On Mon, Nov 16, 2020 at 09:46:01PM -0300, James Almer wrote: > On 11/16/2020 12:25 PM, Hendrik Leppkes wrote: > > On Mon, Nov 16, 2020 at 4:20 PM James Almer <jamr...@gmail.com> wrote: > > > > > > On 11/16/2020 3:01 AM, Anton Khirnov wrote: > > > > Quoting Xiang, Haihao (2020-11-16 06:16:55) > > > > > > > > > > This change breaks the compiling of gst-libav ( > > > > > https://gitlab.freedesktop.org/gstreamer/gst-libav), I filed > > > > > https://trac.ffmpeg.org/ticket/8988 to track this regression. > > > > > > > > This is not a regression, it's a bug in gst-libav. These fields are > > > > private and have always been private, applications accessing them are > > > > broken. > > > > > > Looking at that ticket, it seems gst-libav wants the timestamp for a > > > given index entry. Unless this can already be achieved in some other > > > way, it could maybe be implemented cleanly with a new public function > > > (We have av_index_search_timestamp() to fetch an index from a timestamp > > > after all). > > > > I also like being able to access the index, it can be used by players > > to efficiently offer seeking straight to keyframes (eg. index > > entries), which basically requires iterating over the full index and > > getting the full information (timestamp, flags at least) > > > > - Hendrik > > What do you suggest, implement something like what you added to you > LAVFilters fork? I don't know if returning a pointer to a given AVIndexEntry > is ideal. If that were the case, then it wouldn't be an internal field. > > Perhaps something like >
> int av_index_get_entries_count(AVStream *st);
> int av_index_get_timestamp(AVStream *st, int64_t *timestamp, int *flags, int
> idx);
If the (only) goal is to export the whole list then a better option might be
to use an opaque state and some sort of iterator.
Because the suggestion requires N index based lookups and this is only fast
with some conceivable implementations.
for example consider an index stored in some sort of tree structure
a index based lookup might be O(log n) while one step iterating over all
elements could be O(1)
AVIndexEntry *av_index_iterate(AVStream *st, AVIndexIterator **i);
and
AVIndexIterator *i = NULL;
AVIndexEntry *entry;
for (entry = av_index_iterate(st, &i); i; entry = av_index_iterate(st, &i))
...
[...]
--
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
He who knows, does not speak. He who speaks, does not know. -- Lao Tsu
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