Byte-Range Marker Distribution for VoD Bandwidth Reduction
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Solution Overview
Problem
Current methods for delivering Video on Demand (VoD) logical content are inefficient, particularly in terms of bandwidth usage, as they often require downloading the entire VoD media file to play a portion of it, which is not user-friendly or cost-effective, especially in scenarios with limited bandwidth.
Innovation Solution
A distributed system where the first Set-Top Box (STB) requesting logical content calculates and transmits byte-range markers to the IPTV Application Server, allowing subsequent STBs to download only the required portion of the VoD media file using HTTP Range headers, eliminating the need for decryption and re-encryption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the entire VoD media file is downloaded to play a portion of it (logical content), then the content can be delivered without requiring complex server-side clipping operations, but the bandwidth consumption increases significantly and download time is extended
Solution Approach 1:
The system performs preliminary calculation of byte-range markers corresponding to temporal start/end markers during the first download. These calculated markers are stored and reused for subsequent logical content deliveries, eliminating the need to recalculate them each time and reducing bandwidth consumption for repeated content.
Solution Approach 2:
The system creates a copy of the calculated byte-range marker information and stores it on the server. Subsequent clients can obtain these markers from the server without performing the calculation themselves, effectively copying the computational result rather than repeating the work.
2Device complexity
If the entire VoD media file is downloaded to the STB to play only a portion (logical content), then no decryption and re-encryption operations are required, but the download time is significantly extended especially in low bandwidth scenarios
Solution Approach 1:
The system extracts only the necessary byte-range marker information from the full media file download. Instead of requiring the entire file to be downloaded and processed, the system extracts and transmits only the specific byte ranges corresponding to the logical content boundaries, significantly reducing download time while avoiding complex decryption operations.
3Adaptability or versatility
If byte-range markers are calculated on each STB individually, then each STB can independently determine the correct byte ranges, but the same calculation work is repeated across multiple STBs wasting computational resources
Solution Approach 1:
The system merges the computational task of calculating byte-range markers from multiple independent STBs into a single centralized calculation performed during the first download. The result is stored on the server and shared with all subsequent STBs, combining the efforts of multiple potential calculators into one efficient operation.
Solution Approach 2:
The system implements a feedback mechanism where the first STB's calculated byte-range markers are transmitted back to the server and stored. Subsequent STBs receive this feedback information from the server, allowing them to use pre-calculated markers without performing redundant computations.
4Ease of operation
If server-based logical content clipping is implemented, then the server can control the exact content delivered, but most media servers do not support time-range downloads as they only support byte-range downloads per HTTP standards
Solution Approach 1:
The system changes the parameter representation from temporal (startNPT/endNPT markers) to spatial (byte-range markers). By calculating and providing byte-range markers that correspond to the temporal boundaries, the system maintains server control over exact content delivery while using standard HTTP byte-range request parameters that all compliant media servers support.
Data Source
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AI summary
Logical content is defined by start/end times into a VoD media offering. The calculation of byte-range markers corresponding to the start/end times is distributed among the STBs to first request the particular logical content. Upon receiving an initial request for a logical content offering, an IPTV AS returns a VoD media file URL, start/end times, and null values of byte-range markers corresponding to the start/end times. In response to the null values, the initially-requesting STB downloads the entire VoD media file from a Download Media Server, and calculates the byte-range markers by comparing the start/end times to timestamps in non-encrypted headers in the VoD media file. The non-null byte-range markers are transmitted back to the IPTV AS, which provides them to STBs subsequently requesting the same logical content. The subsequently-requesting STBs may download only the logical content by providing the non-null byte-range markers to the Download Media Server.