movenc: Allow writing a DASH sidx atom at the start of files

Multimedia / Libav - Martin Storsjö [martin.st] - 17 November 2014 08:17 UTC

This is mapped to the faststart flag (which in this case perhaps should be called "shift and write index at the start of the file"), which for fragmented files will write a sidx index at the start.

When segmenting DASH into files, there's usually one sidx at the start of each segment (although it's not clear to me whether that actually is necessary). When storing all of it in one file, the MPD doesn't necessarily need to describe the individual segments, but the offsets of the fragments can be fetched from one large sidx atom at the start of the file. This allows creating files for the DASH ISO BMFF on-demand profile.

40ed1cb movenc: Allow writing a DASH sidx atom at the start of files
libavformat/movenc.c | 117 +++++++++++++++++++++++++++++++++++++++-----------
libavformat/movenc.h | 1 +
2 files changed, 92 insertions(+), 26 deletions(-)

Upstream: git.libav.org


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