TheRock/rocm-systems/projects/rocprofiler-systems/examples/jpegdecode

JPEG Decode

Overview

This example benchmarks JPEG image decoding performance using the AMD rocJPEG library for GPU-accelerated JPEG decompression. It batch-decodes JPEG images on a selected GPU device, measuring throughput in images per second and megapixels per second. The program detects JPEG properties (chroma subsampling, component channels) and supports optional ROI (region of interest) decoding. This is useful for profiling GPU media pipeline performance and VCN (Video Core Next) hardware decoder utilization.

Source Files

• jpegdecodeperf.cpp - Main benchmark with DecodeImages() function for batch processing, JPEG property detection, throughput measurement, and GPU device selection.
• rocjpeg_samples_utils.h - Utility functions for rocJPEG sample programs.

Prerequisites

• CMake 3.25+
• HIP runtime
• rocJPEG library
• rocprofiler-register
• Sample JPEG images (copied from ROCm installation at build time)

Building

Standalone build:

cmake -B <build_dir> -S <project_root>/examples/jpegdecode -DCMAKE_PREFIX_PATH=/opt/rocm
cmake --build <build_dir>

As part of the examples suite:

cmake -B <build_dir> -S <project_root>/examples/ -DCMAKE_PREFIX_PATH=/opt/rocm
cmake --build <build_dir> --target jpegdecode

Running

# Decode sample images on default GPU
./jpegdecode -i /path/to/jpeg/images/ -b 4

# Specify GPU device
./jpegdecode -i /path/to/jpeg/images/ -b 8 -d 1

Key parameters:

Parameter	Description
-i	Input directory containing JPEG files
-b	Batch size (images per decode batch)
-d	GPU device ID
-o	Output directory for decoded images (optional)

VA drivers (LIBVA_DRIVERS_PATH) — only if decode fails

rocJPEG hardware decode may use libva under the hood. On a typical desktop, libva finds a driver under the distro’s default paths, so you often need no extra variables.

Set LIBVA_DRIVERS_PATH when decode fails or no VA driver is found. For example, when building with TheRock, point libva at the vendored sysdeps directory:

export LIBVA_DRIVERS_PATH="${ROCM_PATH}/lib/rocm_sysdeps/lib"

Profiling with rocprofiler-systems

rocprof-sys-run -- ./jpegdecode -i /path/to/images/ -b 4

Recommended Configuration

Variable	Value	Purpose
ROCPROFSYS_ROCM_DOMAINS	hip_runtime_api,kernel_dispatch,memory_copy	Trace HIP API and GPU operations
ROCPROFSYS_TRACE	true	Generate Perfetto trace
ROCPROFSYS_PROFILE	true	Generate call-stack profile

rocprof-sys-run \
    -e ROCPROFSYS_ROCM_DOMAINS=hip_runtime_api,kernel_dispatch,memory_copy \
    -e ROCPROFSYS_TRACE=true \
    -- ./jpegdecode -i /path/to/images/ -b 4