luis herranz , jose´ m. martı´nez
DESCRIPTION
On the use of hierarchical prediction structures for efficient summary generation of H.264/AVC bitstreams. Luis Herranz , Jose´ M. Martı´nez. Image Communication 2009. Outline. Introduction System Framework Skimming Unit (SU) Coding order Generation of the summary - PowerPoint PPT PresentationTRANSCRIPT
On the use of hierarchical prediction structures for efficient summary generation of H.264/AVC
bitstreams
Luis Herranz, Jose´ M. Martı´nez
Image Communication 2009
Outline
• Introduction• System Framework– Skimming Unit (SU)– Coding order– Generation of the summary– Presentation of the summary
• Experiment
Introduction
• MPEG-2 prediction structure
Introduction
• Hierarchical prediction structure in H.264/AVC using P frames (delay 0)
Introduction
• Hierarchical prediction structure in H.264/AVC using B frames (delay 8)
System FrameworkAnalyzing input bitstream Generating the summarized bitstream
# frames selected
Skimming unit (SU)
-The selection of SUs-Temporal level
Skimming Units
Skimming Unit (SU)
Temporal layerIndex
𝑆𝑠𝑜𝑢𝑟𝑐𝑒 𝐹𝑟𝑎𝑚𝑒
1
𝑆𝑠𝑜𝑢𝑟𝑐𝑒=(𝐺0𝑇 ,𝐺1
𝑇 ,…,𝐺𝑀−1𝑇 )
Skimming Units
Overlapped SUs
Generation of the Summary
• Bit stream adaptation guided by skimming parameters
Presentation of the Summary
• Constant frame rate• Variable frame rate– Signaling the changes of frame rate– Using a predefined set of SPSs
Summarization Modalities
• Image storyboard: • Video Skim: • Frame dropping• Fast preview
Frame selection Skimming curve
Image Storyboard
• Clustered using K-means algorithm
Video Skimming• Face detection• Moving median filter
(a) Frames with face detected
(b) Skimming parameters -- 32 frames per GOP
(c) Skimming parameters -- 2 frames per GOP
Fast Preview
• Motion activity• Median filter
(a) Filtered activity
(b) Skimming parameters -- 32 frames GOP
(c) Skimming parameters -- 2 frames GOP
Subjective Evaluation
Visual distortion Semantic distortion
Performance Evaluation
• Coding efficiency and processing time
Performance Evaluation
• Bit stream extraction– Low computational cost– Faster generation of the bit stream
skim storyboard
Fast playback