Multimedia Stream Intra Frame Timing for IPTV Channel Switching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing IPTV systems face significant channel switching delays due to the need for receiving a full intra frame before switching, which increases bandwidth requirements and user-perceived delay, and previous solutions either require unicast or result in reduced video quality from parallel processing of multiple streams.
Innovation Solution
A multimedia provider generates a main stream with intra and inter frames and an auxiliary stream with intra frames based on the main stream's inter frames, along with a stream information channel providing time instances of intra frames, allowing user terminals to selectively connect to the stream with the next intra frame, reducing the need for parallel processing and bandwidth increase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the STB waits for a full intra frame before switching channels, then video decoding can proceed correctly, but the channel switching delay increases
Solution Approach 1:
The system generates and transmits auxiliary intra frames in advance at predetermined time intervals, so that when a channel switch is requested, ready-to-use intra frames are already available in the buffer, eliminating the need to wait for the next intra frame in the main stream
Solution Approach 2:
The solution separates the intra frame generation into two independent streams: the main stream with normal intra frame intervals and an auxiliary stream with frequently generated intra frames at predetermined short intervals, allowing the STB to selectively use either stream
2Speed
If shift registers store short sequences of multimedia data to enable fast channel switching, then channel switching speed improves, but bandwidth increases due to unicast transmission
Solution Approach 1:
The auxiliary intra frames are generated at periodic predetermined time intervals rather than continuously, reducing the amount of data that needs to be stored in buffers while still ensuring that an intra frame is available within a known time window, thus reducing buffer size and associated bandwidth requirements
Solution Approach 2:
The system changes the temporal parameter of intra frame generation by creating auxiliary frames at different time intervals than the main stream, allowing optimization of buffer sizes and bandwidth usage while maintaining fast channel switching capability
3Loss of time
If parallel processing of normal and channel change streams is performed to identify the first intra frame, then channel switching delay reduces, but video quality decreases due to lower quality intra frames
Solution Approach 1:
The auxiliary intra frames are generated based on the same multimedia data as the main stream but transmitted as separate copy streams, allowing the STB to select which stream to use without degradation, as both streams contain valid video data that can be decoded
4Reliability
If extensive data management is performed for parallel reception and processing of multiple streams, then intra frame availability improves, but device complexity increases
Solution Approach 1:
The system includes timing information indicating when auxiliary intra frames will be generated and transmitted, allowing the STB to proactively buffer the correct amount of data and switch streams at optimal times without complex real-time analysis or extensive data management
Data Source
Figure 1~4
Figure 2~6
Figure 5~9
AI summary
A multimedia provider (100) multicasts a main multimedia stream (10) comprising a mixture of intra (12) and inter frames (14, 16, 18) and multicasts an associated auxiliary stream (20) comprising intra frames (22, 24). At least a portion of the intra frames (24) in the auxiliary stream (20) are generated based on same multimedia data as at least a portion of the inter frames (14) of the main stream (10). The provider (100) also transmits a stream information channel (30) comprising information (32, 34) descriptive of time instances of intra frames (12; 22, 24) in the main (10) and auxiliary (20) streams. This information (32, 34) allows a set top box (200) to selectively connect, in connection with session set-up and channel switch, to the main (10) or auxiliary (20) stream to receive an intra frame (12; 22, 24) with as a low delay as possible.