New FMO Type to Flag ROI in H264/AVC

Yongsheng Wang, Maire O'Neill, Fatih Kurugollu

Research output: Chapter in Book/Report/Conference proceedingConference contribution


This paper presents a new type of Flexible Macroblock Ordering (FMO) type for the H.264 Advanced Video Coding (AVC) standard, which can more efficiently flag the position and shape of regions of interest (ROIs) in each frame. In H.264/AVC, 7 types of FMO have been defined, all of which are designed for error resilience. Most previous work related to ROI processing has adopted Type-2 (foreground & background), or Type-6 (explicit), to flag the position and shape of the ROI. However, only rectangular shapes are allowed in Type-2 and for non-rectangular shapes, the non-ROI macroblocks may be wrongly flagged as being within the ROI, which could seriously affect subsequent processing of the ROI. In Type-6, each macroblock in a frame uses fixed-length bits to indicate to its slice group. In general, each ROI is assigned to one slice group identity. Although this FMO type can more accurately flag the position and shape of the ROI, it incurs a significant bitrate overhead. The proposed new FMO type uses the smallest rectangle that covers the ROI to indicate its position and a spiral binary mask is employed within the rectangle to indicate the shape of the ROI. This technique can accurately flag the ROI and provide significantly savings in the bitrate overhead. Compared with Type-6, an 80% to 90% reduction in the bitrate overhead can be obtained while achieving the same accuracy.
Original languageEnglish
Title of host publication5th European Workshop on Visual Information Processing (EUVIP)
PublisherInstitute of Electrical and Electronics Engineers (IEEE)
Number of pages5
ISBN (Print)9781479945719
Publication statusPublished - Dec 2014
Event5th European Workshop on Visual Information Processing, EUVIP 2014 - Paris, France
Duration: 10 Dec 201412 Dec 2014


Conference5th European Workshop on Visual Information Processing, EUVIP 2014


  • binary mask
  • FMO
  • H.264/AVC
  • Regions of Interest
  • slice group

ASJC Scopus subject areas

  • Computer Vision and Pattern Recognition
  • Information Systems
  • Signal Processing

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