mp42str

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Project Overview

mp42str is a C++ utility program designed to extract timecodes and additional data from MP4 files that comply with the ISO Base Media File Format (ISO/IEC 14496-12 - MPEG-4 Part 12). The program can extract timecodes to .str files and additional data in XML format from specific atoms/boxes within the MP4 file. More specifically, the program reads the following atoms/boxes:

• ftyp: File Type Box
• moov: Movie Box
• mvhd: Movie Header Box
• meta: Metadata Box

More info on what each atom/box contains can be found in the mp4atoms.pdf and mep4metaAtom.pdf.

This repo is based on the original dv2str project for DV video.

Generated .srt file example

1
00:00:00,00 --> 00:00:01,00
13-12-2024
23:11:12

2
00:00:01,00 --> 00:00:02,00
13-12-2024
23:11:13

3
00:00:02,00 --> 00:00:03,00
13-12-2024
23:11:14

...

Features

• Extracts timecodes from MP4 files and writes them to .str files.
• Capable of extracting additional data in XML format from meta and xml atoms/boxes.
• Provides options to extract only XML data, if present in the mpeg4 file.

Usage

mp42str <video_file_path> [options]
Options:
-xml: Extract additional data in XML format only.
-debug: Print debug information.

Code Overview

The main C++ file contains the following key components:

• Timestamp Conversion: Converts timestamps to human-readable date formats.
• Box Reading: Reads and processes different MP4 atoms/boxes (ftyp, moov, mvhd, meta).
• FTYP Parsing: Determines the MPEG4 encoding type.
• MOOV/MVHD Parsing: These atoms provide the first timecode example of the file.
• Meta Parsing: Extracts and processes data from meta and xml atoms/boxes.
• SRT Writing: Writes extracted timecodes to an SRT file.