[FFmpeg-devel] Possible leak in RTSP to disk copy writing

Michael Niedermayer michaelni
Mon Mar 15 22:09:46 CET 2010

On Mon, Mar 15, 2010 at 06:29:35PM +0100, Reimar D?ffinger wrote:
> On Mon, Mar 15, 2010 at 02:28:19PM +0200, Stas Oskin wrote:
> > Shouldn't every FFmpeg container support copy? It basically follows same
> > pattern as encoding - just instead of being re-coded, the data moves
> > straight to disk.
> This really does not belong on this list, at least so far.
> Anyway what you want is copying without using up more memory if more
> data is copied, which is a far higher requirement.
> MOV/MP4 is a format with a mandatory index, and at least without very ugly
> hacks the index must be in one piece. Which means that the index can only
> be written at the end and after all other data was written, which means
> that unless you store it in a temporary file (which has quite serious issues),
> the index must be kept in memory and grows in size with every audio or video
> frame added to the file.
> If you don't want that you definitely must one of
> 1) use a format where the index is optional and FFmpeg supports not generating
>    the index (no idea if there is a option to disable index generation at all).

formats that just store a index for keyframes and not all frames should also be
less problematic

> 2) use a format where the index can be written in segments and FFmpeg supports that
>    (I don't think such a format exists, and such an index is of somewhat limited use).

avi, although we start new index just after 2gb this could be made
user settable if someone wants and sends a patch

> 3) use a format that does not support any index at all, e.g. MPEG-TS or so.

also theres the option of making storeage in memory more efficicent, vlc coding
of differences comes to mind ....

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Republics decline into democracies and democracies degenerate into
despotisms. -- Aristotle
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