IDR Frame Generation in H.264/AVC Streams Without Transcoding
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Solution Overview
Problem
Existing methods require transcoding of H.264/AVC video streams to insert IDR frames, which is resource-intensive and beyond the capabilities of typical end-user devices like smartphones and smart TVs, especially for real-time processing.
Innovation Solution
A method to generate IDR frames within the H.264/AVC stream by identifying an I-type picture, modifying its slice headers with IDR-specific syntax elements, removing non-IDR specific elements, and eliminating reference B slices, while correcting frame_num and MMCO structures to ensure valid decoding without altering the video pixel data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If transcoding is used to insert IDR frames into H.264/AVC streams, then IDR frame generation is achieved, but system resource requirements increase significantly
Solution Approach 1:
The patent segments the IDR frame generation process into discrete operations: identifying I-type pictures, modifying slice headers with IDR-specific syntax elements, removing non-IDR specific elements, and eliminating reference B slices. This segmentation allows the process to be performed on existing streams without requiring full transcoding, thereby reducing system resource requirements while maintaining IDR frame generation capability.
Solution Approach 2:
The patent changes parameters within the H.264/AVC stream structure, specifically modifying slice header syntax elements and frame_num parameters, to convert existing I-type pictures into IDR-compliant frames. This parameter-based transformation avoids the need for complete re-encoding, significantly reducing computational resource consumption while achieving the desired IDR frame generation.
2Reliability
If transcoding is used to generate IDR frames, then IDR compliance is achieved, but processing time increases
Solution Approach 1:
The patent performs preliminary identification of I-type pictures and pre-modification of slice headers before actual IDR frame generation is needed. By preparing the stream structure in advance and performing modifications on existing pictures rather than re-encoding, the processing time is significantly reduced while maintaining full IDR compliance.
Solution Approach 2:
The patent copies and modifies existing I-type pictures and their slice headers to create IDR-compliant frames, rather than creating new frames through full transcoding. This copying approach preserves the original picture data while adding the necessary IDR-specific syntax elements, thereby reducing processing time and resource consumption.
3Reliability
If full transcoding is performed, then IDR frame generation is achieved, but device complexity increases
Solution Approach 1:
The patent segments the complex transcoding process into simpler, manageable operations that can be performed by typical end-user devices. By dividing the IDR frame generation into discrete steps (identification, modification, removal, correction), the patent reduces the complexity requirement while maintaining reliable IDR frame generation capability.
Solution Approach 2:
The patent relies on parameter changes within existing H.264/AVC structures rather than complete re-encoding. By modifying slice header syntax elements and frame_num parameters, the system achieves IDR compliance with minimal device complexity, making the solution feasible for standard consumer electronics.
4Reliability
If reference B slices are removed, then IDR compliance is improved, but data loss occurs
Solution Approach 1:
The patent extracts and removes only the specific reference B slices that prevent IDR compliance, while preserving all other video data. By selectively removing only the problematic reference slices between I pictures rather than discarding entire sequences, the patent achieves IDR compliance with minimal data loss, maintaining the integrity of the remaining video content.
Solution Approach 2:
The patent discards the reference B slices that are incompatible with IDR framing, but recovers and preserves the I-type pictures and their associated syntax elements. The method ensures that the removed reference slices are replaced with appropriate references to the I pictures, thereby recovering the necessary reference functionality while eliminating the conflicting data.
Data Source
AI summary
Method for generating an IDR picture slice in an H.264/AVC stream, the method including finding an I-type picture and identifying it as a start picture, modifying and/or adding, in each slice header of the start picture, IDR-specific elements, removing, from each slice header of the start picture, non-IDR-specific elements, removing all reference and non-reference B-slices between the start picture and the next I-picture or P-picture, following the start picture, that is a frame or the first field, in decoding order, of a complementary field pair. Starting from the first picture after the removed slices, for each slice header executing: correcting frame_num so that they are valid with reference to the previous picture, correcting references, in the MMCO, as a function of the removed reference B-pictures, correcting references, found in the “Reference picture list reordering” structure, as a function of the removed reference B-pictures and restoring slice encapsulation for modified slices.