31 MAY 2017
License type changed from LGPL to MIT License.
21 AUG 2011
New revision 70. contains new BUF_FIFO contributed Ahmet Tekyildiz which needs circa 9.5 line buffer but achieves performance very close to old design with ~16 lines (8 extra lines). So it heavily reduces on-chip RAM utilization without performance sacrifice.
Also this version contains nearest integer rounding in DCT-2D instead of truncation when bit growth/precision is reduced. Truncation caused 8x8 block artifacts easily visible in very high quality modes (>95% quantization tables). Rounding alleviates this problem.
Warning! WebSVN does not work correctly for project, use link below to download latest rev: • DOWNLOAD LATEST REVISION 61 • EV_JPEG_ENC core is intended to encode raw bitmap images into JPEG compliant coded bit stream. JPEG baseline encoding method is used. • LICENSE: MIT
• JPEG baseline encoding JPEG ITU-T T.81 | ISO/IEC 10918-1
• Standard JFIF header v 1.01 automatic generation
• Color images only (3 components, RGB 24 or 16 bit, YUV input)
• Two programmable Quantization tables
• Hardcoded Huffman tables (luminance and chrominance)
• 2.3 to 2.7 clock cycles per one input 24 bit pixel @ 50% Quality
• OPB programming and data Host interface
• 4:2:2 subsampling
• Source code target independent, synthesizable RTL VHDL code
• Detailed documentation
Measured from JPEG encoding start till encoding done:
• Input image 640x480 24 bit RGB color. New sample loaded every cycle until FIFO full.
• Quantization tables at 50% quality setting
• 7.3 ms processing time @ 100 MHz clock
• 1000/7.3=136 frames per second @ 100 MHz
• Input file size = 921 kB. Output file size = 44 kB (depends on image)
Compression stats (from JPEGSnoop software):
• Compression Ratio: 21.31:1
• Bits per pixel: 1.13:1
100 MHz is achievable under Stratix II S90 for example. Optimization set to performance.
• replace OPB interface used for programming with PLB or WishBone
Here is a quite detailed low level design document for the Core: Low Level Design Document
EV_JPEG_ENC is software released under MIT license and can be used freely for commercial and noncommercial purposes under NO WARRANTY.
Device Utilization Summary for Stratix II S90 (mkjpeg revision 57)
Performance: above 100 MHz
Build configured for maximum image width 640 pixels and highest performance and memory usage (settable in JPEG_PKG.VHD)