本文分析了MP4文件中的一些容器盒子（如stsd/avc1/avcC/stco），重点研究了avc1和avcC盒子的数据结构及其在stsd盒子中的位置。avc1盒子的数据完全包含在stsd盒子中，而avcC盒子的数据则被整合到stsd盒子内。文章还讨论了stco盒子中的chunk_offset字段如何指示媒体文件中chunk的偏移。
the analysis of some mp4 container boxes(stsd/avcC/stco...)
the stsd/avc1/avcC boxes:
the analysises of the stsd/avc1/avcc boxes are:
from the analysis, we can know
1. avc1 box data showed by this mp4info is fully included in the middle of stsd box showed by mp4info.
2. avcC box data is included to stsd box in this mp4info tool.
notice:
1. get to know the avcC box layout can refer to AVC Decoder Configuration Atom (‘avcC’) of QuickTime File Format Specification[2]
2. the "AVC Decoder Configuration Record" field of avcC box is:
stco box
entry_count: is an integer that gives the number of entries in the following table
chunk_offset: is a 32 or 64 bit integer that gives the offset of the start of a chunk into its containing
media file.
chunk_offset: is a 32 or 64 bit integer that gives the offset of the start of a chunk into its containing
media file.
from above, we can know the count of chunk in a media mp4 file is numerous
reference
1. Information technology — Coding of audio-visual objects —Part 12:ISO base media file format
2. QuickTime File Format Specification
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