MP4 File Recording Control for Interruption Resilience
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Solution Overview
Problem
Existing data recording devices using MP4 Ver. 1 format struggle to reproduce files if the external storage is removed during recording, as they do not conform to the MP4 Ver. 1 standard, leading to incomplete file formats that cannot be played by MP4 players corresponding to MP4 Ver. 1.
Innovation Solution
A data recording control device that generates a file format with a file type box, media data box, movie box, and free space box, updating the box sizes and appending media data to the free space box, allowing for seamless reproduction even if the external storage is removed during recording.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the external storage is removed during recording, then the recording process can be interrupted or stopped, but the file format becomes damaged and cannot be reproduced by MP4 players
Solution Approach 1:
The patent applies preliminary action by pre-writing the movie box and updating the box size in the media data box header before actual media data recording completes. This ensures that even if the external storage is removed during recording, the file structure remains complete and valid for MP4 Ver. 1 players. The free space box is also prepared in advance to accommodate subsequent data without affecting the integrity of already-recorded data.
2Reliability
If MP4 Ver. 2 format is used to enable playback during interrupted recording, then playback reliability improves, but compatibility with MP4 Ver. 1 players is lost
Solution Approach 1:
The patent applies local quality by maintaining different structural characteristics in different parts of the file. The movie box and media data box header are structured according to MP4 Ver. 1 standards for compatibility, while the free space box accommodates additional data for continued playback. This allows the file to simultaneously support both MP4 Ver. 1 players and continued recording functionality.
Data Source
AI summary
A data recording control device includes a recording preparator that generates the file which includes a file type box including information related to a type indicating a type of a player capable of reproducing the file and header information of a media data box storing media data according to the stream data, on the recording media; a box determiner that writes a movie box which includes information used for reproducing the media data, updates a box size included in the header information of the media data box to a size of immediately before the movie box, and appends header information of a free space box which stores predetermined information to a tail of the movie box, during a predetermined period; and a data writer that appends the media data according to the stream data to a tail of the header information of the free space box.