|
Summary:
|
Recommendation ITU-T P.1202 provides an overview of algorithmic models for non-intrusive monitoring of the video quality of IP-based video services based on packet-header and bitstream information. P.1202 addresses two application areas:
- P.1202.1 specifies the model algorithm for the lower resolution/LR (formerly referred to as low-bitrate, LBR) application area, including services such as mobile TV.
- The model algorithm for the higher resolution/HR (formerly referred to as high-bitrate, HBR) application area, which includes services such as IPTV. This application area is currently under study but not yet completed.
The ITU-T Study Group 12 work item that resulted in this new recommendation was formerly referred to as P.NBAMS (Parametric non-intrusive bitstream assessment of video streaming quality). Hence, this short-title is retained for easier reference.
The P.NBAMS model algorithms are no-reference (i.e. non-intrusive) models which operate by analysing packet header and bitstream information as available from respective packet trace data, provided to the model algorithms in the packet capture format (PCAP). Further input information on more general aspects of the stream which may not be available from packet header and bitstream information, is provided to the model algorithm out-of band, for example in form of stream-specific side information.
As output, the model algorithms provide individual estimates of video quality in terms of the 5-point absolute category rating (ACR) mean opinion score (MOS). Further, diagnostic information on causes of quality degradations can be made available, too, since different types of performance parameters are derived during model calculations.
Complementary to the P.NBAMS models, there are two further models described in P.1201.1 and P.1201.2. The respective entry-document for these so-called P.NAMS models is P.1201. P.NAMS describes packet header only-based video, audio and audiovisual quality models. The main differences with P.NBAMS can be summarized as follows:
- The P.NAMS/P.1201 models provide audio, video and audiovisual quality estimates, while the P.NBAMS/P.1202 only models provides video quality estimates
- The P.NAMS/P.1201 models use packet header information, while the P.NBAMS/P.1202 models exploit further bitstream information, such as coding-related information. As a consequence, the P.NBAMS-models can be more accurate in their quality predictions. In turn, they require non-encrypted streams, to enable the access to payload information. Since the P.1202 models are more complex, they also require more computational power to estimate the video quality.
|
