Difference between revisions of "JEG no-reference hybrid H264"

Latest revision as of 10:41, 5 January 2016

JEG no-reference hybrid H264

As a first focus, JEG intends to develop a Hybrid No Reference metric suited for H264-AVC.

Main idea

A no-reference metric will not have access to the original source video for evaluation. Hybrid metrics are combination of perceptual and parametric metrics, it means that the metric takes a bitstream, decoded video signal and QoS parameters as input, as shown in the following figure. As a first profile, the metric is expected to handle parameters of the stream at least at the NAL level. Possible extended profiles could be defined to cover protocol level parameters (UDP, RTP, DVB ...). As a final step, the metric could cover several profiles, e.g. scenario applications.

(Origin: VQEG-JEG_NR_hybrid_H264_v3.pdf)

Project set up

The JEG NR hybrid H264 project consists in three general work packages:

WP 1: Generation of a Hypothetical Reference Circuit (HRC)

Main article: WP1: HRC Generation

The XStreamer is used to create a processed video stream (PVS) using the H.264/AVC codec and introducing packet loss according to the Gilbert-Elliott model. First, the data is encoded, then streamed over a lossy link, decoded and synchronized. In the image below, the complete toolchain is depicted.

WP 2: Creation of the Hybrid Model Input XML file (HMIX) files

Main article: WP2: HMIX Creation

The HMIX File is an XML file containing information of the transmission as well as of the decoded data. Relevant parameters from traced PCAP files are collected and are merged with significant parts of decoding traces. The result represents the input of the hybrid model and is visualized in the following picture.

(Origin: hybrid_input.pdf)

WP 3: Hybrid Model

Main arcitle: WP3: Hybrid Model

On the basis of obtained results from WP1: HRC Generation and WP2: HMIX Creation, a new architecture for a No Reference Hybrid Model will be developed.

Deliverables

The Working Group is expected to produce:

• HRC generation toolchain
• HMIX files and merging tools
• A hybrid model using the HMIX files as input
• Validation through subjective tests

Milestones

Currently, there are no milestones defined.

Duration

Currently, there is no expiration date of the charter.

Links and Downloads

Source content

• SRC

Objective measurements

• P.1201.2 scores on Hybrid H.264 no loss database. Quality scores were computed with the T-Labs implementation of the ITU-T P.1201.2 software.

Common Abbreviations

* HMIX Hybrid Model Input XML file
* HRC  Hypothetical Reference Circuit – VQEG term for a combination of encoder (settings) and source video 
* PVS  Processed Video Stream
* SRC  Source Video