Number of chapters in AVChapter array.
When muxing, chapters are normally written in the file header,
so nb_chapters should normally be initialized before write_header
is called. Some muxers (e.g. mov and mkv) can also write chapters
in the trailer. To write chapters in the trailer, nb_chapters
must be zero when write_header is called and non-zero when
write_trailer is called.
- muxing: set by user
- demuxing: set by libavformat
Number of chapters in AVChapter array. When muxing, chapters are normally written in the file header, so nb_chapters should normally be initialized before write_header is called. Some muxers (e.g. mov and mkv) can also write chapters in the trailer. To write chapters in the trailer, nb_chapters must be zero when write_header is called and non-zero when write_trailer is called. - muxing: set by user - demuxing: set by libavformat