This report outlines the technical approach, data structures, implementation challenges, and performance considerations. | Component | Description | |-----------|-------------| | ftyp | File type and compatibility | | moov | Movie metadata (duration, tracks, sample tables) — critical for indexing | | mdat | Media data (video/audio frames) | | free / skip | Free space |
1. Executive Summary MP4 (MPEG-4 Part 14) is a container format widely used for video, audio, and subtitles. Unlike simple byte streams, MP4 is structured as a hierarchy of atoms (boxes) . Developing an "index of MP4" means building a system to parse these atoms, extract metadata, and create a queryable index enabling fast search, seeking, or content analysis without scanning entire files. index of mp4
self.build_frame_index(stts, stss, stsc, stco, stsz) Unlike simple byte streams, MP4 is structured as
def parse_moov(self, offset): # Traverse to stbl, extract sample tables stts = self.get_table(offset, 'stts') stss = self.get_table(offset, 'stss') stsc = self.get_table(offset, 'stsc') stco = self.get_table(offset, 'stco') stsz = self.get_table(offset, 'stsz') Unlike simple byte streams
This report outlines the technical approach, data structures, implementation challenges, and performance considerations. | Component | Description | |-----------|-------------| | ftyp | File type and compatibility | | moov | Movie metadata (duration, tracks, sample tables) — critical for indexing | | mdat | Media data (video/audio frames) | | free / skip | Free space |
1. Executive Summary MP4 (MPEG-4 Part 14) is a container format widely used for video, audio, and subtitles. Unlike simple byte streams, MP4 is structured as a hierarchy of atoms (boxes) . Developing an "index of MP4" means building a system to parse these atoms, extract metadata, and create a queryable index enabling fast search, seeking, or content analysis without scanning entire files.
self.build_frame_index(stts, stss, stsc, stco, stsz)
def parse_moov(self, offset): # Traverse to stbl, extract sample tables stts = self.get_table(offset, 'stts') stss = self.get_table(offset, 'stss') stsc = self.get_table(offset, 'stsc') stco = self.get_table(offset, 'stco') stsz = self.get_table(offset, 'stsz')