OTT Channel Change Method Using Dual Stream Encoding
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Solution Overview
Problem
OTT video services experience significant channel change delays and time deviations due to the lack of a standardized Fast Channel Change solution, as conventional IPTV FCC solutions are not applicable and OTT protocols like HLS/DASH/MSS lack FCC-related recommendations, resulting in inefficient channel switching.
Innovation Solution
A method and apparatus for OTT video services that involve separately encoding live streams into main and sub streams, with the sub stream used for channel change, utilizing auxiliary frames like change I and P frames to provide additional stream access points, allowing for real-time decoding and playback, thereby reducing channel change delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional IPTV FCC solution (CBR multicast+variable speed unicast+multicast switching) is used, then channel change delay is limited to approximately 1 second with controllable time deviation, but this solution is not applicable to OTT services due to different bottom-layer streaming protocols (HLS/DASH/MSS based on TCP) and unicast transmission manner
Solution Approach 1:
The patent divides the live stream into multiple media file sets with different coding manners (main stream and sub stream). The sub stream is specifically encoded for fast channel change with features like more frequent I-frames and lower resolution, while the main stream maintains high quality for normal playback. This segmentation allows the system to use different streams for different purposes, resolving the contradiction between OTT protocol requirements and fast channel change performance.
Solution Approach 2:
The patent performs preliminary encoding of the live stream into multiple versions (main and sub streams) before channel change is requested. The sub stream is pre-prepared with coding characteristics optimized for fast decoding and channel switching. When a channel change request occurs, the system can immediately switch to the pre-prepared sub stream, eliminating the need for real-time encoding during channel change and thus reducing delay.
2Adaptability or versatility
If mainstream OTT protocols (HLS/DASH/MSS) are used without FCC-related recommendations, then OTT services can be provided over standard TCP networks, but channel change delay and time deviation become relatively large
Solution Approach 1:
The patent applies different coding qualities and characteristics to different parts of the stream (main stream vs. sub stream). The sub stream has local quality characteristics optimized for channel change (more I-frames, lower resolution, different bit rate) while the main stream maintains overall high quality for normal viewing. This local differentiation resolves the contradiction between network compatibility and channel change performance.
Solution Approach 2:
The patent changes key encoding parameters when creating the sub stream compared to the main stream. The sub stream uses different coding parameters (higher I-frame frequency, lower resolution, different bit rate allocation) that are specifically tuned for fast channel change. These parameter changes enable the OTT protocol to support fast channel change without requiring changes to the underlying TCP network infrastructure.
3Device complexity
If a single main stream is used for both live broadcast and channel change, then encoding complexity is reduced, but channel change efficiency is insufficient due to lack of dedicated channel change optimization
Solution Approach 1:
The patent segments the encoding process into two parallel streams with different characteristics. The encoder simultaneously produces a main stream for normal playback and a sub stream optimized for channel change. This segmentation increases encoding complexity but dramatically improves channel change efficiency by providing a pre-optimized stream for switching.
Solution Approach 2:
The patent creates a multi-functional streaming system where the sub stream serves multiple purposes: it enables fast channel change, provides a backup stream, and can be used for catching up on missed content. This multi-functionality justifies the additional encoding complexity by providing multiple benefits from a single encoding process.
Data Source
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AI summary
Embodiments of the present invention disclose a channel change method and a related apparatus. The channel change method includes: receiving a live stream of a first channel, where the live stream of the first channel includes N media file sets; separately encoding the live stream of the first channel in different coding manners, to generate both a main stream and a sub stream; and generating a playlist of the first channel according to channel information of the first channel, coding information of the main stream, and coding information of the sub stream, where the playlist is used to: when a client sends a channel change instruction, instruct the client to perform channel change according to the main stream and the sub stream. Technical solutions provided in the embodiments of the present invention help improve channel change efficiency of an OTT video service.