buffers as GstBuffer objects and pushes them downstream through the corresponding source pads
• Returns buffers to the camera service upon downstream consumption

This architecture enables zero-copy camera output by retaining buffer ownership and stream resources within the service layer — maximizing pipeline throughput while minimizing memory overhead.

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Related Information

Camera use cases

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AI Inference Architecture

The QIM SDK provides end-to-end support for AI/ML video and audio analytics pipelines, covering the full processing chain from raw media ingestion through model inference to real-time result visualization. AI pipelines in QIM SDK are built around a tensor-based, three-stage processing model: preprocessing, inference, and postprocessing. Each stage is handled by a dedicated plugin and executes in parallel across consecutive frames — source capture at frame N-2, preprocessing at N-1, inference at N, and postprocessing at N+1 — delivering maximum pipeline throughput and optimal hardware utilization. The pipeline source can be live camera frames via qticamsrc (YUV) or offline media via filesrc (with format conversion); the sink can be an on-screen display via waylandsink or local storage via filesink. The qtimlvconverter preprocessing plugin converts raw video frames into normalized tensors by performing color space conversion, resizing, and mean subtraction. It queries tensor dimensions and format requirements directly from the downstream inference plugin at runtime, making it a fully generic, model-agnostic preprocessing stage compatible with all inference backends. All inference plugins operate in tensor-in / tensor-out mode and share the same qtimlvconverter for preprocessing. QIM SDK supports the following inference engines, each with hardware delegate support for acceleration across Qualcomm’s neural processing subsystems: Inference output tensors are passed directly to task-specific postprocessing plugins that decode multi-dimensional tensor data — bounding boxes, class labels, segmentation masks, and keypoints — into structured ML metadata. The postprocessing layer follows a modular sub-module architecture, allowing developers to author custom postprocessing modules to support proprietary or non-standard model architectures. Finally, the qtivoverlay plugin consumes the structured ML metadata and renders inference results directly onto the video buffer in real time. The annotated stream can then be rendered to a display, encoded and stored locally, or streamed over a network.

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Related information

Run AI/ML use cases

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Video Architecture

The QIM SDK provides hardware-accelerated video encode and decode through V4L2-based plugins that interface directly with the Qualcomm multimedia engine. Video encoding and decoding are performed entirely on the dedicated VPU (Video Processing Unit), offloading this work from the CPU and allowing concurrent camera capture, AI inference, and video processing without resource contention. The architecture supports AVC (H.264) and HEVC (H.265) formats for both encode and decode paths. Encoded output can be written to file via a multiplexer or streamed over the network. Decoded output is delivered as DMA-buf-backed NV12 frames, compatible with all downstream QIM SDK plugins including AI preprocessing and display.

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Encode

Video frames captured from the camera via qticamsrc are passed directly to the hardware encoder. The encoded bitstream is parsed and multiplexed into an MP4 or MPEGTS container before being written to file or transmitted over the network.

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Decode

A video file is demultiplexed, the elementary stream is parsed, and the hardware decoder produces raw NV12 frames for display or downstream AI processing. Decode parameters are exposed as GStreamer element properties for direct application control.

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Related Information

Video encode and decode use cases Video playback use cases

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Audio Architecture

Audio capture and playback in QIM SDK are handled through the pulsesrc and pulsesink GStreamer plugins, which interface with the system-level PulseAudio server. The PulseAudio server in turn communicates with the ALSA driver to interact with the underlying audio hardware. Audio encode and decode use open-source GStreamer plugins (such as flacenc, flacparse, flacdec, lamemp3enc, mpegaudioparse, mpg123audiodec) combined with the PulseAudio integration, enabling a complete audio pipeline without requiring custom hardware-specific code.

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Capture

The pulsesrc plugin captures raw PCM audio from the microphone and passes it to the PulseAudio server, which handles hardware interaction via the ALSA driver. The PCM stream can then be encoded or written directly to file.

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Playback

The pulsesink plugin receives PCM audio data and routes it through the PulseAudio server for hardware playback. It supports both live audio sources and pre-encoded audio files after decoding.

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Encode

Captured PCM audio is encoded using an open-source encoder, parsed, and multiplexed into a container before being written to file.

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Decode

An encoded audio file is read, demultiplexed, decoded back to PCM, and played back through pulsesink.

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Related Information

Audio use cases

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Graphics and Display Architecture

The QIM SDK uses the Wayland display protocol with the Weston compositor to manage display composition and output. Weston runs as an independent process and handles all display composition using OpenGL ES, communicating with the display hardware through the DRM/KMS subsystem. QIM SDK plugins deliver video buffers as GBM-backed DMA-buf handles. Weston receives these buffers via the Wayland protocol and composites them directly onto the display without intermediate CPU copies, maintaining the zero-copy path from camera capture or video decode through to the screen.

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Related Information

Display and composition use cases